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Digic 5 - whats *really* inside?

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Digic 5 - whats *really* inside?
« on: 27 / April / 2013, 11:10:03 »
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I've been scouring the web looking for real (i.e not Canon marketing-based nonsense) about the Digic 5 and what is really inside - CPU, DSPs etc.  It does not help that Google is getting more useless by the day - I've been through reams of unrelated stuff even when searching for the real name of the processor (Canon CK4-1304).

I see there is plenty of dev work going on here with Digic V powered cameras so surely someone here is privy to the secrets of that chip  :)  Some solid intel would be appreciated.

P.S the CAPTCHA below is really going overboard IMO.  I'm human and I don't recognize some of the pics zoomed-in on my 55" TV.

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Offline reyalp

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Re: Digic 5 - whats *really* inside?
« Reply #1 on: 27 / April / 2013, 15:32:19 »
I've been scouring the web looking for real (i.e not Canon marketing-based nonsense) about the Digic 5 and what is really inside - CPU, DSPs etc.  It does not help that Google is getting more useless by the day - I've been through reams of unrelated stuff even when searching for the real name of the processor (Canon CK4-1304).
Digic (II-V) is composed of an apparently vanilla ARM 946e-s implementation and a proprietary DSP / image processing engine designed by Canon.

You are unlikely to find much about the DSP side, though search Canon owned patents (or patents by the people who's names have appeared in Canon firmwares) might find some hints.

This article has a nice teardown of Digic IV (including SEM images and estimates of total number of gates etc) http://techon.nikkeibp.co.jp/english/NEWS_EN/20090217/165748/

I'm not sure what the captcha requirement is these days, I never see one. It's possible it is triggered until you have a minimum number of posts?
Don't forget what the H stands for.

Re: Digic 5 - whats *really* inside?
« Reply #2 on: 27 / April / 2013, 16:02:54 »
I see, thanks for the info.  So in all versions they are using the same CPU and just changing the DSP parts?  I somehow expected a newer/more powerful CPU for an image processor with such a diverse range of uses (point 'n shoot to semi-pro cameras).

Gotcha on the Captcha - guess it is because I'm a new user here.  What an initiation :_p

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Offline reyalp

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Re: Digic 5 - whats *really* inside?
« Reply #3 on: 27 / April / 2013, 16:43:07 »
I see, thanks for the info.  So in all versions they are using the same CPU and just changing the DSP parts?
They are using the same CPU *architecture*, not necessarily the CPU. It does seem to get faster every generation. There are also indications the RAM and peripheral interfaces have gotten faster.

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  I somehow expected a newer/more powerful CPU for an image processor with such a diverse range of uses (point 'n shoot to semi-pro cameras).
The majority of the grunt work is done by the proprietary Digic side, the ARM is more like a manager. It runs the firmware logic, but it doesn't do the heavy processing. You can see this in the article I linked: Digic IV has roughly 256Kbyte of SRAM but the ARM core only has two 8K caches and two 4k TCMs. All the rest must be for the image processor.

Similarly, tech-on estimates Digic IV has 18 million gates in the "logic block", where the google references I can find suggest an ARM 946 would be on the order of a few hundred thousand (not clear if this includes any caches/tcm)
Don't forget what the H stands for.


 

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