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

[Adam]

Hi Elena,

Can you specify what model of omnivision camera are you going to use? Generally I agree with Marc that there is not enough memory on the nRF51 to buffer images. Alternatively, you can change the resolution of the camera, e.g. to QCIF resolution (176x144) if this option is available in your camera. For more omnivision cameras settings please visit www.mobilerobots.pl/index.php You should use the TWI code example from Nordic as a base and modify it to your needs. There is a little difference between SCCB and TWI(I2C). In TWI there is an ACK bit after each byte of transmission and in SCCB the slave don't need to send ACK (Don't care bit) - please see the answer in this post devzone.nordicsemi.com/.../

[Marc Nicholas]

Even QCIF would be well beyond the capabilities of the nRF51 (~25K @ 8-bits)....plus it'd take several seconds per frame to transfer via BLE and even using an external SRAM, you also blow-up the short duty-cycle == long battery life use-case too as you'd be running the SPI peripheral continuously.

BLE is just not optimized for these use-cases.

-m