Console buffer size

Michael Hamel mhamel at
Wed Mar 18 22:59:11 UTC 2009

My BSP uses the standard 16550 driver found in ../powerpc/shared/ 
console, which seems to hook in to the termios code in cpukit/ 
libcsupport/src. After some searching it looks as though the code is  
interrupt-driven, but is limited to a rather small buffer size which  
is hard-coded in that file as rtems_termios_raw_output_size. The baud  
rate is also hard coded as 9600 in console_first_open() in console.c.

The limitations of my debugger mean that I use console debugging  
rather a lot and as I'm not at all short of RAM I would like to use a  
much larger buffer and higher baud rates so that generating log  
information doesn't suspend my tasks while they wait for the UART. I'm  
sure that editing the shared termios.c and console.c isn't the right  
way to do this(!)

Is there some appropriate way of configuring the console buffer size  
(and baud rate) in bsp.h, or some way of calling the termios code to  
get the rate changed and buffer resized at startup? I can't find any  
documentation or examples that seem to cover this...

Thanks for any assistance,

"Quick! Burn the books. Tear up those revolting postcards. Chase those  
women out of my room. Take all those "For Sale" signs off the  
furniture and help me get the floor back under this carpet."

Michael Hamel
ADInstruments Ltd, Dunedin, NZ

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