1797 строки
51 КиБ
Go
1797 строки
51 КиБ
Go
//go:build sam && atsamd21
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// +build sam,atsamd21
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// Peripheral abstraction layer for the atsamd21.
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//
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// Datasheet:
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// http://ww1.microchip.com/downloads/en/DeviceDoc/SAMD21-Family-DataSheet-DS40001882D.pdf
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//
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package machine
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import (
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"device/arm"
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"device/sam"
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"errors"
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"runtime/interrupt"
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"unsafe"
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)
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const deviceName = sam.Device
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const (
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PinAnalog PinMode = 1
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PinSERCOM PinMode = 2
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PinSERCOMAlt PinMode = 3
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PinTimer PinMode = 4
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PinTimerAlt PinMode = 5
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PinCom PinMode = 6
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//PinAC_CLK PinMode = 7
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PinDigital PinMode = 8
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PinInput PinMode = 9
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PinInputPullup PinMode = 10
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PinOutput PinMode = 11
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PinTCC PinMode = PinTimer
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PinTCCAlt PinMode = PinTimerAlt
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PinInputPulldown PinMode = 12
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)
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type PinChange uint8
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// Pin change interrupt constants for SetInterrupt.
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const (
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PinRising PinChange = sam.EIC_CONFIG_SENSE0_RISE
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PinFalling PinChange = sam.EIC_CONFIG_SENSE0_FALL
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PinToggle PinChange = sam.EIC_CONFIG_SENSE0_BOTH
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)
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// Callbacks to be called for pins configured with SetInterrupt. Unfortunately,
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// we also need to keep track of which interrupt channel is used by which pin,
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// as the only alternative would be iterating through all pins.
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//
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// We're using the magic constant 16 here because the SAM D21 has 16 interrupt
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// channels configurable for pins.
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var (
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interruptPins [16]Pin // warning: the value is invalid when pinCallbacks[i] is not set!
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pinCallbacks [16]func(Pin)
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)
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const (
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pinPadMapSERCOM0Pad0 byte = (0x10 << 1) | 0x00
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pinPadMapSERCOM1Pad0 byte = (0x20 << 1) | 0x00
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pinPadMapSERCOM2Pad0 byte = (0x30 << 1) | 0x00
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pinPadMapSERCOM3Pad0 byte = (0x40 << 1) | 0x00
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pinPadMapSERCOM4Pad0 byte = (0x50 << 1) | 0x00
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pinPadMapSERCOM5Pad0 byte = (0x60 << 1) | 0x00
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pinPadMapSERCOM0Pad2 byte = (0x10 << 1) | 0x10
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pinPadMapSERCOM1Pad2 byte = (0x20 << 1) | 0x10
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pinPadMapSERCOM2Pad2 byte = (0x30 << 1) | 0x10
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pinPadMapSERCOM3Pad2 byte = (0x40 << 1) | 0x10
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pinPadMapSERCOM4Pad2 byte = (0x50 << 1) | 0x10
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pinPadMapSERCOM5Pad2 byte = (0x60 << 1) | 0x10
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pinPadMapSERCOM0AltPad0 byte = (0x01 << 1) | 0x00
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pinPadMapSERCOM1AltPad0 byte = (0x02 << 1) | 0x00
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pinPadMapSERCOM2AltPad0 byte = (0x03 << 1) | 0x00
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pinPadMapSERCOM3AltPad0 byte = (0x04 << 1) | 0x00
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pinPadMapSERCOM4AltPad0 byte = (0x05 << 1) | 0x00
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pinPadMapSERCOM5AltPad0 byte = (0x06 << 1) | 0x00
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pinPadMapSERCOM0AltPad2 byte = (0x01 << 1) | 0x01
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pinPadMapSERCOM1AltPad2 byte = (0x02 << 1) | 0x01
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pinPadMapSERCOM2AltPad2 byte = (0x03 << 1) | 0x01
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pinPadMapSERCOM3AltPad2 byte = (0x04 << 1) | 0x01
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pinPadMapSERCOM4AltPad2 byte = (0x05 << 1) | 0x01
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pinPadMapSERCOM5AltPad2 byte = (0x06 << 1) | 0x01
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)
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// pinPadMapping lists which pins have which SERCOMs attached to them.
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// The encoding is rather dense, with each byte encoding two pins and both
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// SERCOM and SERCOM-ALT.
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//
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// Observations:
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// * There are six SERCOMs. Those SERCOM numbers can be encoded in 3 bits.
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// * Even pad numbers are always on even pins, and odd pad numbers are always on
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// odd pins.
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// * Pin pads come in pairs. If PA00 has pad 0, then PA01 has pad 1.
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// With this information, we can encode SERCOM pin/pad numbers much more
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// efficiently. First of all, due to pads coming in pairs, we can ignore half
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// the pins: the information for an odd pin can be calculated easily from the
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// preceding even pin. And second, if odd pads are always on odd pins and even
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// pads on even pins, we can drop a single bit from the pad number.
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//
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// Each byte below is split in two nibbles. The 4 high bits are for SERCOM and
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// the 4 low bits are for SERCOM-ALT. Of each nibble, the 3 high bits encode the
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// SERCOM + 1 while the low bit encodes whether this is PAD0 or PAD2 (0 means
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// PAD0, 1 means PAD2). It encodes SERCOM + 1 instead of just the SERCOM number,
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// to make it easy to check whether a nibble is set at all.
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var pinPadMapping = [32]byte{
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// page 21
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PA00 / 2: 0 | pinPadMapSERCOM1AltPad0,
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PB08 / 2: 0 | pinPadMapSERCOM4AltPad0,
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PA04 / 2: 0 | pinPadMapSERCOM0AltPad0,
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PA06 / 2: 0 | pinPadMapSERCOM0AltPad2,
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PA08 / 2: pinPadMapSERCOM0Pad0 | pinPadMapSERCOM2AltPad0,
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PA10 / 2: pinPadMapSERCOM0Pad2 | pinPadMapSERCOM2AltPad2,
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// page 22
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PB10 / 2: 0 | pinPadMapSERCOM4AltPad2,
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PB12 / 2: pinPadMapSERCOM4Pad0 | 0,
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PB14 / 2: pinPadMapSERCOM4Pad2 | 0,
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PA12 / 2: pinPadMapSERCOM2Pad0 | pinPadMapSERCOM4AltPad0,
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PA14 / 2: pinPadMapSERCOM2Pad2 | pinPadMapSERCOM4AltPad2,
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PA16 / 2: pinPadMapSERCOM1Pad0 | pinPadMapSERCOM3AltPad0,
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PA18 / 2: pinPadMapSERCOM1Pad2 | pinPadMapSERCOM3AltPad2,
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PB16 / 2: pinPadMapSERCOM5Pad0 | 0,
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PA20 / 2: pinPadMapSERCOM5Pad2 | pinPadMapSERCOM3AltPad2,
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PA22 / 2: pinPadMapSERCOM3Pad0 | pinPadMapSERCOM5AltPad0,
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PA24 / 2: pinPadMapSERCOM3Pad2 | pinPadMapSERCOM5AltPad2,
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// page 23
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PB22 / 2: 0 | pinPadMapSERCOM5AltPad2,
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PA30 / 2: 0 | pinPadMapSERCOM1AltPad2,
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PB30 / 2: 0 | pinPadMapSERCOM5AltPad0,
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PB00 / 2: 0 | pinPadMapSERCOM5AltPad2,
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PB02 / 2: 0 | pinPadMapSERCOM5AltPad0,
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}
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// findPinPadMapping looks up the pad number and the pinmode for a given pin,
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// given a SERCOM number. The result can either be SERCOM, SERCOM-ALT, or "not
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// found" (indicated by returning ok=false). The pad number is returned to
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// calculate the DOPO/DIPO bitfields of the various serial peripherals.
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func findPinPadMapping(sercom uint8, pin Pin) (pinMode PinMode, pad uint32, ok bool) {
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if int(pin)/2 >= len(pinPadMapping) {
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// This is probably NoPin, for which no mapping is available.
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return
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}
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nibbles := pinPadMapping[pin/2]
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upper := nibbles >> 4
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lower := nibbles & 0xf
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if upper != 0 {
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// SERCOM
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if (upper>>1)-1 == sercom {
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pinMode = PinSERCOM
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pad |= uint32((upper & 1) << 1)
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ok = true
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}
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}
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if lower != 0 {
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// SERCOM-ALT
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if (lower>>1)-1 == sercom {
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pinMode = PinSERCOMAlt
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pad |= uint32((lower & 1) << 1)
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ok = true
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}
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}
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if ok {
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// The lower bit of the pad is the same as the lower bit of the pin number.
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pad |= uint32(pin & 1)
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}
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return
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}
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// SetInterrupt sets an interrupt to be executed when a particular pin changes
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// state. The pin should already be configured as an input, including a pull up
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// or down if no external pull is provided.
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//
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// This call will replace a previously set callback on this pin. You can pass a
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// nil func to unset the pin change interrupt. If you do so, the change
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// parameter is ignored and can be set to any value (such as 0).
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func (p Pin) SetInterrupt(change PinChange, callback func(Pin)) error {
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// Most pins follow a common pattern where the EXTINT value is the pin
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// number modulo 16. However, there are a few exceptions, as you can see
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// below.
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extint := uint8(0)
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switch p {
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case PA08:
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// Connected to NMI. This is not currently supported.
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return ErrInvalidInputPin
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case PA24:
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extint = 12
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case PA25:
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extint = 13
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case PA27:
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extint = 15
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case PA28:
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extint = 8
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case PA30:
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extint = 10
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case PA31:
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extint = 11
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default:
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// All other pins follow a normal pattern.
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extint = uint8(p) % 16
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}
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if callback == nil {
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// Disable this pin interrupt (if it was enabled).
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sam.EIC.INTENCLR.Set(1 << extint)
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if pinCallbacks[extint] != nil {
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pinCallbacks[extint] = nil
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}
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return nil
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}
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if pinCallbacks[extint] != nil {
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// The pin was already configured.
