Is it possible to use the UART without the Soft Device?

RE: Is it possible to use the UART without the Soft Device?

Eliot Stock — Thu, 10 Apr 2014 11:42:27 GMT

A couple of further issues here:

I actually found this only works without the call to __WFI(). Those seem to block forever for me, at least while debugging. Can't get my head around what's actually happening with the interrupts.
I'm also doing some stuff with timers and can caught by an issue where when you're not using the Soft Device, you have to explicitly start the RTC. See my older post about that here: https://devzone.nordicsemi.com/index.php/timer-handler-never-called

RE: Is it possible to use the UART without the Soft Device?

Eliot Stock — Wed, 09 Apr 2014 00:48:33 GMT

It's working just fine now, without me having changed anything, which isn't much help in figuring out what the issue was. Thanks for your help.

RE: Is it possible to use the UART without the Soft Device?

Ulrich Myhre — Tue, 08 Apr 2014 22:27:50 GMT

In what way do you initialize the app_uart? Are interrupts enabled in that routine? Is the UART0_IRQHandler ever called? Does it work without the WFI instruction?

I'm on thin ice here, since I haven't used the app_uart library that much. I see that the default app_uart_init() enables interrupt for the RX, TX and ERROR events, and this should wake up the CPU. There's some additional information to be found in this thread: https://devzone.nordicsemi.com/index.php/how-to-make-the-cpu-to-sleep-module-by-the-uart-interrupt

RE: Is it possible to use the UART without the Soft Device?

Eliot Stock — Tue, 08 Apr 2014 20:33:25 GMT

Thanks again. I now seem to be stuck at the __WFI() call in this loop when reading from the UART:

do
{
    err_code = app_uart_get(&amp;ch);
    
    if (NRF_ERROR_NOT_FOUND == err_code)
    {

#ifdef USE_SOFTDEVICE sd_app_evt_wait(); #else __WFI(); #endif } else if (NRF_SUCCESS == err_code) { response[i++] = ch; } else { APP_ERROR_CHECK(err_code); }

    ended = gsm_response_ended((char *)response);
}
while (!ended);

Also the timer that should make gsm_response_ended() return true eventually even if the peripheral stays quiet is never getting its timeout handler called. Any ideas?

RE: Is it possible to use the UART without the Soft Device?

Ulrich Myhre — Tue, 08 Apr 2014 19:54:07 GMT

__WFI();

RE: Is it possible to use the UART without the Soft Device?

Eliot Stock — Tue, 08 Apr 2014 16:43:24 GMT

Thanks. I'm using the types in app_uart.h and want to keep using them, so I'll try copying app_common out of the SDK to an app_common_no_sd in my source tree and breaking the dependencies.

What's the non-SD equivalent to sd_app_evt_wait() though?

RE: Is it possible to use the UART without the Soft Device?

Ulrich Myhre — Tue, 08 Apr 2014 13:55:44 GMT

You could temporarily remove the CRITICAL_REGION_ENTER / EXIT fields from app_util to remove the dependency to nrf_error, but it's also possible to just access the peripherals directly using the same setup routine as found in app_uart.c. For simply logging data coming in, I think the latter approach would be very simple to set up.

RE: Is it possible to use the UART without the Soft Device?

Eliot Stock — Tue, 08 Apr 2014 13:42:45 GMT

How then would you recommend breaking that dependency? Do I have it right above?

RE: Is it possible to use the UART without the Soft Device?

Ulrich Myhre — Tue, 08 Apr 2014 13:39:44 GMT

The softdevice is not needed to use the UART peripheral. You should be able to get along just fine with nrf51.h and nrf51_bitfields.h.