Thanks.
I haven't been able to find any other camera with this kind of Digic. Every other Digic (I) camera has the CPU-less version of it. That package is much smaller, and is always used together with a separate x86 MCU. All of those use DOS as OS (which makes them all unsuitable for CHDK).
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[tt] [/tt] |
 [tt] [/tt] |
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| The DIGIC of the S1 IS |
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The DIGIC in the A85 |
The MCU of the A85 |
[hr]
Hmmm, I just realized that
Rayer's site is gone 🙁. It worked a few months ago, when I downloaded the sources (again) which helped decrypting/dissecting the firmware...
update: Site not gone, only
moved.[hr]
This is a very interesting camera, together with its firmware. I think, its specifications required a multitasking environment (no other DIGIC (I) camera featured continuous metering, focus, zoom in movie mode). The camera framework has huge differences compared to the one they used for DIGIC II. The property cases and flash params are all identified by strings, and the values they store are also often strings. The event procedures are referenced by their names, and used with ExecuteEventProcedure in the firmware routines. So, the code is full of strcmp and the like. The ARM CPU also seems much less powerful than the one they used in DIGIC II (our benchmark shows about 17MB/s memory read speed), and it's a previous ARM core generation (as I mentioned it elsewhere).
There are interesting DSP-related blobs in the ROM with strings like
[tt]predecode_mpeg2() rev-0.10 2001/4/23
decode_mpeg1() rev-0.18 2001/07/09
decode_mpeg2() rev-0.18 2001/07/09
encode_mpeg1() rev-0.20 2001/5/13
encode_mpeg2() rev-0.19 2002/5/13[/tt]
which IMHO means they could have decided to use MPEG1 or 2 for video. They used MJPEG instead, probably to not compete with their own camcorders... The DSP core is JP51, the one in DIGIC II is JP52.
I'll probably write more about the camera
here later.
Needless to say, that this is not a usual port. Almost everything has to be emulated to match the behaviour expected by CHDK. When it gets a few more features, I'll release the source too 😀
Of course I also know that 2004 was a long time ago, and this camera was usually manufactured with those flaky Sony plastic case CCDs. (The camera I'm using got a new CCD recently)
