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Raspberry Pi, PyFace Digital, the lost documentation, I found it finally

The Raspberry PI or R-pi from http://www.raspberrypi.org/ is well known these days.
It is not an accident that I have one, I have been doing Linux stuff since 1991, and professionally since 1996 I can not skip over these developments, have to keep up with the new kids. :-)
Times have changed, hardware has become very affordable, everybody knows the Arduino, Raspberry Pi and Beagle-Bone-Black (BBB). Not everybody knows the stuff that http://www.acmesystems.it/ aka Acme-Systems and https://github.com/OLIMEX/OLINUXINO aka Olimex make, so I will endorse them here.
Since I am an engineer I expect to connect switches and relays to the boards and some documentation with products, not so with the "PiFace Digital" board, it comes without serious documentation, not a even the schematic. All links on their blog point nowhere. People asked them many times, yet nowhere is the schematic to be found.

I finally found some info after hours of google-work, someone made a copy!
https://github.com/Elektordi/pi-accesscontrol/tree/master/doc
So I quickly copied that and put it here for you to find, that is the reason you are here right?
Here is a picture.
Pi Face digital schematic

Have fun with it.
I will report adventures with the board when I get time.

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Update: this schematic is for an old board, look at JP3, where does it go? Are the INTA INTB not connected to a GPIO pin, what is that?, do we have to poll the 16-bit I/O Port Expander (mcp23s17) to see if there is a pin toggled. If that is the case this board is an example of how NOT to design an IO board.

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Update 23 aug 2013
I sent a mail to pi AT cs.man.ac.uk

And I got a prompt reply:

Hi Edwin,
Unfortunately the schematics are not available however if you're looking to use interrupts then the new software supports them.

You can find the most up-to-date Python libraries for PiFace Digital here: https://github.com/piface/pifacedigitalio
And here is some documentation on how to use interrupts: http://piface.github.io/pifacedigitalio/example.html#interrupts

Pins INTA (20) and INTB (19) are both wired to GPIO pin 25.

Hope that helps!
Tom

===

So things are not as bad as they seemed. I will update the schematic picture above to reflect the new information today.
After measuring the connections, I found that INTB is connected to GPIO25 (pin 22 on the connector, in the schematic it is marked GPIO6) but INTA is just not connected.

Reacties

Hi Edwin,
Seven years after you wrote this post, it saved another Maxtor Shared Storage — and with it, twenty years of my family's files.
My MSS (the original 200GB model, H01P200) died the slow death you'd recognize: SMB timeouts, freezes, whole weeks trying to rescue files over the network at 0.02 MB/s. Your post gave me the map for the endgame: pull the drive (a PATA DiamondMax 10, in my case), image it with ddrescue — 200GB, 3h48m, zero bad sectors, the disk was fine all along, it was the firmware dying — and then find the ReiserFS hiding inside the Broadcom partition scheme.
The detail that made me smile: my data partition was at byte offset 528785408 — exactly the same as yours. Same firmware, same layout, 300km... I mean, 7 years apart. The disk_configuration.c you linked from k0lee.com let me write a small parser that confirmed the offset from the partition table itself (my header said "Broadcom NAS Version 1.1", pool name 'mss-hdd'), and the ReiserFS signature scan agreed. Mounted with your exact loop/offset trick, journal replay warning and all.
Final tally: 26,471 files, 81.85 GB, every single one copied out with SHA-256 verification. Nothing lost.
Thank you for taking the time to write it all down back in 2019. The internet is better because people like you document the weird stuff.
Rubens (Brazil)

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