[NTLK] Followup eMate memory upgrade boards

[Matthias Melcher]

> On Aug 28, 2018, at 16:32, Randy Glenn <randy.glenn at gmail.com> wrote:
> 
> On Tue, Aug 28, 2018 at 09:01 Matthias Melcher <mm at matthiasm.com> wrote:
> 
>> Sorry, I was out for a while.
>> 
>> Ok, so measuring the known pins of the chips will give us the extension
>> port pinout, but I assume that has been done already, if Frank already
>> ordered circuit boards.
> 
> 
> I'm not sure if Frank has the schematics and pinout easily available - I
> think he was ordering boards from Gerber files - but I reverse-engineered a
> memory module here:
> 
> https://github.com/OpenNewt/Memory300/blob/master/memory-300.pdf

Oh, wow, thanks! So, first of all, the layout is compatible to my ROM reader. That means that we can read and write the Flash devices on these memory cards. The scary part are the CAS lines (I never thought I would see RAS and CAS again in my life, but here we go ;-) ). I can't do anything with those, so no reading or writing RAM, which would not help us anyway, because the contents is gone as soon as it is unplugged anyway. The sad part is, that these lines take up lines that are used as address lines on the ROM board, physically limiting the memory board to a maximum of 2MB RAM and 2MB Flash.

Other than that, great news. So chances are that the eMate ROM board and the MP board are electrically the same, just not by outline. A reflashable ROM board would work in both machines if we can make it small enough.

Thanks,

 Matthias