pw_digital_io_mcuxpresso#

Digital I/O for NXP MCUXpresso

Stable C++

pw_digital_io_mcuxpresso implements the pw_digital_io interface using the NXP MCUXpresso SDK.

Overview#

This module consists of these main classes:

Setup#

Use of this module requires setting up the MCUXpresso SDK for use with Pigweed. Follow the steps in pw_build_mcuxpresso to create a pw_source_set for an MCUXpresso SDK. Include the GPIO and PINT driver components in this SDK definition.

Examples#

Digital input#

Use McuxpressoDigitalIn to read the state of an input.

Example code to use GPIO pins from an NXP SDK board definition:

#include "board/pin_mux.h"
#include "pw_digital_io_mcuxpresso/digital_io.h"

McuxpressoDigitalIn input(BOARD_INITPINS_D9_GPIO,
                          BOARD_INITPINS_D9_PORT,
                          BOARD_INITPINS_D9_PIN);

Status Init() { return input.Enable(); }

Status InputExample() {
  PW_TRY_ASSIGN(const DigitalIo::State state, input.GetState());
  // ...
}

Digital output#

Use McuxpressoDigitalOut to set the state of an output.

Example code to use GPIO pins from an NXP SDK board definition:

#include "board/pin_mux.h"
#include "pw_digital_io_mcuxpresso/digital_io.h"
#include "pw_status/status.h"

McuxpressoDigitalOut output(BOARD_INITPINS_D8_GPIO,
                            BOARD_INITPINS_D8_PORT,
                            BOARD_INITPINS_D8_PIN,
                            pw::digital_io::State::kActive);

Status Init() { return output.Enable(); }

Status OutputExample() {
  return output.SetState(pw::digital_io::State::kInactive);
}

GPIO interrupt#

Use McuxpressoDigitalInOutInterrupt to handle interrupts via the GPIO module.

Example code to use GPIO pins from an NXP SDK board definition:

#include "board/pin_mux.h"
#include "pw_digital_io_mcuxpresso/digital_io.h"
#include "pw_status/status.h"

McuxpressoDigitalInOutInterrupt irq_pin(BOARD_INITPINS_D9_GPIO,
                                        BOARD_INITPINS_D9_PORT,
                                        BOARD_INITPINS_D9_PIN,
                                        /* output= */ false);

Status Init() {
  PW_TRY(irq_pin.Enable());
  PW_TRY(irq_pin.SetInterruptHandler(
      pw::digital_io::InterruptTrigger::kDeactivatingEdge,
      [](State /* state */) { irq_count++; }));
  PW_TRY(irq_pin.EnableInterruptHandler());
  return OkStatus();
}

PINT interrupt#

pw::digital_io::McuxpressoPintInterrupt can also be used to handle interrupts, via the PINT module, which supports other features:

  • Dedicated (non-shared) IRQs for each interrupt

  • Double edge detection (InterruptTrigger::kBothEdges)

  • Waking from deep sleep with edge detection

  • Pattern matching support (currently unsupported here)

  • Triggering interrupts on pins configured for a non-GPIO function

It must be used with an instance of McuxpressoPintController.

#include "pw_digital_io_mcuxpresso/pint.h"
#include "pw_sync/interrupt_spin_lock.h"

McuxpressoPintController raw_pint_controller(PINT);

pw::sync::VirtualInterruptSpinLock controller_lock;

pw::sync::Borrowable<McuxpressoPintController> pint_controller(
    raw_pint_controller, controller_lock);

McuxpressoPintInterrupt irq_line0(pint_controller, kPINT_PinInt0);

Status Init() {
  // Attach pin PIO0_4 to PINT interrupt 0.
  INPUTMUX_AttachSignal(
      INPUTMUX, kPINT_PinInt0, kINPUTMUX_GpioPort0Pin4ToPintsel);

  PW_TRY(irq_line0.Enable());
  PW_TRY(irq_line0.SetInterruptHandler(
      pw::digital_io::InterruptTrigger::kBothEdges,
      [](State /* state */) { irq_count++; }));
  PW_TRY(irq_line0.EnableInterruptHandler());
  return OkStatus();
}

API reference#

Moved: pw_digital_io_mcuxpresso

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