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// To properly re-configure a pin, unset it first and set a new
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// configuration.
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return ErrNoPinChangeChannel
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}
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pinCallbacks[extint] = callback
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interruptPins[extint] = p
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if sam.EIC.CTRL.Get() == 0 {
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// EIC peripheral has not yet been initialized. Initialize it now.
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// The EIC needs two clocks: CLK_EIC_APB and GCLK_EIC. CLK_EIC_APB is
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// enabled by default, so doesn't have to be re-enabled. The other is
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// required for detecting edges and must be enabled manually.
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sam.GCLK.CLKCTRL.Set(sam.GCLK_CLKCTRL_ID_EIC<<sam.GCLK_CLKCTRL_ID_Pos |
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sam.GCLK_CLKCTRL_GEN_GCLK0<<sam.GCLK_CLKCTRL_GEN_Pos |
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sam.GCLK_CLKCTRL_CLKEN)
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// should not be necessary (CLKCTRL is not synchronized)
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for sam.GCLK.STATUS.HasBits(sam.GCLK_STATUS_SYNCBUSY) {
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}
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sam.EIC.CTRL.Set(sam.EIC_CTRL_ENABLE)
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for sam.EIC.STATUS.HasBits(sam.EIC_STATUS_SYNCBUSY) {
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}
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}
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// Configure this pin. Set the 4 bits of the EIC.CONFIGx register to the
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// sense value (filter bit set to 0, sense bits set to the change value).
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addr := &sam.EIC.CONFIG0
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if extint >= 8 {
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addr = &sam.EIC.CONFIG1
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}
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pos := (extint % 8) * 4 // bit position in register
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addr.ReplaceBits(uint32(change), 0xf, pos)
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// Enable external interrupt for this pin.
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sam.EIC.INTENSET.Set(1 << extint)
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// Set the PMUXEN flag, while keeping the INEN and PULLEN flags (if they
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// were set before). This avoids clearing the pin pull mode while
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// configuring the pin interrupt.
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p.setPinCfg(sam.PORT_PINCFG0_PMUXEN | (p.getPinCfg() & (sam.PORT_PINCFG0_INEN | sam.PORT_PINCFG0_PULLEN)))
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if p&1 > 0 {
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// odd pin, so save the even pins
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val := p.getPMux() & sam.PORT_PMUX0_PMUXE_Msk
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p.setPMux(val | (sam.PORT_PMUX0_PMUXO_A << sam.PORT_PMUX0_PMUXO_Pos))
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} else {
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// even pin, so save the odd pins
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val := p.getPMux() & sam.PORT_PMUX0_PMUXO_Msk
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p.setPMux(val | (sam.PORT_PMUX0_PMUXE_A << sam.PORT_PMUX0_PMUXE_Pos))
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}
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interrupt.New(sam.IRQ_EIC, func(interrupt.Interrupt) {
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flags := sam.EIC.INTFLAG.Get()
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sam.EIC.INTFLAG.Set(flags) // clear interrupt
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for i := uint(0); i < 16; i++ { // there are 16 channels
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if flags&(1<<i) != 0 {
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pinCallbacks[i](interruptPins[i])
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}
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}
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}).Enable()
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return nil
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}
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// InitADC initializes the ADC.
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func InitADC() {
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// ADC Bias Calibration
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// #define ADC_FUSES_BIASCAL_ADDR (NVMCTRL_OTP4 + 4)
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// #define ADC_FUSES_BIASCAL_Pos 3 /**< \brief (NVMCTRL_OTP4) ADC Bias Calibration */
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// #define ADC_FUSES_BIASCAL_Msk (0x7u << ADC_FUSES_BIASCAL_Pos)
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// #define ADC_FUSES_BIASCAL(value) ((ADC_FUSES_BIASCAL_Msk & ((value) << ADC_FUSES_BIASCAL_Pos)))
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// #define ADC_FUSES_LINEARITY_0_ADDR NVMCTRL_OTP4
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// #define ADC_FUSES_LINEARITY_0_Pos 27 /**< \brief (NVMCTRL_OTP4) ADC Linearity bits 4:0 */
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// #define ADC_FUSES_LINEARITY_0_Msk (0x1Fu << ADC_FUSES_LINEARITY_0_Pos)
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// #define ADC_FUSES_LINEARITY_0(value) ((ADC_FUSES_LINEARITY_0_Msk & ((value) << ADC_FUSES_LINEARITY_0_Pos)))
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// #define ADC_FUSES_LINEARITY_1_ADDR (NVMCTRL_OTP4 + 4)
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// #define ADC_FUSES_LINEARITY_1_Pos 0 /**< \brief (NVMCTRL_OTP4) ADC Linearity bits 7:5 */
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// #define ADC_FUSES_LINEARITY_1_Msk (0x7u << ADC_FUSES_LINEARITY_1_Pos)
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// #define ADC_FUSES_LINEARITY_1(value) ((ADC_FUSES_LINEARITY_1_Msk & ((value) << ADC_FUSES_LINEARITY_1_Pos)))
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biasFuse := *(*uint32)(unsafe.Pointer(uintptr(0x00806020) + 4))
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bias := uint16(biasFuse>>3) & uint16(0x7)
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// ADC Linearity bits 4:0
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linearity0Fuse := *(*uint32)(unsafe.Pointer(uintptr(0x00806020)))
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linearity := uint16(linearity0Fuse>>27) & uint16(0x1f)
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// ADC Linearity bits 7:5
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linearity1Fuse := *(*uint32)(unsafe.Pointer(uintptr(0x00806020) + 4))
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linearity |= uint16(linearity1Fuse) & uint16(0x7) << 5
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// set calibration
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sam.ADC.CALIB.Set((bias << 8) | linearity)
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}
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// Configure configures a ADC pin to be able to be used to read data.
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func (a ADC) Configure(config ADCConfig) {
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// Wait for synchronization
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waitADCSync()
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var resolution uint32
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switch config.Resolution {
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case 8:
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resolution = sam.ADC_CTRLB_RESSEL_8BIT
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case 10:
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resolution = sam.ADC_CTRLB_RESSEL_10BIT
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case 12:
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resolution = sam.ADC_CTRLB_RESSEL_12BIT
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case 16:
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resolution = sam.ADC_CTRLB_RESSEL_16BIT
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default:
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resolution = sam.ADC_CTRLB_RESSEL_12BIT
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}
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// Divide Clock by 32 with 12 bits resolution as default
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sam.ADC.CTRLB.Set((sam.ADC_CTRLB_PRESCALER_DIV32 << sam.ADC_CTRLB_PRESCALER_Pos) |
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uint16(resolution<<sam.ADC_CTRLB_RESSEL_Pos))
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// Sampling Time Length
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sam.ADC.SAMPCTRL.Set(5)
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// Wait for synchronization
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waitADCSync()
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// Use internal ground
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sam.ADC.INPUTCTRL.Set(sam.ADC_INPUTCTRL_MUXNEG_GND << sam.ADC_INPUTCTRL_MUXNEG_Pos)
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// Averaging (see datasheet table in AVGCTRL register description)
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var samples uint32
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switch config.Samples {
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case 1:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_1
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case 2:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_2
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case 4:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_4
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case 8:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_8
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case 16:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_16
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case 32:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_32
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case 64:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_64
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case 128:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_128
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case 256:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_256
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case 512:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_512
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case 1024:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_1024
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default:
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samples = sam.ADC_AVGCTRL_SAMPLENUM_1
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}
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sam.ADC.AVGCTRL.Set(uint8(samples<<sam.ADC_AVGCTRL_SAMPLENUM_Pos) |
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(0x0 << sam.ADC_AVGCTRL_ADJRES_Pos))
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// TODO: use config.Reference to set AREF level
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// Analog Reference is AREF pin (3.3v)
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sam.ADC.INPUTCTRL.SetBits(sam.ADC_INPUTCTRL_GAIN_DIV2 << sam.ADC_INPUTCTRL_GAIN_Pos)
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// 1/2 VDDANA = 0.5 * 3V3 = 1.65V
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sam.ADC.REFCTRL.SetBits(sam.ADC_REFCTRL_REFSEL_INTVCC1 << sam.ADC_REFCTRL_REFSEL_Pos)
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a.Pin.Configure(PinConfig{Mode: PinAnalog})
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return
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}
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// Get returns the current value of a ADC pin, in the range 0..0xffff.
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func (a ADC) Get() uint16 {
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ch := a.getADCChannel()
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// Selection for the positive ADC input
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sam.ADC.INPUTCTRL.ClearBits(sam.ADC_INPUTCTRL_MUXPOS_Msk)
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waitADCSync()
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sam.ADC.INPUTCTRL.SetBits(uint32(ch << sam.ADC_INPUTCTRL_MUXPOS_Pos))
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waitADCSync()
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// Select internal ground for ADC input
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sam.ADC.INPUTCTRL.ClearBits(sam.ADC_INPUTCTRL_MUXNEG_Msk)
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waitADCSync()
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sam.ADC.INPUTCTRL.SetBits(sam.ADC_INPUTCTRL_MUXNEG_GND << sam.ADC_INPUTCTRL_MUXNEG_Pos)
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waitADCSync()
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// Enable ADC
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sam.ADC.CTRLA.SetBits(sam.ADC_CTRLA_ENABLE)
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waitADCSync()
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// Start conversion
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sam.ADC.SWTRIG.SetBits(sam.ADC_SWTRIG_START)
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waitADCSync()
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// wait for first conversion to finish to fix same issue as
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// https://github.com/arduino/ArduinoCore-samd/issues/446
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for !sam.ADC.INTFLAG.HasBits(sam.ADC_INTFLAG_RESRDY) {
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}
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// Clear the Data Ready flag
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sam.ADC.INTFLAG.SetBits(sam.ADC_INTFLAG_RESRDY)
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waitADCSync()
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// Start conversion again, since first conversion after reference voltage changed is invalid.
