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I've seen the System on Chip of Raspberry Pi referred to usually as "BCM2835" (e.g. on Wikipedia), but sometimes as "BCM2708" (e.g. sources for Linux SPI driver are in bcm2708.c, or in comments to my other question).

Which is right, or are both - why? Specially, if there are inconsistencies in datasheets for both, which shall be understood as "more important"?

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3 Answers

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Further to Steve's answer, there is a discussion here on the git hub issue log for linux drivers discussing how the drivers should be labeled. The pertinent posts are:

popcornmix:

Technically 2708 is the family, and 2835 is a specific implementation. We now know that 2835 is the only implementation in the family that can run linux, (and there won't be new models of this family), so it probably doesn't matter which model is used, although it should be consistent.

lp0:

So it would be reasonable to name all the drivers 2708 but the specific device tree file 2835? (assuming that if there is ever another model of that family that can run linux it would need a different list of devices)

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Another comment suggests that maybe "BCM2708 is the CPU component which is part of the BCM2835". Some links to first-hand evidence would be nice... (also, I posted this question because I'd like something more than what I've already found in first Google result) – akavel Jun 29 '12 at 11:44
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I tried to find some. The broadcom data sheet is linked here: raspberrypi.org/wp-content/uploads/2012/02/…. However it makes no reference of the BCM2708 number. As far as I can see the only place those two numbers appear together are on posts asking this sort of question. – Jon Egerton Jun 29 '12 at 11:50
up vote 6 down vote

Technically 2708 is the name for the family of chips, and 2835 is the specific chip in the Pi. As to which datasheet supersedes the other, I would chose the BCM2835 (specific) over the BCM2708 (family).

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Hard citation needed. Another poster suggests that maybe "BCM2708 is the CPU component which is part of the BCM2835". Excuse me, but why am I to believe you, not him? – akavel Jun 29 '12 at 12:56
As the "other poster" - I'd like to say that it was speculation based on the kernel sources. I have no hard evidence either ... and we really should have some sort of canonical (preferably Broadcomm) source answer. – Maria Zverina Jun 29 '12 at 13:09
@MariaZverina In this particular case such a canonical source may not be available from anyone - since even getting full details on the chip requires an NDA. As a result a more pragmatic approach may be called for. Let me ask a question as means of getting the context for the question. What are you trying to do that you can't as a result of this naming question? – Steve Robillard Jun 29 '12 at 16:05
@MariaZverina and akavel I just came across this video on YouTube youtube.com/watch?v=5jEVBK7P1GA of Geert van Leuw talking about the chip in the Pi and he refers to it as the 2835. As a source of information on the Pi hardware I think you will have agree that it does not get much better. – Steve Robillard Jul 16 '12 at 9:58
up vote -3 down vote

My search for this question was prompted by this page

Note the response from command cat /proc/cpuinfo

...

Hardware : BCM2708

Revision : 1000002

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Hm, interesting! Although, in light of the other answers, I believe it still doesn't solve the situation enough - it can still be both family name, or specific implementation name, or something else... – akavel Aug 31 '12 at 13:29

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