ViewSonic CD4620 Car Video System User Manual


 
ViewSonic CD4620 49
5.3 Get-Function Listing
The PC can interrogate the LCD Monitor for specific information. The Get-Function packet format
consists of 5 bytes which is similar to the Set-Function packet structure. Note that the “Value” byte is
always = 00.
Get-Function description:
Length:
Total Byte of Message excluding “CR”
TV ID
Identification for each of TV
Command Type
Identify command type,
“g” (0x67h) : Get Command
Command:
Function command code: One byte ASCII code
Value[1~3]:
Three bytes ASCII that defines the value
CR
0x0D
Get-Function format
Send: (Command Type=”g”)
Name Length ID Command Type Command Value1 Value2 Value3 CR
Byte
Count
1 Byte 2 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte
Bytes
order
1 2~3 4 5 6 7 8 9
Reply: (Command Type=”r” or “-”)
If the Command is valid, Command Type =”r”
Name Length ID Command Type Command Value1 Value2 Value3 CR
Byte
Count
1 Byte 2 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte
Bytes
order
1 2~3 4 5 6 7 8 9
If the Command is Not valid, Command Type=”-“
Name Length ID Command Type CR
Byte
Count
1 Byte 2 Byte 1 Byte 1 Byte
Bytes
order
1 2~3 4 5
Example1: Get Brightness from TV-05 and this command is valid.
The Brightness value is 67.
Send (Hex Format)
Name Length ID Command Type Command Value1 Value2 Value3 CR
Hex 0x38 0x30
0x35
0x67
0x62 0x30 0x30 0x30 0x0D
Reply(Hex Format)
Name Length ID Command Type Command Value1 Value2 Value3 CR
Hex 0x38 0x30
0x35
0x72
0x62 0x30 0x36 0x37 0x0D
Example2: Get Brightness from TV-05 , but the Brightness command ID is error
and it is NOT in the command table.
Send (Hex Format)
Name Length ID Command Type Command Value1 Value2 Value3 CR
Hex 0x38 0x30
0x35
0x67
0XD3 0x30 0x30 0x30 0x0D
Reply (Hex Format)
Name Length ID Command Type CR
Hex 0x34 0x30
0x35
0x2D
0x0D
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