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ADV7626 SPI write/read issue

Question asked by JustinWu_Ans on Aug 24, 2015
Latest reply on Oct 4, 2015 by JustinWu_Ans

We got issue at SPI writing and reading when we use OSD interface. We try to write and read string data from ADV7626 OSD ram.

But we got wrong values from ADV7626 when we read data back from OSD RAM.


Write waveform :

tek00052_write packet.png

Read waveform :
tek00053_read packet.png


Could anyone give us advice for this issue?

We simulate SPI by GPIO , the speed about 6KHz , is there any limit for SPI speed?

BTW, We also set ADV7626 into SPI_slave mode.


The SPI timing parameters as below.



t20 = 546us

t22 = 162us

t23 = 3.613ms

t24 = 85.2us

t25 = 9.46us

t26 = 160us