u-boot/doc/README.serial_multi
Wolfgang Denk c12cffc543 Add support for CONFIG_SERIAL_MULTI on MPC5xxx
Patch by Martin Krause, 8 Jun 2006

This patch supports two serial consoles on boards with
a MPC5xxx CPU. The console can be switched at runtime
by setting stdin, stdout and stderr to the desired serial
interface (serial0 or serial1). The PSCs to be used as
console port are definded by CONFIG_PSC_CONSOLE
and CONFIG_PSC_CONSOLE2.
See README.serial_multi for details.
2006-06-16 17:04:45 +02:00

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The support for multiple serial interfaces as implemented is mainly
intended to allow for modem dial-in / dial-out while still being able
to use a serial console on a (different) serial port.
MPC8XX Specific
===============
At the moment, the ports must be split on a SMC and a SCC port on a
8xx processor; other configurations are not (yet) supported.
Support for hardware handshake has not been implemented yet (but is
in the works).
*) The default console depends on the keys pressed:
- SMC if keys not pressed (modem not enabled)
- SCC if keys pressed (modem enabled)
*) The console can be switched to SCC by any of the following commands:
setenv stdout serial_scc
setenv stdin serial_scc
setenv stderr serial_scc
*) The console can be switched to SMC by any of the following commands:
setenv stdout serial_smc
setenv stdin serial_smc
setenv stderr serial_smc
*) If a file descriptor is set to "serial" then the current serial device
will be used which, in turn, can be switched by above commands.
*) The baudrate is the same for all serial devices. But it can be switched
just after switching the console:
setenv sout serial_scc; setenv baudrate 38400
After that press 'enter' at the SCC console. Note that baudrates <38400
are not allowed on LWMON with watchdog enabled (see CFG_BAUDRATE_TABLE in
include/configs/lwmon.h).
PPC4XX Specific
===============
*) The default console is UART0
*) The console can be switched to UART1 by any of the following commands:
setenv stdout serial1
setenv stderr serial1
setenv stdin serial1
*) The console can be switched to UART0 by any of the following commands:
setenv stdout serial0
setenv stderr serial0
setenv stdin serial0
MPC5xxx Specific
================
Up to two PSCs can be used as console.
Support for hardware handshake has not been implemented yet.
*) The first (default) console port is defined by:
#define CONFIG_PSC_CONSOLE <PSC number>
*) The second (alternative) console port is defined by:
#define CONFIG_PSC_CONSOLE2 <PSC number>
*) Commands to switch to the second console:
setenv stdout serial1
setenv stderr serial1
setenv stdin serial1
*) Commands to switch to the first console:
setenv stdout serial0
setenv stderr serial0
setenv stdin serial0
*) If a file descriptor is set to "serial" then the
current serial device will be used.