Re: SCC or SMC for console ?

Dear Laurent,

in message [off-list ref] you wrote:

I need 4 serial ports at runtime, and was wondering if I should rather
use 2SMC + 2SCC or 4 SCC (or 1SMC + 3SCC).

Assuming that you need Ethernet: if you can use the FEC for Ethernet,
that it does not matter much; otherwise I'd recommend to use  2SMC  +
2SCC  or  1SMC  +  3SCC  so  that  you  have at east one SCC left for
Ethernet.

I need a console, but no hardware flow control (which would force the
use of SCC).

Should be no problem. The kernel on our FTP server was tested with  6
serial  ports  on  a  MPC860, with HW flow controll on all SCC's. The
only problem in such a configuration is that you have only 4 BRG's so
two ports have to share the baudrate with another port.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
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Should be no problem. The kernel on our FTP server was tested with  6
serial  ports  on  a  MPC860, with HW flow controll on all SCC's.

Reading arch/ppc/8xx_io/uart.c, I found out that all the flow control
related code was surrounded by false #if #endif. It seems that there is
no flow control at all on either the SMC or SCC serial ports in UART
mode. Is there a patch somewhere to implement flow control, or is it
still missing ? I was wondering what to do with CD/DTR/DSR (as Linux
only support RTS/CTS flow control for now), and had hoped to find an
answer in the source code...

Laurent Pinchart


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