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ADV7625 Lost PLL locking issues

Question asked by feng.wenlong@excelpoint.com.cn on Mar 25, 2014
Latest reply on Mar 27, 2014 by feng.wenlong@excelpoint.com.cn

Issues:

the ADV7625’s 3840*2160@30hz(4k2k@30hz), output Lost display.

Test equipment: ASTRO VG-871B, Display TV: skyworths 50E78U

our Board

 

IC P/N: ADV7625KBCZ-8-U2, #1331,2675006.1 CHINA

 

ADI’s Demo Board: A0364-2012 REV 0.1.IC P/N:ADV7625KBCZ-8,#1342,2723987.1 CHINA

soft script version: ADV7625ES2C-VER.1.2c.

 

soft setting: RXA->RX1->TXA ;mode: HDMI- MUX Mode

 

help for item:

1.       Recheck if the IC’s version result the issues?

2.       Recheck the 0XB8(TXA_MAP),0XF3,Bit[0]’s meaning and affect to the Tx. This register not label in the design files.

3.       We think the ADV7625’s Rx locking the signal, but ADV7625’s Tx Lost locking it. Advise some better way to solve the issues.

Result of issues:

Suspect:

1)       The IC’s Version result the problem ?

=>

We think the different version IC if use the different soft setting which we not get? if ture ,please give us the new script

2)       HDMI’s Layout different match?

=> our layout PCB Z value:  95.89Ω(PCB factory test date) , requirement (range 90Ω-110Ω)

used the same rule for both of the HDMI input and output. And the HDMI input could lock the 4K2K’s clock. Read register : TMDSFREQ[8:0]=296,TMDSFREQ_FRAC[6:0]=88, =>Result = 296.6875Mhz.(when the input tmds clock= 296.703Mhz)

or for the 296.687Mhz locking rate is in error's torelance and result in lost locking of Tx block ?

 

3)       Test the signal out. (Test oscilloscope  RIGOL- DS6062, 600MHZ bandwith, input 4K2K@30Hz)

 

Input’s clock wave, stable , and the RX could lock too.

figure 1

Output’s clock wave, un-stable, and think the output’s in the un-stable.

figure 2

4)       Read back the HDMI Tx Main 0XE4[7]=0, means the Tx block not lock the video PLL.

5)       And for this bit .TXA-Main -0XE4=00, meaning the PLL video not lock.(4k2k@30hz), but the 720p could lock it. Value =0x80, but for the 1080p, need to set the TXA-Main-0XF3-Bit[0]=0, (default setting =1).could lock it.

6)       Recheck the soft setting .use the ADI’s script to refresh in the our board , it is not well, So for software , think maybe the IC’s version and need the other’s setting script.

7)       For hardware , measure the power supply but the power supply looks well. our board: PVDD:1.78V,ripple wave 28mV, ADI’s PVDD:1.79V, ripple wave 30mV.

And used the PVDD of ADI’s Board supply to the customer board. It is not well too.

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