??? 06/23/04 07:53 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#72995 - RE: Current & Voltage Monitor with RS232 out Responding to: ???'s previous message |
I have following comments:
1) Newer MAX232 are "sattisfied" with only 100nF (C9-C12) 2) For display contrast (pin 3) you should apply negative voltage (-3 to -5V). And you have -9V. 3) Backlight for the display requires much higher current than you can get through 1k. This resistor should be about ten times lower. 4) I suppose the voltage divider R13/R12 and C6 (?) should give 2 levels, depending on P3.7. Do you really get it ? 5) By opening U12A and U12B at the same time, you shorten them ? Should not it be an inverter to one of them, so only one is open at a time ? |