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ADV7842 HPA Operation

Question asked by MatthewDSE on Sep 25, 2012
Latest reply on Oct 3, 2012 by GuenterL



I am using the port A HDMI input of the ADV7842 and have been unsuccessful in getting the HPA_A (Hot Plug Assert) pin to output a high when 5V is supplied to RXA_5V.  I have been looked through the 5V Cable Detection section and Hot Plug Assert section in the UG-214 guide to help troubleshoot but, can't find the cause of the problem.

Here are things I have tested:

- I verified the registers mentioned in the Hot Plug Assert section actually matched the default values in the guide. HPA_TRISTATE_A was 0 (pin is active), HPA_AUTO_INT_EDID[1:0] was 01'b, HPA_MAN_VALUE_A was 0'b, etc.

- CABLE_DET_A_RAW accurately detects +5V on RXA_5V when a HDMI video source in connected and disconnected.

- HPA_STATUS_PORT_A status bit was 1, indicating the chip should have asserted 5V to the pin.  This bit also changed when the video source was connected and disconnected.

- The HPA_A pin could not be forced on by setting HPA _MANUAL to 1 and HPA_MAN_VALUE to 1.

- Our design has the recommended 1-KOhm resistance between the +5V and HPA.


Any suggestions on getting the HPA_A working would be greatly appreciated.