Dear Team,
our customer wants to use DP159 but runs into issues during the HDMI compliance testing. Below their description.
Any advice is very much appreciated.
Best Regards
Martin
Currently we are developing a product with an HDMI output based on a Xilinx Ultrascale+ FPGA and a SN75DP159RGZ. We have the HDMI output operational when it is connected to a monitor.
To make sure that our output is compliant with the HDMI standard, we want to do a compliancy test. We use a HDMI2-TPA-P adapter in combination with a Tektronix MSO73304DX scope.
Unfortunately, we have some issues in creating an output signal at the HDMI output connector when the compliancy tool is connected. The HPD pin is forced high, which should enable the output.
We see that the FPGA streams the TMDS signal towards the DP159. Though, the DP159 seems to block the signal and does not output it to the HDMI output connector.
When looking at the i2c control registers we see no differences between the state where a monitor is connected compared to the state where the compliance tool is connected:
Register |
Register value |
Register value |
0x09 |
0x06 |
0x06 |
0x0a |
0x31 |
0x31 |
0x0b |
0x80 |
0x80 |
0x0c |
0x48 |
0x48 |
0x0d |
0x00 |
0x00 |
0x0e |
0x00 |
0x00 |
0x0f |
0x0f |
0x0f |
0x10 |
0x00 |
0x00 |
0x11 |
0x00 |
0x00 |
0x12 |
0x00 |
0x00 |
0x13 |
0x00 |
0x00 |
0x14 |
0x00 |
0x00 |
0x15 |
0x80 |
0x80 |
0x16 |
0x00 |
0x00 |
0x17 |
0x20 |
0x20 |
0x18 |
0x00 |
0x00 |
0x19 |
0x00 |
0x00 |
0x1a |
0x00 |
0x00 |
0x1b |
0x00 |
0x00 |
0x1c |
0x00 |
0x00 |
0x1d |
0x00 |
0x00 |
0x1e |
0xa8 |
0xa8 |
0x1f |
0x0f |
0x0f |
0x20 |
0x0a |
0x0a |
What is preventing the DP159 from outputting the HDMI signal?
And how can we force it to output the signal?