FPD Link III DS90UB913A/914A Forward Channel Issue

hi,

The following is our board setup:

FPD link III : single ended coax cable of 5m supplied by Rosenberger with suitabe male - female Fakra connector required for the spec.

                                   59S10K-40MT5-Y on Board   and 59K16B-102T4-Z on Dacar 140 coax cable

Video signal rate : 74.2 MHz, 720p

Mode: 12 bit High Frequency Mode selected in Des Rmde 3k.

Ser Clk:  Pixel Clk from Image Sensor, Rmode 100k.

Channel: RIN0+(Des) Dout+(Ser)

Bi-directional back channel is working fine.

i can able to configure sensor registers to kick start the image sensor through BCC i2c communication by image  processor.

Also i can drive GPIO of Ser through Des from Image processor.

Also i transferred power to the board 1 from Board 2 over FPD link - 9V  ( few mV volt drops around 30 to 40mV over coax cable)

Issue:

The Image Sensor is giving Data, PCLK, Lv, FV signal, but i couldn't receive the these sensor outs on the Des side. What will be the issue?

The SerDes Ckt is developed with reference to its TI Ser - Des EVM also used recommended coilcraft inductors. impedance matching in brd is taken care.

Also unused channels are terminated with 50ohm and 0.047uF in series as recommended in both Ser and Des.

Observations:

1. Before Image Sensor is kickstarted, Des and Ser runs with its internal clock as per device functionality.  At this time, Des PCLK out is 37.5 MHz, as per datasheet and i observed the same in our board

2.  Once sensor is alive and PCLK out is available to Ser,  Ser Register 0x0C b[2] is 1, i.e valid PCLK is detected. But no output on Des side, still its PCLK out is 37.5 Mhz.

3.  On Des      BISTEN = 0.  OEN, OSS_SEL set 1,  PDB and LOCK are high.    Sel =0;

4. On Ser, PDB is high.

5. All Devices are active.

6. Des is configured in i2C pass through mode for i2c comm to sensor.

Please tell us what may be the issue?  which are the register bits need to check to identify the issue? how to overcome this problem.

Regards

S.Muthukumar