Markus Pietrek wrote:
Hi George,
The next big step is print some messages in the serial console. I assume
that when we fprintf in stdout or stderr, our messages should be
redirected to the systems console. Am I write on this? When executing a
regular application in /bin/sh this application should be able to output
formatted messages to the serial port?
How do you launch your application? Do you replace init by your application or
modify init to call your application?
Actually I was using my applcation in place of init which I suppose is
wrong. I will compile init from the userland.old repo of uClinux and try
to execute it instead.
The application inherits stdout, stderr and stdin from its parent. And I think
init must open /dev/ttyS0 or /dev/tty itself first.
And /dev/console provides only output, so it may be ok for stdout and stderr.
It also uses many kernel buffers for retreiving the messages later (like
dmesg does). It is also important that /dev/console is used by other kernel
functions, so your text may be overwritten.
I understand. I also made some tests trying to open /dev/ttyS0. I open
it and tried to output something there. It works fine and outputs the
messages in the serial port. Thus /dev/ttyS0 works OK.
Thanks for your help,
- George
--
"Luck is what happens when preparation meets opportunity"
