DS90UB947-Q1: UB947-UB948: The devices fails to pass through a live 1080P signal from the camera. However, it is able to pass through a 1080P colorbar without issue.

Hi Kexiang,

To evaluate the quality of the FPD-Link, there is the Margin Analysis Program (MAP) which is featured in the ALP Profile for the UB948. Below is the link for the app note that covers the features of MAP. MAP allows the user to check for strobe and EQ positions that are prone to loss of lock.

Note that MAP must be run locally on the UB948 I2C bus. It cannot be run remotely from the UB947 I2C bus.

MAP App Note: Link

Best,

Jack

Hi Jack, 

Thank you very much. However, I have one concern about the MAP. 

Refer to FPD-Link Margin Analysis Program (MAP) user's guide, for IVI devices (948, 940, 928, 926, and 924), only lock is monitored.  how can I know the poor quality (e.g. BER etc) given the locked link?  we verified the link using a colorbar from the ISP for several hours without any problems. However, when we switch the video source to live 1080P from the camera, the displayed video is unstable. 

Regards,

Kexiang

Hi Kexiang,

You are correct that the MAP program does not provide a BER measurement for the FPD-Link. Did you already run MAP on your system? 

There are two tools I will mention that you can use to check the link

1. Built-in Self Test (BIST). BIST is outlined in both the UB947 and UB948 datasheet. BIST is enabled at the UB948. BIST tells the UB947 to send a known pattern and the UB948 will tell the user if it detects errors. 

2. UB947 pattern generation (PATGEN). The UB947 contains an internal pattern generator which can be used to check if the flickering feed from the camera is a link issue or a camera issue. 

If you are wanting a specific BER measurement, this will need to be done using external equipment that sends a known pattern into the UB947 and compares it to the output at the UB948. Hopefully, the two tools I listed above will illuminate the issue without a more rigorous BER measurement.

Best,

Jack