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//go:build stm32l4 || stm32l5
package machine
import (
"device/stm32"
)
// This variant of the GPIO input interrupt logic is for
// chips with a larger number of interrupt channels (more
// than fits in a single register).
//
// STM32 allows one interrupt source per pin number, with
// the same pin number in different ports sharing a single
// interrupt source (so PA0, PB0, PC0 all share). Only a
// single physical pin can be connected to each interrupt
// line.
//
// To call interrupt callbacks, we record here for each
// pin number the callback and the actual associated pin.
//
// Callbacks for pin interrupt events
var pinCallbacks [16]func(Pin)
// The pin currently associated with interrupt callback
// for a given slot.
var interruptPins [16]Pin
// SetInterrupt sets an interrupt to be executed when a particular pin changes
// state. The pin should already be configured as an input, including a pull up
// or down if no external pull is provided.
//
// This call will replace a previously set callback on this pin. You can pass a
// nil func to unset the pin change interrupt. If you do so, the change
// parameter is ignored and can be set to any value (such as 0).
func (p Pin) SetInterrupt(change PinChange, callback func(Pin)) error {
port := uint32(uint8(p) / 16)
pin := uint8(p) % 16
enableEXTIConfigRegisters()
if callback == nil {
stm32.EXTI.IMR1.ClearBits(1 << pin)
pinCallbacks[pin] = nil
return nil
}
if pinCallbacks[pin] != nil {
// The pin was already configured.
// To properly re-configure a pin, unset it first and set a new
// configuration.
return ErrNoPinChangeChannel
}
// Set the callback now (before the interrupt is enabled) to avoid
// possible race condition
pinCallbacks[pin] = callback
interruptPins[pin] = p
crReg := getEXTIConfigRegister(pin)
shift := (pin & 0x3) * 4
crReg.ReplaceBits(port, 0xf, shift)
if (change & PinRising) != 0 {
stm32.EXTI.RTSR1.SetBits(1 << pin)
}
if (change & PinFalling) != 0 {
stm32.EXTI.FTSR1.SetBits(1 << pin)
}
stm32.EXTI.IMR1.SetBits(1 << pin)
intr := p.registerInterrupt()
intr.SetPriority(0)
intr.Enable()
return nil
}
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