I am using AD5700 for HART 2 wire transmitter. In the design, AD5700 is interfaced with microcontroller ATxmega 128A4U. While starting the HART communication with HART master , I am facing the issue with RTS line. While transmission , my RTS pin does not go low to trasmit data from controller to modem AD5700. When i pull down the RTS line through a 1Mohm resistor, RTS pin goes low while transmission but that also happens sometimes. Sometimes it does not go low. Is there any specific software code needs to be written for the RTS pin. Right now i am using normal GPIO pin for RTS and configuring it as output pin.