4f4d7976c6
* machine/uart: add core support for multiple UARTs by allowing for multiple RingBuffers * machine/uart: complete core support for multiple UARTs * machine/uart: no need to store pointer to UART, better to treat like I2C and SPI * machine/uart: increase ring buffer size to 128 bytes * machine/uart: improve godocs comments and use comma-ok idiom for buffer Put/Get methods
96 строки
2,6 КиБ
Go
96 строки
2,6 КиБ
Go
// +build avr
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package machine
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import (
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"device/avr"
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)
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type GPIOMode uint8
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const (
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GPIO_INPUT = iota
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GPIO_OUTPUT
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)
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// Set changes the value of the GPIO pin. The pin must be configured as output.
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func (p GPIO) Set(value bool) {
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if value { // set bits
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port, mask := p.PortMaskSet()
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*port = mask
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} else { // clear bits
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port, mask := p.PortMaskClear()
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*port = mask
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}
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}
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// Return the register and mask to enable a given GPIO pin. This can be used to
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// implement bit-banged drivers.
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//
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// Warning: there are no separate pin set/clear registers on the AVR. The
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// returned mask is only valid as long as no other pin in the same port has been
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// changed.
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func (p GPIO) PortMaskSet() (*avr.RegValue, avr.RegValue) {
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port, mask := p.getPortMask()
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return port, *port | avr.RegValue(mask)
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}
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// Return the register and mask to disable a given port. This can be used to
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// implement bit-banged drivers.
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//
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// Warning: there are no separate pin set/clear registers on the AVR. The
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// returned mask is only valid as long as no other pin in the same port has been
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// changed.
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func (p GPIO) PortMaskClear() (*avr.RegValue, avr.RegValue) {
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port, mask := p.getPortMask()
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return port, *port &^ avr.RegValue(mask)
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}
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// InitADC initializes the registers needed for ADC.
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func InitADC() {
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// set a2d prescaler so we are inside the desired 50-200 KHz range at 16MHz.
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*avr.ADCSRA |= (avr.ADCSRA_ADPS2 | avr.ADCSRA_ADPS1 | avr.ADCSRA_ADPS0)
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// enable a2d conversions
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*avr.ADCSRA |= avr.ADCSRA_ADEN
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}
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// Configure configures a ADCPin to be able to be used to read data.
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func (a ADC) Configure() {
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return // no pin specific setup on AVR machine.
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}
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// Get returns the current value of a ADC pin, in the range 0..0xffff. The AVR
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// has an ADC of 10 bits precision so the lower 6 bits will be zero.
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func (a ADC) Get() uint16 {
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// set the analog reference (high two bits of ADMUX) and select the
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// channel (low 4 bits), masked to only turn on one ADC at a time.
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// set the ADLAR bit (left-adjusted result) to get a value scaled to 16
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// bits. This has the same effect as shifting the return value left by 6
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// bits.
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*avr.ADMUX = avr.RegValue(avr.ADMUX_REFS0 | avr.ADMUX_ADLAR | (a.Pin & 0x07))
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// start the conversion
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*avr.ADCSRA |= avr.ADCSRA_ADSC
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// ADSC is cleared when the conversion finishes
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for ok := true; ok; ok = (*avr.ADCSRA & avr.ADCSRA_ADSC) > 0 {
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}
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low := uint16(*avr.ADCL)
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high := uint16(*avr.ADCH)
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return uint16(low) | uint16(high<<8)
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}
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// I2C on AVR.
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type I2C struct {
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}
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// I2C0 is the only I2C interface on most AVRs.
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var I2C0 = I2C{}
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// UART
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var (
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// UART0 is the hardware serial port on the AVR.
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UART0 = UART{Buffer: NewRingBuffer()}
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)
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