User's Manual

4. Communication Frame
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On the LT/MT/SX/GT series projectors communication is done in a frame
composed of header, data, and checksum.
The frame sent from the controller to the projector is referred to as
a command, and the one sent from the projector to the command as an
reply is referred to as a response.
The response has two types; Acknowledge (hereafter referred to as ACK)
that recognizes a command and Negative Acknowledge (hereafter referred
to as NAK) that fails to recognize a command.
+--------------+ Command +--------------+
| |-------------->| |
| Controller | | Projector |
| |<--------------| |
+--------------+ Response +--------------+
(ACK or NAK)
4-1. Frame Format
**********************************************************************
One frame comprises a header, a data portion, and a checksum.
Frame Format:
+-------------------------------+----------------------+--------+
| Header portion | Data portion |Checksum|
| | (Max. 4095 Bytes) | |
+-----+-----+-----+-------+-----+-----+-- --+-------+--------+
| 1 | 2 | 3 | 4 | 5 | 6 | ~ | n | m |
+-----+-----+-----+---+---+-----+-----+-- --+-------+--------+
| 8 | 8 | 8 | 4 | 12 | 8 | ~ | 8 | 8 |
| Bit | Bit | Bit |Bit| Bit | Bit | ~ | Bit | Bit |
+-----+-----+-----+---+---------+-----+-- ~ --+-------+--------+
| | | | |
| | | | +------------- Data length
| | | +-------------------- Model code
| | +------------------------- Projector ID
| +------------------------------- ID2
+------------------------------------- ID1
* ID1: (8 Bit)
This is an identification data assigned to each command.
Command :
This sets an identification data assigned to each command to send it.
( See each command description.)
Response :
This returns the 6th bit of received ID1 as HIGH.
For ACK it sends the 8th bit back as LOW (recognized); for NAK it
sends the 8th bit back as HIGH (not recognized).
* ID2: (8 Bit)
This is an identification data assigned to each command.
Command :
This sets an identification data assigned to each command to send it.