Using multiple UART instances on the nrf52840

RE: Using multiple UART instances on the nrf52840

ovrebekk — Fri, 21 Jun 2019 08:56:54 GMT

Hi Timothy

Are you able to assign UARTE1 to your third party chip rather than UARTE0?

Then it should be quite straight forward to enable logging on UARTE0 like normal.

For this to work you have to enable both UART's in the sdk_config.h file.

Best regards
Torbjørn

RE: Using multiple UART instances on the nrf52840

awneil — Thu, 20 Jun 2019 10:50:09 GMT

Presumably, in what you currently have for your "custom chip" comms, there must be a "UART init" somewhere early on ... ?

RE: Using multiple UART instances on the nrf52840

Tim Adu — Thu, 20 Jun 2019 10:50:03 GMT

Maybe I wasn't very clear - what I'm really asking is how to enable/initialize both instances and have them running at the same time?

RE: Using multiple UART instances on the nrf52840

Tim Adu — Thu, 20 Jun 2019 10:42:42 GMT

That makes perfect sense; but it's not exactly obvious how to select the other UART instance.
Thanks anyways for backing me up (that's why I responded to your thread).

RE: Using multiple UART instances on the nrf52840

awneil — Thu, 20 Jun 2019 10:38:21 GMT

I don't know - I'm following this thread to find out!

I guess the easiest approach would probably to use the default UART for the NRF_LOG, and then select the other one for your "custom chip" comms ... ?

RE: Using multiple UART instances on the nrf52840

Tim Adu — Thu, 20 Jun 2019 10:34:53 GMT

Precisely!
And I'm currently using the nrf52840 development kit, but will eventually move to a custom board

RE: Using multiple UART instances on the nrf52840

awneil — Thu, 20 Jun 2019 10:32:44 GMT

I think you've missed the point - I think he's asking how he can use the two UARTs on the nRF52840 at the same time...?

RE: Using multiple UART instances on the nrf52840

RK — Thu, 20 Jun 2019 10:18:32 GMT

You are using the nRF52840 chip or you are using Nordic's development board based off the chip? Two rather different things. If you are using the chip in a custom design you can do whatever you want, if you are using the nRF52840 dev kit then yes one of the two UARTs is presented via a USB-CDC device as a serial port. You can just open that serial device on your PC/linux box/mac and read it as a .. serial device and you can log via the UART backend. That's the point of the logging interface, you can select whether it's presented via RTT or through the UART. And if you want to connect directly to the UART with a UART you can cut the solder bridges (see the manual).

I think you're overcomplicating it - yes one UART goes via a third party chip, however it does that in order that you can open it as a serial device on your computer, it's not stolen from you, it's made available to you in a consumable form. I think that's what you actually want.