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Author Topic: Baud rates and resistors.  (Read 265 times)
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Scunthorpe, UK
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Hi all.

A little question for you all. Do different baud rates require different pullup resistors for the receive pin?

Thanks.
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Scotland
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Ive used 9600 to 115200 with no pullups!
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Drew.
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Scunthorpe, UK
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Sorry, i mean if the transmit pin of the other device is open drain.
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Leeds, UK
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I wouldn't of thought it would matter too much. You may find that the internal pullup of the Arduino is all it needs.

The only reason it would make a difference is if there was a lot of stray capacitance around (are you using a breadboard?), but if that is the case, you just need to pick one which works at the highest baud rate you will use, and it will work very well at lower ones.
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~Tom~

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Open Drain - I tend to use 2K, 8.7K(Because I have about 10,000 on 2 reels) or 10K - I start with the 8.7 and change if unstable.
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Drew.
http://www.uk-pcb.co.uk - My UK Based PCB Fab & Assembly Company
Design work undertaken
SMD & Thru-Hole assembly

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