Problem running nrf52 SDK 0.9.1 uart example.

RE: Problem running nrf52 SDK 0.9.1 uart example.

Susheel Nuguru — Tue, 01 Sep 2015 07:33:23 GMT

Hi,

The engineer of the driver team explained that this is not necessarily a bug, it is the implementation limitation because of the way how app_uart works. So the app_fifo library is not ready to work with EasyDMA. Anyhow I see that the nrf_driver_uart (layer below app_uart) has full capabilities to woth with easydma and with the workaround I provided above (in app_uart), it works just fine. In the next SDK release, the driver team promised to update documentation for this and will also TRY to support app_uart with easydma.

RE: Problem running nrf52 SDK 0.9.1 uart example.

Susheel Nuguru — Mon, 31 Aug 2015 13:17:24 GMT

in app_uart_fifo.c-> uart_event_handler function Add these two lines in the start of the function

{
    static uint32_t  count = 0;
    if (count == 0) { count ++ ; return; }
}

for some reason the RX buffer gets a byte before the transmit is done. If you ignore the first RX event then everything else in sync. I will have to redirect it to the driver team, but this workaround will fix your problem.

RE: Problem running nrf52 SDK 0.9.1 uart example.

Susheel Nuguru — Mon, 31 Aug 2015 12:41:40 GMT

i confirm what you said. It does not work as intended, I will have a look into it.

RE: Problem running nrf52 SDK 0.9.1 uart example.

Susheel Nuguru — Fri, 28 Aug 2015 07:00:33 GMT

i am working from home today and do not have access to hardware, i will test this on monday, sorry about that.

RE: Problem running nrf52 SDK 0.9.1 uart example.

Chris smith — Wed, 26 Aug 2015 19:38:14 GMT

Yes, I have connected TX with RX and RTS with CTS (Defined in pca10036.h:TX=6, RX=8, CTS=7, RTS=5). I'm pretty sure that I have everything set up correctly because the UART loopback works perfectly without EasyDma. I only changed what is stated above in the question. Let me know how your testing turns out and hopefully we can figure out whats going on.

I tested the spi_master loopback example a little while back with both EasyDma enabled and disabled and it works.

RE: Problem running nrf52 SDK 0.9.1 uart example.

Susheel Nuguru — Wed, 26 Aug 2015 07:59:08 GMT

you have enabled loopback so have you connected TX with RX and if HW enabled RTS with CTS? Yesterday I did exactly same thing for SPIM example modifying it to work with EasyDma and it worked perfectly. I will have to try your example today.