DLP / Pico /I2C

Can someone tell me the difference between i2c and bus3-i2c (other than i2c doesn’t
work for me talking to the pico projector).

Has anyone tried inputing data vi the cpu interface mode (as opposed to DVI-D)?

I am desperate to bypass the image processing and get a 1:1 relation ship between the
data in and the pixels. The source resolution modes set by register 0x05 seem to apply
to the cpu interface mode and NOT the DVI-D input (otherwise0x05=0x7 would be ideal).
the DLP programmer’s manul is not very clear here.

It appears CPU input requires finding the output signal CPUVSYNC does anyone know
where this might be found?