Mesh serial example with a timeout event

RE: Mesh serial example with a timeout event

tesc — Mon, 05 Oct 2020 14:04:30 GMT

Hi,

Sorry for the late reply.

"IF OFF" / "IF MCU" is whether or not the interface MCU on the nRF52840 DK should use the UART connection to the nRF. It is an internal signal line on the DK board. From what I can tell from the hardware files, the interface MCU will use the UART lines if SW6 is set to "DEFAULT" and USB is detected on the interface MCU USB connector. I do not see how it should affect your setup. In any case, what you see is on the third party board, not on the nRF52840 DK, right?

If you have any activity on the nRF UART pins, when the application is downloaded, then I guess it would be possible to end up in a bad state, that a reset would mitigate.

Regards,
Terje

RE: Mesh serial example with a timeout event

sada pix — Tue, 22 Sep 2020 13:54:03 GMT

Hi Terje:

Thanks again for the reply. I have find the PCB design of my board. The UART part is shown as below:

I checked the PCB of nrf52840 DK, it seems that the UART pin definations are all reversed (e.g. P0.05 is used for RTS on nrf52840 DK but CTS on my board)? Also there is a switch on the nrf52840 DK which can switch between "IF OFF" and "IF MCU". So what is the function of the switch? Is it possible that this is the reason why serial has a timeout problem after a cold start?

Best Regards

Yeming Li

RE: Mesh serial example with a timeout event

sada pix — Tue, 22 Sep 2020 04:49:00 GMT

Hi Terje:

Many thanks for your reply! The Jlnik is outside of the board and connect to the board via a TTL port. The reason I attach the UART port on PC is just to show that I need two ports to finish the programming and serial output, respectivly. But in the RIOT tutorial, it seems that they only need one ttyACM port to finish both the programming and serial output.

I'ii try to get a PCB desgn from the manufacturer.

Thanks!

RE: Mesh serial example with a timeout event

tesc — Mon, 21 Sep 2020 14:40:36 GMT

Hi,

What port (on the PC) you get UART communication over is not something that the nRF can control. From what you describe, it sounds like both the J-Link programmer and the mini-usb with USB-to-serial are connected to the same UART pins of the nRF, and which one of those to use is controlled by logic on the board itself.

If I understand correctly, there is a J-Link programmer on your board? Maybe it also controls (overrides) the USB-to-serial converter with the mini-USB port, and whether it is connected to the nRF UART pins? You need to consult the documentation for the board, in order to see how things are connected...

Regards,
Terje