SPRUJF2A March 2026 – March 2026 AM13E23019
RS485 is a standard used in serial communications systems. This standard can be used effectively over long distances and in electrically noisy environments. Multiple receivers can be connected to a RS-485 network. These characteristics make RS-485 useful in industrial control systems and other similar applications.
The RS485 direction signal controls the external RS485 PHY. The RTS I/O is used in this mode as the direction signal. The signal is set automatically to high once a data transmit is started. This siganl stays high between back to back byte transmits. If a data receive operation is ongoing, a new transmit must be delayed until this data has been received and the direction signal has been set to transmit.
The data exchange sequence is show in Figure 23-11:EXTDIR_SETUP bits define number of functional clocks between RTS assertion and beginning of START bit
EXTDIR_HOLD bits define number of functional clocks between STOP (entire bit duration) and RTS de-assertion