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sam.ADC.SWTRIG.SetBits(sam.ADC_SWTRIG_START)
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waitADCSync()
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// Waiting for conversion to complete
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for !sam.ADC.INTFLAG.HasBits(sam.ADC_INTFLAG_RESRDY) {
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}
|
|
val := sam.ADC.RESULT.Get()
|
|
|
|
// Disable ADC
|
|
sam.ADC.CTRLA.ClearBits(sam.ADC_CTRLA_ENABLE)
|
|
waitADCSync()
|
|
|
|
// scales to 16-bit result
|
|
switch (sam.ADC.CTRLB.Get() & sam.ADC_CTRLB_RESSEL_Msk) >> sam.ADC_CTRLB_RESSEL_Pos {
|
|
case sam.ADC_CTRLB_RESSEL_8BIT:
|
|
val = val << 8
|
|
case sam.ADC_CTRLB_RESSEL_10BIT:
|
|
val = val << 6
|
|
case sam.ADC_CTRLB_RESSEL_16BIT:
|
|
val = val << 4
|
|
case sam.ADC_CTRLB_RESSEL_12BIT:
|
|
val = val << 4
|
|
}
|
|
return val
|
|
}
|
|
|
|
func (a ADC) getADCChannel() uint8 {
|
|
switch a.Pin {
|
|
case PA02:
|
|
return 0
|
|
case PA03:
|
|
return 1
|
|
case PB04:
|
|
return 12
|
|
case PB05:
|
|
return 13
|
|
case PB06:
|
|
return 14
|
|
case PB07:
|
|
return 15
|
|
case PB08:
|
|
return 2
|
|
case PB09:
|
|
return 3
|
|
case PA04:
|
|
return 4
|
|
case PA05:
|
|
return 5
|
|
case PA06:
|
|
return 6
|
|
case PA07:
|
|
return 7
|
|
case PA08:
|
|
return 16
|
|
case PA09:
|
|
return 17
|
|
case PA10:
|
|
return 18
|
|
case PA11:
|
|
return 19
|
|
case PB00:
|
|
return 8
|
|
case PB01:
|
|
return 9
|
|
case PB02:
|
|
return 10
|
|
case PB03:
|
|
return 11
|
|
default:
|
|
return 0
|
|
}
|
|
}
|
|
|
|
func waitADCSync() {
|
|
for sam.ADC.STATUS.HasBits(sam.ADC_STATUS_SYNCBUSY) {
|
|
}
|
|
}
|
|
|
|
// UART on the SAMD21.
|
|
type UART struct {
|
|
Buffer *RingBuffer
|
|
Bus *sam.SERCOM_USART_Type
|
|
SERCOM uint8
|
|
Interrupt interrupt.Interrupt
|
|
}
|
|
|
|
const (
|
|
sampleRate16X = 16
|
|
lsbFirst = 1
|
|
)
|
|
|
|
// Configure the UART.
|
|
func (uart *UART) Configure(config UARTConfig) error {
|
|
// Default baud rate to 115200.
|
|
if config.BaudRate == 0 {
|
|
config.BaudRate = 115200
|
|
}
|
|
|
|
// Use default pins if pins are not set.
|
|
if config.TX == 0 && config.RX == 0 {
|
|
// use default pins
|
|
config.TX = UART_TX_PIN
|
|
config.RX = UART_RX_PIN
|
|
}
|
|
|
|
// Determine transmit pinout.
|
|
txPinMode, txPad, ok := findPinPadMapping(uart.SERCOM, config.TX)
|
|
if !ok {
|
|
return ErrInvalidOutputPin
|
|
}
|
|
var txPinOut uint32
|
|
// See table 25-9 of the datasheet (page 459) for how pads are mapped to
|
|
// pinout values.
|
|
switch txPad {
|
|
case 0:
|
|
txPinOut = 0
|
|
case 2:
|
|
txPinOut = 1
|
|
default:
|
|
// TODO: flow control (RTS/CTS)
|
|
return ErrInvalidOutputPin
|
|
}
|
|
|
|
// Determine receive pinout.
|
|
rxPinMode, rxPad, ok := findPinPadMapping(uart.SERCOM, config.RX)
|
|
if !ok {
|
|
return ErrInvalidInputPin
|
|
}
|
|
// As you can see in table 25-8 on page 459 of the datasheet, input pins
|
|
// are mapped directly.
|
|
rxPinOut := rxPad
|
|
|
|
// configure pins
|
|
config.TX.Configure(PinConfig{Mode: txPinMode})
|
|
config.RX.Configure(PinConfig{Mode: rxPinMode})
|
|
|
|
// reset SERCOM0
|
|
uart.Bus.CTRLA.SetBits(sam.SERCOM_USART_CTRLA_SWRST)
|
|
for uart.Bus.CTRLA.HasBits(sam.SERCOM_USART_CTRLA_SWRST) ||
|
|
uart.Bus.SYNCBUSY.HasBits(sam.SERCOM_USART_SYNCBUSY_SWRST) {
|
|
}
|
|
|
|
// set UART mode/sample rate
|
|
// SERCOM_USART_CTRLA_MODE(mode) |
|
|
// SERCOM_USART_CTRLA_SAMPR(sampleRate);
|
|
uart.Bus.CTRLA.Set((sam.SERCOM_USART_CTRLA_MODE_USART_INT_CLK << sam.SERCOM_USART_CTRLA_MODE_Pos) |
|
|
(1 << sam.SERCOM_USART_CTRLA_SAMPR_Pos)) // sample rate of 16x
|
|
|
|
// Set baud rate
|
|
uart.SetBaudRate(config.BaudRate)
|
|
|
|
// setup UART frame
|
|
// SERCOM_USART_CTRLA_FORM( (parityMode == SERCOM_NO_PARITY ? 0 : 1) ) |
|
|
// dataOrder << SERCOM_USART_CTRLA_DORD_Pos;
|
|
uart.Bus.CTRLA.SetBits((0 << sam.SERCOM_USART_CTRLA_FORM_Pos) | // no parity
|
|
(lsbFirst << sam.SERCOM_USART_CTRLA_DORD_Pos)) // data order
|
|
|
|
// set UART stop bits/parity
|
|
// SERCOM_USART_CTRLB_CHSIZE(charSize) |
|
|
// nbStopBits << SERCOM_USART_CTRLB_SBMODE_Pos |
|
|
// (parityMode == SERCOM_NO_PARITY ? 0 : parityMode) << SERCOM_USART_CTRLB_PMODE_Pos; //If no parity use default value
|
|
uart.Bus.CTRLB.SetBits((0 << sam.SERCOM_USART_CTRLB_CHSIZE_Pos) | // 8 bits is 0
|
|
(0 << sam.SERCOM_USART_CTRLB_SBMODE_Pos) | // 1 stop bit is zero
|
|
(0 << sam.SERCOM_USART_CTRLB_PMODE_Pos)) // no parity
|
|
|
|
// set UART pads. This is not same as pins...
|
|
// SERCOM_USART_CTRLA_TXPO(txPad) |
|
|
// SERCOM_USART_CTRLA_RXPO(rxPad);
|
|
uart.Bus.CTRLA.SetBits((txPinOut << sam.SERCOM_USART_CTRLA_TXPO_Pos) |
|
|
(rxPinOut << sam.SERCOM_USART_CTRLA_RXPO_Pos))
|
|
|
|
// Enable Transceiver and Receiver
|
|
//sercom->USART.CTRLB.reg |= SERCOM_USART_CTRLB_TXEN | SERCOM_USART_CTRLB_RXEN ;
|
|
uart.Bus.CTRLB.SetBits(sam.SERCOM_USART_CTRLB_TXEN | sam.SERCOM_USART_CTRLB_RXEN)
|
|
|
|
// Enable USART1 port.
|
|
// sercom->USART.CTRLA.bit.ENABLE = 0x1u;
|
|
uart.Bus.CTRLA.SetBits(sam.SERCOM_USART_CTRLA_ENABLE)
|
|
for uart.Bus.SYNCBUSY.HasBits(sam.SERCOM_USART_SYNCBUSY_ENABLE) {
|
|
}
|
|
|
|
// setup interrupt on receive
|
|
uart.Bus.INTENSET.Set(sam.SERCOM_USART_INTENSET_RXC)
|
|
|
|
// Enable RX IRQ.
|
|
uart.Interrupt.Enable()
|
|
|
|
return nil
|
|
}
|
|
|
|
// SetBaudRate sets the communication speed for the UART.
|
|
func (uart *UART) SetBaudRate(br uint32) {
|
|
// Asynchronous fractional mode (Table 24-2 in datasheet)
|
|
// BAUD = fref / (sampleRateValue * fbaud)
|
|
// (multiply by 8, to calculate fractional piece)
|
|
// uint32_t baudTimes8 = (SystemCoreClock * 8) / (16 * baudrate);
|
|
baud := (CPUFrequency() * 8) / (sampleRate16X * br)
|
|
|
|
// sercom->USART.BAUD.FRAC.FP = (baudTimes8 % 8);
|
|
// sercom->USART.BAUD.FRAC.BAUD = (baudTimes8 / 8);
|
|
uart.Bus.BAUD.Set(uint16(((baud % 8) << sam.SERCOM_USART_BAUD_FRAC_MODE_FP_Pos) |
|
|
((baud / 8) << sam.SERCOM_USART_BAUD_FRAC_MODE_BAUD_Pos)))
|
|
}
|
|
|
|
// WriteByte writes a byte of data to the UART.
|
|
func (uart *UART) WriteByte(c byte) error {
|
|
// wait until ready to receive
|
|
for !uart.Bus.INTFLAG.HasBits(sam.SERCOM_USART_INTFLAG_DRE) {
|
|
}
|
|
uart.Bus.DATA.Set(uint16(c))
|
|
return nil
|
|
}
|
|
|
|
// handleInterrupt should be called from the appropriate interrupt handler for
|
|
// this UART instance.
|
|
func (uart *UART) handleInterrupt(interrupt.Interrupt) {
|
|
// should reset IRQ
|
|
uart.Receive(byte((uart.Bus.DATA.Get() & 0xFF)))
|
|
uart.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INTFLAG_RXC)
|
|
}
|
|
|
|
// I2C on the SAMD21.
