ViewSonic VP2650WB Service Manual page 39

<Note A> Byte4 (cksum) = Byte1 + Byte2 + Byte3
<Note B> Data = The value write to MCU or EEPROM
<Note C> XX = don't care, any value (<=0xFF).
<Note D>
When PC Host sends 0x7D command to MCU, MCU must return as following (2
bytes)
Return Code
Checksum error code
Normal return code
If normal return code is exact FCh
<Note E>
DDC/CI command
Command code for DDC/CI mode change to IIC alignment mode
Byte2
Byte1
0x6E 0x51
Description:
1. For DDC/CI supported model, its default IIC slave address is set to 0x6E, not 0x7C. So the
above command words must be issued before doing IIC alignment procedure. It is to inform
MCU that change IIC slave address from 0x6E to 0x7C.
Where Byte8 (checksum) = Byte1 xor Byte2 xor ... xor Byte7
2. EEPROM mapping
ViewSonic Corporation
IIC command
Byte3 Byte4
0x03
0x84
R-Byte1
FC
the above Byte3 (/data)
FC
Byte5 Byte6
0xff 0x00
36
Confidential - Do Not Copy
R-Byte2
AA
FC
CF
Byte7 Byte8
0x00 checksum
VP2650wb-1