Hi!
Currently I am using 4 channels multiplexer (switch) which:
1. Is working as a slave,
2. Receives commands from master through RS232,
3. By the command user can choose 1 of 4 input/output channels,
4. RS232 is redirected to 1 of 4 channels.
This device is using AT89C2051 as a controller. RS232 input is connected to the analog switch inputs/outputs and the AT89 sets proper channel (only one in the same moment!). Is my description clear??? I am not sure ;)
I want to do this using microcontroller only - without analog switches. My idea is to use 1 serial hardware interface (built-in micro) and 4 channels software serial interface (both RXD&TXD lines). TTL level is ok - I am not going to translate it.
Do you think it is possible? How to do it? TI flag is going to be set on after SPI receives full frame and from this moment my software SPI can work. I have solution of software SPI up to 2400 bps. Can input signal be higher speed than 2400 bps?
Any other ideas?

Jacek