Change serial speed on raspberry pi?
Adam McDougall
mcdouga9 at egr.msu.edu
Sat May 23 02:41:15 UTC 2015
On 05/20/2015 18:42, Ulrich Grey wrote:
> This works for me:
> cu -l/dev/cuaU0 -s115200
>
> In /etc/ttys:
> ttyu0 "/usr/libexec/getty 3wire.115200" dialup on secure
> ----------------------------------
> On Wed, 20 May 2015 18:20:33 -0400
> Adam McDougall <mcdouga9 at egr.msu.edu> wrote:
>
>> I have been experimenting and googling for at least a half hour but am
>> getting seemingly nowhere. Is it possible to make a raspberry pi with a
>> serial adapter board run at a speed less than 115200? I am getting
>> serial corruption during uboot and after the system has booted. My
>> usual instinct is to try a slower speed but I have no idea how. I'd
>> like it to work for the uboot environment as well as after the kernel.
>> I should try the FreeBSD side of it but I need to switch tasks right
>> now. Can anyone give me a hint? Is it compiled into uboot? Thanks.
>>
>> I have:
>> http://www.52pi.com/en/raspberry-pi/56-original-raspberry-pi-bb-plus-accessories-rpi-uart-expand-module-uart-extend-board-.html?
>>
>> I've tried both I got, on two different pis, with different serial
>> adapters and cables.
I was able to change the speed to 9600 in /etc/ttys and use cu -l
/dev/cuaU0 without line noise. I do not want to use 115200 because of
the line noise, and I don't need the speed. How do I get uboot to use
9600? I still want a usable uboot environment before the kernel boots.
I've tried setting CONFIG_BAUDRATE=9600 in the source in various ways,
recompiled it and replaced U-BOOT.BIN on the flash but I didn't make any
useful progress. I tried putting init_uart_baud=9600 in config.txt on
the flash but it did not make any difference. Thanks.
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