NRF52832 Bluetooth UART and RTC2

[L.B.]

Hello everyone,

I've been struggling to use the Bluetooth UART example and the RTC2 module but so far I haven't succeeded.

Either I have Bluetooth, or RTC2, but not both. Here is how I've modified the UART example code:

void RTC2_IRQHandler(void){
    if(NRF_RTC2->EVENTS_COMPARE[0]){
        NRF_RTC2->EVENTS_COMPARE[0] = 0;
        NRF_RTC2->TASKS_CLEAR = 1;
	nrf_gpio_pin_toggle(22);
    }
}

/**@brief Application main function.
 */
int main(void)
{
    bool erase_bonds;

    // Initialize.
    uart_init();
    log_init();
    timers_init();
    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();

    // Start execution.
    printf("\r\nUART started.\r\n");
    NRF_LOG_INFO("Debug logging for UART over RTT started.");
    advertising_start();

    nrf_gpio_cfg_output(22);	
 
/*  This code alone works, but when added here
    it doesn't!

    NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
    NRF_CLOCK->LFCLKSRC = 0x00; 
    NRF_CLOCK->TASKS_LFCLKSTART = 1;
    while(NRF_CLOCK->EVENTS_LFCLKSTARTED == 0);
    NRF_RTC2->PRESCALER = 0xFFF;
    NRF_RTC2->EVTENSET = RTC_EVTENSET_COMPARE0_Msk;
    NRF_RTC2->INTENSET = RTC_INTENSET_COMPARE0_Msk;
    NRF_RTC2->TASKS_CLEAR = 1;
    NRF_RTC2->TASKS_START = 1;
    NRF_RTC2->CC[0] = 8 * 1;
    NVIC_SetPriority(RTC2_IRQn, 3);
    NVIC_ClearPendingIRQ(RTC2_IRQn);
    NVIC_EnableIRQ(RTC2_IRQn);
*/



    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

I'm using nRF5_SDK_17.0.0_9d13099

Thank you in advance.

L. B.

[Jared]

Hi,

Not sure what you did wrong when you tried to merge it, but I've attached an example that has merged ble_app_uart together with the RTC example. I've tested it and verified that it works successfully. Notice that it uses LED 3 and 4 instead of 1 and 2 as in the original example, this is because they are already in use in the ble_app_uart example.

Cheers

Jared

ble_app_uart_rtc.7z

[L.B.]

OK, I will try this code later in the week /I'm out of office now/ and will write back to you with the result.

However, I suspect that if you:

- wait a few seconds,

- then do sd_softdevice_disable()

- wait some more seconds

- and then try to enable the bluetooth again

it might not work.

Regards,

L. B.

[L.B.]

Hi, again! You're code works, indeed, I have to enable the RTC2 before the Bluetooth.

Note, however, that in order to stop and start the Bluetooth again, one must use

sd_softdevice_disable();

to stop it, then this procedure to start it:

    ret_code_t err;

    const nrf_clock_lf_cfg_t sd_lf_config =
    {
    .source       = NRF_SDH_CLOCK_LF_SRC,
    .rc_ctiv      = NRF_SDH_CLOCK_LF_RC_CTIV,
    .rc_temp_ctiv = NRF_SDH_CLOCK_LF_RC_TEMP_CTIV,
    .accuracy     = NRF_SDH_CLOCK_LF_ACCURACY
    };

    err = sd_softdevice_enable(&sd_lf_config, fault_handler);
    APP_ERROR_CHECK(err);

    // Configure the BLE stack using the default settings.
    // Fetch the start address of the application RAM.
    uint32_t ram_start = 0;
    err = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
    APP_ERROR_CHECK(err);

    // Enable BLE stack.
    err = nrf_sdh_ble_enable(&ram_start);
    APP_ERROR_CHECK(err);

    advertising_start();

So, here is an example program that will turn on the Bluetooth for 7 seconds, then turn it off for another 7 seconds, then turn it on again. During all this time, the RTC2 will remain operational.

const nrf_drv_rtc_t rtc = NRF_DRV_RTC_INSTANCE(2); /**< Declaring an instance of nrf_drv_rtc for RTC2. */

#define COMPARE_COUNTERTIME  (3UL)

/** @brief: Function for handling the RTC2 interrupts.
 * Triggered on TICK and COMPARE0 match.
 */
static void rtc_handler(nrf_drv_rtc_int_type_t int_type)
{
    if (int_type == NRF_DRV_RTC_INT_COMPARE0)
    {
        nrf_gpio_pin_toggle(22);
    }
    else if (int_type == NRF_DRV_RTC_INT_TICK)
    {
    	nrf_gpio_pin_toggle(22);
    }
}

/** @brief Function starting the internal LFCLK XTAL oscillator.
 */
static void lfclk_config(void)
{
    ret_code_t err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_clock_lfclk_request(NULL);
}

/** @brief Function initialization and configuration of RTC driver instance.
 */
static void rtc_config(void)
{
    uint32_t err_code;

    //Initialize RTC instance
    nrf_drv_rtc_config_t config = NRF_DRV_RTC_DEFAULT_CONFIG;
    config.prescaler = 4095;
    err_code = nrf_drv_rtc_init(&rtc, &config, rtc_handler);
    APP_ERROR_CHECK(err_code);

    //Enable tick event & interrupt
    nrf_drv_rtc_tick_enable(&rtc,true);

    //Set compare channel to trigger interrupt after COMPARE_COUNTERTIME seconds
    err_code = nrf_drv_rtc_cc_set(&rtc,0,COMPARE_COUNTERTIME * 8,true);
    APP_ERROR_CHECK(err_code);

    //Power on RTC instance
    nrf_drv_rtc_enable(&rtc);
}

void fault_handler(uint32_t id, uint32_t pc, uint32_t info){

}

/**@brief Application main function.
 */
int main(void)
{
	volatile int i = 0;
    bool erase_bonds;

    lfclk_config();
    rtc_config();

    // Initialize.
    uart_init();
    log_init();
    timers_init();
    buttons_leds_init(&erase_bonds);
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();

    nrf_gpio_cfg_output(22);

    // Start execution.
    printf("\r\nUART started.\r\n");
    NRF_LOG_INFO("Debug logging for UART over RTT started.");

    advertising_start();

    nrf_delay_ms(7000);

    sd_softdevice_disable();

    nrf_delay_ms(7000);

    ret_code_t err;

    const nrf_clock_lf_cfg_t sd_lf_config =
    {
    .source       = NRF_SDH_CLOCK_LF_SRC,
    .rc_ctiv      = NRF_SDH_CLOCK_LF_RC_CTIV,
    .rc_temp_ctiv = NRF_SDH_CLOCK_LF_RC_TEMP_CTIV,
    .accuracy     = NRF_SDH_CLOCK_LF_ACCURACY
    };

    err = sd_softdevice_enable(&sd_lf_config, fault_handler);
    APP_ERROR_CHECK(err);

    // Configure the BLE stack using the default settings.
    // Fetch the start address of the application RAM.
    uint32_t ram_start = 0;
    err = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
    APP_ERROR_CHECK(err);

    // Enable BLE stack.
    err = nrf_sdh_ble_enable(&ram_start);
    APP_ERROR_CHECK(err);

    advertising_start();

    // Enter main loop.
    for (;;)
    {
       idle_state_handle();
    }
}

Note: this code is not low-power because the UART is also working. If you don't need it, turn it off.

Hope that this will help other folks in the forum.

Thank you for your help, Jared!

L. B.