GPIO Interrupt not triggering for FRDM-KL25z

MelonM — Fri, 17 Nov 2023 07:00:58 GMT

IMPORTANT: Updates at bottom of post

I'm trying to set up interrupts for pins 0,5, and 2 of Port D of my FRDM-KL25z. I want the interrupts to trigger on a falling edge. For testing purposes, I have written the ISR to turn on the Red LED, using code that wrote for a previous project (LED.c). Below is my main code file.

I've tried to execute the following steps to set up interrupts:

Use the NVIC_EnableIRQ function to enable interrupts from Port D
Configure pins 0,2,5 as GPIO inputs and to request interrupts on the falling edge
Write the PORTD_IRQHandler function to do something (in this case, turn on the red LED).

Unfortunately, the red LED is not turning on when I transition any of the pins from logical 1 to 0. I've confirmed that the pins are functioning as inputs through some code that I haven't included in this post, so I must conclude that I have done something incorrectly or that I have missed a step.

Main code file:

#include <stdio.h> #include "board.h" #include "peripherals.h" #include "pin_mux.h" #include "clock_config.h" #include "MKL25Z4.h" #include "fsl_debug_console.h" /* TODO: insert other include files here. */ #include "LED.h" /* TODO: insert other definitions and declarations here. */ /* * @brief Application entry point. */ const uint32_t INPUT_CONFIG = PORT_PCR_IRQC(1010) | // IRQ Falling Edge PORT_PCR_MUX(001) | // Pin set to GPIO PORT_PCR_DSE(0) | // Low drive strength PORT_PCR_PFE(0) | // TODO: Passive filter disabled, try enabling if noisy PORT_PCR_SRE(0) | // TODO: Fast slew rate, look up what slow would mean PORT_PCR_PE(0) | // Pull resistor is disabled PORT_PCR_PS(0); // Pull resistor is set to pulldown (but is still disabled) int main(void) { /* Init board hardware. */ BOARD_InitBootPins(); BOARD_InitBootClocks(); BOARD_InitBootPeripherals(); #ifndef BOARD_INIT_DEBUG_CONSOLE_PERIPHERAL /* Init FSL debug console. */ BOARD_InitDebugConsole(); #endif NVIC_EnableIRQ(PORTD_IRQn); // LED Initialization LED_Initialize(); LED_Off(); // Enable and setup 3 pins in PORTA SIM->SCGC5 |= SIM_SCGC5_PORTD_MASK; //Enable the clock to port D PORTD->PCR[5] = INPUT_CONFIG; //Setup PTD5 PORTD->PCR[0] = INPUT_CONFIG; //Setup PTD0 PORTD->PCR[2] = INPUT_CONFIG; //Setup PTD2 /* Force the counter to be placed into memory. */ volatile static int i = 0 ; /* Enter an infinite loop, just incrementing a counter. */ while(1) { i++ ; /* 'Dummy' NOP to allow source level single stepping of tight while() loop */ __asm volatile ("nop"); } return 0 ; } void PORTD_IRQHandler(void){ //TODO: USE ISFR to see which pin triggered the interrupt LEDRed_On(); //CLEAR INTERRUPT FLAG PORTD->ISFR = 0xFFFFFFFF; }

LED Utility Functions

#include <MKL25Z4.h> #include <LED.h> /*---------------------------------------------------------------------------- Function that initializes LEDs Note: You need to perform the following steps 1. Turn on the clock gating to the appropriate ports 2. Set the pin MUX to GPIO 3. Set the pin to output ----------------------------------------------------------------------------*/ void LED_Initialize(void){ //ENABLE RED LED SIM->SCGC5 |= (1 << 10); //Enable the clock to port B PORTB->PCR[18] = PORT_PCR_MUX(001); //Set up PTB18 as GPIO PTB->PDDR |= (1 << 18); //Set bit 18 of PDDR for Port B to 1 (Port data direction register) //ENABLE GREEN LED //clock is already enabled to port B, don't need to do it again PORTB->PCR[19] = PORT_PCR_MUX(001); //Set up PTB19 as GPIO PTB->PDDR |= (1 << 19); //Set bit 19 of PDDR for Port B to 1 (Port data direction register) //Enable Blue LED SIM->SCGC5 |= (1 << 12); //Enable the clock to port D PORTD->PCR[1] = PORT_PCR_MUX(001); //Set up PTD1 as GPIO PTD->PDDR |= (1 << 1); //Set bit 1 of PDDR for Port D to 1 (Port data direction register) } /*--------------------------------------------------------------------------- Three functions for toggling the current state of each LED individually ----------------------------------------------------------------------------*/ void LEDRed_Toggle(void){ if(((PTB->PDOR >> 18) & 0b1) == 1){ //If pin 18 of port B is 1, the LED is off LEDRed_On(); //so turn it on }else{ LEDRed_Off(); //else turn it off } } void LEDGreen_Toggle(void){ if(((PTB->PDOR >> 19) & 0b1) == 1){ //If pin 19 of port B is 1, the LED is off LEDGreen_On(); //so turn it on }else{ LEDGreen_Off(); //else turn it off } } void LEDBlue_Toggle(void){ if(((PTD->PDOR >> 1) & 0b1) == 1){ //If pin 1 of port D is 1, the LED is off LEDBlue_On(); //so turn it on }else{ LEDBlue_Off(); //else turn it off } } /*--------------------------------------------------------------------------- Three functions for toggling the turning ON LEDs individually ----------------------------------------------------------------------------*/ void LEDRed_On(void){ PTB->PCOR |= (1 << 18); //Turn on the red LED (Using PCOR because LED is active-low) } void LEDGreen_On(void){ PTB->PCOR |= (1 << 19); //Turn on the green LED (Using PCOR because LED is active-low) } void LEDBlue_On(void){ PTD->PCOR |= (1 << 1); //Turn on the blue LED (Using PCOR because LED is active-low) } /*--------------------------------------------------------------------------- Three functions for toggling the turning OFF LEDs individually ----------------------------------------------------------------------------*/ void LEDRed_Off(void){ PTB->PSOR |= (1 << 18); //Turn off the red LED (Using PSOR because LED is active-low) } void LEDGreen_Off(void){ PTB->PSOR |= (1 << 19); //Turn off the green LED (Using PSOR because LED is active-low) } void LEDBlue_Off(void){ PTD->PSOR |= (1 << 1); //Turn on the blue LED (Using PSOR because LED is active-low) } /*--------------------------------------------------------------------------- One function turning OFF all 3 LEDs ----------------------------------------------------------------------------*/ void LED_Off(void){ LEDRed_Off(); LEDGreen_Off(); LEDBlue_Off(); }

UPDATE: I have confirmed that bits in Port D's ISFR are being set when pins 0,5, and 2 experience a falling edge. This makes me think that the problem lies how I have enabled Port D interrupts rather than how I have configured the pins. The program continues running as normal despite the interrupt flags not being cleared. It seems that PORTD_IRQHandler is never being called.

UPDATE 2: The interrupts do not seem to be reaching NVIC->ISPR register. Attached is a console screenshot showing this behavior.

Re: GPIO Interrupt not triggering for FRDM-KL25z

MelonM — Mon, 20 Nov 2023 02:10:54 GMT

I discovered the problem. In my declaration of the INPUT_CONFIG const, I wrote.

PORT_PCR_IRQC(1010)

I intended to have this value be binary, but I forgot to write indicate it as such. Replacing it with the below line fixed the issue.

PORT_PCR_IRQC(0b1010)

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