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Need help with TWR-K70F120M and TWR-SER2

Question asked by John Breyer on Nov 1, 2013
Latest reply on Nov 14, 2013 by David E Seymour

Hello.  I need some help with getting the serial ports working on a TWR-SER2.  My system configuration is:



  • 700-27166 REV A
  • SCH-27166 REV C2



  • 700-26185 REV B
  • SCH-26185 REV D


I can communicate from the Kinetis board to a PC using printf and the BSP_DEFAULT_IO_CHANNEL, which happens to be ttyc:.  This causes communication to go over the OSBDM/OSJTAG - CDC Serial port and works fine.


I have enabled BSPCFG_ENABLE_TTYA through TTYF in user_config.h and recompiled the BSP.  I try to open a port and send a string using code like the following:


fh_ptr_a = (pointer)fopen("ttya:":, BSP_DEFAULT_IO_OPEN_MODE);

_io_set_handle(IO_STDOUT, fh_ptr_a);

printf("Port a\n")



I am trying to see the result on my PC through the Serial-to-USB connection (UART 0)


No matter which port I choose (except for "ttyc:"), I do not get any communication to the PC.  I have installed the driver on the PC side, and the connection shows up as a valid com port on the PC.


I have not modified any default jumpers on the TWR-SER2.

I have tried changing J19 on the TWR-K70F120M, and neither setting seems to make a difference.


I have a feeling that am missing some basic setting, or that there is an incompatibility that I am not aware of.  Any help would be greatly appreciated.  Thanks.