|
|
type I2C struct {
|
|
Bus *sam.SERCOM_I2CM_Type
|
|
SERCOM uint8
|
|
}
|
|
|
|
// I2CConfig is used to store config info for I2C.
|
|
type I2CConfig struct {
|
|
Frequency uint32
|
|
SCL Pin
|
|
SDA Pin
|
|
}
|
|
|
|
const (
|
|
// Default rise time in nanoseconds, based on 4.7K ohm pull up resistors
|
|
riseTimeNanoseconds = 125
|
|
|
|
// wire bus states
|
|
wireUnknownState = 0
|
|
wireIdleState = 1
|
|
wireOwnerState = 2
|
|
wireBusyState = 3
|
|
|
|
// wire commands
|
|
wireCmdNoAction = 0
|
|
wireCmdRepeatStart = 1
|
|
wireCmdRead = 2
|
|
wireCmdStop = 3
|
|
)
|
|
|
|
const i2cTimeout = 1000
|
|
|
|
// Configure is intended to setup the I2C interface.
|
|
func (i2c *I2C) Configure(config I2CConfig) error {
|
|
// Default I2C bus speed is 100 kHz.
|
|
if config.Frequency == 0 {
|
|
config.Frequency = TWI_FREQ_100KHZ
|
|
}
|
|
if config.SDA == 0 && config.SCL == 0 {
|
|
config.SDA = SDA_PIN
|
|
config.SCL = SCL_PIN
|
|
}
|
|
|
|
sclPinMode, sclPad, ok := findPinPadMapping(i2c.SERCOM, config.SCL)
|
|
if !ok || sclPad != 1 {
|
|
// SCL must be on pad 1, according to section 27.5 of the datasheet.
|
|
// Note: this is not an exhaustive test for I2C support on the pin: not
|
|
// all pins support I2C.
|
|
return ErrInvalidClockPin
|
|
}
|
|
sdaPinMode, sdaPad, ok := findPinPadMapping(i2c.SERCOM, config.SDA)
|
|
if !ok || sdaPad != 0 {
|
|
// SDA must be on pad 0, according to section 27.5 of the datasheet.
|
|
// Note: this is not an exhaustive test for I2C support on the pin: not
|
|
// all pins support I2C.
|
|
return ErrInvalidDataPin
|
|
}
|
|
|
|
// reset SERCOM
|
|
i2c.Bus.CTRLA.SetBits(sam.SERCOM_I2CM_CTRLA_SWRST)
|
|
for i2c.Bus.CTRLA.HasBits(sam.SERCOM_I2CM_CTRLA_SWRST) ||
|
|
i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_SWRST) {
|
|
}
|
|
|
|
// Set i2c controller mode
|
|
//SERCOM_I2CM_CTRLA_MODE( I2C_MASTER_OPERATION )
|
|
i2c.Bus.CTRLA.Set(sam.SERCOM_I2CM_CTRLA_MODE_I2C_MASTER << sam.SERCOM_I2CM_CTRLA_MODE_Pos) // |
|
|
|
|
i2c.SetBaudRate(config.Frequency)
|
|
|
|
// Enable I2CM port.
|
|
// sercom->USART.CTRLA.bit.ENABLE = 0x1u;
|
|
i2c.Bus.CTRLA.SetBits(sam.SERCOM_I2CM_CTRLA_ENABLE)
|
|
for i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_ENABLE) {
|
|
}
|
|
|
|
// set bus idle mode
|
|
i2c.Bus.STATUS.SetBits(wireIdleState << sam.SERCOM_I2CM_STATUS_BUSSTATE_Pos)
|
|
for i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_SYSOP) {
|
|
}
|
|
|
|
// enable pins
|
|
config.SDA.Configure(PinConfig{Mode: sdaPinMode})
|
|
config.SCL.Configure(PinConfig{Mode: sclPinMode})
|
|
|
|
return nil
|
|
}
|
|
|
|
// SetBaudRate sets the communication speed for the I2C.
|
|
func (i2c *I2C) SetBaudRate(br uint32) {
|
|
// Synchronous arithmetic baudrate, via Arduino SAMD implementation:
|
|
// SystemCoreClock / ( 2 * baudrate) - 5 - (((SystemCoreClock / 1000000) * WIRE_RISE_TIME_NANOSECONDS) / (2 * 1000));
|
|
baud := CPUFrequency()/(2*br) - 5 - (((CPUFrequency() / 1000000) * riseTimeNanoseconds) / (2 * 1000))
|
|
i2c.Bus.BAUD.Set(baud)
|
|
}
|
|
|
|
// Tx does a single I2C transaction at the specified address.
|
|
// It clocks out the given address, writes the bytes in w, reads back len(r)
|
|
// bytes and stores them in r, and generates a stop condition on the bus.
|
|
func (i2c *I2C) Tx(addr uint16, w, r []byte) error {
|
|
var err error
|
|
if len(w) != 0 {
|
|
// send start/address for write
|
|
i2c.sendAddress(addr, true)
|
|
|
|
// wait until transmission complete
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_MB) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
// ACK received (0: ACK, 1: NACK)
|
|
if i2c.Bus.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_RXNACK) {
|
|
return errI2CAckExpected
|
|
}
|
|
|
|
// write data
|
|
for _, b := range w {
|
|
err = i2c.WriteByte(b)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
err = i2c.signalStop()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
if len(r) != 0 {
|
|
// send start/address for read
|
|
i2c.sendAddress(addr, false)
|
|
|
|
// wait transmission complete
|
|
for !i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_SB) {
|
|
// If the peripheral NACKS the address, the MB bit will be set.
|
|
// In that case, send a stop condition and return error.
|
|
if i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_MB) {
|
|
i2c.Bus.CTRLB.SetBits(wireCmdStop << sam.SERCOM_I2CM_CTRLB_CMD_Pos) // Stop condition
|
|
return errI2CAckExpected
|
|
}
|
|
}
|
|
|
|
// ACK received (0: ACK, 1: NACK)
|
|
if i2c.Bus.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_RXNACK) {
|
|
return errI2CAckExpected
|
|
}
|
|
|
|
// read first byte
|
|
r[0] = i2c.readByte()
|
|
for i := 1; i < len(r); i++ {
|
|
// Send an ACK
|
|
i2c.Bus.CTRLB.ClearBits(sam.SERCOM_I2CM_CTRLB_ACKACT)
|
|
|
|
i2c.signalRead()
|
|
|
|
// Read data and send the ACK
|
|
r[i] = i2c.readByte()
|
|
}
|
|
|
|
// Send NACK to end transmission
|
|
i2c.Bus.CTRLB.SetBits(sam.SERCOM_I2CM_CTRLB_ACKACT)
|
|
|
|
err = i2c.signalStop()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// WriteByte writes a single byte to the I2C bus.
|
|
func (i2c *I2C) WriteByte(data byte) error {
|
|
// Send data byte
|
|
i2c.Bus.DATA.Set(data)
|
|
|
|
// wait until transmission successful
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_MB) {
|
|
// check for bus error
|
|
if sam.SERCOM3_I2CM.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_BUSERR) {
|
|
return errI2CBusError
|
|
}
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
if i2c.Bus.STATUS.HasBits(sam.SERCOM_I2CM_STATUS_RXNACK) {
|
|
return errI2CAckExpected
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// sendAddress sends the address and start signal
|
|
func (i2c *I2C) sendAddress(address uint16, write bool) error {
|
|
data := (address << 1)
|
|
if !write {
|
|
data |= 1 // set read flag
|
|
}
|
|
|
|
// wait until bus ready
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.STATUS.HasBits(wireIdleState<<sam.SERCOM_I2CM_STATUS_BUSSTATE_Pos) &&
|
|
!i2c.Bus.STATUS.HasBits(wireOwnerState<<sam.SERCOM_I2CM_STATUS_BUSSTATE_Pos) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CBusReadyTimeout
|
|
}
|
|
}
|
|
i2c.Bus.ADDR.Set(uint32(data))
|
|
|
|
return nil
|
|
}
|
|
|
|
func (i2c *I2C) signalStop() error {
|
|
i2c.Bus.CTRLB.SetBits(wireCmdStop << sam.SERCOM_I2CM_CTRLB_CMD_Pos) // Stop command
|
|
timeout := i2cTimeout
|
|
for i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_SYSOP) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CSignalStopTimeout
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (i2c *I2C) signalRead() error {
|
|
i2c.Bus.CTRLB.SetBits(wireCmdRead << sam.SERCOM_I2CM_CTRLB_CMD_Pos) // Read command
|
|
timeout := i2cTimeout
|
|
for i2c.Bus.SYNCBUSY.HasBits(sam.SERCOM_I2CM_SYNCBUSY_SYSOP) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CSignalReadTimeout
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (i2c *I2C) readByte() byte {
|
|
for !i2c.Bus.INTFLAG.HasBits(sam.SERCOM_I2CM_INTFLAG_SB) {
|
|
}
|
|
return byte(i2c.Bus.DATA.Get())
|
|
}
|
|
|
|
// I2S on the SAMD21.
|
|
|
|
// I2S
|
|
type I2S struct {
|
|
Bus *sam.I2S_Type
|
|
}
|
|
|
|
var I2S0 = I2S{Bus: sam.I2S}
|
|
|
|
// Configure is used to configure the I2S interface. You must call this
|
|
// before you can use the I2S bus.
|
|
func (i2s I2S) Configure(config I2SConfig) {
|
|
// handle defaults
|
|
if config.SCK == 0 {
|
|
config.SCK = I2S_SCK_PIN
|
|
config.WS = I2S_WS_PIN
|
|
config.SD = I2S_SD_PIN
|
|
}
|
|
|
|
if config.AudioFrequency == 0 {
|
|
config.AudioFrequency = 48000
|
|
}
|
|
|
|
if config.DataFormat == I2SDataFormatDefault {
|
|
if config.Stereo {
|
|
config.DataFormat = I2SDataFormat16bit
|
|
} else {
|
|
config.DataFormat = I2SDataFormat32bit
|
|
}
|
|
}
|
|
|
|
// Turn on clock for I2S
|
|
sam.PM.APBCMASK.SetBits(sam.PM_APBCMASK_I2S_)
|
|
|
|
// setting clock rate for sample.
