I'm now frustrated trying to use the MSP430FR5738 uart. From what I've read, it's just not possible to determine if the transmit buffer register is ready for another character.
(I've programmed UART code in more than a dozen different processors, so I'm quite familiar with this).
I'm using two 64 byte FIFOs for XMIT arnd RCV. What I need to do is insert characters at the front of the line occasionally, for example XOFF if the receive FIFO is getting too full or BEL if it is full. Everything I've tried failed, sometimes even crashing if I fuss with the IFG bit.
Alas, I see no possible solution. I guess I'll have to monitor the GPIO for xmit data, and if it's in stop bit state for a while, at least I'm sure the transmitter is idle.
This wastes a character time, though. Too bad the busy bit monitors the receiver also, as the receiver is likely to be busy all the time.
Are there any tricks you know?
Thanks.