I only see 1 EDID i2C for the VGA but we are using 2. Is there any
clever scheme we should know about or do we need to supply our own EE for the
Also, can you confirm if EDID is copied to all 4 inputs of the HDMI at the same
If you want both VGAs to be potentially active at the same time then you will have to provide a separate I2C EDID memory for the 2nd source to read.
The EDID information is not copied to all 4 blocks at the same time. You can configure the EDID SPI EEPROM to contain 4 identical blocks of EDID data. There is only one internal memory for EDID data. All EDID request will attempt to pull from the internal memory What happens is, if enable, upon a DDC request the correct EDID is loaded from SPI memory to the internal memory and then the source is released to pull that EDID block from internal memory.
When the power is off can the HDMI and VGA inputs still retrieve EDID
info from ADV7850?
Normally the HDMI or VGA source will supply 5v to power the EE through the connector to read the EDID regardless if the device is powered on or not. Normally we have a EE with diode from the 5v of the units main board and another diode from the 5v that is fed through the connector. This way if the EE is not power because the unit is unplugged the source device connected through the cable can still activate the EE for the EDID info. The chip has the 5v from the connector going to the ADV so the question is does that portion of the IC still work even if the reset of the IC is off.
As long as you follow the example Figure 4, in the hardware guide3 you should be fine
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