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ADV7623 voltage on 5V detect and HPD with no HDMI cables connected

Question asked by torbenmp on Sep 6, 2017
Latest reply on Sep 8, 2017 by GuenterL

Hi

 

We are implementing a custom board using an NXP kinetis k60 and an ADV7623-P.

We are using the ADV software driver to configure the ADV7623-P as a HDMI switch with automatic sensing if there is signal on an input or not.

 

We have followed the schematics in the hardware manual and on ADV7623 evaluation board.

 

The issue is: With no HDMI cabbles connected to our board we measure a voltage of 2.3-2.4V at both 5V_DET and HP_CTRL (for all inputs A,B,C).

I would expect to measure 0V. This is also what I measure on the evaluation board. 

The 2.3V results in CABLE_DET_X_RAW (IO MAP 0x6F ) register to return "cable detected on Port X). This messes up the HDMI switching as implementet in ADV driver. 

 

If I erase flash on our kinetis (which sets up the ADV), then I measure 0V on these pins as i would expect.

This leads me to think that this is FW related.

 

So my qeustion: Which registers or the like which could cause this behaviour?

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