UART framing error after NVIC softreset

RE: UART framing error after NVIC softreset

Inspectron — Tue, 12 Jul 2016 16:05:35 GMT

Of course. I will send it on your mail in a few minutes.

RE: UART framing error after NVIC softreset

FormerMember — Tue, 12 Jul 2016 15:54:26 GMT

Could I have a picture, schematic, and layout of the rigado board?

RE: UART framing error after NVIC softreset

Inspectron — Tue, 12 Jul 2016 15:41:24 GMT

The sensor has a STI32F100 with a 12MHz Crystal on it. The crystal has 10ppm accuracy. I tested now the same application with RC LFCLK on the nRF52-DK and its working. So it should work with the RC LFCLK.

With the Rigado board I tested all LFCK's and none of this worked. And with the nRF52-DK all of these worked...

RE: UART framing error after NVIC softreset

FormerMember — Tue, 12 Jul 2016 15:41:23 GMT

Could you also try yo make the HFCLK run at all time?

RE: UART framing error after NVIC softreset

FormerMember — Tue, 12 Jul 2016 15:31:20 GMT

Okay, I see, it means that there is a bit error. Could you check if you see the same problem when using RC oscillator or synthesized clock with the nRF52-DK?

Also, what is the clock source on the sensor? How accurate is that clock?

RE: UART framing error after NVIC softreset

Inspectron — Tue, 12 Jul 2016 15:14:12 GMT

Yes, I have APP_UART_COMMUNICATION_ERROR and APP_UART_FIFO_ERROR, like it is in the example. And I will get into APP_UART_COMMUNICATION_ERROR with the err_code = 9

RE: UART framing error after NVIC softreset

FormerMember — Tue, 12 Jul 2016 15:08:38 GMT

The problem can be related to a bit error. It will lead to an APP_UART_COMMUNICATION_ERROR error. (How) Do you handle UART errors? Do you have a uart_error_handle(..) like in the UART example in the SDK?

It can also be useful to take a look at this post regarding system reset.

RE: UART framing error after NVIC softreset

Inspectron — Tue, 12 Jul 2016 14:54:10 GMT

I will now try it with the synthesized LFCLK. In the uart event handler the p_event->evt_type is APP_UART_TX_EMPTY. But when I try the same software on the nRF52-DK, then p_event->evt_type wont be APP_UART_TX_EMPTY and I then the CPU wont reset.

RE: UART framing error after NVIC softreset

FormerMember — Tue, 12 Jul 2016 14:44:06 GMT

Yes, you can try to use the synthesized LFCLK instead. It has a considerably better frequency tolerance, but it also uses considerably more current, see here.

By handling asserts I meant how you handle errors, if you check and handle error codes?

RE: UART framing error after NVIC softreset

Inspectron — Tue, 12 Jul 2016 14:37:02 GMT

The wires from the sensor to uC are 30cm long. We cant change the Baudrate because the sensor has a fix baudrate(19200).

Would it be better if we use the Synthesized LFCLK?

What do you mean with, how do you handle asserts?

RE: UART framing error after NVIC softreset

FormerMember — Tue, 12 Jul 2016 14:30:20 GMT

What is the distance between the nRF52 and the sensor? UART doesn't work for more than 2-3m.

How do you handle asserts?

When using the internal RC oscillator instead of external crystal, the clock rate on UART will not be that accurate.

You can also consider to reduce the rate over UART.

RE: UART framing error after NVIC softreset

Inspectron — Tue, 12 Jul 2016 12:29:54 GMT

I have the same problem. I work with a distance sensor which communicates trough UART. With an crystal oscillator everything works. But when I try the same without the crystal, then I will get a System reset, as soon as I recieve data from the sensor.

RE: UART framing error after NVIC softreset

Susheel Nuguru — Mon, 21 Sep 2015 17:58:56 GMT

and i assume that the GPIO is set high when UART re-initialization has finished? Can you check if there is a glitch on the GPIO pin after the reset? The technique of using gpio as a signal to other side is good, and this way it should not mater if disabling the softdevice or not OR using XTAL or RC. I am interested to look into your code, any possibility of sharing it in PM or in MY Page support portal?

RE: UART framing error after NVIC softreset

Remo — Mon, 21 Sep 2015 14:42:44 GMT

Hi Aryan. Thanks for the response. No, we don't use the HW flow control of the UART interface. But we use a dedicated GPIO to signal the peer device when the interface of the nRF chip is ready and initialized. More precisely, as soon as this GPIO is set to HIGH by the nRF, the peer device may start sending commands.

RE: UART framing error after NVIC softreset

Susheel Nuguru — Mon, 21 Sep 2015 12:11:34 GMT

When you said that there is a framing error, then it means that the device that is sending commands over serial port got out of sync. Is it using hardware flow control on UART?

How does the peer device know that nRF chip booted up from its reset, and all its UART configuration re-initialized before sending new commands?

I have a couple of theories of why disabling softdevice or using XTAL clock works for you. But before going that way, we have to make sure that your peer device is waiting enough time for the chip to come to a stable state. Please let me know how your peer device waits?