OPT9221 interface to Qualcomm AP (MSM89xx) using SPI

James,

SSI can be made compatible to almost any SPI interface by configuring the polarities and the output interface related timing parameters. Please refer to OPT9221 datasheet sections -

4-Lane Mode – SSI

1-Lane Mode – SSI

The only limitation is that depending on the configuration, the frame rate will be limited. What is the maximum frame that you are looking at?

Regards

Hi Bharath,

If we use SPI as an interface between OPT9221 and host, will OPT9221 be the SPI master and the Qualcomm AP should work as SPI slave?

There is no specific target frame rate now but can I expect roughly one eighth of maximum frame rate when we use 1-lane SPI interface (compared to 8-lane mode)?
For example the maximum frame rate we can get with 320x240 resolution, 4-byte mode, and 24MHz of OP_CLK will be roughly:
1. 8-lane SSI
frame rate = (8 lane x 24MHz) / (320 x 240 x 4 bytes x 8 bits) = 78.125 fps
2. 1-lane SPI
frame rate = (1 lane x 24MHz) / (320 x 240 x 4 bytes x 8 bits) = 9.766 fps

And in case we use 4-lane SSI mode to connect OPT9221 to the host AP through SPI port, should it be quad-SPI which has 4bits bus?

James,

Your understanding is right. But if we use 2-byte mode, the frame rate can be doubled. Also, if you use binning or ROI features, the frame rate can be increased accordingly.

Regards

Hi James,

Were you successful in using either 1 or 4 lane SSI mode in your application? I'm having trouble enabling SSI mode at the moment. All other settings in DE register 39h take effect like clock polarity and output freq., but writing to bits 9..8 don't seem to have any effect in changing the output mode.

Thanks,
Mike

James or Mike,

Is this issue resolved? If not I like to understand where you're at and see if we can have it working for you.

-Larry