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w1res
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Where is the official documentation?

Thu Apr 25, 2013 3:03 am

Hi,

A coworker recently let me borrow his Pi for a while. I've gotten the system hooked up to my monitor, configured, and running.

I'm trying to figure out the GPIO and peripherals on this this thing, but I can't seem to find the official documentation and datasheets.

I've found a good amount of information on elinux, but this seems to be written by the community and it is filled with many "as far as I know," "probably correct for this version," or "after tinkering around I managed to find"...

So where is the official datasheet for this thing :?:

Thanks!

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rurwin
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Re: Where is the official documentation?

Thu Apr 25, 2013 3:14 am

Here: BCM2835 ARM Peripherals

It's an abridged version of the full Broadcom datasheet, which is only available under non-disclosure agreement, but it tells you everything you need to know. There's a few other documents, mostly less formal, floating around detailing the video stuff, the boot process and the boot options.

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w1res
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Re: Where is the official documentation?

Thu Apr 25, 2013 3:28 am

rurwin wrote:Here: BCM2835 ARM Peripherals

It's an abridged version of the full Broadcom datasheet, which is only available under non-disclosure agreement, but it tells you everything you need to know. There's a few other documents, mostly less formal, floating around detailing the video stuff, the boot process and the boot options.
Do they not even have an official pinout of the breakout header? Or specify which MCU pins each breakout header pin goes to?

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Re: Where is the official documentation?

Thu Apr 25, 2013 4:58 am

w1res wrote:Do they not even have an official pinout of the breakout header? Or specify which MCU pins each breakout header pin goes to?
There is no need, as the pinouts on elinux are correct. They are based on information provided by the Foundation and the official schematic http://www.raspberrypi.org/wp-content/u ... .2_027.pdf pdf.

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rurwin
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Re: Where is the official documentation?

Thu Apr 25, 2013 11:14 am

w1res wrote:Do they not even have an official pinout of the breakout header? Or specify which MCU pins each breakout header pin goes to?
That is the datasheet for the CPU, not a datasheet for the board. As rpdom says, the elinux pinout is correct, and the numbers on there match the numbers on the datasheet. If you really need official, then the schematic is it, and what you want is on page 2. But the elinux data is, in my opinion, easier to use.

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Re: Where is the official documentation?

Thu Apr 25, 2013 12:03 pm

Sometimes, the answer is (a simple) "No."
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

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w1res
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Re: Where is the official documentation?

Thu Apr 25, 2013 2:05 pm

Thanks for the links, a schematic is perfect!

I think that I might have had the wrong idea about what the Pi is. I've been working with microcontrollers lately and I guess I was thinking about the Pi as just another demo board, but it seems like it is best just to think about it as a cheap "black box" computer.

What confuses me is how this is aimed to be an educational computer if the documentation is so scarce/hard to find, and all of the hardware they decided to use was so closed off... I guess that rather then educational, they should have just called it accessible and low cost.

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mahjongg
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Re: Where is the official documentation?

Thu Apr 25, 2013 2:20 pm

Were still in the preliminary phase, the phase before the actual "educational release". Which will coincide with the release of educational material such as books, and perhaps a slightly improved models (not performance wise, but perhaps ease of use wise, but it is my private speculation that this might happen).

But what have datasheets and schematics to do with it, other than that they are there so that volunteers can extract the info they need to write educational material.

Also, there are already several commercial books available about the PI, including one written by the foundation (by eben upton).

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rurwin
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Re: Where is the official documentation?

Thu Apr 25, 2013 2:40 pm

You have the datasheet, you have the schematic. What other documentation are you missing? We can probably help you find it.

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Re: Where is the official documentation?

Thu Apr 25, 2013 8:23 pm

w1res wrote:Thanks for the links, a schematic is perfect!

I think that I might have had the wrong idea about what the Pi is. I've been working with microcontrollers lately and I guess I was thinking about the Pi as just another demo board, but it seems like it is best just to think about it as a cheap "black box" computer.

What confuses me is how this is aimed to be an educational computer if the documentation is so scarce/hard to find, and all of the hardware they decided to use was so closed off... I guess that rather then educational, they should have just called it accessible and low cost.
Why do you think the HW is any more closed off that, say, a normal laptop PC? It runs a standard Arm instruction set, a standard OS, runs most standard computer languages, all ARM side code is publicly available. The schematic for the board is available, along with a datasheet describing all peripherals attached to the ARM.

As to being hard to find, well, the majority of documentation is on Elinux which you seemed to find OK - always has been (may not always be). It's always been a community effort to document the device. It only been the last few months where the Raspi foundation has had any full time employees...I'd expect documentation levels to improve nicely as time goes by.
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w1res
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Re: Where is the official documentation?

Fri Apr 26, 2013 2:26 am

rurwin wrote:You have the datasheet, you have the schematic. What other documentation are you missing? We can probably help you find it.
Schematic perfect, don't need anything more than that! :) (just as an example of what I as originally expecting, you could take a look here http://www.microchip.com/stellent/idcpl ... t=DM240001)
jamesh wrote: Why do you think the HW is any more closed off that, say, a normal laptop PC?
I don't. Like I was saying in my later post, I realized that I had the wrong frame of reference going in. What I was trying to say is that I was thinking of the Pi as a hardware development platform (demo board) rather than a computer. Like you say, computers don't come with more documentation than what is needed to get it running (e.g., my Lenovo laptop doesn't come with any kind of datasheet or schematic).

As far as the schematic goes, I woudn't have been able to find it on this website without asking!

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Re: Where is the official documentation?

Fri Apr 26, 2013 4:45 am

w1res wrote:
rurwin wrote:You have the datasheet, you have the schematic. What other documentation are you missing? We can probably help you find it.
Schematic perfect, don't need anything more than that! :) (just as an example of what I as originally expecting, you could take a look here http://www.microchip.com/stellent/idcpl ... t=DM240001)
jamesh wrote: Why do you think the HW is any more closed off that, say, a normal laptop PC?
I don't. Like I was saying in my later post, I realized that I had the wrong frame of reference going in. What I was trying to say is that I was thinking of the Pi as a hardware development platform (demo board) rather than a computer. Like you say, computers don't come with more documentation than what is needed to get it running (e.g., my Lenovo laptop doesn't come with any kind of datasheet or schematic).

As far as the schematic goes, I woudn't have been able to find it on this website without asking!
Thanks for the explanation. I agree that it can be difficult to find stuff - that's an area being looked at.
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