Fan out of UART


#1

HI,
i am using Q24plus, i planned to connect two devices to uart1 of wavecom. one device will work in RS232 level.one device work in cmos level(3.3)(Each device has its own commands so no need for MUX).can i connect this two devices? will it work?

thanks&regards
karthikeyan


#2

No.

At least, not as you’ve described!

You cannot just connect the two outputs of your device together to feed the one input of the Q24 UART - or any other UART, for that matter:

Output 1 -------+
                |
                +------> Input
                |
Output 2 -------+

You need some means to ensure that Output 1 is OFF while Output 2 is active, and vice-versa


#3

I guess rs232 to rs485 adapter could help. It is very cheap (at least 3.3V chips) and rs485 supports mulptiple devices on bus.