UARTE - START BIT INTERRUPT - documentatation question

RE: UARTE - START BIT INTERRUPT - documentatation question

pawel_krzy — Wed, 04 Apr 2018 08:59:07 GMT

Thanks a lot.

Unfortunetly the device I am communicating with may have a delayed response, so it maight occure that it will start sending response (or any information) and if I will be unlucky (with thousends of devices and thousends of tries at least few times I will be) while I will start transmiting to it and the communication will fail.

Thanks a lot I will need to change a hardware to use flow control if this is a must in my application.

RE: UARTE - START BIT INTERRUPT - documentatation question

Kenneth — Wed, 04 Apr 2018 08:11:42 GMT

> Does nRF52 have an event if a start condition on it's RX line is detected?

Sorry no, only an RXDRDY event when an entire byte is received.

Not sure what you want to do here, but it may be possible to disable UART, setup RXD as a normal GPIO input with wakeup/interrupt on low level, and then immediately enable UART receive if pin go low, however you likely will loose the first byte this way. I guess you can also use flow control instead.

RE: UARTE - START BIT INTERRUPT - documentatation question

pawel_krzy — Wed, 04 Apr 2018 06:03:50 GMT

Hi,

thanks for the answear.

I am using almost exactly the same approach you mentioned. Clearing RAM buffer and have timeout for the loop (simple iteration counter since we are using timers already and we don't care of ISR since they are very short.

As I understand my 2nd question regarding different new data cannot be resolved since I dont know if incomings 1's are inside message or there is nothing new. OK that should be not a problem.

I am little concerned about my 1st question:

Does nRF52 have an event if a start condition on it's RX line is detected?

RE: UARTE - START BIT INTERRUPT - documentatation question

Kenneth — Tue, 03 Apr 2018 17:59:57 GMT

Hi, typically your problems can be handled by init the RAM buffer with zeros before STARTRX, and then you can at any time just check the RAM location to manually see how many bytes (if any) have been updated since STARTRX. A cleaner approach may be to hook the RXRDY event using PPI to start a timer or use as a counter for the timer, thereby you can use the RXRDY event to either start a timer that timeout or to count the number of received bytes.

RE: UARTE - START BIT INTERRUPT - documentatation question

pawel_krzy — Wed, 28 Mar 2018 09:47:15 GMT