NRFX_ERROR_INVALID_PARAM error on nrfx_timer_init with

[Julian1999]

I'm trying too use a timer as a counter on my nRF52840.
This is the function in question:

static void timer_init(void)

{

    nrfx_timer_config_t timer_cfg = {

        .mode      = NRF_TIMER_MODE_COUNTER,

        .bit_width = NRF_TIMER_BIT_WIDTH_32,

        .frequency = NRF_TIMER_FREQ_1MHz,  

        .interrupt_priority = NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,

        .p_context = NULL

    };

    nrfx_err_t err = nrfx_timer_init(&timer, &timer_cfg, NULL);

    if (err != NRFX_SUCCESS) {

        printk("Timer init failed: %d\n", err);

        return;

    }

    nrfx_timer_enable(&timer);

}

I have tried all frequencies and I get NRFX_ERROR_INVALID_PARAM with all of them expect for NRF_TIMER_FREQ_16MHz where I get:

[00:00:00.027,954] <err> os: ***** USAGE FAULT ***** [00:00:00.027,984] <err> os: Division by zero [00:00:00.028,015] <err> os: r0/a1: 0x0005223c r1/a2: 0x2000e12c r2/a3: 0x00f42400 [00:00:00.028,015] <err> os: r3/a4: 0x00000003 r12/ip: 0x00000000 r14/lr: 0x0003e1ef [00:00:00.028,045] <err> os: xpsr: 0x61000000 [00:00:00.028,045] <err> os: Faulting instruction address (r15/pc): 0x0003e106 [00:00:00.028,076] <err> os: >>> ZEPHYR FATAL ERROR 30: Unknown error on CPU 0 [00:00:00.028,137] <err> os: Current thread: 0x20006aa0 (main)

On line 86 of the nrfx_timer.c

I'm on nRF Connect SDK V3.0.2

[Thomas_E]

What does your timer variable initialization look like ?

[Julian1999]

Hi Thomas,
This is my current code including the timer variable initialization:

#include <zephyr/kernel.h>
#include <nrfx_gpiote.h>
#include <nrfx_timer.h>
#include <nrfx_ppi.h>
#include <zephyr/sys/printk.h>
#include <zephyr/drivers/gpio.h>
#include "encoder_handler.h"

#define PIN_A 28
#define PIN_B 29
#define GPIOTE_INSTANCE_IDX 0

// TIMER instance for counting
#define TIMER_INSTANCE 2
static const nrfx_timer_t timer = NRFX_TIMER_INSTANCE(TIMER_INSTANCE);

// PPI channels
static uint8_t ppi_ch_a;
static uint8_t ppi_ch_b;

// Encoder power pin from DeviceTree
#define ENCODER_POWER_NODE DT_ALIAS(encoder_power)
static const struct gpio_dt_spec encoder_power = GPIO_DT_SPEC_GET(ENCODER_POWER_NODE, gpios);

// Forward declaration of helper ISR
static void encoder_dir_isr(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action);

/**
 * @brief Initialize TIMER in COUNTER mode
 */
static void timer_init(void)
{
    nrfx_timer_config_t timer_cfg = {
        .mode      = NRF_TIMER_MODE_COUNTER,
        .bit_width = NRF_TIMER_BIT_WIDTH_32,
        .frequency = NRF_TIMER_FREQ_1MHz,  
        .interrupt_priority = NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,
        .p_context = NULL
    };
    nrfx_err_t err = nrfx_timer_init(&timer, &timer_cfg, NULL);
    if (err != NRFX_SUCCESS) {
        printk("Timer init failed: %d\n", err);
        return;
    }
    nrfx_timer_enable(&timer);
}

/**
 * @brief Initialize GPIOTE pins
 * Pin A and B generate events, sampled in ISR to determine direction
 */
static void gpiote_init(void)
{
    static const nrfx_gpiote_t pio_instance = NRFX_GPIOTE_INSTANCE(GPIOTE_INSTANCE_IDX);

    if (!nrfx_gpiote_init_check(&pio_instance)) {
        nrfx_err_t err = nrfx_gpiote_init(&pio_instance, NRFX_GPIOTE_DEFAULT_CONFIG_IRQ_PRIORITY);
        // Optionally handle error here
    }

    static const nrf_gpio_pin_pull_t pull_config = NRF_GPIO_PIN_PULLUP;
    static const nrfx_gpiote_trigger_config_t trigger_config = {
        .trigger = NRFX_GPIOTE_TRIGGER_TOGGLE,
        .p_in_channel = NULL, // Not needed for simple input
    };
    static const nrfx_gpiote_handler_config_t handler_config = {
        .handler = encoder_dir_isr,
    };
    nrfx_gpiote_input_pin_config_t input_pin_cfg = {
        .p_pull_config = &pull_config,
        .p_trigger_config = &trigger_config,
        .p_handler_config = &handler_config,
    };

    nrfx_gpiote_input_configure(&pio_instance, PIN_A, &input_pin_cfg);
    nrfx_gpiote_trigger_enable(&pio_instance, PIN_A, true);

