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Author Topic: Baud rates and resistors.  (Read 153 times)
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Pavilion1984
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« on: August 11, 2012, 04:42:40 am »
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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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spycatcher2k
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« Reply #1 on: August 11, 2012, 04:44:54 am »
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Ive used 9600 to 115200 with no pullups!
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Drew.
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Pavilion1984
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« Reply #2 on: August 11, 2012, 04:59:00 am »
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Sorry, i mean if the transmit pin of the other device is open drain.
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Tom Carpenter
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« Reply #3 on: August 11, 2012, 05:07:10 am »
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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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spycatcher2k
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« Reply #4 on: August 11, 2012, 05:19:54 am »
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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.
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