New to MSP430 world and have a couple of questions…
With a controller such as the MSP430F2121, if I wanted to implement a 56kBPs software UART, do I have to have a crystal or can I just depend on the DCO?
If I use a part such as a MSP430F1222 which has a hardware UART, do I still have to have a crystal?
In either case, would a 32.768Khz crystal suffice if a crystal is necessary?
The DCO of F2xx has small temperature coefficient and calibrated register settings (stored in info Flash). You can get 2% accuracy and should be okay for most UART on the other side.
I think it is more difficult for F1xx to get accurate clock. You will have to depend on the cooperation of the device on the other side to help you if you do not have a crystal for reference.