Pulse, timer and UART with GPIOTE and PPI

RE: Pulse, timer and UART with GPIOTE and PPI

nordev — Mon, 14 Sep 2020 16:15:15 GMT

Sorry, will do. Thanks!

RE: Pulse, timer and UART with GPIOTE and PPI

Susheel Nuguru — Mon, 14 Sep 2020 07:10:10 GMT

nordev, please open a new ticket for that and keep this thread focussed on one thing.

RE: Pulse, timer and UART with GPIOTE and PPI

nordev — Fri, 11 Sep 2020 00:38:36 GMT

Hi Susheel Nuguru, sorry if this is a basic Q, but how do you start the UART, and what happens after starting the UART?

The below is from the UART example code, and it seems to print "UART Start!", but none of the commands surrounding this log statement seems to have anything to do with UART. Please explain how the UART is actual started, thanks a lot!

RE: Pulse, timer and UART with GPIOTE and PPI

Susheel Nuguru — Mon, 03 Sep 2018 17:23:32 GMT

TimerCC_event --> PPI -->UART_START

UART_ENDTX _event--> PPI --> Timer_start

These two connections seem necessary.

But the main challenge is that if you have only one timer, then you need to reconfigure the CC from 30us to 60us. And it is difficult to do it exactly when last byte is transmitted (if UART_ENDTX event generates interrupt that is with highest priority, then you can do it). But if you have two timers to spare, then you can easily do it.

Good luck with it, let me know if you have some challenges, it seems interesting.

RE: Pulse, timer and UART with GPIOTE and PPI

RO — Fri, 31 Aug 2018 12:50:16 GMT

Hmm. I don't have an external trigger for the GPIO in my setup. So I think I have to manually set/clear anyway to pull it high/low.

In this case, does it make any sense to use it as a GPIOTE to be coupled with a PPI task?

Or should I use PPI for the timer and UART event-task pair?

Or is there a way to use all 3 in a GPIOTE-PPI combination?

RE: Pulse, timer and UART with GPIOTE and PPI

Susheel Nuguru — Fri, 31 Aug 2018 07:57:47 GMT

If you want this to happen completely without MCU involving after configuration then Option 1) seems wise choice. Since in option 2 you need to manually set GPIO high which might add possible delays based on MCU availability.