|
|
division_factor := CPUFrequency() / (config.AudioFrequency * uint32(config.DataFormat))
|
|
|
|
// Switch Generic Clock Generator 3 to DFLL48M.
|
|
sam.GCLK.GENDIV.Set((sam.GCLK_CLKCTRL_GEN_GCLK3 << sam.GCLK_GENDIV_ID_Pos) |
|
|
(division_factor << sam.GCLK_GENDIV_DIV_Pos))
|
|
waitForSync()
|
|
|
|
sam.GCLK.GENCTRL.Set((sam.GCLK_CLKCTRL_GEN_GCLK3 << sam.GCLK_GENCTRL_ID_Pos) |
|
|
(sam.GCLK_GENCTRL_SRC_DFLL48M << sam.GCLK_GENCTRL_SRC_Pos) |
|
|
sam.GCLK_GENCTRL_IDC |
|
|
sam.GCLK_GENCTRL_GENEN)
|
|
waitForSync()
|
|
|
|
// Use Generic Clock Generator 3 as source for I2S.
|
|
sam.GCLK.CLKCTRL.Set((sam.GCLK_CLKCTRL_ID_I2S_0 << sam.GCLK_CLKCTRL_ID_Pos) |
|
|
(sam.GCLK_CLKCTRL_GEN_GCLK3 << sam.GCLK_CLKCTRL_GEN_Pos) |
|
|
sam.GCLK_CLKCTRL_CLKEN)
|
|
waitForSync()
|
|
|
|
// reset the device
|
|
i2s.Bus.CTRLA.SetBits(sam.I2S_CTRLA_SWRST)
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_SWRST) {
|
|
}
|
|
|
|
// disable device before continuing
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_ENABLE) {
|
|
}
|
|
i2s.Bus.CTRLA.ClearBits(sam.I2S_CTRLA_ENABLE)
|
|
|
|
// setup clock
|
|
if config.ClockSource == I2SClockSourceInternal {
|
|
// TODO: make sure correct for I2S output
|
|
|
|
// set serial clock select pin
|
|
i2s.Bus.CLKCTRL0.SetBits(sam.I2S_CLKCTRL_SCKSEL)
|
|
|
|
// set frame select pin
|
|
i2s.Bus.CLKCTRL0.SetBits(sam.I2S_CLKCTRL_FSSEL)
|
|
} else {
|
|
// Configure FS generation from SCK clock.
|
|
i2s.Bus.CLKCTRL0.ClearBits(sam.I2S_CLKCTRL_FSSEL)
|
|
}
|
|
|
|
if config.Standard == I2StandardPhilips {
|
|
// set 1-bit delay
|
|
i2s.Bus.CLKCTRL0.SetBits(sam.I2S_CLKCTRL_BITDELAY)
|
|
} else {
|
|
// set 0-bit delay
|
|
i2s.Bus.CLKCTRL0.ClearBits(sam.I2S_CLKCTRL_BITDELAY)
|
|
}
|
|
|
|
// set number of slots.
|
|
if config.Stereo {
|
|
i2s.Bus.CLKCTRL0.SetBits(1 << sam.I2S_CLKCTRL_NBSLOTS_Pos)
|
|
} else {
|
|
i2s.Bus.CLKCTRL0.ClearBits(1 << sam.I2S_CLKCTRL_NBSLOTS_Pos)
|
|
}
|
|
|
|
// set slot size
|
|
switch config.DataFormat {
|
|
case I2SDataFormat8bit:
|
|
i2s.Bus.CLKCTRL0.SetBits(sam.I2S_CLKCTRL_SLOTSIZE_8)
|
|
|
|
case I2SDataFormat16bit:
|
|
i2s.Bus.CLKCTRL0.SetBits(sam.I2S_CLKCTRL_SLOTSIZE_16)
|
|
|
|
case I2SDataFormat24bit:
|
|
i2s.Bus.CLKCTRL0.SetBits(sam.I2S_CLKCTRL_SLOTSIZE_24)
|
|
|
|
case I2SDataFormat32bit:
|
|
i2s.Bus.CLKCTRL0.SetBits(sam.I2S_CLKCTRL_SLOTSIZE_32)
|
|
}
|
|
|
|
// configure pin for clock
|
|
config.SCK.Configure(PinConfig{Mode: PinCom})
|
|
|
|
// configure pin for WS, if needed
|
|
if config.WS != NoPin {
|
|
config.WS.Configure(PinConfig{Mode: PinCom})
|
|
}
|
|
|
|
// now set serializer data size.
|
|
switch config.DataFormat {
|
|
case I2SDataFormat8bit:
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_DATASIZE_8 << sam.I2S_SERCTRL_DATASIZE_Pos)
|
|
|
|
case I2SDataFormat16bit:
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_DATASIZE_16 << sam.I2S_SERCTRL_DATASIZE_Pos)
|
|
|
|
case I2SDataFormat24bit:
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_DATASIZE_24 << sam.I2S_SERCTRL_DATASIZE_Pos)
|
|
|
|
case I2SDataFormat32bit:
|
|
case I2SDataFormatDefault:
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_DATASIZE_32 << sam.I2S_SERCTRL_DATASIZE_Pos)
|
|
}
|
|
|
|
// set serializer slot adjustment
|
|
if config.Standard == I2SStandardLSB {
|
|
// adjust right
|
|
i2s.Bus.SERCTRL1.ClearBits(sam.I2S_SERCTRL_SLOTADJ)
|
|
|
|
// transfer LSB first
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_BITREV)
|
|
} else {
|
|
// adjust left
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_SLOTADJ)
|
|
}
|
|
|
|
// set serializer mode.
|
|
if config.Mode == I2SModePDM {
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_SERMODE_PDM2)
|
|
} else {
|
|
i2s.Bus.SERCTRL1.SetBits(sam.I2S_SERCTRL_SERMODE_RX)
|
|
}
|
|
|
|
// configure data pin
|
|
config.SD.Configure(PinConfig{Mode: PinCom})
|
|
|
|
// re-enable
|
|
i2s.Bus.CTRLA.SetBits(sam.I2S_CTRLA_ENABLE)
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_ENABLE) {
|
|
}
|
|
|
|
// enable i2s clock
|
|
i2s.Bus.CTRLA.SetBits(sam.I2S_CTRLA_CKEN0)
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_CKEN0) {
|
|
}
|
|
|
|
// enable i2s serializer
|
|
i2s.Bus.CTRLA.SetBits(sam.I2S_CTRLA_SEREN1)
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_SEREN1) {
|
|
}
|
|
}
|
|
|
|
// Read data from the I2S bus into the provided slice.
|
|
// The I2S bus must already have been configured correctly.
|
|
func (i2s I2S) Read(p []uint32) (n int, err error) {
|
|
i := 0
|
|
for i = 0; i < len(p); i++ {
|
|
// Wait until ready
|
|
for !i2s.Bus.INTFLAG.HasBits(sam.I2S_INTFLAG_RXRDY1) {
|
|
}
|
|
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_DATA1) {
|
|
}
|
|
|
|
// read data
|
|
p[i] = i2s.Bus.DATA1.Get()
|
|
|
|
// indicate read complete
|
|
i2s.Bus.INTFLAG.Set(sam.I2S_INTFLAG_RXRDY1)
|
|
}
|
|
|
|
return i, nil
|
|
}
|
|
|
|
// Write data to the I2S bus from the provided slice.
|
|
// The I2S bus must already have been configured correctly.
|
|
func (i2s I2S) Write(p []uint32) (n int, err error) {
|
|
i := 0
|
|
for i = 0; i < len(p); i++ {
|
|
// Wait until ready
|
|
for !i2s.Bus.INTFLAG.HasBits(sam.I2S_INTFLAG_TXRDY1) {
|
|
}
|
|
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_DATA1) {
|
|
}
|
|
|
|
// write data
|
|
i2s.Bus.DATA1.Set(p[i])
|
|
|
|
// indicate write complete
|
|
i2s.Bus.INTFLAG.Set(sam.I2S_INTFLAG_TXRDY1)
|
|
}
|
|
|
|
return i, nil
|
|
}
|
|
|
|
// Close the I2S bus.
|
|
func (i2s I2S) Close() error {
|
|
// Sync wait
|
|
for i2s.Bus.SYNCBUSY.HasBits(sam.I2S_SYNCBUSY_ENABLE) {
|
|
}
|
|
|
|
// disable I2S
|
|
i2s.Bus.CTRLA.ClearBits(sam.I2S_CTRLA_ENABLE)
|
|
|
|
return nil
|
|
}
|
|
|
|
func waitForSync() {
|
|
for sam.GCLK.STATUS.HasBits(sam.GCLK_STATUS_SYNCBUSY) {
|
|
}
|
|
}
|
|
|
|
// SPI
|
|
type SPI struct {
|
|
Bus *sam.SERCOM_SPI_Type
|
|
SERCOM uint8
|
|
}
|
|
|
|
// SPIConfig is used to store config info for SPI.
|
|
type SPIConfig struct {
|
|
Frequency uint32
|
|
SCK Pin
|
|
SDO Pin
|
|
SDI Pin
|
|
LSBFirst bool
|
|
Mode uint8
|
|
}
|
|
|
|
// Configure is intended to setup the SPI interface.
|
|
func (spi SPI) Configure(config SPIConfig) error {
|
|
// Use default pins if not set.
|
|
if config.SCK == 0 && config.SDO == 0 && config.SDI == 0 {
|
|
config.SCK = SPI0_SCK_PIN
|
|
config.SDO = SPI0_SDO_PIN
|
|
config.SDI = SPI0_SDI_PIN
|
|
}
|
|
|
|
// set default frequency
|
|
if config.Frequency == 0 {
|
|
config.Frequency = 4000000
|
|
}
|
|
|
|
// Determine the input pinout (for SDI).
