Hi Clemens, On Sun, Feb 19, 2017 at 7:26 PM, Clemens Gruber <clemens.gruber@xxxxxxxxxxxx> wrote: > But CTS_B is an active-low output, according to the IMX6DQ reference > manual. This 'active-low' term is what causes confusion in my opinion. Active-low or active-high depends on how the user sets SER_RS485_RTS_ON_SEND flag. > > The CTS field in _UCR2 has the following description on page 5252: > 0 The CTS_B pin is high (inactive) > 1 The CTS_B pin is low (active) The logic levels mentioned here are correct. > > We had to invert the signal in hardware before connecting it to the > active-high transceive-enable pin of a transceiver. > > If you want CTS_B high during transmit, I think you need it the other > way around: SER_RS485_RTS_ON_SEND cleared and SER_RS485_RTS_AFTER_SEND > set. On the system I tried I need to drive CTS_B pin high so that the TXEN RS485 transceiver can trasmit data. Then it needs to go low so that RX can happen. In order to do so: SER_RS485_RTS_ON_SEND set SER_RS485_RTS_AFTER_SEND cleared. ,which works for the native CTS_B case and also the gpio-rts case. -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
