AnsweredAssumed Answered

ADV7403 I2C read issue

Question asked by HankZ on Jun 24, 2013
Latest reply on Jul 12, 2013 by DaveD

I have developed an interface board to receive VGA data and output to RGB888

(24 bit RGB digital data).  I am having an issue where the I2C appears to be

programming the device correctly but read-back does not appear to work.  I have

worked on this for the last few days and thought that several things could be

wrong.  First, I connected TEST0 and TEST1 per the evaluation board design of

the 7403.  I have since disconnected these lines and there is no change.  I

have modified my I2C pullups and series resistors and this has not had an

impact.  When I write data, the device acknowledges on the 9th bit correctly. 

When I read data, I get the slave acknowledge up and until I begin to generate

clocks and perform a master acknowledge to the device.  The device appears to

not be giving any data back.  I also know that through the configurations I

have programmed, the pixel clock should be specific frequencies (65MHz, 75MHz,

etc.).  I have confirmed that these frequencies are in place so I am certain

that the device is operational.  I am just uncertain as to why it appears to be

block from the reads.  I am using a PIC 32MX795F512L with integrated I2C

peripheral to talk.  Any help would be greatly appreciated.

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