|
|
SDIPinMode, SDIPad, ok := findPinPadMapping(spi.SERCOM, config.SDI)
|
|
if !ok {
|
|
return ErrInvalidInputPin
|
|
}
|
|
dataInPinout := SDIPad // mapped directly
|
|
|
|
// Determine the output pinout (for SDO/SCK).
|
|
// See table 26-7 on page 494 of the datasheet.
|
|
var dataOutPinout uint32
|
|
sckPinMode, sckPad, ok := findPinPadMapping(spi.SERCOM, config.SCK)
|
|
if !ok {
|
|
return ErrInvalidOutputPin
|
|
}
|
|
SDOPinMode, SDOPad, ok := findPinPadMapping(spi.SERCOM, config.SDO)
|
|
if !ok {
|
|
return ErrInvalidOutputPin
|
|
}
|
|
switch sckPad {
|
|
case 1:
|
|
switch SDOPad {
|
|
case 0:
|
|
dataOutPinout = 0x0
|
|
case 3:
|
|
dataOutPinout = 0x2
|
|
default:
|
|
return ErrInvalidOutputPin
|
|
}
|
|
case 3:
|
|
switch SDOPad {
|
|
case 2:
|
|
dataOutPinout = 0x1
|
|
case 0:
|
|
dataOutPinout = 0x3
|
|
default:
|
|
return ErrInvalidOutputPin
|
|
}
|
|
default:
|
|
return ErrInvalidOutputPin
|
|
}
|
|
|
|
// Disable SPI port.
|
|
spi.Bus.CTRLA.ClearBits(sam.SERCOM_SPI_CTRLA_ENABLE)
|
|
for spi.Bus.SYNCBUSY.HasBits(sam.SERCOM_SPI_SYNCBUSY_ENABLE) {
|
|
}
|
|
|
|
// enable pins
|
|
config.SCK.Configure(PinConfig{Mode: sckPinMode})
|
|
config.SDO.Configure(PinConfig{Mode: SDOPinMode})
|
|
config.SDI.Configure(PinConfig{Mode: SDIPinMode})
|
|
|
|
// reset SERCOM
|
|
spi.Bus.CTRLA.SetBits(sam.SERCOM_SPI_CTRLA_SWRST)
|
|
for spi.Bus.CTRLA.HasBits(sam.SERCOM_SPI_CTRLA_SWRST) ||
|
|
spi.Bus.SYNCBUSY.HasBits(sam.SERCOM_SPI_SYNCBUSY_SWRST) {
|
|
}
|
|
|
|
// set bit transfer order
|
|
dataOrder := uint32(0)
|
|
if config.LSBFirst {
|
|
dataOrder = 1
|
|
}
|
|
|
|
// Set SPI mode to controller
|
|
spi.Bus.CTRLA.Set((sam.SERCOM_SPI_CTRLA_MODE_SPI_MASTER << sam.SERCOM_SPI_CTRLA_MODE_Pos) |
|
|
(dataOutPinout << sam.SERCOM_SPI_CTRLA_DOPO_Pos) |
|
|
(dataInPinout << sam.SERCOM_SPI_CTRLA_DIPO_Pos) |
|
|
(dataOrder << sam.SERCOM_SPI_CTRLA_DORD_Pos))
|
|
|
|
spi.Bus.CTRLB.SetBits((0 << sam.SERCOM_SPI_CTRLB_CHSIZE_Pos) | // 8bit char size
|
|
sam.SERCOM_SPI_CTRLB_RXEN) // receive enable
|
|
|
|
for spi.Bus.SYNCBUSY.HasBits(sam.SERCOM_SPI_SYNCBUSY_CTRLB) {
|
|
}
|
|
|
|
// set mode
|
|
switch config.Mode {
|
|
case 0:
|
|
spi.Bus.CTRLA.ClearBits(sam.SERCOM_SPI_CTRLA_CPHA)
|
|
spi.Bus.CTRLA.ClearBits(sam.SERCOM_SPI_CTRLA_CPOL)
|
|
case 1:
|
|
spi.Bus.CTRLA.SetBits(sam.SERCOM_SPI_CTRLA_CPHA)
|
|
spi.Bus.CTRLA.ClearBits(sam.SERCOM_SPI_CTRLA_CPOL)
|
|
case 2:
|
|
spi.Bus.CTRLA.ClearBits(sam.SERCOM_SPI_CTRLA_CPHA)
|
|
spi.Bus.CTRLA.SetBits(sam.SERCOM_SPI_CTRLA_CPOL)
|
|
case 3:
|
|
spi.Bus.CTRLA.SetBits(sam.SERCOM_SPI_CTRLA_CPHA | sam.SERCOM_SPI_CTRLA_CPOL)
|
|
default: // to mode 0
|
|
spi.Bus.CTRLA.ClearBits(sam.SERCOM_SPI_CTRLA_CPHA)
|
|
spi.Bus.CTRLA.ClearBits(sam.SERCOM_SPI_CTRLA_CPOL)
|
|
}
|
|
|
|
// Set synch speed for SPI
|
|
baudRate := CPUFrequency() / (2 * config.Frequency)
|
|
if baudRate > 0 {
|
|
baudRate--
|
|
}
|
|
spi.Bus.BAUD.Set(uint8(baudRate))
|
|
|
|
// Enable SPI port.
|
|
spi.Bus.CTRLA.SetBits(sam.SERCOM_SPI_CTRLA_ENABLE)
|
|
for spi.Bus.SYNCBUSY.HasBits(sam.SERCOM_SPI_SYNCBUSY_ENABLE) {
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Transfer writes/reads a single byte using the SPI interface.
|
|
func (spi SPI) Transfer(w byte) (byte, error) {
|
|
// write data
|
|
spi.Bus.DATA.Set(uint32(w))
|
|
|
|
// wait for receive
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_RXC) {
|
|
}
|
|
|
|
// return data
|
|
return byte(spi.Bus.DATA.Get()), nil
|
|
}
|
|
|
|
var (
|
|
ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
|
|
)
|
|
|
|
// Tx handles read/write operation for SPI interface. Since SPI is a syncronous write/read
|
|
// interface, there must always be the same number of bytes written as bytes read.
|
|
// The Tx method knows about this, and offers a few different ways of calling it.
|
|
//
|
|
// This form sends the bytes in tx buffer, putting the resulting bytes read into the rx buffer.
|
|
// Note that the tx and rx buffers must be the same size:
|
|
//
|
|
// spi.Tx(tx, rx)
|
|
//
|
|
// This form sends the tx buffer, ignoring the result. Useful for sending "commands" that return zeros
|
|
// until all the bytes in the command packet have been received:
|
|
//
|
|
// spi.Tx(tx, nil)
|
|
//
|
|
// This form sends zeros, putting the result into the rx buffer. Good for reading a "result packet":
|
|
//
|
|
// spi.Tx(nil, rx)
|
|
//
|
|
func (spi SPI) Tx(w, r []byte) error {
|
|
switch {
|
|
case w == nil:
|
|
// read only, so write zero and read a result.
|
|
spi.rx(r)
|
|
case r == nil:
|
|
// write only
|
|
spi.tx(w)
|
|
|
|
default:
|
|
// write/read
|
|
if len(w) != len(r) {
|
|
return ErrTxInvalidSliceSize
|
|
}
|
|
|
|
spi.txrx(w, r)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (spi SPI) tx(tx []byte) {
|
|
for i := 0; i < len(tx); i++ {
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_DRE) {
|
|
}
|
|
spi.Bus.DATA.Set(uint32(tx[i]))
|
|
}
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_TXC) {
|
|
}
|
|
|
|
// read to clear RXC register
|
|
for spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_RXC) {
|
|
spi.Bus.DATA.Get()
|
|
}
|
|
}
|
|
|
|
func (spi SPI) rx(rx []byte) {
|
|
spi.Bus.DATA.Set(0)
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_DRE) {
|
|
}
|
|
|
|
for i := 1; i < len(rx); i++ {
|
|
spi.Bus.DATA.Set(0)
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_RXC) {
|
|
}
|
|
rx[i-1] = byte(spi.Bus.DATA.Get())
|
|
}
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_RXC) {
|
|
}
|
|
rx[len(rx)-1] = byte(spi.Bus.DATA.Get())
|
|
}
|
|
|
|
func (spi SPI) txrx(tx, rx []byte) {
|
|
spi.Bus.DATA.Set(uint32(tx[0]))
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_DRE) {
|
|
}
|
|
|
|
for i := 1; i < len(rx); i++ {
|
|
spi.Bus.DATA.Set(uint32(tx[i]))
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_RXC) {
|
|
}
|
|
rx[i-1] = byte(spi.Bus.DATA.Get())
|
|
}
|
|
for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPI_INTFLAG_RXC) {
|
|
}
|
|
rx[len(rx)-1] = byte(spi.Bus.DATA.Get())
|
|
}
|
|
|
|
// TCC is one timer/counter peripheral, which consists of a counter and multiple
|
|
// output channels (that can be connected to actual pins). You can set the
|
|
// frequency using SetPeriod, but only for all the channels in this TCC
|
|
// peripheral at once.
|
|
type TCC sam.TCC_Type
|
|
|
|
// The SAM D21 has three TCC peripherals, which have PWM as one feature.
|
|
var (
|
|
TCC0 = (*TCC)(sam.TCC0)
|
|
TCC1 = (*TCC)(sam.TCC1)
|
|
TCC2 = (*TCC)(sam.TCC2)
|
|
)
|
|
|
|
//go:inline
|
|
func (tcc *TCC) timer() *sam.TCC_Type {
|
|
return (*sam.TCC_Type)(tcc)
|
|
}
|
|
|
|
// Configure enables and configures this TCC.
|
|
func (tcc *TCC) Configure(config PWMConfig) error {
|
|
// Enable the clock source for this timer.
