dj jarvis
Posts: 1
Joined: Sun Nov 22, 2015 7:04 pm

Oric atmos retro fit PI

Sun Nov 22, 2015 7:19 pm

Hi All

First time poster - apologies if the wrong section of the forum ( Maybe a mod can move to the correct one? )

I still have my very first computer i got in 1984 , its a ORIC Atmos 48k , and unfortunately its gone to the retro computer heaven :o

But , i would like to retro fit a PI 2 into its case , my question is this , would i be able to use the original keyboard ?
It would be a shame not to be able to use it !!

i am a total PI noob , this would be my first project and would appreciate a push int he right direction :-)

Thanks in advance

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

Re: Oric atmos retro fit PI

Mon Nov 23, 2015 10:03 am

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Doug.
Building Management Systems Engineer.

ame
Posts: 3172
Joined: Sat Aug 18, 2012 1:21 am
Location: Korea

Re: Oric atmos retro fit PI

Mon Nov 23, 2015 10:20 am

An excellent project!

Are you sure you can't make the original board run? If it is truly dead then you're in luck (sort of. I mean, it's unlucky that it's dead, but you probably can use the keyboard).

Anyway, grab this:
http://www.48katmos.freeuk.com/servman.pdf

And look at page 79. The keyboard schematic looks pretty simple, and I expect you can drive it with the Pi. I don't know how much you don't know, but I recommend you Google for "4051", which is a 4000-series logic chip, and get a datasheet. Or read this: http://playground.arduino.cc/Learning/4051

To poll the keyboard you should set one of the column pins high, then change the address pins on the 4051 (to select the row) and look at the output. If it's high then a switch is pressed. Do this for all columns and all rows and you will build up a data map of which keys are pressed.

If that sounds too daunting, don't worry. I, or someone else, will help you understand the details.

The biggest issue will be to be careful that the voltages on the Pi GPIO pins are kept to 3.3V and not allowed to go to 5V. Again, this is easy to do.

ca_equinoxe
Posts: 1
Joined: Sat May 18, 2019 2:19 am

Re: Oric atmos retro fit PI

Sat May 18, 2019 7:38 pm

I'm really interested in doing this exact same thing but I'm trying to figure out if it's better to hook up the 4051 to a teensy to act as a USB HID controller or attach the 4051 directly to the PI. Does anyone have any advice to share in this regard?

Thanks!

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