uarte doesn't send data

RE: uarte doesn't send data

Stavros Makridis — Tue, 08 Sep 2020 20:40:08 GMT

omg.....you are so right......I feel stupid now 😞

Thanks so much.....I checked again and again and again if RX_PIN_NUMBER and TX_PIN_NUMBER point to the correct physical pins but I have never thought to check the assignment to struct fields.

Thank you so much.

RE: uarte doesn't send data

hmolesworth — Tue, 08 Sep 2020 16:39:22 GMT

You can use this as an interview question - spot the bug:

    .pseltxd = RX_PIN_NUMBER,
    .pselrxd = TX_PIN_NUMBER,

Hint: tx on TX

RE: uarte doesn't send data

Stavros Makridis — Tue, 08 Sep 2020 15:59:26 GMT

Hi Jared,

First of all thank you for your immediate response.

I followed your suggestion and your are right. The tx done interrupt triggered but I still don't see data coming out. I have checked it with both a uart to USB converter and a oscilloscope.

As I mentioned earlier, I tried to toggle TX pin in a while loop and I got a 330KHz square wave on oscilloscope so I believe there is no hardware issue at least on this pin.

Any ideas?

RE: uarte doesn't send data

Jared — Tue, 08 Sep 2020 11:29:12 GMT

Hi,

The nrfx_uarte_tx() function uses EasyDMA and therefore requires the transfer buffer to be placed in the Data RAM region. Pass the data as a buffer and it will be placed in the Data RAM region.