> Note that,for this bit-at-a-time method to work from 38.4K to 31.25K,you need
> to make the host send 38.4K bit characters at a 31.25K/(word size) character
> rate since you have no provision to buffer the faster message. This shouldn't
> be too hard with a timer interrupt.

Actually, this is do-able with the PC's uart.  All you need to do is set it
for 38,400 bps, MARK parity, TWO stop bits.  This will result in a character
time of 9.77 bits at 31.25Kbps; while the stop bit will be a little shaved,
it will exceed the 0.5-bit-time stop bit most UARTs require and this should
usually not pose a problem unless the receiver is using a software async
receiver which uses the stop-bit time to do things.