Communication Protocol - Datavideo HDR-45 Quick Start Manual

4. Communication Protocol

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All communications between the CONTROLLER and the DEVICE will be under the direct supervision of the CONTROLLER.
When the DEVICE (HDR-45/55) receives the COMMAND from CONTROLLER, the following COMMAND is returned.
ACK:
COMMAND+DATA:
NAK+ERROR DATA:
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The CONTROLLER must not transmit additional COMMAND blocks to a DEVICE (HDR-45/55) prior to response to a previous COMMAND block.
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The CONTROLLER must transmit of bytes in a COMMAND block for with intervals less than 10 milliseconds. If a DEVICE (HDR-45/55) detects an
interruption of a byte in a COMMAND block that exceeds 10 milliseconds, it executes a TIME-OUT error sequence, voids the receiving COMMAND
block, and transmit a NAK (TIME OUT).
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When a DEVICE (HDR-45/55) receives a COMMAND block from the CONTROLLER, the DEVICE must transmit a response within 9 milliseconds.
Therefore if the CONTROLLER cannot receive the appropriate response from the DEVICE within 10 milliseconds after transmitting the COMMAND
block the CONTROLLER detects a communication error, and must execute an appropriate process.
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When a DEVICE (HDR-45/55) detects a communication error, it must immediately transmit a NAK to the CONTROLLER. (The content of an error is
shown on the COMMAND tables.) When the CONTROLLER receives a NAK, if must immediately stop transmission of the block. The DEVICE
must not accept a subsequent command within 10 milliseconds after that (except NAK-UNDEFINED command) and must execute a necessary process.
In case that the DEVICE receives a COMMAND not requiring data
In case that the DEVICE receives a COMMAND requiring data
In case that a communication error is detected or an undefined
COMMAND is received
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