thank you very much for the reply.. honestly, in case modules with spi really exist, i'm not quite sure how i'll make it work.. but then, I can't think of a way to control multiple gsm modules using just one uart..:sad:
You can try to use a buffer with an OE input. Basically give every module its own buffer which you can enable individually. But your biggest problem (no matter how you are going to multiplex them) is how to handle the situations that multiple modules are sending something at the same time... Therefore the only decent solution is (IMHO) to use external UARTS which you control from your controller...
Thanks for the reply =)
Actually, my mcu has several uart pins and I can actually go with the task by using the other uart pins. If there's no any other solution, perhaps, I'll really have to settle with that.. =(
Thanks again..=)