nRF52 DK UART RX pin

RE: nRF52 DK UART RX pin

tmloos — Tue, 29 Sep 2015 10:47:43 GMT

Can you give some more information on your setup and what you are trying to accomplish?

Generally, as long as you are paying close attention to the schematic for the DK board and choose two pins that aren't already being used, it does not matter. I reworked the connections to the secondary board and the problem was fixed. I believe that I had a bad solder joint, or fatigue caused the wiring to fail. Also make sure that you have a common ground between your boards else there will be no reference for either. This will surely cause the pins to float.

RE: nRF52 DK UART RX pin

lisong — Tue, 29 Sep 2015 04:04:46 GMT

I am taking the same error on my nRF52 DK, You say you have had some success with this, so which pin we can use without this error? Thanks very much .

RE: nRF52 DK UART RX pin

tmloos — Fri, 04 Sep 2015 13:01:29 GMT

I submitted this issue to Nordic and it was determined that the RX pin was floating causing the Uart to enter the APP_UART_COMMUNICATION_ERROR case. This would prevent LED1 operation and would basically hang the system. I am going to see what can be done to the Uart driver to make it a little more tolerant to errors so that the system continues to function even though the Uart may be in an error condition.

RE: nRF52 DK UART RX pin

tmloos — Tue, 01 Sep 2015 23:57:32 GMT

no problem at all... I do have a debugger, I'm switching between Eclipse/GCC and Keil. Keil is much friendlier and the debugger seems to work (I think). I set optimization to 0 and try to step through and there seems to be a lot of disassembly going on. I have never tried to step through code with the soft device so I'm not sure what to expect. When trying to start from main with the rx pin plugged in, it won't run at all. If I unplug, hit Run and then plug in the cable the light stops blinking and when I hit Stop. It is stuck in disassembly again but seems to be in the softdevice_handler.c -> softdevice_handler_init() function. It gets stuck and it's not behaving like I expect.

RE: nRF52 DK UART RX pin

RK — Tue, 01 Sep 2015 23:51:21 GMT

It's me not reading the question properly - sorry - I saw 'DK' and thought nRF51-DK, now I see you're talking about the nRF52 DK and indeed P22 etc are free, well they're used for SPI0 by default but only if you're using the SPI, which I'm sure you're not.

Do you have a debugger on the board when it stops advertising, where is it?

RE: nRF52 DK UART RX pin

tmloos — Tue, 01 Sep 2015 15:31:13 GMT

I have the schematic printed out for the DK and LEDs are P0.17 - P0.20. What schematic are you looking at?

When I say Pin 22/23/24, I mean P0.22 GPIO pin numbers.

RE: nRF52 DK UART RX pin

RK — Tue, 01 Sep 2015 15:05:13 GMT

What do you mean by Pin 22/23/24? Do you mean pin on the chip (pins 23 and 24 on that are the ARM serial debug) or do you mean a pin number on one of the headers counting from 1 or do you mean P0.22, the GPIO pin number?

P0.21, 22, 23 and 24 are hooked up to the LEDs on the DK (see the schematic or the manual) and have resistors to VCC, so they aren't a good choice for UART pins.