Acorn ARM Evaluation System

[retrolimber]

Hi there. I'm the happy owner of an ARM Evaluation System "cheese wedge" module for the BBC Micro / BBC Master.
The module is in a good shape and has a very low serial number (below 30). I tested its built-in power supply and it works as it should.
Now I'd like to try the ARM module with my BBC Micro but I'm not sure on how to connect the flat cable to the TUBE expansion connector on the computer, as there isn't a "notch" on the flat
cable ... and I don't want to fry the ULA TUBE chip by doing a wrong connection of the module to the computer. So I'm asking if somebody has this module and was able to connect
it to a BBC Micro or BBC Master if he can send me a picture showing how to connect the flat cable, and some general information to get the ARM System up and running.
I'm also curious to see how many of these ARM modules are still around, so, if you have one I'm happy to see pictures of it.
Thanks in advance
Alessandro

 

[Pernod]

Hi Alessandro,

I think you'd struggle to insert the cable the wrong way around. You can see there are notches at different positions from either end to prevent incorrect insertion, the actual cable generally feeds away from the computer.

Will you be using this with a BBC Micro or BBC Master? It's really intended for use with a Master as that contains everything you'll need to use it. To use with a BBC Micro you'll need an Acorn 1770 Disc Interface upgrade (assuming yours has a standard 8271 fitted), and you'll need an ADFS ROM in there to access the ARM Evaluation floppies which are double density. Details of requirements can be found at https://www.g7jjf.com/acornArm/Acorn_ARMEvalSystemUG.pdf and floppy images at https://www.g7jjf.com/acornArm_disc_images.htm.

These ARM co-pros aren't very common, and tend to sell for silly money, and presumably you have the only one in Italy!

 

[retrolimber]

Hi, many thanks for the reply. I didn't consider the small carvings at the 2 ends, I was looking for the central notch as in the standard floppy cables ^^'
That was the main struggle, thanks for pointing it out. At the moment I have a BBC Micro but I don't remember if it has the ADFS ROM already installed, I'll check.
I don't think I have the floppy drive but I'm in touch with a friend that can lend me a BBC Master with dual floppy drive if it is more convenient to use.
Thanks for the links, I'm going to write back diskettes from the images with the Greaseweazle.
It will take me some time but I will post here the results if I can get the system up and running.
Many thanks
Alessandro

 

[jltursan]

Wow, be cautious, this is probably the rarest BCC item out there!. If you know how to use a multimeter and have one, you can always double-check that the ground/5V pins of the wedge match the ones present in the Tube connector...

 

[retrolimber]

Thanks. Yes, I have a multimeter. Before powering up the system I'll try to check the continuity between the ARM ground line and the ground line in the computer and also for the +5V line.

 

[Gary C]

Red core on the connector pin 1

Pin 1 is marked on the BBC micro with a white triangle



It naturally fits like this when you plug it in anyway, but its worth being sure.

Though looking at the pinout, just like a floppy, I dont think it would do any damage (but I wouldn't risk it to find out )

The small 'carvings' rarely act as registers, but its odd that Acorn didn't use a connector with the bump when they had put it on the machine itself.