Connecting several Rxd pins and Txd pins together ?

[arunb]

MCU: 16F628
Compiler: PCM


Hi,

I connected the Rxd pin and the TXd of two PIC 16F628s together. The junction I connected to a MAX 232 Ic ( the way it should be done). The PC's COM port is then connected to the MAX IC.

I find that I am unable to communicate with either of the PICs. when both of them are connected together, but each of them worked well when alone. I checked supply voltages they were OK.


I could post the code as well , but I would like to know if this kind of connection is OK ?. Or do I have to use I2C , SPI for this ?


thanks
arun

[Mark]

So you tied 2 outputs together! So how can one of them transmit a low when the other is high? To answer your question, No you just can't tie them together. Your best bet is to use RS485 and each chip will need its own transceiver.

[Neutone]