DS90UB936-Q1: Bt656 stream with DS90UB936-Q1

Casey,

  I read through those threads, We understand that BT656 doesn't require additional HSYNC and VSYNC .

In this case the transmitting microcontroller in addition to sending BT656 sends discrete HSYNC/VSYNC digital input to 913A serilaizer.

On reception side the HSYNC and VSYNC are received , will the deserializer in this case convert the received Data to CSI2 and forward to SOC

Hello Rajendra,

Ok, so can you describe in more detail what problem you are seeing here? Have you set register 0x70 to match the expected data type for your video?

Select the desired RX port with 0x4C

Set 0x70 = 0x1E for YUV422 8 bit 

or 

Set 0x70 = 0x18 for YUV420 8 bit 

or 

Set 0x70 = 0x1C for YUV420 8 bit chroma shifted

Best Regards,

Casey 

Casey,

  The Issue is that Serializer input is a BT656 (YUV) Stream with EAV and SAV fields.

We wanted to understand  , if HYSNC and VSYNC pulses are sent along with BT656, Will De-Serializer construct the CSI-2 packets using the external HSYNC and VSYNC?

The assumption is that Since the SAV , Blanking and EAV fields are during the HSYNC , they will simply be ignored by 936 while constructing the CSI packet and the same applies to VSYNC.

If this is the case, we could look into register configurations/VSYNC/HSYNC adjustments.

The register 0x70 is configured to 0x1E and RX port is set to 0x4C .

Hello Rajendra,

If HSYNC/VSYNC are sent along with the data, then it can work. The HSYNC and VSYNC signals are used to generate the CSI-2 packet structure. There should be no configuration needed for this. What issue are you seeing?

Best Regards,

Casey 

The Output is being fed to a CSI 2 Peripheral of a Qualcomm 6150 Microcontroller.

We are getting a Image front end overflow error, Initially we were suspecting if the BT656 encoded stream was being sent on the CSI-2 packets , It is now clear that only YUV 4 22 raw packets are part of the CSI 2 packets.

We will now look into whether the VSYNC and HSYNC pulses are synchronized with the BT656 packets sent , Do you have any suggestions or areas we can look into

Hello Rajendra,

I would suggest taking a look at the DS90UB936-Q1 registers for the RX port which is attached to your camera. Specifically 0x73-0x76 which show information on the received line count and line length. You can check those during operation to see if they meet expectations.

Also, you can map out frame valid and line valid signals to 936 GPIO which is described in the datasheet. This will allow you to probe the sync signals for the incoming video to help diagnose any issues

Best Regards,

Casey 

We are facing a minor issue. We could see a green patch at the end, as told earlier, we see 935 lines from de-Serializer, we are checking with i.mx6 input as well in parallel( we suspsect a wrong video configuration), but wanted to understand if there is a possibility that de-Serializer does a pass through of the data during VYSNC instead of sending CSI-2 Blanking packets?