Subject: Re: 230400 on com.c?
To: Frank van der Linden <firstname.lastname@example.org>
From: Herb Peyerl <email@example.com>
Date: 05/02/2002 10:42:36
Frank van der Linden <firstname.lastname@example.org> wrote:
> You can only really use a speed > 115200 if the serial chip is clocked
> with a frequency high enough to deal with it. If you have a 16x50 with
> a higher clock, you can change COM_FREQ in sys/dev/ic/comreg.h to
> match it. There's currently no way to change that at runtime.
> The hardware must actually allow it though. You can't make a 16550
> with a crystal at 1.8432 Mhz do 230400.
Ok. I've gotten to the bottom of it. They're using a 7.3728Mhz oscillator
on the card so I'll have to change COM_FREQ.
However, that means I'll either have to boot a custom kernel every time
I want to use this card on my Jornada _or_ divide my baud rates by 4
whenever I want to use some other serial device.
What's the right way to solve this?