RE: How to make rotary encoder work with nrf52832

jalan — Tue, 21 Oct 2025 18:34:08 GMT

Per the information, I modified the location of "nrf_drv_qdec_enable();" in the while loop. It still doesn't work. Please advise. Thanks.

#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>

#include "nrf.h"
#include "bsp.h"
#include "nrf_delay.h"
#include "nrf_drv_qdec.h"
#include "nrf_error.h"
#include "app_error.h"
#include "nordic_common.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

static volatile bool m_report_ready_flag = false;
static volatile uint32_t m_accdblread;
static volatile int32_t m_accread;
static int32_t m_total_position = 0;

static nrf_drv_qdec_config_t m_qdec_config = {
    .reportper          = 0x00,  // Adjust as needed (e.g., 10 samples per report)
    .sampleper          = 0x06,  // e.g., 8192 us (adjust as needed; 0x00=128us to 0x06=16384us)
    .psela              = 9,   // Change to your rotary encoder A pin 
    .pselb              = 10,   // Change to your rotary encoder B pin 
    .pselled            = NRF_QDEC_LED_NOT_CONNECTED,  // No LED for mechanical encoder
    .ledpre             = 0,   // No LED pre-time
    .ledpol             = NRF_QDEC_LEPOL_ACTIVE_HIGH,
    .dbfen              = false,  // Enable debouncing filter for mechanical encoder
    .sample_inten       = false, // Use report interrupts, not sample
    .interrupt_priority = 6
};


static void qdec_event_handler(nrf_drv_qdec_event_t event)
{
    if (event.type == NRF_QDEC_EVENT_REPORTRDY)
    {
        m_accdblread        = event.data.report.accdbl;
        m_accread           = event.data.report.acc;
        m_report_ready_flag = true;
        nrf_drv_qdec_disable(); // Do not disable QDEC for continuous operation
    }
}

int main(void)
{
    uint32_t err_code;

    err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();

    // Initialize hardware with custom config for real encoder
    err_code = nrf_drv_qdec_init(&m_qdec_config, qdec_event_handler);
    APP_ERROR_CHECK(err_code);


    //Configure pull-ups AFTER init (important for mechanical encoders without external pull-ups)
    nrf_gpio_cfg_input(9, NRF_GPIO_PIN_PULLUP);
    nrf_gpio_cfg_input(10, NRF_GPIO_PIN_PULLUP);



    NRF_LOG_INFO("pin A: %d", m_qdec_config.psela);
    NRF_LOG_FLUSH();
    NRF_LOG_INFO("pin B: %d", m_qdec_config.pselb);
    NRF_LOG_FLUSH();
    NRF_LOG_INFO("Sampling period: %d", m_qdec_config.sampleper);
    NRF_LOG_FLUSH();
    NRF_LOG_INFO("Report period: %d", m_qdec_config.reportper);
    NRF_LOG_FLUSH();

    NRF_LOG_INFO("QDEC with real rotary encoder started. Turn the encoder to see position updates.");
    NRF_LOG_FLUSH();

    while (true)
    {
        nrf_drv_qdec_enable();
        // Wait for a report
        while (! m_report_ready_flag)
        {
            __WFE();
        }

        // Check for double accumulation (should be 0 unless double resolution enabled)
        if (m_accdblread != 0)
        {
            NRF_LOG_WARNING("Double accumulation detected: %u", m_accdblread);
        }

        // Accumulate position
        m_total_position += m_accread;

        NRF_LOG_INFO("Report ready. Delta: %d, Total position: %d", (int)m_accread, (int)m_total_position);
        NRF_LOG_FLUSH();

        m_report_ready_flag = false;

        
    }
}

/** @} */

RE: How to make rotary encoder work with nrf52832

Kenneth — Thu, 16 Oct 2025 11:22:42 GMT

Hello,

I suggest to take a step back and use the example as-is first:
https://docs.nordicsemi.com/bundle/sdk_nrf5_v17.1.0/page/qdec_example.html

And it can always be a good idea to check the documentation on expected behavior:
https://docs.nordicsemi.com/bundle/ps_nrf52832/page/qdec.html

Edit: For new development I would also suggest to check out the nRF54L15 and the nRF connect sdk bare metal option:
https://www.nordicsemi.com/Products/Development-software/nRF-Connect-SDK/Bare-Metal-option-for-nRF54L-Series

Kenneth