|
|
switch tcc.timer() {
|
|
case sam.TCC0:
|
|
sam.PM.APBCMASK.SetBits(sam.PM_APBCMASK_TCC0_)
|
|
// Use GCLK0 for TCC0/TCC1
|
|
sam.GCLK.CLKCTRL.Set((sam.GCLK_CLKCTRL_ID_TCC0_TCC1 << sam.GCLK_CLKCTRL_ID_Pos) |
|
|
(sam.GCLK_CLKCTRL_GEN_GCLK0 << sam.GCLK_CLKCTRL_GEN_Pos) |
|
|
sam.GCLK_CLKCTRL_CLKEN)
|
|
for sam.GCLK.STATUS.HasBits(sam.GCLK_STATUS_SYNCBUSY) {
|
|
}
|
|
case sam.TCC1:
|
|
sam.PM.APBCMASK.SetBits(sam.PM_APBCMASK_TCC1_)
|
|
// Use GCLK0 for TCC0/TCC1
|
|
sam.GCLK.CLKCTRL.Set((sam.GCLK_CLKCTRL_ID_TCC0_TCC1 << sam.GCLK_CLKCTRL_ID_Pos) |
|
|
(sam.GCLK_CLKCTRL_GEN_GCLK0 << sam.GCLK_CLKCTRL_GEN_Pos) |
|
|
sam.GCLK_CLKCTRL_CLKEN)
|
|
for sam.GCLK.STATUS.HasBits(sam.GCLK_STATUS_SYNCBUSY) {
|
|
}
|
|
case sam.TCC2:
|
|
sam.PM.APBCMASK.SetBits(sam.PM_APBCMASK_TCC2_)
|
|
// Use GCLK0 for TCC2/TC3
|
|
sam.GCLK.CLKCTRL.Set((sam.GCLK_CLKCTRL_ID_TCC2_TC3 << sam.GCLK_CLKCTRL_ID_Pos) |
|
|
(sam.GCLK_CLKCTRL_GEN_GCLK0 << sam.GCLK_CLKCTRL_GEN_Pos) |
|
|
sam.GCLK_CLKCTRL_CLKEN)
|
|
for sam.GCLK.STATUS.HasBits(sam.GCLK_STATUS_SYNCBUSY) {
|
|
}
|
|
}
|
|
|
|
// Disable timer (if it was enabled). This is necessary because
|
|
// tcc.setPeriod may want to change the prescaler bits in CTRLA, which is
|
|
// only allowed when the TCC is disabled.
|
|
tcc.timer().CTRLA.ClearBits(sam.TCC_CTRLA_ENABLE)
|
|
|
|
// Use "Normal PWM" (single-slope PWM)
|
|
tcc.timer().WAVE.Set(sam.TCC_WAVE_WAVEGEN_NPWM)
|
|
|
|
// Wait for synchronization of all changed registers.
|
|
for tcc.timer().SYNCBUSY.Get() != 0 {
|
|
}
|
|
|
|
// Set the period and prescaler.
|
|
err := tcc.setPeriod(config.Period, true)
|
|
|
|
// Enable the timer.
|
|
tcc.timer().CTRLA.SetBits(sam.TCC_CTRLA_ENABLE)
|
|
|
|
// Wait for synchronization of all changed registers.
|
|
for tcc.timer().SYNCBUSY.Get() != 0 {
|
|
}
|
|
|
|
// Return any error that might have occured in the tcc.setPeriod call.
|
|
return err
|
|
}
|
|
|
|
// SetPeriod updates the period of this TCC peripheral.
|
|
// To set a particular frequency, use the following formula:
|
|
//
|
|
// period = 1e9 / frequency
|
|
//
|
|
// If you use a period of 0, a period that works well for LEDs will be picked.
|
|
//
|
|
// SetPeriod will not change the prescaler, but also won't change the current
|
|
// value in any of the channels. This means that you may need to update the
|
|
// value for the particular channel.
|
|
//
|
|
// Note that you cannot pick any arbitrary period after the TCC peripheral has
|
|
// been configured. If you want to switch between frequencies, pick the lowest
|
|
// frequency (longest period) once when calling Configure and adjust the
|
|
// frequency here as needed.
|
|
func (tcc *TCC) SetPeriod(period uint64) error {
|
|
err := tcc.setPeriod(period, false)
|
|
if err == nil {
|
|
if tcc.Counter() >= tcc.Top() {
|
|
// When setting the timer to a shorter period, there is a chance
|
|
// that it passes the counter value and thus goes all the way to MAX
|
|
// before wrapping back to zero.
|
|
// To avoid this, reset the counter back to 0.
|
|
tcc.timer().COUNT.Set(0)
|
|
}
|
|
}
|
|
return err
|
|
}
|
|
|
|
// setPeriod sets the period of this TCC, possibly updating the prescaler as
|
|
// well. The prescaler can only modified when the TCC is disabled, that is, in
|
|
// the Configure function.
|
|
func (tcc *TCC) setPeriod(period uint64, updatePrescaler bool) error {
|
|
var top uint64
|
|
if period == 0 {
|
|
// Make sure the TOP value is at 0xffff (enough for a 16-bit timer).
|
|
top = 0xffff
|
|
} else {
|
|
// The formula below calculates the following formula, optimized:
|
|
// period * (48e6 / 1e9)
|
|
// This assumes that the chip is running at the (default) 48MHz speed.
|
|
top = period * 6 / 125
|
|
}
|
|
|
|
maxTop := uint64(0xffffff)
|
|
if tcc.timer() == sam.TCC2 {
|
|
// TCC2 is a 16-bit timer, not a 24-bit timer.
|
|
maxTop = 0xffff
|
|
}
|
|
|
|
if updatePrescaler {
|
|
// This function was called during Configure(), with the timer disabled.
|
|
// Note that updating the prescaler can only happen while the peripheral
|
|
// is disabled.
|
|
var prescaler uint32
|
|
switch {
|
|
case top <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV1
|
|
case top/2 <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV2
|
|
top = top / 2
|
|
case top/4 <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV4
|
|
top = top / 4
|
|
case top/8 <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV8
|
|
top = top / 8
|
|
case top/16 <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV16
|
|
top = top / 16
|
|
case top/64 <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV64
|
|
top = top / 64
|
|
case top/256 <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV256
|
|
top = top / 256
|
|
case top/1024 <= maxTop:
|
|
prescaler = sam.TCC_CTRLA_PRESCALER_DIV1024
|
|
top = top / 1024
|
|
default:
|
|
return ErrPWMPeriodTooLong
|
|
}
|
|
tcc.timer().CTRLA.Set((tcc.timer().CTRLA.Get() &^ sam.TCC_CTRLA_PRESCALER_Msk) | (prescaler << sam.TCC_CTRLA_PRESCALER_Pos))
|
|
} else {
|
|
// Do not update the prescaler, but use the already-configured
|
|
// prescaler. This is the normal SetPeriod case, where the prescaler
|
|
// must not be changed.
|
|
prescaler := (tcc.timer().CTRLA.Get() & sam.TCC_CTRLA_PRESCALER_Msk) >> sam.TCC_CTRLA_PRESCALER_Pos
|
|
switch prescaler {
|
|
case sam.TCC_CTRLA_PRESCALER_DIV1:
|
|
top /= 1 // no-op
|
|
case sam.TCC_CTRLA_PRESCALER_DIV2:
|
|
top /= 2
|
|
case sam.TCC_CTRLA_PRESCALER_DIV4:
|
|
top /= 4
|
|
case sam.TCC_CTRLA_PRESCALER_DIV8:
|
|
top /= 8
|
|
case sam.TCC_CTRLA_PRESCALER_DIV16:
|
|
top /= 16
|
|
case sam.TCC_CTRLA_PRESCALER_DIV64:
|
|
top /= 64
|
|
case sam.TCC_CTRLA_PRESCALER_DIV256:
|
|
top /= 256
|
|
case sam.TCC_CTRLA_PRESCALER_DIV1024:
|
|
top /= 1024
|
|
default:
|
|
// unreachable
|
|
}
|
|
if top > maxTop {
|
|
return ErrPWMPeriodTooLong
|
|
}
|
|
}
|
|
|
|
// Set the period (the counter top).
|
|
tcc.timer().PER.Set(uint32(top) - 1)
|
|
|
|
// Wait for synchronization of CTRLA.PRESCALER and PER registers.
|
|
for tcc.timer().SYNCBUSY.Get() != 0 {
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Top returns the current counter top, for use in duty cycle calculation. It
|
|
// will only change with a call to Configure or SetPeriod, otherwise it is
|
|
// constant.
|
|
//
|
|
// The value returned here is hardware dependent. In general, it's best to treat
|
|
// it as an opaque value that can be divided by some number and passed to Set
|
|
// (see Set documentation for more information).
|
|
func (tcc *TCC) Top() uint32 {
|
|
return tcc.timer().PER.Get() + 1
|
|
}
|
|
|
|
// Counter returns the current counter value of the timer in this TCC
|
|
// peripheral. It may be useful for debugging.
|
|
func (tcc *TCC) Counter() uint32 {
|
|
tcc.timer().CTRLBSET.Set(sam.TCC_CTRLBSET_CMD_READSYNC << sam.TCC_CTRLBSET_CMD_Pos)
|
|
for tcc.timer().SYNCBUSY.Get() != 0 {
|
|
}
|
|
return tcc.timer().COUNT.Get()
|
|
}
|
|
|
|
// Some constans to make pinTimerMapping below easier to read.
|
|
const (
|
|
pinTCC0 = 1
|
|
pinTCC1 = 2
|
|
pinTCC2 = 3
|
|
pinTimerCh0 = 0 << 3
|
|
pinTimerCh2 = 1 << 3
|
|
pinTCC0Ch0 = pinTCC0 | pinTimerCh0
|
|
pinTCC0Ch2 = pinTCC0 | pinTimerCh2
|
|
pinTCC1Ch0 = pinTCC1 | pinTimerCh0
|
|
pinTCC1Ch2 = pinTCC1 | pinTimerCh2
|
|
pinTCC2Ch0 = pinTCC2 | pinTimerCh0
|
|
)
|
|
|
|
// Mapping from pin number to TCC peripheral and channel using a special
|
|
// encoding. Note that only TCC0-TCC2 are included, not TC3 and up.
