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RE: [AVR-Chat] Re: comms problem

2008-04-09 by John Samperi

At 02:45 AM 10/04/2008, you wrote:
>For a 2.4567 MHz xtal:
>
>             UBRR = (2456700/(16 * 9600)) - 1 = 15


The data sheet shows a xtal frequency of 2.4576 MHz
which I'm ASS-U-MEing is what is being used.

At 9600 baud and a UBRR of 15 it gives 0% error....
unless Atmel's calculators are broken too. :-)



Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495       Fax (02) 9674-8745
Email: john@ampertronics.com.au
Website  http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
********************************************************

RE: [AVR-Chat] Re: comms problem

2008-04-09 by Raymond Hurst

I'm not sure what you're trying to say here.

My point was that 15 is the correct value for UBRR for a 2.4567 MHz clock as
you pointed out from the data sheet.

 

The value that Brian is using for UBRR is 16 which results in a 3.1% error.

 

Ray

 

 

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From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of John Samperi
Sent: Wednesday, April 09, 2008 2:12 PM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Re: comms problem

 

At 02:45 AM 10/04/2008, you wrote:
>For a 2.4567 MHz xtal:
>
> UBRR = (2456700/(16 * 9600)) - 1 = 15

The data sheet shows a xtal frequency of 2.4576 MHz
which I'm ASS-U-MEing is what is being used.

At 9600 baud and a UBRR of 15 it gives 0% error....
unless Atmel's calculators are broken too. :-)

Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495 Fax (02) 9674-8745
Email: john@ampertronics.com.au <mailto:john%40ampertronics.com.au> 
Website http://www.ampertronics.com.au <http://www.ampertronics.com.au> 
*Electronic Design * Custom Products * Contract Assembly
********************************************************



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