EAO Configurable HMI Panel - Manual (Page 11)

Configurable HMI Panel
Installation Guide and User Manual
Page 10 / 16
Serial Interface
Port settings
To communicate via serial interface, the following settings must be used for the Host COM
port:
 38.400
bytes/s
 8 data bytes
 1 stop bit
 no
parity
RS232 protocol
For the implementation of a serial connection between the host and keyboard, the
information of the keyboard protocol is necessary. First, an overview of commands is given.
Subsequently, the structure of the data frames and control sequences is defined.
Command definitions
Command Dec Hex Description
START_HOST 170 AA Start of frame (from Host)
START_CONTROLLER 171 AB Start of frame (from µC)
END_IDENTIFIER 204 CC End of frame (both Host+µC)
ACK 240 F0 Acknowledgement
ERROR 242 F2 Error in data frame
CODE_UNKNOWN 243 F3 Unknown command
CODE_LEDi 176 B0 Set LED status
CODE_LEDo 177 B1 Get LED Status
Table 3 - RS232 frame commands
Data frame definition
Within the host/keyboard protocol the following data frames are defined (see
Table
4 ). The assignment of the LED’s is the same as for the USB protocol and can
be found in
Table 2 . The key codes (hex values) are also the same as the Usage ID”s
for the HID keyboard report