MD-215 Hardware
Display Control Interface
4-5
CMD (Message Commands and Queries)
The command portion of the message will be one of the following values. For details, refer to the Display UART
Commands section.
CMD 0
CMD 1
CMD 2
ASCII
Description
0x42
0x52
0x49
“BRI”
Brightness Minimum Value
0x42
0x52
0x4C
“BRL”
Set LED Brightness of Touch Keypad
0x42
0x52
0x4D
“BRM”
Brightness Maximum Value
0x42
0x52
0x54
“BRT”
User Brightness Control
0x42
0x52
0x55
“BRU”
Glass Display Control - Brilliance Button
0x42
0x5A
0x5A
“BZZ”
Buzzer Control
0x44
0x4C
0x4E
“DLN”
Download ECDIS RGB package
0x44
0x4C
0x3F
“DL?”
ECDIS RGB package Query
0x44
0x32
0x4E
“D2N”
Download ECDIS RGB package(Second)
0x44
0x32
0x3F
“D2?”
ECDIS RGB package Query(Second)
0x45
0x54
0x43
“ETC”
Elapsed Time Counter Query
0x47
0x4D
0x42
“GMB”
Glass Display Control - Minimum Brightness
0x50
0x4F
0x54
“POT”
Potentiometer Control
0x53
0x57
0x49
“SWI”
Scalar Firmware Version Query
0x53
0x57
0x4B
“SWK”
Touch Keypad Firmware Version Query
0x41
0x44
0x46
“ADF”
AC Input Power Detect Function
0x41
0x44
0x3F
“AD?”
Query AC Input Power Detect Function Status
0x44
0x44
0x46
“DDF”
DC Input Power Detect Function
0x44
0x44
0x3F
“DD?”
Query DC Input Power Detect Function Status
0x42
0x4C
0x49
“BLI”
Brightness Control
0x44
0x55
0x46
“DUF”
Disable UART Command Function
0x45
0x4D
0x53
“EMS”
ECDIS Mode Select
0x43
0x54
0x3F
“CT?”
Current Temperature Query
0x53
0x53
0x3F
“SS?”
System Status Query
0x4D
0x43
0x43
“MCC”
OSD Control Command
LEN (Data Length)
This byte defines the length of data in the message in bytes. The maximum value for this field is 74 bytes, and
the minimum value is 0.
IHCHK (Inverse Header Checksum)
This is a simple 8-bit checksum of the first six bytes of the packet (bytes 0 to 5) after a bitwise inversion has
been performed on them. This means the 8-bit sum (without carrying) of bytes 0, 1, 2, 3, 4, 5, and 6 is 0xFF.
IHCHK = 0xFF – [the sum of bits 0, 1, 2, 3, 4, 5]
DATA (Data Field)
The data field must have a LEN larger than 0; some commands do not have any data, so this field is left blank.
IDCHK (Inverse Data Checksum)
This is a simple 8-bit checksum of the data field, message bytes 7 to 7+ (LEN-1) after a bit-wise inversion has
been performed on each bit. This means that the IDCHK bit is equal to 0xFF, the sum of all data bits:
IDCHK = 0xFF – [the sum of bits 7 to 7+[LEN-1]]
If the message carries no data, then this checksum is not transmitted.