PCA10040 UART problem

RE: PCA10040 UART problem

f.salvatore — Fri, 31 Mar 2017 07:09:18 GMT

It affects the UART maybe because J-Link is seen like an USB storage but onestly i don't why Ubuntu has this behaviour.

UPDATE: i update the answer.

RE: PCA10040 UART problem

koniho — Thu, 30 Mar 2017 17:45:59 GMT

The automount only affects the mass storage device that appears on USB connect right? Why would that affect the UART?

RE: PCA10040 UART problem

f.salvatore — Thu, 30 Mar 2017 15:56:14 GMT

I had the same problem. I solved changing mount settings by disabling auto-mount of devices.

UPDATE: It seems that the problem is caused only by certain USB ports. I tried changing port and everything works. So the mount settings are not impacting on this issue. I'll try to investigate.

I forgot to say that i had also another issue on Ubuntu: when i connect the device to the USB a system daemon (ModemManager) sends some garbage (AT commands) to test if the device was a modem. I killed the daemon (search it with ps -aux | grep ModemManager) and everything is ok.

RE: PCA10040 UART problem

patrick — Thu, 29 Sep 2016 18:33:29 GMT

Hi,

the logic analyzer confirms that the nRF52 receives the data already corrupted (see attached screenshot).

I can't seem to reproduce the problem with a Windows machine, though. So the problem must be lying with the linux driver. I've tried the latest and greatest version of cdc_acm, to no avail.

Any ideas how to further investigate ?

RE: PCA10040 UART problem

Stefan Birnir Sverrisson — Thu, 29 Sep 2016 17:34:41 GMT

Hi Patrick

I have not used Ubuntu that much, so I don't have much input there.

To find out if this is a nRF52 problem or PC/Ubuntu problem, you could connect logical analyzer to the UART communication pins on the nRF52-DK (PCA10040) board and read the bytes directly from RX and TX pins.

You should find the pin mapping in pca10040.h file, which are

#define RX_PIN_NUMBER  8
#define TX_PIN_NUMBER  6
#define CTS_PIN_NUMBER 7
#define RTS_PIN_NUMBER 5

Which maps to pins P0.08, P0.06, P0.07, P0.05 on the PCA10040 board.