|
|
// Every byte is split in two nibbles where the low nibble describes PinTCC and
|
|
// the high nibble describes PinTCCAlt. Within a nibble, there is one bit that
|
|
// indicates Ch0/Ch1 or Ch2/Ch3, and three other bits that contain the TCC
|
|
// peripheral number plus one (to distinguish between TCC0Ch0 and 0).
|
|
//
|
|
// The encoding can be so compact because all pins are configured in pairs, so
|
|
// if you know PA00 you can infer the configuration of PA01. And only channel 0
|
|
// or 2 need to be included (taking up just one bit), because channel 0 and 2
|
|
// are only ever used on odd pins and channel 1 and 3 on even pins, again using
|
|
// the pin pair pattern to reduce the amount of information needed to be stored.
|
|
//
|
|
// Datasheet: https://cdn.sparkfun.com/datasheets/Dev/Arduino/Boards/Atmel-42181-SAM-D21_Datasheet.pdf
|
|
var pinTimerMapping = [...]uint8{
|
|
// page 21
|
|
PA00 / 2: pinTCC2Ch0 | 0,
|
|
PA04 / 2: pinTCC0Ch0 | 0,
|
|
PA06 / 2: pinTCC1Ch0 | 0,
|
|
PA08 / 2: pinTCC0Ch0 | pinTCC1Ch2<<4,
|
|
PA10 / 2: pinTCC1Ch0 | pinTCC0Ch2<<4,
|
|
// page 22
|
|
PB10 / 2: 0 | pinTCC0Ch0<<4,
|
|
PB12 / 2: 0 | pinTCC0Ch2<<4,
|
|
PA12 / 2: pinTCC2Ch0 | pinTCC0Ch2<<4,
|
|
PA14 / 2: 0 | pinTCC0Ch0<<4,
|
|
PA16 / 2: pinTCC2Ch0 | pinTCC0Ch2<<4,
|
|
PA18 / 2: 0 | pinTCC0Ch2<<4,
|
|
PB16 / 2: 0 | pinTCC0Ch0<<4,
|
|
PA20 / 2: 0 | pinTCC0Ch2<<4,
|
|
PA22 / 2: 0 | pinTCC0Ch0<<4,
|
|
PA24 / 2: 0 | pinTCC1Ch2<<4,
|
|
// page 23
|
|
PA30 / 2: 0 | pinTCC1Ch0<<4,
|
|
PB30 / 2: pinTCC0Ch0 | pinTCC1Ch2<<4,
|
|
}
|
|
|
|
// findPinPadMapping returns the pin mode (PinTCC or PinTCCAlt) and the channel
|
|
// number for a given timer and pin. A zero PinMode is returned if no mapping
|
|
// could be found.
|
|
func findPinTimerMapping(timer uint8, pin Pin) (PinMode, uint8) {
|
|
mapping := pinTimerMapping[pin/2]
|
|
// evenChannel below indicates the channel 0 or 2, for the even part of the
|
|
// pin pair. The next pin will also have the next channel (1 or 3).
|
|
if mapping&0x07 == timer+1 {
|
|
// PWM output is on peripheral function E.
|
|
evenChannel := ((mapping >> 3) & 1) * 2
|
|
return PinTCC, evenChannel + uint8(pin&1)
|
|
}
|
|
if (mapping&0x70)>>4 == timer+1 {
|
|
// PWM output is on peripheral function F.
|
|
evenChannel := ((mapping >> 7) & 1) * 2
|
|
return PinTCCAlt, evenChannel + uint8(pin&1)
|
|
}
|
|
return 0, 0
|
|
}
|
|
|
|
// Channel returns a PWM channel for the given pin. Note that one channel may be
|
|
// shared between multiple pins, and so will have the same duty cycle. If this
|
|
// is not desirable, look for a different TCC peripheral or consider using a
|
|
// different pin.
|
|
func (tcc *TCC) Channel(pin Pin) (uint8, error) {
|
|
var pinMode PinMode
|
|
var channel uint8
|
|
switch tcc.timer() {
|
|
case sam.TCC0:
|
|
pinMode, channel = findPinTimerMapping(0, pin)
|
|
case sam.TCC1:
|
|
pinMode, channel = findPinTimerMapping(1, pin)
|
|
case sam.TCC2:
|
|
pinMode, channel = findPinTimerMapping(2, pin)
|
|
}
|
|
|
|
if pinMode == 0 {
|
|
// No pin could be found.
|
|
return 0, ErrInvalidOutputPin
|
|
}
|
|
|
|
// Enable the port multiplexer for pin
|
|
pin.setPinCfg(sam.PORT_PINCFG0_PMUXEN)
|
|
|
|
if pin&1 > 0 {
|
|
// odd pin, so save the even pins
|
|
val := pin.getPMux() & sam.PORT_PMUX0_PMUXE_Msk
|
|
pin.setPMux(val | uint8(pinMode<<sam.PORT_PMUX0_PMUXO_Pos))
|
|
} else {
|
|
// even pin, so save the odd pins
|
|
val := pin.getPMux() & sam.PORT_PMUX0_PMUXO_Msk
|
|
pin.setPMux(val | uint8(pinMode<<sam.PORT_PMUX0_PMUXE_Pos))
|
|
}
|
|
return channel, nil
|
|
}
|
|
|
|
// SetInverting sets whether to invert the output of this channel.
|
|
// Without inverting, a 25% duty cycle would mean the output is high for 25% of
|
|
// the time and low for the rest. Inverting flips the output as if a NOT gate
|
|
// was placed at the output, meaning that the output would be 25% low and 75%
|
|
// high with a duty cycle of 25%.
|
|
func (tcc *TCC) SetInverting(channel uint8, inverting bool) {
|
|
if inverting {
|
|
tcc.timer().WAVE.SetBits(1 << (sam.TCC_WAVE_POL0_Pos + channel))
|
|
} else {
|
|
tcc.timer().WAVE.ClearBits(1 << (sam.TCC_WAVE_POL0_Pos + channel))
|
|
}
|
|
|
|
// Wait for synchronization of the WAVE register.
|
|
for tcc.timer().SYNCBUSY.Get() != 0 {
|
|
}
|
|
}
|
|
|
|
// Set updates the channel value. This is used to control the channel duty
|
|
// cycle, in other words the fraction of time the channel output is high (or low
|
|
// when inverted). For example, to set it to a 25% duty cycle, use:
|
|
//
|
|
// tcc.Set(channel, tcc.Top() / 4)
|
|
//
|
|
// tcc.Set(channel, 0) will set the output to low and tcc.Set(channel,
|
|
// tcc.Top()) will set the output to high, assuming the output isn't inverted.
|
|
func (tcc *TCC) Set(channel uint8, value uint32) {
|
|
// Set PWM signal to output duty cycle
|
|
switch channel {
|
|
case 0:
|
|
tcc.timer().CC0.Set(value)
|
|
case 1:
|
|
tcc.timer().CC1.Set(value)
|
|
case 2:
|
|
tcc.timer().CC2.Set(value)
|
|
case 3:
|
|
tcc.timer().CC3.Set(value)
|
|
default:
|
|
// invalid PWM channel, ignore.
|
|
}
|
|
|
|
// Wait for synchronization on all channels (or anything in this peripheral,
|
|
// really).
|
|
for tcc.timer().SYNCBUSY.Get() != 0 {
|
|
}
|
|
}
|
|
|
|
// EnterBootloader should perform a system reset in preperation
|
|
// to switch to the bootloader to flash new firmware.
|
|
func EnterBootloader() {
|
|
arm.DisableInterrupts()
|
|
|
|
// Perform magic reset into bootloader, as mentioned in
|
|
// https://github.com/arduino/ArduinoCore-samd/issues/197
|
|
*(*uint32)(unsafe.Pointer(uintptr(0x20007FFC))) = RESET_MAGIC_VALUE
|
|
|
|
arm.SystemReset()
|
|
}
|
|
|
|
// DAC on the SAMD21.
|
|
type DAC struct {
|
|
}
|
|
|
|
var (
|
|
DAC0 = DAC{}
|
|
)
|
|
|
|
// DACConfig placeholder for future expansion.
|
|
type DACConfig struct {
|
|
}
|
|
|
|
// Configure the DAC.
|
|
// output pin must already be configured.
|
|
func (dac DAC) Configure(config DACConfig) {
|
|
// Turn on clock for DAC
|
|
sam.PM.APBCMASK.SetBits(sam.PM_APBCMASK_DAC_)
|
|
|
|
// Use Generic Clock Generator 0 as source for DAC.
|
|
sam.GCLK.CLKCTRL.Set((sam.GCLK_CLKCTRL_ID_DAC << sam.GCLK_CLKCTRL_ID_Pos) |
|
|
(sam.GCLK_CLKCTRL_GEN_GCLK0 << sam.GCLK_CLKCTRL_GEN_Pos) |
|
|
sam.GCLK_CLKCTRL_CLKEN)
|
|
waitForSync()
|
|
|
|
// reset DAC
|
|
sam.DAC.CTRLA.Set(sam.DAC_CTRLA_SWRST)
|
|
syncDAC()
|
|
|
|
// wait for reset complete
|
|
for sam.DAC.CTRLA.HasBits(sam.DAC_CTRLA_SWRST) {
|
|
}
|
|
|
|
// enable
|
|
sam.DAC.CTRLB.Set(sam.DAC_CTRLB_EOEN | sam.DAC_CTRLB_REFSEL_AVCC)
|
|
sam.DAC.CTRLA.Set(sam.DAC_CTRLA_ENABLE)
|
|
}
|
|
|
|
// Set writes a single 16-bit value to the DAC.
|
|
// Since the ATSAMD21 only has a 10-bit DAC, the passed-in value will be scaled down.
|
|
func (dac DAC) Set(value uint16) error {
|
|
sam.DAC.DATA.Set(value >> 6)
|
|
syncDAC()
|
|
return nil
|
|
}
|
|
|
|
func syncDAC() {
|
|
for sam.DAC.STATUS.HasBits(sam.DAC_STATUS_SYNCBUSY) {
|
|
}
|
|
}
|