Epson PowerLite 8150i RS-232 Reference Manual (ESC/VP) - Page 5

ESC/VP Level 6 Serial Communication Manual (Abridged Edition) 5. COMMAND STRUCTURE • ECommands are expressed as hexadecimal codes. • All commands start with an ID code and end with a checksum. When an ESC/VP command which is sent from the computer is received by the projector, a reply is returned. However, the replies which are returned by the projector only indicate whether the initial command was received by the projector, and do not indicate whether the command was executed or not. Acquisition commands are sent in order to check the execution of a command. In addition, if the next command is sent before the reply to a previous command has been received from the projector, it may result in a communication error. The command structure is shown below. bytes. (1) STX (2) Size (3) Attribute (4) FromTo (5) Group * The maximum length for a command is 1024 * Command layout is BigEndian. (6) Item (7) Parameter (8) Check Sum (1) STX : 0x1D (1 byte) (2) Size : Size of a command packet (Specifies a number of the data from 1D to CS) (2 bytes) Example) To turn the power on over a serial connection 1D 000x 01 01 00 03 01 CS ---> 0x0009 Example) To check the power status over a serial connection 1D 000x 02 01 00 03 01 CS ---> 0x0008 (3) Attribute : Indicates attributes such as apply command/reply command, OK/Not OK, etc. (1 byte) The attribute codes are shown below. Table 5-1. Attribute of the Apply command Attribute Set Get Initialize Package Attribute code Caption 0x01 Sets, reports and indicates values. 0x02 Gets the current value. 0x03 Initializes a value. 0x05 Command which combines the attributes of setting, reporting, indicating and requesting. Table 5-2. Attribute of the Reply command Attribute Attribute code Caption Return Packet for setting (OK) 0x81 Indicates that the set command received was analyzed correctly. Return Packet for setting (NG) 0xC1 Indicates that the set command received was not analyzed correctly. Return Packet for getting (OK) 0x82 Indicates that the get command received was analyzed correctly. Return Packet for getting (NG) 0xC2 Indicates that the get command received was not analyzed correctly. Return Packet for initializing (OK) 0x83 Indicates that the initialize command received was analyzed correctly. Return Packet for initializing (NG) 0xC3 Indicates that the initialize command received was not analyzed correctly. Response to package (OK) 0x85 Indicates that the combined attribute command received has been parsed correctly. Response to package (not OK) 0xC5 Indicates that the combined attribute command received has not been parsed correctly. Alert response to commands 0x8F Indicates that the command received contained an error and could not be parsed correctly. 5 of 20