Rs232 multiplexer needed?

[tonyyy]

Hi.

I develpoed a board with PIC16F. Now I need to add a programmable module which convert serial to ethernet. The module need to be connected to the PIC via RS232 line (tx and rx). Because I would like to us those line also for reading other pheriperal how I can do that?

Shoul I add a mux chip to sync the access to the tx and rx line?

Any suggestion?

Thanks
Tony

 

[barry]

I think you are asking for trouble. Since ethernet is asynchronous to your PIC, there's no way to know when a message is coming in. If you've got the input assigned to your other input (non-ethernet), you could miss a message.

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You COULD mux your TX signal, since you control when you are transmitting. But if you've got line(s) available for controlling a multiplexer, why don't you just use THOSE lines for your other inputs?

 

[horace1]

use the hardware UART for the Ethernet device and a software UART to talk to your PC
do a web search for pic16 software uart and you will get plenty of links

 

[tonyyy]

How I can allow another rs232 device to communicate with pic?

See the pic

What about 74HC125D?

 

[barry]

Several of the PIC16s have 2 UARTs; you could use one of those. Or, as Horace suggests, roll your own software UART.