RS232 with only 3V power supply

[Exo]

I'm building a project wich involves a pic, and i want it to communicate to a pc using the serial port. Now this project runs on 2 AA batteries so it only gets 3V. My Max232 won't run with this (stops below 4.2V).

Does anyone have some other idea on how to communicate with rs232 levels with only a 3V supply?

 

[Nigel Goodwin]

I would suggest you check the RS232 specifications, it works at a lot less tha +/-12V - obviously you have no problems receiving from RS232, and your transmit can be +3V and 0V, which will probably manage OK.

 

[Andy_123]

Check other ICs at TI and maxim
www.ti.com
www.maxim-ic.com
They making some new RS232 ICs with 3V supply.
I am using MAX3243, but few more available.

 

[Exo]

I would suggest you check the RS232 specifications, it works at a lot less tha +/-12V - obviously you have no problems receiving from RS232, and your transmit can be +3V and 0V, which will probably manage OK.

I tried it, but it seems 3V is just a little too less, sometimes some bits are missed.
I found this yesterday, it uses the pc's own handshaking lines and swiches them back for a '1' or a '0'. Should have thought about it myself
**broken link removed**

 

[zelka]

try MAX202 or MAX3232