Add simx00x driver

[skilvingr]

UART driver based upon embedded-io for the SIM800L module.

[BartMassey]

Looks great! Thanks much.

Since you depend on heapless, you might want to use heapless::Dequeue instead of your own ring buffer, but maybe there's some constraint that makes that not work?

The crate name is a bit surprising, since this is specifically for the SIM800L it looks like?

All of this is fine, though.

[skilvingr]

Since you depend on heapless, you might want to use heapless::Dequeue instead of your own ring buffer, but maybe there's some constraint that makes that not work?

No, it's just that I didn't know it existed at all. Thanks for the suggestion. I'll run some benchmarks and, if it makes sense, I'll update the crate.

The crate name is a bit surprising, since this is specifically for the SIM800L it looks like?

Well, it has been tested only with a SIM800L for the moment, but it seems that similar modules, like SIM800H and SIM900L, work with the same set of commands, hence the surprisingname.

Given this, should I change at least the description in the README or is it still fine?

[BartMassey]

Things are fine. Thanks much for sharing this crate!