UART Peripheral Dead?

RE: UART Peripheral Dead?

phipi — Wed, 27 Sep 2017 17:38:25 GMT

I'm on the nRF51822 and 1.8V is working fine.

RE: UART Peripheral Dead?

Matt — Wed, 27 Sep 2017 16:35:28 GMT

How about your original 1.8V test? Would it work now? I don't know much about nRF51 but 1.8V may just be too "low" for nRF52.

RE: UART Peripheral Dead?

MartinBL — Wed, 27 Sep 2017 15:37:57 GMT

The UART errors are not defined in the header files as the usual NRF_ERROR_XXX... error codes in the SDKs are. They are read from the ERRORSCR register which is documented here.

RE: UART Peripheral Dead?

phipi — Wed, 27 Sep 2017 15:25:12 GMT

I definitely had that floating. Thanks for explaining that. I've added the RX line now and it's working with the error handlers added back in!

Where are the error codes documented?

RE: UART Peripheral Dead?

MartinBL — Wed, 27 Sep 2017 14:48:36 GMT

Have you connected the RX pin on the nRF52 to anything or is it floating? APP_UART_COMMUNICATION_ERRORs and error 4 indicates that the UART experiences an RX framing error. This can happen if the RX pin is left unconnected and picking up random noise which the UART thinks is data. It is possible to set the PSEL.RXD register to 0x80 to disconnect the pin from the UART logic.

RE: UART Peripheral Dead?

phipi — Wed, 27 Sep 2017 14:41:14 GMT

I'm not sure what you mean... it was calling APP_ERROR_HANDLER which I thought by default (not in DEBUG mode) just performed a system reset.

RE: UART Peripheral Dead?

RichieJH — Wed, 27 Sep 2017 14:14:39 GMT

Commenting out the UART handler should not have made a difference since as you can see your UART handler did nothing for that error case.

RE: UART Peripheral Dead?

phipi — Wed, 27 Sep 2017 14:09:41 GMT

Updated original post with new findings

RE: UART Peripheral Dead?

phipi — Wed, 27 Sep 2017 14:00:13 GMT

Hardware flow control has been disabled the whole time. The UART interface did send some data before starting this behaviour the first time it was powered, but I'm really not sure how the debugger could possibly cause this.

I just tried with 3.3V and I'm still seeing the same behaviour

RE: UART Peripheral Dead?

Matt — Wed, 27 Sep 2017 13:19:48 GMT

Or, as Nguyen mentioned above, does your custom board support the flow control signals at all?

RE: UART Peripheral Dead?

Nguyen Hoan Hoang — Wed, 27 Sep 2017 02:28:35 GMT

Did you enable flow control (RTS/CTS pins) ? If you do, check the CTS pin. It might the cause of uart stop transmitting. Disable Flow control to see what happen.

RE: UART Peripheral Dead?

phipi — Tue, 26 Sep 2017 21:47:09 GMT

Yes, I'll try that test.

RE: UART Peripheral Dead?

Matt — Tue, 26 Sep 2017 20:44:45 GMT

Any possibility to run the same test with 3.3V VDD?