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Topic: Baud rates and resistors. (Read 285 times) previous topic - next topic

Pavilion1984

Hi all.

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

Thanks.

spycatcher2k

Ive used 9600 to 115200 with no pullups!
Drew.
http://www.uk-pcb.co.uk - My UK Based PCB Fab & Assembly Company
Design work undertaken
SMD & Thru-Hole assembly

Pavilion1984

Sorry, i mean if the transmit pin of the other device is open drain.

Tom Carpenter

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.
~Tom~

spycatcher2k

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.
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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