On my J6 Dra7xx board, there is a DS90ub925q IC, from which the display data should be transfered to the remote LCD monitor, who has a DS90ub928q.
And now, I can access the two device after the linux driver initialized them done. But the LCD has no picture shown. I have checked the VSYNC, HSYNC,DE,PIXCLOCK, and input RGB data, all the signals OK.
Now, I do not know what's wrong with the link. Im sure the monitor is OK.
Then, I have to do a BIST for it, I do it following the datasheet:
1) I set the remote deserializer to BIST mode, write register address 0x24 to 1( its original value is 8)
2) I found the locale serializer has been on BIST mode too, its register address 0x14 value is 1(the original value is 0), so, i think the pair of the devices are in BIST status
3) Now, I found no way to stop the BIST status. Now I can't access the remote 928 deserializer device via I2C. From the document, it will stop BIST status via set the BISTEN pin to low, I hardwire the pin to ground, I still can not access the deserializer via I2C. I check the local serializer BIST mode register, it still be 01, and can not be changed.
The document says, if the PASS output of the deserializer was low, indicated there were one or more errors. I checked the PASS output, found it's LOW now, and it was High before BIST mode. Im not sure if its right because I had not stop the BIST mode. If the method was two, where should I got the error results?
Another question, what's the typically initialization sequence of the two device to make them work for driver the monitor?
Thanks