[HLUG] Serial port setting

[Paul Maddox]

Alan,
 
> I assume you are using a PIC or something similar. Using different
> baud rates will give you smaller errors i.e.: 33600 give around 0.,7%
> error.
> Small errors should not cause problems.

I'm using a coldfire 5251 for the linux, and an AVR for the display/remote
portion.

Any baud over 4800 causes errors, I suspect its because the codlfire is
running at 3.3v and the AVR at 5v, so I'm going to build a simple level
converter (couple of transistors and resistors) this weekend.

Paul


> 
> Alan
> 
> 
> On 24 Apr 2008, at 14:52, Mark Broadbent wrote:
> 
>> Hi Paul,
>> 
>> On 20/04/2008, paul.maddox.mail-list at synth.net
>> <paul.maddox.mail-list at synth.net> wrote:
>>> Andy,
>>> 
>>>> The valid baud rates are listed in /usr/include/asm-i386/termbits.h
>>>> and 62500 isn't one of them.  I believe you'll need to patch your
>>>> kernel a bit like this:
>>> 
>>> Hmmm, that's a bit awkward for me, but I'll look into it, thanks.
>>> 
>>>> It would seem a lot easier to just change the other device to 57600
>>>> or 115200, but I suppose there is a good reason why this isn't
>>>> possible in your case..
>>> 
>>> The device attached is an 8 bit micro and because it's running from a
>>>  16Mhz clock anything that's non divisible gives me errors, for
>>> example at
>>>  115200 I get 3.7% rate error (ie, it's 3.7% off the correct
>>> rate). At
>>>  31250 (MIDI) and 62500 (double MIDI) I get 0%.
>>> 
>>>  I'll have a tinker and see what I can do.
>>> 
>>>  This explains what I'm doing - http://qix.synth.net/Blog/?p=6
>>>  And this is the background - http://qix.synth.net/
>> 
>> This might be an weird suggestion but why don't you get a MIDI card
>> and use that to communicate with your board?
>> 
>> Thanks
>> Mark
>> 
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>