Raspberry Pi 3 Model B GPIO 40 Pin Block Pinout

Are there any actual electrical specs for this I/O?  In particular,

• what voltage standard do these I/Os employ?
• if not 5V I/Os, are they 5V tolerant inputs?
• how much current can they deliver?
• are there requirements regarding power-up sequence relative to attached devices?

Also, schematics?

Thanks, Graham

Thanks to @shabaz and @clem57 for your comments. (That mosiac doc site is nice!)  But...

I want to point out that I'm asking specifically about Raspberry Pi THREE. I realize that RasPi 3 may have been designed to be compatible with 2 and previous, hence experience with previous models may be illuminating.

However, to be confident rather than guessing, what I want to know is actual official info on:

(a)  whether the RPi3's I/O logic voltage standard is actually 3.3V.

(b) whether the header I/O pins are directly connected to the SoC (hence SoC datasheet electrical specs pertain, though I'm not seeing a datasheet on the BCM2837 anywhere), or via buffers, in which case what sort of buffers?

No schematic means users are helpless to determine trivial things like this for themselves.

Again, thanks for responses here, just hoping someone is able to point to official word on these basic questions.

Graham

And for what it's worth, the reason for wanting an actual data sheet is to avoid incorrect info like here:

http://www.scribd.com/doc/101830961/GPIO-Pads-Control2

.. in which someone managed to get hold of a BCM2835 datasheet that's more complete than the one from RasPi site (yay for that, but I wish I could find the same doc), and actually includes a few details about controlling I/O drive current. (This is absolutely essential info, and even the info in this excerpt isn't enough to determine whether all GPIOs are controlled together, which seems silly, or individually or in groups of what size? )

And then this user incorrectly interprets VIL and VIH specs as pertaining to outputs.

(And BTW, interestingly if those VIL/VIH values are to be believed, the inputs appear to use 3.3V-scaled version of old-style TTL compatible levels, rather than CMOS 1/3*VDD and 2/3*VDD levels. Essential to know if interfacing to, you know, other devices.)

And of course that all doesn't necessarily pertain to RasPi3.

Having to guess electrical specs is pure amateur hour. Surely these chips and boards were actually engineered, and there are some proper docs somewhere?

Graham

Hi Graham,

Apparently it is compatible electrically with the Pi 2. However we know that I/O pads can be different. And we know schematics and detailed electrical specifications are important.

Basically you're preaching to the converted : ) Many people feel your pain, as I do. The source to direct this to is the Raspberry Pi Foundation, but they haven't listened to this issue in about 4 years.. if you ask them, you'll maybe get a response from them saying "you have all the information that is needed, schematics have no benefit over what information is already available". However we as engineers know this is not the case. You could ask Broadcom for a copy of the BCM.. datasheet. Again, I doubt this will get you far, just letting you know that others have asked for years on the RPF forum which has Broadcom and ex-Broadcom engineers frequenting it.

You know, I don't even understand what the big deal is about releasing the schematics. It's not like they performed some engineering miracle, they put a microprocessor on a board and hooked it up. Just like every other manufacturer. Hardkernel releases full schematics of their boards, maybe not on launch day, but soon after. It's not like anyone can get the broadcom processors to make clones anyway. When you release a tinkerer's board you need to expect people want to know this stuff.

Idk,

Mike

You know, I don't even understand what the big deal is about releasing the schematics. It's not like they performed some engineering miracle, they put a microprocessor on a board and hooked it up. Just like every other manufacturer. Hardkernel releases full schematics of their boards, maybe not on launch day, but soon after. It's not like anyone can get the broadcom processors to make clones anyway. When you release a tinkerer's board you need to expect people want to know this stuff.

Idk,

Mike

True Michael it's really the minimum to get it going .. Problem here is since this is a new and I belive custom SOC for the RPI then the documentation is probably not forthcoming any time soon. Therefore everything could easily be totally different from the Pi2 or the same how is any one to know. Open sourcing the PCB only gives you a taste especially when t he SOC where the complexity lies is largely a black box

Strangely there was a schematic of an earlier version released, then withdrawn ....

Luckily I come from a dial-up age where saving stuff locally was necessary.

I also cannot fathom why a schematic is so precious.

People assummed it was open source and maybe the original intention may have been, so the board layout is withheld.

Anyone that actually wants to copy it can, they simply need the broadcom chip and some time.

Asking for the specs is a reasonable request so that you can determine if your design will work.

Sadly some people think that guessing and a quick trial is good engineering.

Mark