6. Communication Procedure
6-1. Outline of Communication
All communication between CONTROLLER (PC, etc.) and DEVICE (PROJECTOR) is performed by the command block format. Communication is started by the issue of a command at CONTROLLER and ended when the return data is sent to CONTROLLER after DEVICE receives the command. CONTROLLER is prohibited from sending several commands at one time. This means that after CONTROLLER sends one command, it cannot send other commands until DEVICE returns the return data. DEVICE sends the return data after processing the command. The time from when CONTROLLER sends the command until the return data is returned differs according to the contents of the command.
In some cases, CONTROLLER may receive data from DEVICE even though it has not sent a command. (For example, during SYS setting, SIRCS command, and switcher information when switcher is selected.)
Note: When Sircs Direct Command (CMD1 = 17 hex) is sent, return data may not be returned in some cases.
6-2. Reading the Command Tables
The command tables can be found in Section 9 (page 11).
CMD1 indicates the command category. The ACK from the projector is returned attached with the command category sent from the controller. However, when errors of the communication line occur, 10 hex (COMMON) will be returned.
CMD2 indicates the command processing method and processing results. 00 hex (SET) is set when setting data from the controller to the projector or when requesting for data processing. 01 hex (GET) is set when acquiring data. 2 hex (RETURN) is set when returning the ACK of the command received from the projector to the controller and when attaching data. 03 hex (ACK) is set when returning only the processing results.
However, F0 hex (COMM NAK) is set when the command the projector receives from the controller has a communication line error or checksum inconsistency.
The top of each category indicates the meaning of the data.
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