nRF52832 disable SD to use ESB causes problems with timers or PPI

[Philip]

Hi all.

In our project we are using BLE, but at some point switch to ESB. The code below disables the SD, and sets up ESB which is then used from then on.

if(radio_switch_delay == 0)
                  {
                      start_esb = true;
                      ble_stack_stop();
                      if(!nrf_drv_clock_lfclk_is_running()) nrf_drv_clock_lfclk_request(NULL);
                      //Setup ESB
                      esb_init();
                  }

void ble_stack_stop(void)
{
    uint32_t err_code;

    err_code = nrf_sdh_disable_request();
    APP_ERROR_CHECK(err_code);

    ASSERT(!nrf_sdh_is_enabled());
}

This all works fine, and we are sending ESB messages. The first problem was that stopping the SD also stopped the lfclk, so we have to re-start it when we switch over.

There is a frequency counter also implemented, that uses Timer 1, Timer 2, and two PPI channels. This freq counter stops working after the SD is disabled.

Any idea in what was stopping the SD would impact timer 1/2 and or PPI?

Thanks

[Philip]

Update2 - The cause of the problem is not the SD being disabled, it is once ESB has been initialised.

nrf_ESB may be using some of the same peripherals

[Philip]

I think the problem was that ESB uses timer 2 and 3. So I changed my freq counter to use timer 4 instead of 2 and it works now. 

[ovrebekk]

Hi Philip

You are correct. On the nRF52832 the ESB library will use both TIMER2 and TIMER3, to fix a bug in earlier revisions of the nRF52832. 

On other devices only TIMER2 is used. 

Best regards
Torbjørn