Dear expert,
Customer system is camera->UB935->UB954->SoC.
Problem description:
For some boards, SoC cannot get video from UB954 after PDB is active. Then try PDB OFF/ON, sometimes problem is gone. Sometimes SoC still cannot get video from UB954 even after 10 times cycle PDB OFF/ON.
Among 1000pcs boards, there are 8 boards have this issue randomly.
We've tried a lot of test and find the problem go with UB954 silicon. If we re-solder "bad" UB954 to a new board, the phenomenon go with UB954 silicon.
Below attached xls file is UB954 all registers comparison between good UB954 and bad UB954. We read for 3 times for good silicon and read 9 times for bad silicon.
I find the main difference between good and bad is below 0x73, 0x74 registers.
Camera in fact send 640*480 video to UB935.
Good UB954 is 960*964 as below registers. I think this include blanking , right?
954 0x73 0x3
954 0x74 0xc4
954 0x75 0x3
954 0x76 0xc0
Bad UB954 is 960*482. It seems blanking line is missing.
954 0x73 0x1
954 0x74 0xe2
954 0x75 0x3
954 0x76 0xc0
Margin analysis looks normal. NO ECC or other CSI error reported.
From these data, it seems camera is sending wrong video data, but the problem goes with UB954 silicon which is very confusing.
Could you give any suggestion about this issue? This project is already in mass production. Need your quick help here.
UB954 register comparison:
