The EDID is transmitted through the two “DDC” lines in the HDMI cable. This a dedicated I2C bus to read out the EDID block, which is stored in RAM and initialized from EPROM each time that the PiCapture board is powered up. From everything you have described, it sounds as though this issue is somewhere in the end-to-end physical connection for these two signals. Getting all 0x00 or all 0xFF is a good indication that the link isn’t working at all. I was hoping that it was just the cable itself, or the connectors on the cable side, but it could also be the connectors on either the PiCapture board or your laptop.
Just for completeness, you might want to try a different power supply for the RPi/PiCapture as well.
You mentioned that the HDMI out on the RPi wasn’t working – are your sure that the output resolution for the RPi was set to one of the supported resolutions (480p/720p/1080p)?
Since you can read the EDID data with another system it seems unlikely that it is the PiCapture board, but I am glad to continue to help try to debug the problem. You could also return it for us to test.
- This reply was modified 4 years, 6 months ago by mwlinder.