turning off qdec led

RE: turning off qdec led

Erik — Tue, 25 Sep 2018 12:39:28 GMT

Note, if you are using the nrf_drv_qdec driver in SDK 12 (at least) you can NOT set the LED-pin to 0xFFFFFFFF! (you may do that for the psel.led register directly, but not when using the driver)

This will in best case end up in an assert in nrf_gpio_pin_port_decode(), in worst case if assert is not enabled it will actually write to reg->PIN_CNF[0xFFFFFFFF] which is way out of range..

This happens because nrf_drv_qdec_init calls:

nrf_gpio_cfg_input(p_config->pselled, NRF_GPIO_PIN_NOPULL);

----> nrf_gpio_cfg(pin_number, ...)
{
    NRF_GPIO_Type * reg = nrf_gpio_pin_port_decode(&pin_number);
    reg->PIN_CNF[pin_number] = .... // pin_number = 0xFFFFFFFF

RE: turning off qdec led

Ole Bauck — Wed, 10 Aug 2016 12:20:02 GMT

You can set the pin to 0xFFFFFFFF.

When using the default configuration (nrf_drv_qdec_init(NULL, qdec_event_handler)) you can set the default pin in nrf_drv_config.h:

#define QDEC_CONFIG_PIO_LED 0xFFFFFFFF

When using your own config:

nrf_drv_qdec_config_t qdec_config;
qdec_config.pselled = 0xFFFFFFFF;
...
nrf_drv_qdec_init(&qdec_config, qdec_event_handler)

RE: turning off qdec led

Øyvind Karlsen — Wed, 10 Aug 2016 12:10:52 GMT

Hi,

Like this

    nrf_drv_qdec_config_t qdec_cfg = 
    {
        .reportper = NRF_QDEC_REPORTPER_10,             /**< Report period in samples. */
        .sampleper = NRF_QDEC_SAMPLEPER_128us,         /**< Sampling period in microseconds. */
        .psela = GPIO_INPUT_A,                          /**< Pin number for A input. */
        .pselb = GPIO_INPUT_B,                          /**< Pin number for B input. */
        .pselled = GPIO_INPUT_LED,                      /**< Pin number for LED output. */
        .ledpre = 10,                                   /**< Time (in microseconds) how long LED is switched on before sampling. */
        .ledpol = 0,                                    /**< Active LED polarity. */
        .dbfen = false,                                 /**< State of debouncing filter. */
        .sample_inten = true,                           /**< Enabling sample ready interrupt. */
        .interrupt_priority = 3,                        /**< QDEC interrupt priority. */
    };
    
    err_code = nrf_drv_qdec_init(&qdec_cfg, qdec_event_handler);
    APP_ERROR_CHECK(err_code);
    
    // Needed for my quad enc. as I have no external pulls
    nrf_gpio_cfg_input(qdec_cfg.pselb,NRF_GPIO_PIN_PULLUP);
    nrf_gpio_cfg_input(qdec_cfg.psela,NRF_GPIO_PIN_PULLUP);
    nrf_drv_qdec_enable();
    
    while (true)
    {
        __WFI();
    }

Here you can set .pselled to whatever you like, for example disconnected.

Best regards,

Øyvind