[uClinux-dev] slow UART on MCF 5272!

Magnusson, Johan johan.magnusson at sd.teleca.se
Thu Nov 15 06:34:45 EST 2001


Hi again!

First of all. Thanks for taking interest in my problems!

(Greg U wrote)
> baudclk = ((MCF_CLK / mcfrs_baud_table[i]) + 16) / 32; 
--Yes I se your point about the rounding problem and..-- 

(I previously wrote)
>>I also noticed someone pointing out a rounding´problem(in mcfserial.c)
>>I implemented the proposed solution, without any luck.
--I added 0.5 instead of 16/32 is that ok too? :) --

(Wei Wang wrote)
> with the 66MHz crystal, there is no common divider value for all baud 
--Bad--

(Tom W wrote)
>I do believe that the error rate is much tighter than %5, IIRC, the 
>buadrate should be within %2. 
--Makes it worse if my UART is that sensitive--

So what now?
I am probably not getting exactly 115200. The reason your soultion works for
you Greg and not for me could be that the other side of our systems have
baud rate errors in opposite directions, right? Your's to your advantage and
my to my disadvantage. But what do I know? I'm just a happy amateur!

At least your fix made it possible to run my system in 57600Bps and that's
good enough! Thanks!! I'm dropping this now, but many thanks again.

Happy hacking guys!
Johan K Magnusson
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