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the problem about ad9388 in HD1080i

Question asked by jackiewong on Oct 28, 2010
Latest reply on Feb 28, 2011 by DaveD

ADI expert:

We now use AD9388a(the signature on the top plane is: bstz-5p #0831 14855841) in HD video system. The basic configuration of ad9388 are:

1,Input video format is HDTV1080i@60( HDMI(portA), 74.25MHz). The input clock of chip on PIN66 is 28.6363MHz.

2,The analog input is not used, SOG,SOY,Hsync,Vsync,AIN1-AIN12 are connected to GND。

3,According to Appendix B in hardware datasheet,Rev. J June 2010,pp238 Typical Connection Diagram, GND is not split, in others word, the Bead inductors are not used to connect analog GND and digital GND.

4,Audio port is not used(the pins about audio are open )

5,The different power such as PVDD_1.8V, AVDD_1.8V, DVDD_1.8V, DVDDIO, CVDD_1.8V and TVDD_3.3V, are separated with Bead inductors。

6,DVI input pairs are welded well, connected correctly, and have same layout length.

7,DDCA channel and DDCB channel are not used and was connected to 3.3V through 4.7k resistors.

8,The output video format is 4:2:2 16bitYCrCb mode(mode 6).P0,P1,P10,P11 and P20-P29 are open.

9,The output clock on PIN51 is 74.25MHz。

10,Power on and reset correctly , PIN107,PIN108(test4,test5)have about 53.25KHz and 106.5KHz square wave.

11,According to Appendix B in hardware datasheet,Rev. J June 2010,pp238 Typical Connection Diagram, the other pins are configured.

 

The problem is the waves in DE,VS,HS(PIN16,17,18) are wrong, especially the VS is not the expectedly 30Hz, it is not stable. The image captured by DSP is bad. I use AD9388 first time. Please help me, thank you.

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