MCUXpresso Config ToolsのトピックUART stop bit framing issue https://community.nxp.com/t5/MCUXpresso-Config-Tools/UART-stop-bit-framing-issue/m-p/537423#M24 <HTML><HEAD></HEAD><BODY><P>We are having compatibility trouble with a modbus device we are trying to interface with a KE06 processor over RS485 2-wire.&nbsp; It appears that the Kinetis UART samples the RX line 3 times and if one of the other samples doesn't match, it throws away the byte due to noise in the processor expert generated drivers.&nbsp; The reason that this is a problem with us with this particular modbus device is that they are turning off their RS485 driver before the last stop bit in their message is complete.</P><P style="min- padding: 0px;">&nbsp;</P><P>So, we have modified the drivers to not throw away the byte, but I guess my question would be should the byte really be flagged as "noisy" if the data and parity were fine?</P><P style="min- padding: 0px;">&nbsp;</P><P>Also, it appears as though changing it to 2 stop bits also works around the issue.&nbsp; They are effectively transmitting 1.5 stop bits in 2 stop bit mode, but the kinetis UART appears to be ok with that, so it must only be checking if the first stop bit is "noisy" in 2 stop bit mode.</P></BODY></HTML> Thu, 18 Aug 2016 14:08:41 GMT justinjansen 2016-08-18T14:08:41Z UART stop bit framing issue https://community.nxp.com/t5/MCUXpresso-Config-Tools/UART-stop-bit-framing-issue/m-p/537423#M24 <HTML><HEAD></HEAD><BODY><P>We are having compatibility trouble with a modbus device we are trying to interface with a KE06 processor over RS485 2-wire.&nbsp; It appears that the Kinetis UART samples the RX line 3 times and if one of the other samples doesn't match, it throws away the byte due to noise in the processor expert generated drivers.&nbsp; The reason that this is a problem with us with this particular modbus device is that they are turning off their RS485 driver before the last stop bit in their message is complete.</P><P style="min- padding: 0px;">&nbsp;</P><P>So, we have modified the drivers to not throw away the byte, but I guess my question would be should the byte really be flagged as "noisy" if the data and parity were fine?</P><P style="min- padding: 0px;">&nbsp;</P><P>Also, it appears as though changing it to 2 stop bits also works around the issue.&nbsp; They are effectively transmitting 1.5 stop bits in 2 stop bit mode, but the kinetis UART appears to be ok with that, so it must only be checking if the first stop bit is "noisy" in 2 stop bit mode.</P></BODY></HTML> Thu, 18 Aug 2016 14:08:41 GMT https://community.nxp.com/t5/MCUXpresso-Config-Tools/UART-stop-bit-framing-issue/m-p/537423#M24 justinjansen 2016-08-18T14:08:41Z