Non-console UART issues with 8xx

Eran Duchan pavius at
Fri Apr 15 09:52:22 EST 2011

Hey list

I have a custom MPC875 board running 2.6.37. SMC1 is the console, SCC4 is a
general purpose UART (DTS is set up accordingly). No hardware or software
flow control for either.

The issue is simple: the non-console UART transmits garbled characters at
the end of the transmission. For example, set up SMC1 to console (works
perfect) and SCC4 as non-console, run stty -F /dev/ttyCPM1 19200 raw and
then echo -n 1234567890 > /dev/ttyCPM1 - transmission may be something like
"1234567ø". Set the SCC4 as console (same baud rates) and the problem is
reversed (SCC4 works perfect, SMC1 transmit garbled).

Rx direction seems fine, after some rudementary testing.

I dived into the code and see that the console UART has a completely
different initialization sequence than the non-console UART. Short of diving
into this ancient CPM architecture - does anyone have an idea?

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Linuxppc-dev mailing list