79 строки
2,1 КиБ
Go
79 строки
2,1 КиБ
Go
// +build stm32l4 stm32l5
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package machine
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import (
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"device/stm32"
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)
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// This variant of the GPIO input interrupt logic is for
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// chips with a larger number of interrupt channels (more
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// than fits in a single register).
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//
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// STM32 allows one interrupt source per pin number, with
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// the same pin number in different ports sharing a single
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// interrupt source (so PA0, PB0, PC0 all share). Only a
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// single physical pin can be connected to each interrupt
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// line.
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//
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// To call interrupt callbacks, we record here for each
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// pin number the callback and the actual associated pin.
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//
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// Callbacks for pin interrupt events
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var pinCallbacks [16]func(Pin)
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// The pin currently associated with interrupt callback
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// for a given slot.
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var interruptPins [16]Pin
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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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port := uint32(uint8(p) / 16)
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pin := uint8(p) % 16
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enableEXTIConfigRegisters()
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if callback == nil {
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stm32.EXTI.IMR1.ClearBits(1 << pin)
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pinCallbacks[pin] = nil
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return nil
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}
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if pinCallbacks[pin] != 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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// Set the callback now (before the interrupt is enabled) to avoid
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// possible race condition
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pinCallbacks[pin] = callback
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interruptPins[pin] = p
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crReg := getEXTIConfigRegister(pin)
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shift := (pin & 0x3) * 4
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crReg.ReplaceBits(port, 0xf, shift)
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if (change & PinRising) != 0 {
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stm32.EXTI.RTSR1.SetBits(1 << pin)
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}
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if (change & PinFalling) != 0 {
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stm32.EXTI.FTSR1.SetBits(1 << pin)
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}
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stm32.EXTI.IMR1.SetBits(1 << pin)
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intr := p.registerInterrupt()
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intr.SetPriority(0)
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intr.Enable()
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return nil
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}
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