How to connect a low-cost CMOS imager directly to BBB CPU?

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1

Hi all,

I am looking for a low-cost solution to connect a sub $3 CMOS imager to a sub $6 application processor. This is for a cost-sensitive video application.

Unfortunately, it looks like the TI processor at the heart of the BBB cannot directly decode CMOS imagers. All camera capes I have seen appear to require an ASIC between the imager & CPU to act as ‘glue logic’, which significantly raises costs.

Has anyone been able to connect a low-cost CMOS imager to the CPU without glue logic? (Like it can be done with the RaspberryPi or the i.MX25)

Thanks!

2

Have you looked at a cape? http://elinux.org/Beagleboard:BeagleBone_Capes

I counted two listed at the cape website.

Gerald

3

Hi Gerald, thanks for taking the time.

Unfortunately, it appears that both of these capes rely on an ASIC to perform the glue logic between the CMOS imager and the TI CPU, which greatly increases BOM costs.

I’m currently trying to find a chip that can beat a $7 Freescale i.MX25 connected directly to a sub-$3 CMOS imager for a cost-sensitive application.

Is there anyway to connect a CMOS imager directly to the TI Cortex A8?

Thanks!

4

The AM37xx supports a camera interface. It is used in the BeagleBoard-xM.

Gerald

5

Hi Gerald, thanks for that useful info.

The AM37xx does indeed appear to have a video input port capable of interfacing to CMOS imager. Unfortunately for us the $14 per chip price is too much for this next application… although a high-end product using this chip could be of use eventually.

Cheers!

6

It does. AM3730. There is even a CMOS imager add-on board. http://www.elinux.org/Beagleboard:BeagleBoard-xM

Gerald

7

Hi!

What CMOS imager do you use? $3 sounds tasty

8

I have directly interfaced the BBB with low cost camera modules using a PRU on the TI AM335x. I have only tried using the parallel digital video port (DVP) type of image sensor interface. I used PRU1 since it has a maximum of 15 input pins available [PRU0 has a maximum of 11 input pins available] and I wanted to support 10-bit DVP which requires a total of 13 input pins (10 data out, a pixel clock, a horizontal reference, and a vertical sync).

My design includes provision for a crystal oscillator to clock the image sensor, but a timer (timer4, timer5, timer6, or timer7) on the AM335x can be used to supply a clock.

So it is possible to interface directly (without any glue logic).