I'm not sure exactly what you intend to do, but TRMT gets asserted half-way into the STOP bit, so if you immediately disable the TX then the STOP bit will be half the time and generate a framing...
I would not give up on the 18877 chip. Sometimes the view seems great but has pitfalls and all you need is to sleep on this. Next day will come the aha moment!
Re: Framing error if I disable transmitter after shift register is empty?
I'm not sure exactly what you intend to do, but TRMT gets asserted half-way into the STOP bit, so if you immediately disable the TX then the STOP bit will be half the time and generate a framing...
tumbleweed Today, 21:12