Basic RS-232 Question Teensy 3.0

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doggitz

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I have a very basic question and can't seem to find the answer in the older threads - I did look

For a Teensy 3 which uses 3.3 volts can I use a MAX 232 or do I need the 3232 3.3 V version? (Most of the prior posts deal with SPI, etc)

I hooked up a 232 to my Teensy 3 and it worked perfectly, but am I "overvoltage" or is this Ok

Thanks
 
Powering the MAX232 with 3.3V is unlikely to cause damage to the rest of the Teensy 3.0 hardware, unless due to wiring errors the relatively high voltage RS-232 signals sneak into the 3.3V side. ...That Said.... The MAX232 is a 5V part, so it *may* work in a 3.3V circuit if you're "lucky" but don't count on it. I just downloaded and checked the Texas Instruments datasheet and the MAX232 is only specified to run down to 4.5V.

Go with a 3.3V rated part like the 3232 if you want to count on your circuit working properly.

Checking the Sparkfun site shows that the 3232 is specified to work from 2.7V to 6V, which makes it a near drop-in replacement (with 0.1 uF rather than 10uF chargepump capacitors) for the MAX232 in both 3.3V and 5V circuits.
 
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