I am transferring a project from wirewrap to etched PCB.  Each section of
the wirewrap board is being moved to a separate module with pc/104 stackthru
connectors.
   Everthing was going fine until I got to the RS-232 section.  It uses the
USART of a 16c774 and a Dallas ds275.  It is not identical to the wirewrap
design, as I removed a switching relay because I no longer need to talk to 2
devices, which makes it much simpler.  The wirewrap board works.  The etched
board, however, transmits exactly the corect # of character (to a PC, no
flow control, 115kbps), but they are the incorrect characters.  I put a
simple "echo" program in the PIC to check.  I press an "A", I should get an
"A" back, but instead I get some other character, but always the same
incorrect chacter for a given key.  I checked the math to see if it was a
simple pattern (bit 8 or something), but no pattern.  Some keys produce the
same hex value.
   I tried different chips, eliminating unnecessary modules (only the
processor, PS, and serial boards are left), different bauds, and have
checked the boards for shorts, etc.
   Any ideas?
   Thanks.

Greg Hartung

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