Problem with COM

lawson_whitney at lawson_whitney at
Mon Feb 11 18:53:48 CST 2002

On Mon, 11 Feb 2002, [utf-8] Duško Rusmir wrote:

> All Right, I have unterstand.
> Yes, app want 5726 I write 38400, app got 5760 and work!
> I think I have the Solution.
> Make two scripts:
> first for 5760: baud_base 115200, spd_cust divisor 20, call 38400
> from app
> "setserial /dev/ttyS0 baud_base 115200 spd_cust divisor 20"
> second for 9600:  baud_base 115200, spd_cust divisor 0, call 9600
> from app
> "setserial /dev/ttyS0 baud_base 115200 spd_cust divisor 0"
> Put one in /etc/init.d/boot.local and if I which others Baudrate
> call others script.
By my observation, spd_cust divisor 0 actually _uses_ a divisor of 1,
thus if the app asks for 38400, it actually gets 115200, so that
combination is effectively the same as spd_vhi.  I would just set
spd_normal for general use and use the spd_cust divisor 20 for the case
where you need 5760.  If you don't ever actually need 38400 to _be_
38400, you can just leave it set at spd_cust divisor 20 all the time.
The spd_cust, spd_normal, spd_hi, spd_vhi and divisor options only apply
when the app calls for 38400, so you can use any other supported speed
no matter what they are set at.

IOW, this will also work:
second for 9600:  baud_base 115200, spd_cust divisor 20, call 9600
from app

You should, of course, do what makes sense to you.

All these options come from a time when the C library didn't provide for
speeds greater than 38400, but the kernel did, so historically, they are
a workaround for a limitation of the C library.

> Yes I have forgotten this, but now I have tried and have got
> success with 5760.
> Take a Look on Attachment Wine-COM1.tgz, please.

Yep.  You are well on your way to becoming a linux serial guru.  I'm not
sure what is the significance of the win and nowin logs, but as long as
you got it working, I'm happy.
> Thanks many for Yours Help, this is very nice from You.
You are welcome.  Enjoy Wine, and feel free to help us develop it.
There is still plenty of work left to do.


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