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SERIAL COMMUNICATION INTERFACE (SCOM-RS232)
The host interface uses RS-232 standard with the following settings:
Data Rate:
9600 bits/sec
Data Format:
•
Start Bit = 1
•
Stop Bit = 1
•
Data Bits = 8
•
Parity Bit = None
Flow Control: RTS/CTS (must be connected for proper operation)
Message Format
Sample:
Byte 0
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6 Byte 7
Byte 8
ATTN
ADDR
CMD0
CMD1
CMD2
LEN
IHCHK DATA IDCHK
0x07
0xFF
0x50
0x4F
0x54
0x01
0x05
0x00
0xFF
Byte 0; Byte 0 will always be 07 from the host. The display response can either be 06 ACK
or 15 NAK.
Byte 1; The display need only respond to inputs where Byte 1 is FF. The display response
will always be FF in Byte 1.
Bytes 2/3/4: Bytes 2/3/4 define the message type.
Byte 2 Byte 3
Byte4
ASCII
Message Type
0x42
0x52
0x49
“BRI”
Backlight Brightness Minimum Value
0x42
0x52
0x4D
“BRM” Backlight Brightness Maximum Value
0x42
0x52
0x54
“BRT”
User Brightness Control
0x42
0x5A
0x5A
“BZZ”
Buzzer Control
0x44
0x4E
0x44
“DND”
Download ECDIS DVI-D Table from Display
0x44
0x4E
0x56
“DNV”
Download ECDIS VGA Table from Display
0x43
0x4D
0x44
“CMD” Read ECDIS Table Number of Pages
0x45
0x54
0x43
“ETC”
Elapsed Time Counter
0x4D
0x41
0x4E
“MAN” Manufacturer ID
0x4D
0x43
0x43
“MCC” OSD Control Functionality
0x53
0x4E
0x42
“SNB”
Serial Number
0x53
0x57
0x49
“SWI”
Main Display Firmware Version
0x54
0x4D
0x50
“TMP”
Temperature Sensor
0x54
0x59
0x50
“TYP”
Model Number
Byte 5: Byte 5 indicates how many data words follow IHCHK.
Byte 6: Byte 6 is an Inverse Header Checksum (IHCHK): Sum the first six bytes, then take
the low order eight bits of the result and invert each bit such that the sum plus IHCHK
equals FF.
Byte 7: If there is data in the message, Byte 7 is the first data word. If LEN=0, the message
ends with IHCHK.
