DS90UB929-Q1: Power on lockup issue.

Hello,
We received your question and someone in Apps will review and respond to this.

Hi Ken,
Do you have a deserializer attached? If so which deserializer?
Please do a memory dump of the DS90UB929 registers.

Hello,

We are using the DS90UH926Q deserailizer.

Ken.

Can you monitor, with a scope, the DS90UH926 LOCK pin and see a solid logic HIGH level (meaning that the LOCK never drops LOW?

Hello Darryl,

There is no lock. I checked the cable. I verified the pass thru capacitors for the LVDS. I verified for shorts and opens. It is strange. If I let the board sit, sometimes it just comes up and starts working.

What is the HDMI clock frequency? Can you provide a memory dump of the DS90UB929 registers?
Oh, I just noticed you said the reciever is UH926; any reason you are mixing the UB929 with a UH926?

Hello Darryl,

The deserializer was designed with the 926 - can't change that.  The serializer 929 was used because of the the ability to use a single chip for an HDMI input interface.

I will see if I can get the clock.  The screen resolution is 800x400 by 6bit color (18bit color total)  I believe it is somewhere around 25mhz.  I will get the exact clock.

I am including a register dump of the 929.

20 80 00 DA 80 00 00 50 50 00 00 00 00 15 35 03
00 00 02 8B 00 01 FE 1E A1 A5 00 00 0C 01 01 00
00 00 25 00 00 00 00 00 00 20 20 F8 00 00 A5 5A
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 80 00 00 00 00 00 00 00 00 00 00 01
14 A1 1E 00 22 0C 00 00 00 00 02 20 02 06 44 00
22 02 00 00 10 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 A8 00 40 18 00 00 40 00 00 00 00 00 FF 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 A8 00 40 18 00 00 00 00 00 00 00 00 00 00
5F 55 42 39 32 39 00 00 00 00 00 00 00 00 00 00

Hello Darryl,

Sorry for being so late - working on several other problems.

But the HDMI clock is 33.3mhz

Thank you,

Ken

Hello Darryl,

I assumed that the IC was bad and I replaced it with a new one.  The exact same issue.

I am a bit lost on why I have this lockup issue.

Can you offer any other resources ?

Thank you

Ken.

Hello Darryl,

I replaced the IC and it still has an issue. I am including a screen shot of the timing of the power rails in respect to PDB.

Please review and get back with me with any further details.

Thank you.

Ken.

20171116_150505_.pdf

Hi Ken,

Is there a pullup on the DDC-I2C? If so what value and pulled up to what voltage?

A scope shot of the DDC-I2C pins would be helpful just prior to holding HIGH state.

Regards,

Hello Darryl,

We have 4.7Kohm pullup resistors on DDC_SCL and DDC_SDA tired to RX_5V (+5V from monitor) The EEProm VCC is also tied to RX_5V.

Thanks

Hello Darryl,

Here is a copy of the schematic.  Please review.  I will send you a snap shot of the EEprom when the serializer comes out of reset.

Thank you.

Ken.TI Serializer.pdf