NRF52832 Bluetooth UART and RTC2

RE: NRF52832 Bluetooth UART and RTC2

L.B. — Thu, 29 Apr 2021 14:06:59 GMT

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.

RE: NRF52832 Bluetooth UART and RTC2

L.B. — Tue, 27 Apr 2021 18:35:04 GMT

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.

RE: NRF52832 Bluetooth UART and RTC2

Jared — Tue, 27 Apr 2021 14:13:30 GMT

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

devzone.nordicsemi.com/.../ble_5F00_app_5F00_uart_5F00_rtc.7z

RE: NRF52832 Bluetooth UART and RTC2

L.B. — Mon, 26 Apr 2021 12:17:32 GMT

Actually this is where the problem started from - I tried merging

examples/ble_peripheral/ble_app_uart

and

examples/peripheral/rtc

But it didn't work - I can see no RTC2 and no Bluetooth. For example this code builds but doesn't work:

#define COMPARE_COUNTERTIME 1
const nrf_drv_rtc_t rtc = NRF_DRV_RTC_INSTANCE(2);

static void rtc_handler(nrf_drv_rtc_int_type_t int_type)
{
	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);
}

//!!!!!! THIS CODE DOESN'T WORK!!!!!!

/**@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);	

    lfclk_config();
    rtc_config();

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

I'm trying to achieve a very simple task - I want to be able to turn off and on the Bluetooth on demand, and I want at the same time an RTC to keep track of time (my application needs it) all the time. If you think I'm on the wrong track, please let me know ... maybe I'm not doing it right.

Regards,

L. B.

RE: NRF52832 Bluetooth UART and RTC2

Jared — Mon, 26 Apr 2021 11:26:23 GMT

Hi,

Instead of writing directly to the peripheral. Can you try to use our RTC driver? It will take into consideration if the Softdevice is present and enabled. See the RTC example if you want an example on how to use the driver.

regards

Jared

RE: NRF52832 Bluetooth UART and RTC2

L.B. — Fri, 23 Apr 2021 13:43:27 GMT

It did not work, neither with 6 nor with 7. I'm turning off the Bluetooth with sd_softdevice_disable( ) btw ... This way I can achieve 2 - 3 uA IDLE state + RTC2.

RE: NRF52832 Bluetooth UART and RTC2

Jared — Fri, 23 Apr 2021 13:40:32 GMT

Hi,

Could you try decreasing the priority to 6 or 7?

regards

Jared

RE: NRF52832 Bluetooth UART and RTC2

L.B. — Fri, 23 Apr 2021 08:47:55 GMT

Hello again!

I've just discovered, that if I comment out the RC oscillator initialization, the code works.

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);	
 

/*  Works without this one
    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();
    }
}

However I cannot turn on and off the Bluetooth. Basically I want the RTC2 to work always, and just turn on and off the Bluetooth at specific periods.

Regards,

L. B.