Better way for rs232 - Resistors or MAX202?
Dan Michaels email (remove spam text)
At 10:10 AM 1/22/01 -0800, you wrote:
>I know this might have been asked before, but I was unable to find it in
the list archive. What is they better way to setup a serial port? Lots of
schematics use the MAX202 or MAX232 to transmit the serial data, while
others just use a resistor on the RX and TX line. Is there any particular
advantage to either way? The resistors would be easiest, since I could just
run up to Radio Shack for those, but I don't know much about PICs or EE.
MAX-type chips - best approach, if rigorously meeting the specs is
BJT-inverter type ckts - generally acceptable, but +V usually = 5v,
rather than +12v. Better ckts use a half-wave rectifier on the
Rxd line to develop/hold -12v.
Simple R ckts - very slap-dash [IMO], neg-voltages especially are
hope this helps,
- Dan Michaels
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