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SPI Problem using the ADV7623

Question asked by MDD on Dec 1, 2014
Latest reply on Dec 5, 2014 by MDD

We have been working for some time to communicate with the ADV7623 using the SPI bus, but the only data being sent on MISO is zero, when code is being sent to the device on MISO, along with SCLK and chip select. Trying the ADV7623 in SPI master mode using the script below gives the traces seen in SPI_Master_Mode.png attached:

 

ADV7623 reg 1fh 1

ADV7623 osd reg 0 80h

ADV7623 osd reg 60h 81h

ADV7623 osd reg 61h 1

ADV7623 osd reg 62h 2

ADV7623 osd reg 63h 3

ADV7623 osd reg 64h 13

ADV7623 osd reg 65h 1

ADV7623 osd reg 66h 80h

 

In slave mode we are using the following script:

 

ADV7623 reg 1fh 1

ADV7623 osd reg 0 80h

ADV7623 osd reg 60h 80h

 

The data being sent in slave mode to the colour look-up table, word 6, with RGB= 0xa9 0xaa 0xab as test data. The waveform seen on the logic analyser is shown in SPI_Write_Reg6_0xaa.png and SPI_Read_RAM_Reg6.png.

 

As a last resort to see if the chip would give a response, we tried all the values from 0 to 0xFF for the first command then 1 to 20 as the data, in the hope that the ADV7623 would recognise a command and respond. The results can be seen in the attachment SPI_Test_Write.png.

 

KEY: Please note that in all the waveforms D0 = SCLK, D1 = nCS, D2 = MOSI and D3 = MISO.

 

Any idea why there is no response on MISO?

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