Schematic for RPi 2 Model B

[mtippett]

Seems to be missing from the collection.

In particular, I am wanting to look at the layout to determine if the USB (power) port, can be connected to a PC and appear as a device.

[ghollingworth]

No you cannot do this with a model B since the hub is not by-passable

[lurch]

I guess this is possibly a duplicate of (or at least overlaps with) #224 #193 #188 #182

[mtippett]

I'm fine with it not being possible to do what I was intending/hoping. However, this issue itself is highlighting the gap in the RPi2 schematics. If they are not released yet (or will not be released) the RPi schematic page should indicate as such.

[ihartwig]

This would be really nice to see. It has been months. Can we work out the legalize? I am part of a university group that would like to develop low level ARM/embedded coursework around this board, and it is kind of hard to do that without the documentation.

[JamesH65]

What specifically do you need that isn't covered by the pinouts and the
existing ARM peripherals documentation? The bare metal forum seems to be
active at the moment, so people do seem to be managing well without
official schematics.

On 25 August 2015 at 04:53, Ian Hartwig notifications@github.com wrote:

This would be really nice to see. It has been months. Can we work out the
legalize? I am part of a university group that would like to develop low
level ARM/embedded coursework around this board, and it is kind of hard to
do that without the documentation.

—
Reply to this email directly or view it on GitHub
#235 (comment)
.

[ihartwig]

I am most interested in if these 2 blocks are the same between the Pi 1 B/B+ and Pi 2 B. I assume they haven't changed, but it is hard to tell when it is not documented.

Pi 1 B:

Pi 1 B+:

[bilderbuchi]

I have a similar problem. I want to figure out if there's a safe way to disable the red power led, as that even draws current when the RPi2 B I have is off. Without a schematic it's not easy to see if there will be knock-on effect of just cutting the trace leading to the LED.
edit: scratch that part of the comment, I just realized that the RPi in question is a B+, so the schem is available. Still have to figure out if it's safe to cut the trace of the LED, though.

@ebenupton will the schematics for the RPi2 be made available? If not, (while causing me an OSHW sadface) it would be great to put a clear statement concerning that on the schematics page.

[lurch]

...or you could simply disable the LED in software, like this: http://gpiozero.readthedocs.io/en/v1.2.0/recipes.html#controlling-the-pi-s-own-leds

Regarding schamatics, see also #347

[bilderbuchi]

...or you could simply disable the LED in software, like this: http://gpiozero.readthedocs.io/en/v1.2.0/recipes.html#controlling-the-pi-s-own-leds

That doesn't help me when the RPi is off (as I noted in my comment above). The Pi is for a media server which seldomly runs, but if I leave the PSU connected the red LED is on 24/7. Maybe I'm a power efficiency nut, but I'd like to eliminate the pretty unnecessary power drain.

[lurch]

Ahhh. When the Pi is 'off' it's not really off, the CPU is just held (AFAIK) in the HALT state. I suspect the SoC itself in the 'shutdown state' still probably draws more power than the little red LED? (and of course there'll also be power losses inside the PSU if you're leaving that plugged in, etc.)

I'd like to eliminate the pretty unnecessary power drain.

Perhaps something like https://energenie4u.co.uk/catalogue/product/ENER002-1 would be a better option?

[bennuttall]

Wouldn't allow you to turn the Pi off (ungracefully), but not back on?

[lurch]

@bennuttall Huh? Which bit exactly are you referring to?
If you're talking about the remote-controlled socket, then you'd do a "normal shutdown" first, before hitting the button on the remote to kill the power to the Pi's PSU. And then when you hit the button (on the remote) again to restore power to the PSU, then the Pi would just boot up again as normal.

[bennuttall]

Oh I see. I thought you were referring to turning off the Pi in software with the Energenie add-on.

[lurch]

I thought you were referring to turning off the Pi in software with the Energenie add-on.

Ahhh. No, I deliberately linked to just a 'plain' handheld-remote-control-only Energenie product ;-)

[bilderbuchi]

I once measured the power draw downstream of the PSU, and a quick off-the-cuff calculation led me to believe that most of the shut down power draw came from the LED---unfortunately, I seem to have misplaced my notes regarding that, or I'd have specific figures.

My initial thought was to put together some self-holding relais-like circuit that opens as soon as the power draw falls to shut-off values, but I realised the components I'd need to buy would probably amount to more than the total savings from using the circuit, which doesn't make sense. For the same reason, I'd prefer not to buy additional products like remote-controlled power sockets etc. (but thanks for the hint!).

Then, I thought that by disabling the LED, I'd reduce the shut-off power draw to negligible values, and to wake it up I'd use a momentary switch I have lying around on the reset pins, so I don't have to build a circuit, and don't have to buy any components. This is where I am currently.

Maybe the best best after all is to just buy two micro-usb connectors and a small switch to splice between the PSU and the RPi, that way the Pi is guaranteed to be dead and the (low-standby-power) PSU does not have any load.