Friday, May 3, 2013

Prelude: Poor man's Minimig ARM Controller

I have 2 Minimigs both fitted with the replacement ARM Controller boards.
In a recent cock-up I nearly managed to destroy one of the ARM boards by breaking a pin off whilst hastily pulling it out of the Minimig.

Thanks to a $1 DIP socket I managed to save the controller by soldering the pin back onto the board.... and gently plugging the controller into the new socket:

Which thankfully worked pretty well. During this whole debacle I happened to have a proper look at the mcu on the board and saw that it was an AT91SAM7S256. I remembered that I had a cheap dev board with the same chip on it. The dev board cost me $25 when I bought it, as opposed to the near $100 price tag of the ARM Controller, so I began to wonder if it might serve as a cheap replacement.

After some very careful pin mapping and buzzing the dev board out, I came up with this:

And it works 100% (or seems to so far). Whilst the board I used does not seem to be for sale any more, there are alternatives available and even this board ($27 on eBay as of this post) :

(the bigger brother AT91SAM7S512) should be simple enough to wire up and port the code to (if even necessary).

All in all a fairly cost effective hack that also has the benefit of providing JTAG access for devs that wish to extend the ARM Controller firmware.



  1. What is the purpose of the ARM Controller board anyway? The old Minimig site refers to a PIC18LF252 in the IC10 slot. Given that I have a universal programmer capable of writing to a PIC18LF252, do I need this ARM Controller? Can I just program the PIC and put that directly into the IC10 slot instead?

  2. Hi,

    To be honest I don't have a Minimig any more and can't remember much, only that the ARM board was significantly superior in what it provided over the PIC version (it does look like you could just flash the pic chip and use it straight up). gives some detail and it looks like you could get an ARM controller made up from PCBWay:

    I hope that helps?

    1. Thanks. I do have the PCB for the ARM controller.. so I do have the option of PIC or ARM controller. Just had no idea what the difference is. I might try the PIC first - just because I don't trust my soldering. Soldering that Spartan is going to be a challenge..