882 Video Test Instrument User Guide (Rev A.35) 71
Sending CEC messages from an emulated HDMI CEC device
You can send messages to a device from an emulated device over the command line
using the MSGX command. You can also receive messages from a device and view them
in the CEC log. The procedures below describe how to send basic messages to a CEC
device.
To send CEC messages to a device under test:
1. Determine the logical and physical address of the device.
2. Identify the CEC messages that a device responds to.
Note: The HDMI CEC spec lists the messages that particular devices must respond
to. Consult this specification to ensure that the anticipated response of a device to a
particular message. The CEC spec also provides a list of functions and associated
operational codes that are specified on the CEC message command line.
3. Send a message to the device under test to get its physical address.
CEC1:MSGX 3 0 83 //request physical addr of device at logical addr 0
from address 3
4. Query message log to view response.
CEC1:MSGX? //view most recent response
CEC bus query should return the following:
0F 84 10 00 03 //device under test returns its physical address
the first digit (0) is the logical address of
the target device the device under test);
the second digit (F) is the logical address of
the sending device (the emulated device);
the opcode (84) is the returned message code
(give logical address)
5. Send a message to the device under test to get its vendor ID.
CEC1:MSGX 3 0 8c //request vendor ID of device at logical address 0
6. Query message log to view response (the most recent message).
CEC1:MSGX? //view most recent response
CEC bus query should return the following:
0F 87 00 07 AA //device under test returns its vendor ID
7. Send a message to the sink device under test to return its tuner status.
CEC1:MSGX 3 0 08 //request tuner status of device at logical addr 0
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