Quantum Data 881, User Manual

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882 Video Test Instrument User Guide (Rev A.35) 115
Understanding the HDCP test
Understanding what the 882 does during an HDCP test can help you determine why an
HDCP test failed.
HDMI HDCP test sequence:
The HDMI HDCP test sequence performed by the 882 is listed below.
1. Reset the transmitter HDCP engine.
2. Initialize the transmitter.
3. Check Bcaps over the DDC bus to determine if the sink is a receiver or a repeater and
generate a new An value (8 byte random session number) in the transmitter.
4. Transmitter writes An to the receiver using the DDC bus.
5. Transmitter writes Aksv to the receiver using the DDC bus.
6. Read Bksv from the receiver over the DDC bus and validate that it has exactly 20
zeroes and 20 ones in it. You can query this value with the following command:
i2cr? hdl 74 0 5
I2CR? (OUT1:I2CR?, OUT2:I2CR?, VGA:I2CR?)
The display may return a value such as the following which is:
07BE05CEA9
The value in binary is 0000011110111110000001011100111010101001 which contains 20
zeros and 20 ones.
7. Write the Bksv value to the transmitter to trigger calculation of R0.
8. Wait for the R0 calculation in the transmitter to complete.
9. Wait for at least 100 milliseconds and then read the R0' value out of the receiver over
the DDC bus and compare the value with the R0 calculation in the transmitter. If this
step fails, then go to step 1.
10. Enable encryption and read Ri' from the receiver over the DDC bus every 128 frames
and compare it to the Ri value calculated in the transmitter. As long as the Ri value
matches the Ri' value from the receiver continue to check these every 128 frames.