Samsung SP-L331 Projector User Manual


 
5-2 More Information
5-2 RS-232C Command Table
Communication Format (Complies with the RS232C Standard)
Baud rate : 9,600 bps
parity : None
Data bits : 8, stop bit : 1
Flow Control : None
Serial Communication Protocol
1. Command Packet Structure [7bytes]
A command packet consists of 7 bytes in total.
The two bytes 0x08 and 0x22 signify that the packet is for serial communication.
The following 4 bytes represent a pre-defined command that can be defined by the user.
The last byte is the checksum which checks the validity of the current packet.
Header [2 Byte]: Pre-defined values fixed to 0x08 and 0x22.
Cmd1 [1 Byte]: The first value of the code defined in the command list (Hexadecimal)
Cmd2 [1 Byte]: The second value of the code defined in the command list (Hexadecimal)
Cmd3 [1 Byte]: The third value of the code defined in the command list (Hexadecimal)
Value [1 Byte]: Input parameter for the command (Default: 0) (Decimal)
CS [1 Byte]: Checksum (the 2’s complement of the sum of all the values except for the CS value.)
2. Response Packet Structure [3 Bytes]
1. Success
2. Fail
When the received packet from an external device has a valid value, a Success packet is sent. Otherwise, a Fail
packet is sent.
A Fail packet is sent if:
The received packet length is not equal to 7 bytes.
The 2 byte packet header value is not equal to 0x08, 0x22.
The check sum is incorrect.
Failure detection by an external device
An external device classifies the packet as Fail if it does not receive a Success packet within 100ms.
0x08 0x22 cmd1 cmd2 cmd3 value CS
0x03 0x0C 0xF1
0x03 0x0C 0xFF