I was wondering if someone could help me figure out how to implement the following setup. I'm working on a project where I need to talk multiple RS232 devices with a micro controller configuration. I say configuration because, if necessary, I can use multiple micro controllers with built in RS232 ports, however this is not desirable as I would like to keep power consumption and number of parts as low as possible.

I think I'm going to use an external UART and access it via an SPI connection to the main microcontroller. Due to my current illness of noobism, I'm going to need all the help I can get on implementing this. Does this setup even sound correct?

1) the very best would be if you could use RS485, but I read that you have to connect to existing devices, correct?
2) the second best would be a small cheap '51 for each channel such as a Philips LPC or a SILabs "ultra small".
3) you "can" bit bang a RS-232, but going that route for up tom7 devices is a dead end.
4) the external quad UART may be the best solution for you but do remember that you will need a MAX232(equivalent) for each cannel as well.
5) with that many RS232 transcievers, you need to let go of "power consumption ... as low as possible", you will never be able to pull this one off in a power restricted enviranment.
6) if instead of "an external UART and access it via an SPI" consider IIC it will make it easier to add more external UARTs. With SPI you have to "buss" missing parts, with IIC, you just leave them out.

If you need more info just let me know.
How refereshing to see this insteead of the recently seen "why do you idiots not just solve my problem"

Erik