topic Re: helloworld example on TWR-K64F120M in Kinetis Software Development Kit

helloworld example on TWR-K64F120M

kalden_srcinc — Fri, 23 Jan 2015 14:06:39 GMT

I am trying to get the serial terminal working with the TWR-K64F120M. I have the hello world demo program building and running on the target, but I can never see anything coming out on my PC. I have the JLink openSDA application running on the board and gdb is able to connect, load a program, and step through code no problem. I can see things initialize and the code gets to my PRINTF line. I can also see the activity LED on the board go crazy while printf is executing, so I believe everything on the board is actually running properly.

Now, on the linux side, when I plug into the USB debug port on the board I see a /dev/ttyACM0 device appear. I believe this is meant to be the virtual serial port connected to the K64. I am running the following to open a terminal to it: sudo screen /dev/ttyACM0 115200

Nothing ever shows up though. Am I going about this wrong? Maybe I have a jumper on the board set wrong? Any tips would be appreciated.

Thanks

Re: helloworld example on TWR-K64F120M

kalden_srcinc — Fri, 23 Jan 2015 14:47:18 GMT

My mistake. It appears that it is getting stuck at fput_pad (print_scan.c:509 inside _doprint) within the PRINTF call

Re: helloworld example on TWR-K64F120M

kalden_srcinc — Fri, 23 Jan 2015 15:21:16 GMT

I figured it out. The first problem was I was not initializing the JLink GDB server properly. I needed to provided some switches: ./JLinkGDBServer -select USB -device MK64FN1M0xxx12 -if SWD -speed 1000

The next problem was the J10/J15 jumpers on the board were not what I expected. Based on the documentation, I had to do the opposite of what I would expect to route UART1 to the virtual serial port.