On 14.02.2022 22:30, Tim Harvey wrote: > If using modem-control gpios for CTS we must leave IRTS disabled > as otherwise the hardware will only transmit based on the internal RTS > pin routed to it. > > This allows hardware flow control to be used with cts-gpios. This hardware flow control sounds quite limited. Once CTS becomes inactive, the transmitter will still output all characters from TxFIFO. Transmitting whole TxFIFO already sounds quite bad, but that's the best case scenario where gpio interrupt is handled right away without any delay (so more than TxFIFO characters can actually be transmitted). Does the internal RTS default to inactive when it's not pinmuxed to the actual pin? If so, then controlling UCR2_IRTS based on CTS gpio could halt the transmission when the TxFIFO is not empty. Best Regards, Tomasz Mon
