Using SPI to interface an omnivision camera?

[Elena]

Hello,

I would like to develop an application that makes photos using a small camera from the omnivsion series and send the data via Bluetooht, using the nRF51822. These cameras use the SCCB (Seria Control Camera Bus) interface, which is similar to the I2C. So I would like to know if I could use one of the SPI interfaces to implement the SCCB. Or Maybe Are there any other easier way to contol the camera? I would like to know too, if you have any SPI library or any example code that could help me to program the camera control bus.

Thanks for your help

[Marc Nicholas]

Hi Elana,

The cameras use SCCB as a control channel for setup only. It is I2C, but obviously I2C is a Philips trademark/standard....which is why Nordic called their implementation TWI.

To get data out of the camera, you latch a parallel data bus. Often this requires an external buffer IC.

Three problems you'll face:

(1) The amount of bandwidth the camera requires to latch out an image. (2) Lack of enough memory on the nRF51 to buffer that image, requiring an external SRAM instead. (3) The S110 SoftDevice is actually one of the better performing BLE stacks, but you'll be lucky to get 5Kbytes/sec throughput.

-m