Segmentation fault after enabling BLE stack

[miceuz]

I have my system working with softdevice compiled in but not enabled. System communicates with external chip using SPIM peripheral, everything is working fine until I enable the softdevice.

As soon as I issue

    ret_code_t err_code;
    err_code = nrf_sdh_enable_request();

the first spim_xfer ends with segmentation fault:

#0  0x000257ae in ?? ()
#1  <signal handler called>
#2  nrf_spim_event_clear (spim_event=NRF_SPIM_EVENT_END, p_reg=<optimized out>) at /home/miceuz/nrf/nRF5_SDK/modules/nrfx/hal/nrf_spim.h:517
#3  spim_xfer (flags=0, p_xfer_desc=0x2003ff9c, p_cb=0x20004220 <m_cb+44>, p_spim=<optimized out>) at /home/miceuz/nrf/nRF5_SDK/modules/nrfx/drivers/src/nrfx_spim.c:501
#4  nrfx_spim_xfer (p_instance=<optimized out>, p_xfer_desc=0x2003ff9c, flags=0) at /home/miceuz/nrf/nRF5_SDK/modules/nrfx/drivers/src/nrfx_spim.c:607
#5  0x0000000e in ?? ()
#6  0x000373b0 in _fini ()

I am sure I am missing something simple here, but I can't remember what. Any tips?

[miceuz]

Thanks a lot, Andreas. I am on the move today, but I will have more focus for this tomorrow. At one point in history I had BLE and SPIM working together. I will try and check.

[AndreasF]

Hi.

I've found something, but I have to look a bit more into it, in the mean time, is it possible for you to not use SPIM3? Use SPIM0/1/2 instead?

Best regards,

Andreas

[miceuz]

I am not sure - my design pretty much depends on use of SPIM3 because all the additional functionality it has - now I can fill my 40kb buffer completely with no CPU using hardware CS control, also I am using 16MHz - very cool functionality and doing it manually on lower frequency will severely impact my battery life and general design (which is nearing production at fast pace)

Did I stumble on some kind of undiscovered errata?

[miceuz]

Hi Andreas,

I have looked into my code history - indeed, last time SPI and BLE was working together I have used SPI driver, not SPIM and I have used SPI instance 0.

I have tried running the same segfault example I have posted before changing SPIM instance from 3 to 1 and it worked flawlessly.

So yes, I can confirm, SoftDevice has problems working together with SPIM3.

SPIM3 is pretty critical for our application as I have mentioned in previous post. Please let me know how I could be of assistance in solving this issue.

[AndreasF]

Hi.

I have found the same results as you and reported it to the SDK team.

In the mean time, I think I have a workaround hack that solves the problem somehow:

In your main.c file:

void spi_write() {
    ret_code_t error_code2;
	m_tx_buf[0] = 0x42;
	m_tx_buf[1] = 0x42;
	nrfx_spim_xfer_desc_t xfer = NRFX_SPIM_SINGLE_XFER(m_tx_buf, 2, m_rx_buf, 2);
	error_code2 = nrfx_spim_xfer(&spim, &xfer, 0);
    APP_ERROR_CHECK(error_code2);
}

void app_mwu_enable(void)
{
  NRF_MWU->REGIONENSET
    = ((MWU_REGIONENSET_RGN0WA_Set << MWU_REGIONENSET_RGN0WA_Pos) | (MWU_REGIONENSET_PRGN0WA_Set << MWU_REGIONENSET_PRGN0WA_Pos));
}

void app_mwu_disable(void)
{
  NRF_MWU->REGIONENCLR
    = ((MWU_REGIONENCLR_RGN0WA_Clear << MWU_REGIONENCLR_RGN0WA_Pos) | (MWU_REGIONENCLR_PRGN0WA_Clear << MWU_REGIONENCLR_PRGN0WA_Pos));
}



int main(void) {

    power_management_init();
    log_init();
    NRF_LOG_INFO("Hello");
	ble_stack_init();
    app_mwu_disable();
    spi_init();
    spi_write();
    app_mwu_enable();
    while(1) {
	    NRF_LOG_INFO("I am fine");
        idle_state_handle();
    }
}

The problem with Invalid Access Memory was that an area protected by the memory watch unit is attempting to be written to when nrfx_spim_xfer() is called. I've avoided the error by disabling the memory watch unit before calling any SPIM related API calls, and enabling it afterwards.

Could this help you perhaps?

Best regards,

Andreas