The iLCD Controller has connections to the serial port's RX, TX, CTS, RTS and GND pin only; the RTS pin is ignored. Please note that the controlling application has to monitor the CTS pin to avoid overflowing the controller's buffer, which has a size of 128 characters for all iLCD Controllers up to DPC3050 and 1024 characters for DPC3080 and higher. The command Get Input Buffer Size can be used to request the size of the input buffer. Normally, all commands can be sent, even without monitoring the CTS pin when the application waits for the responding [ACK] character, but we recommend using the hardware handshake if possible. Most commands sent to the iLCD Controller will fit into this buffer. Exceptions are commands like Write Text, Write Scan Line or Write File, in which the length of the parameter is not limited. If no CTS monitoring is used, the user has to take care to break the data into smaller chunks and to wait for the [ACK] character after each block of data to avoid overflowing the input buffer.
When using RS-422 or RS-485 no monitoring of CTS is available therefore the user must take care not to allow the input buffer to be overrun. If a buffer overflow occurs, the controller finishes any currently running output sequence and then sends an OVR flag (0x19). This is not done when the communication runs via I2C; an extra special overrun bit is set in this case.
The serial port of the controlling application has to be set to the baud rate selected via iLCD Manager XE (initially 115200 baud), 8-bit, no parity and 1, 1.5 or 2 stop bits. When using the RS-422/RS-485 mode (only available on Serial Port 1), 2 stop bits must be selected to allow the controller to switch the transmitter off in time.
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