That raises a question I have had.  What % error is acceptable to most
devices (In particular computers)? 



-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Bob Axtell
Sent: Thursday, November 04, 2004 4:52 PM
To: Microcontroller discussion list - Public.
Subject: Re: [PIC]: Framing Error

Padu wrote:

>>Olin Lathrop wrote:
>>You can answer this easily yourself.  The 16x baud clock is created by

>>dividing the oscillator frequency by an integer.  The baud rate 
>>resolution is therefore very poor for low oscillator frequencies and
high baud rates.
>>
>>For example, with 4MHz oscillator here are the fastest few baud rates:
>>
>>  OSC  |  Div  |  Baud
>>  --------------------
>>  4MHz      1     250K
>>  4MHz      2     125K
>>  4MHz      3      83.3K
>>  4MHz      4      62.5K
>>  4MHz      5      50.0K
>>  4MHz      6      41.7K
>>  4MHz      7      35.7K
>>  4MHz      8      31.3K
>>  4MHz      9      27.8K
>>  4MHz     10      25.0K
>>
>>To get 38400 baud, you have a choice of 41.7Kbaud (8.6% too high), or 
>>35.7Kbaud (7.0% too low).  Both those errors are too high.  You 
>>therefore can't do proper 38400 baud with a 4MHz oscillator.


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