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ADV7343 not working

Question asked by tnl on Jul 20, 2015
Latest reply on Jul 21, 2015 by GuenterL

Following up from this thread, we ordered ADV7343 which should be supported. I'm trying to test it using the same setup I had for the ADV7171 - it's soldered onto a DIP adapter, and all the required connections are made via perfboard.




The perfboard connects to another PCB that supplies 1.8V and 3.3V (not isolated from each other), as well as I2C lines from a microcontroller and clock and data lines from an FPGA. The lines are roughly 20cm long.



The configuration I have is intended to generate CVBS color bars on DAC 1:


0x010x808-bit 4:2:2 multiplexed input on Y bus
0x820x02DAC 1 to output CVBS
0x840x40Color bar test pattern enabled
0x8A0x09Timing mode - 0 master


The I2C lines work well, and reading registers confirms what I've written to them. However, there's no meaningful output on the DAC 1 pin and the sync pins (the device is configured in master mode, which means that these pins should output sync signals as far as I understand). Measuring the clock signal I found some significant overshoots of about 1.5V, which means that the nominally 3.3V signal peaks at about 5V and -2V:





Could this be the root of the problem? If so, how can I fix this?


Attached is the schematic I went by when making this. I admit that I had to make a lot of concessions due to limited resources, so I'd appreciate it if someone pointed out any particularly egregious deviations from the recommendation in the datasheet.