Hi Fabio, On Sun, Feb 19, 2017 at 07:07:20PM -0300, Fabio Estevam wrote: > On Sat, Feb 18, 2017 at 8:35 AM, Maarten Brock <m.brock@xxxxxxxxxxxxx> wrote: > > > So setting the SER_RS485_RTS_ON_SEND flag sets CTS_B active high during > > send. > > Yes, correct. > > > And setting the SER_RS485_RTS_AFTER_SEND flag sets CTS_B active low after > > send ? > > No, when SER_RS485_RTS_AFTER_SEND is cleared, the CTS_B is low after send. > > > > > I don't get it. First, isn't CTS an input instead of an output? > > On i.MX CTS is an output. I know this sounds confusing and I will > submit a readme entry about it to help clarify it. > > > And if I follow this through and want CTS_B high during a transmit only then > > I > > must set both SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND. > > In this case you need: > > SER_RS485_RTS_ON_SEND set > SER_RS485_RTS_AFTER_SEND cleared. But CTS_B is an active-low output, according to the IMX6DQ reference manual. 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) 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. Or did I miss something? Very confusing indeed! Thanks, Clemens -- 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
