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ADV7401BSTZ-110 - Hsync Issue

Question asked by lizajake on May 27, 2013
Latest reply on Apr 21, 2014 by GuenterL

Dear All,


I have been using the evaluation board EVAL-ADV7401/3EBZ to generate 24bit RGB output with YPb/Pr being the input mode. The output obtained at pins HS is 64us and Field is 20ms.


We have designed another board with ADV7401KSTZ-140 which is FPGA based and have followed the same schematic as per the Eval Board. The inputs are given at YPr/Pb (AIN4, AIN5, AIN6, SOY). The ALSB is pulled high hence Address is 0x42. I am able to read back the registers and hence I2C write is functioning.


The LLC1 output is 28MHz.


The pins FIELD and VS are having the same output as the EVAL Board. When no input is given, the HS pin has 64us output, but the moment i give the input, the HS output is approximately 52.4 us and is an overlapped signal and cannot be measured correctly.


For the same input given to the Eval board, the output is perfect. I am using the same I2C scripts that is used for the evaluation board, as per the file attached.


Kindly provide any suggestions as to why there is a change in the HS generation. we have used the same schematic and the only change is  the addition of the FPGA and C8051F340 and VGA encoder. Is there any other setting that needs to be done to rectify this.