    // For PIN_B, no handler needed
    nrfx_gpiote_input_pin_config_t input_pin_cfg_b = {
        .p_pull_config = &pull_config,
        .p_trigger_config = &trigger_config,
        .p_handler_config = NULL,
    };
    nrfx_gpiote_input_configure(&pio_instance, PIN_B, &input_pin_cfg_b);
    nrfx_gpiote_trigger_enable(&pio_instance, PIN_B, true);
}

/**
 * @brief Configure PPI: Link A/B pins to TIMER
 */
static void ppi_init(void)
{
    static const nrfx_gpiote_t pio_instance = NRFX_GPIOTE_INSTANCE(GPIOTE_INSTANCE_IDX);

    // Allocate PPI channels
    if (nrfx_ppi_channel_alloc(&ppi_ch_a) != NRFX_SUCCESS) {
        printk("PPI channel A allocation failed!\n");
    }
    if (nrfx_ppi_channel_alloc(&ppi_ch_b) != NRFX_SUCCESS) {
        printk("PPI channel B allocation failed!\n");
    }

    // Connect PIN_A event to TIMER count task
    nrfx_ppi_channel_assign(ppi_ch_a,
        nrfx_gpiote_in_event_address_get(&pio_instance, PIN_A),
        nrfx_timer_task_address_get(&timer, NRF_TIMER_TASK_COUNT));

    // Connect PIN_B event to TIMER count task
    nrfx_ppi_channel_assign(ppi_ch_b,
        nrfx_gpiote_in_event_address_get(&pio_instance, PIN_B),
        nrfx_timer_task_address_get(&timer, NRF_TIMER_TASK_COUNT));

    nrfx_ppi_channel_enable(ppi_ch_a);
    nrfx_ppi_channel_enable(ppi_ch_b);
}

/**
 * @brief Lightweight ISR for determining direction on PIN_A toggle
 * Increments/decrements TIMER via software if needed for direction
 */
static void encoder_dir_isr(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
    bool a_state = nrf_gpio_pin_read(PIN_A);
    bool b_state = nrf_gpio_pin_read(PIN_B);

    // Software correction for direction:
    if ((a_state && !b_state) || (!a_state && b_state)) {
        nrfx_timer_clear(&timer);
    }
}

/**
 * @brief Initialize encoder hardware
 */
int encoder_init(void)
{
    if (!device_is_ready(encoder_power.port)) {
        printk("Encoder power GPIO device not ready!\n");
        return -1;
    }

    gpio_pin_configure_dt(&encoder_power, GPIO_OUTPUT_ACTIVE);
    k_msleep(10); // allow power-up

    timer_init();
    gpiote_init();
    ppi_init();

    printk("Quadrature encoder initialized (GPIOTE + PPI + TIMER)\n");
    return 0;
}

/**
 * @brief Get current encoder count
 */
int32_t encoder_get_count(void)
{
    uint32_t count;
    nrfx_timer_capture(&timer, NRF_TIMER_CC_CHANNEL0); // capture value
    // nrfx_timer_clear(&timer); 
    nrfx_timer_capture_get(&timer, NRF_TIMER_CC_CHANNEL0);
    count = nrfx_timer_capture_get(&timer, NRF_TIMER_CC_CHANNEL0);
    return (int32_t)count;
}

/**
 * @brief Reset encoder count
 */
void encoder_reset_count(void)
{
    nrfx_timer_clear(&timer);
}

[Julian1999]

I got it working like this:

    nrfx_timer_config_t timer_cfg = NRFX_TIMER_DEFAULT_CONFIG(0);

    timer_cfg.mode = NRF_TIMER_MODE_COUNTER;

    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;

    if (nrfx_timer_init(&timer, &timer_cfg, NULL) != NRFX_SUCCESS) {

        printk("Timer init failed!\n");

        return;

    }