> Microchip doesn't yet have an image sensor interface.  Atmel has a few
> parts, but they all require external memory, and are in the $10-$25
> range, rather than $5 - $10.
>
> What other chips have image sensor interfaces?  (YUV 8, RGB 8/10,
> parallel cmos image sensor)
>
> Is there a chip with onboard flash and ram (32k or more of each,
> ideally, but I can deal with lower ram and flash as long as I don't
> have to buy external memory)?
>
> Should I look at FPGA/CPLD (ie, is the cost of a small FPGA + pic32
> going to be lower than an atmel + memory, for example)?
>
> What other options should I look at?
>
> I'm essentially trying to take pictures as cheaply as possible.  Right
> now I'm using this:
> http://www.sparkfun.com/commerce/product_info.php?products_id=9334
> for $50 each
>
> But would like to interface to this:
> http://www.sparkfun.com/commerce/product_info.php?products_id=8668
> for $10 + microcontroller + support circuitry
>
> -Adam

Those are interesting parts, especially with the on-board JPEG
compression. I did a project using a Micron image sensor (now made by
someone else). In this particular application (movie screen illumination
analysis), I was only interested in certain pixels, so I did not need
memory for the whole image. Using a 24H chip, I bit banged the interface
to the camera chip. All pixels were passed to an LCD display (that had
on-board controller and RAM so I didn't have to continuously refresh that
too). When I got to a pixel that I wanted to keep for analysis, I kept
that in internal RAM in the PIC. Running the sensor in "snap shot mode"
(take a picture, then clock out the data, as opposed to simultaneous
taking picture and clocking out the last frame's data), I got about 12
frames per second with a 24H running at 40MIPS.

It seems that there will be RAM shortage issues in any application using a
microcontroller for image manipulation. I did another project where we
needed to update a large graphic LCD. For that, we hung a large static RAM
on a CPLD. The CPLD handled the refresh of the LCD and also made the RAM
visible to the PIC (stuffed PIC requests between RAM accesses for display
refresh).

In several projects, I've needed to drive graphic displays with Unicode
characters. One current project (closed captioning for movie theaters)
uses an OLED display. I had to go to external flash (M25P16) to hold the
character bitmap. At least that's just an 8 pin part and runs fast.

It would be great to see a microcontroller with "video RAM" in it that
would automatically handle image capture and/or display while also
allowing the micro to address it on a pixel by pixel basis. But, that's a
lot of RAM to stick in the chip. In another project (more closed
captioning, but not the display side), I added a 1MB static RAM outside a
24H chip to hold XML files I'm getting from a remote server and for
several large FIFOs for outgoing data.

Let me know what you find!

Harold


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