XPC850SR from 48M to 80M

XPC850SR from 48M to 80M

[li]

Hi all,
i am going to raise xpc850SR freq from 48M to 80M.
with the ppcboot-1.1.6, i still set the freq to 48M,
and i change the freq to 80M in linux kernel file m8xx_setup.c, but when the kernel booting, the console outputs mass characters. i think there must be something wrong about the serial setup. But where is it?
And if it can work i set the different cpu freq in boot an in kernel?
Thanks in advance!
Li


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RE: XPC850SR from 48M to 80M

[Callebaut, Benoit]

I am not a user of this kind of processor, but your strange output is
normal.
Your baudrate is generated by a frequency divider circuit driver by the CPU
clock. If your
CPU clock is higher, your effective baudrate is higher and so your console
can't follow.
Try changing the division factor. It must be in the init function of the
serial driver or
be calculated from the CPU clock. Check your RTC clock code to be sure that
one second
is effectively one second or goes faster. Look for tick_per_jiffies
variable.This variable define a lot of timing related things in Linux (task
switch freq, sleep time, ...)
Normally this initialization happens in board specific init code( see
corresponding directory for your board).

I Hope that will help you.

-----Original Message-----
From: li [mailto:slowforce@21cn.com]
Sent: Friday, March 28, 2003 4:03 PM
To: linuxppc-embedded@lists.linuxppc.org
Subject: XPC850SR from 48M to 80M



Hi all,
i am going to raise xpc850SR freq from 48M to 80M.
with the ppcboot-1.1.6, i still set the freq to 48M,
and i change the freq to 80M in linux kernel file m8xx_setup.c, but when the
kernel booting, the console outputs mass characters. i think there must be
something wrong about the serial setup. But where is it?
And if it can work i set the different cpu freq in boot an in kernel?
Thanks in advance!
Li


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/