The ADV7842 use an EEPROM SPI to load EDID informations at the start-up component.
Once the ADV7842 start up, it use the EEPROM SPI ?
Please check whether this thread helps you https://ez.analog.com/message/63435?
Sorry, but this thread don't help me.
The ADV7842 uses internal memory for the EDID blocks. This internal memory can be loaded over I2C or via the external SPI flash. Our reference boards use I2C to set up and configure EDID access by the source.
In the case, where I use the RAM_EDID (whitout EDID memory component). With the I2C command "STORE_EDID", ADV7842 load the EDID informations form the SPI EEPROM. The load of EDID informations isn't automatic on ADV7842 startup, it's correct ? it's only an I2C request ?
If the EDID block is not stored in an external SPI Flash, than software would have to load up the internal EDID memory at power up. Once loaded the ADV7842 will respond to DDC EDID requests from the source without requiring I2C interaction.
I apologize but I misspoke.
I have two ADV7842 and I want use a FPGA to simulate an EEPROM SPI. In this configuration, I must know if the two ADV will not speake at the same time on the SPI bus.
On start up of board, I release the ADV's reset one after the other
If you can guarantee the the EDID will never be larger than 2 blocks, sequencing the bring up should work. If the EDID is bigger than 2 block then when the source request block 3 & 4 the ADV7842 will initiate another request to the SPI FLASH to load up the next 2 blocks. The sources will be asynchronous and may collide.
I would just load up the internal EDID memory at bring up over I2C and let the ADV7842 respond to DDC requests directly without worrying about the external memory.
It might be easier just to add the external memory. Small SPI Flash is cheap and small.
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