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 :
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