On 06/09/2016 09:43, Fritz Mueller wrote:
But thinking on it, I bet USB has something to do with it here — perhaps buffer latency through the USB drivers is keeping software flow-control (xon/xoff) from functioning effectively at higher baud rates
I've had that problem with a printer and a double-buffered UART. As near as I could determine, the printer waited to send XOFF until there was only one or maybe two characters free in its software buffer, but by that time there was one char in transit, one more in the printer's receiver buffer register and another in the computer's UART's transmitter buffer register. That's at least one too many :-)
-- Pete Pete Turnbull
