[U-Boot-Users] Is serial_init() enough to make output to the serial console?
Wolfgang Denk
wd at denx.de
Tue May 18 20:17:44 CEST 2004
In message <BAY2-F41Q6mBySsxVY60001e29e at hotmail.com> you wrote:
>
> Does serial_init() in cpu/ppc405/serial.c provide essensial initialization
> for UART? If I cut and copy this function and run it in SDRAM, can the
> function like serial_putc put char to the serial output right after the
> serial_init is doen? I tried this but when I tried to put '@' to console, I
> got '.'
> What could be the problem or did I miss anything?
In my opinion it makes little sense to try to rip certain parts of
out of the U-Boot code, obviously without understanding what exactly
they are doing, and then expect certain behaviour.
If you want to implement your own test software, please feel free to
go on and do it, but start with designing the code before you
implement it, and when you then copy from existing code make sure you
understand what you copy, and why.
The other approach is to use U-Boot as is, and let it go through its
"natural" init sequence. Let it boot from flash as it was designed,
just follow the actions in a debugger - this is usually easier, and
it also allows for a much better understanding of what's going on,
which parts of the hardware have been initialized or not, etc.
But don't rip out a single function and ask if it will work in an
undefined environment - the result will be just that: undefined.
Best regards,
Wolfgang Denk
--
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd at denx.de
Status quo. Latin for "the mess we're in."
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