UART not sending data to FTDI USB

RE: UART not sending data to FTDI USB

Doug_H — Fri, 13 Oct 2017 16:45:06 GMT

I tested this with the oscilloscope and electrically everything is fine, so it is not a hardware issue, so I tried the UART example from the latest SDK v14.0 and it works fine. The problem has to be in the SDK11.0 UART driver.

RE: UART not sending data to FTDI USB

martin.richter.supervag — Wed, 11 Oct 2017 20:22:24 GMT

I connected it on other pins and works well. Rx is P0.08, Tx P0.06, CTS P0.07 to ground, picture at os.mbed.com/.../Nordic-...

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 13:53:01 GMT

Really? OK, then there's something going here that I can't figure out. I'll have to keep searching...

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 13:40:51 GMT

I can only say that my PCA10028/40/56 work with FTDI RS232-TTL-3V3 serial to USB convertors without problems for years. I hope you crack it soon...

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 13:39:17 GMT

I can only get the UART on the PCA10040 to work using the onboard JLink OB COM port, it will not work with any external UART interface hardware.

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 13:02:54 GMT

To clarify. it sends and receives via the JLink OB COM port. Interestingly when I attach the logic analyzer I get no readings, which makes me think the error in UART config in my app is also causing the problems with the FTDI dongle. I'll investigate further.

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 13:00:46 GMT

BTW endnode, thanks for your help on this! So, I went back to basics and loaded the uart peripheral example with no softdevice to test in non-loopback mode and it sends and receives correctly to my terminal program. So there is definitely a problem with how I have configured the UART in my application.

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 12:51:35 GMT

Well isn't the problem in your terminal app on PC side (as it usually is)? Can you test it from something reliable (e.g. from Python which can stream raw hexadecimal bytes to serial port)?

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 12:47:42 GMT

Logic analyzer on UART RX P0.8 of the JLink OB COM port is seeing 0x21 no matter what I send on the terminal program.

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 12:31:15 GMT

I configured the JLink OB COM port. I am able to transmit bytes out the UART of the PCA10040 to my terminal program OK. Receiving bytes from the terminal program does not work correctly though. No matter what I send the UART receives 0x21. I'll try putting the logic analyzer on P0.8 to see what's happening in the hardware.

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 12:13:54 GMT

You mean Dev Kit's user guide?:)

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 12:12:44 GMT

I have not tried the segger JLink OB COM port. Is there any documentation on how to use this? I have tried other IO pins on the board without success

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 12:08:47 GMT

I tried connecting CTS to ground. No change.

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 12:08:39 GMT

Have you tried SEGGER J-Link OB COM port on the DK itself? If that works then I'm sorry but it's somewhere in your wiring or FTDI dongle (the fact that it works with STM32 board is encouraging but not a proof of anything).

One more thing: P0.26 and P0.27 are used in I/O expander connection (see Table 5 in nRF52 DK User Guide). I don't see any reason why this should cause the effect but I cannot exclude it so going with some different PIN (not connected to any HW feature on DK;) might be also good debugging step. Actually many PINs are usable if you short Arduino shield detect PIN on P5 header...

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 12:03:28 GMT

Also, when I test the UART signals with a logic analyzer and the dongle disconnected, the UART output is working correctly, so it has to be some kind of hardware issue with the PCA10040. If that's the case, I would expect other people to have the same problem?

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 12:01:05 GMT

Yes, the wiring is fine. I've checked it multiple times and I use this dongle all the time with the STM32 boards it works perfectly. The dongle is 3V3. It will not work at all with the PCA10040

RE: UART not sending data to FTDI USB

martin.richter.supervag — Tue, 10 Oct 2017 11:40:43 GMT

I connected it on other pins and works well. Rx is P0.08, Tx P0.06, CTS P0.07 to ground, picture at os.mbed.com/.../

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 11:07:12 GMT

Are these Tx/Rx from the right point of view?;) Also is the dongle really 3V3 TTL UART?

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 11:05:48 GMT

Also are you sure that Tx/Rx/GND wires are correct on the dongle? Just trying some trivial mistakes...;)

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 11:04:43 GMT

It looks OK. Simple test would be: use Tx/Rx pins attached to J-Link OB chip on the Dev Kit and see if SEGGER emulation of COM port works. If yes then it's most probably in your dongle or clumpsy wiring...

RE: UART not sending data to FTDI USB

Doug_H — Tue, 10 Oct 2017 10:39:58 GMT

Yes, I'm using jumper wires. I have PCA10040 TX=P0.27, RX=P0.26. I added a link to a photo of the way the boards are connected in the original post

RE: UART not sending data to FTDI USB

endnode — Tue, 10 Oct 2017 10:05:21 GMT

Maybe more details on how you exactly connect the dongle to the board? Are there some jumper wires between nRF52 GPIO header pins and your FTDI convertor? Do you have the system grounded properly? Maybe photo would help...