Last but not least i intended from the very
beginning to also develop a RAMexpansioncard for the Apple-1
with as free as possible configuring options.
there have been already some contributions published that described
how owners of the original Apple-1 manipulated their mainboards
to be populated
with 4116 chips and then those boards had 20 kB RAM. in
fact there are different variations of possible
RAMconfigurations and therefor it is upmost importent
to also keep this card as variable as possible by offering wide
range of adressing and allocating the different RAMbanks and
offering to use different kinds
of RAMchip population. The Mainboard offers either 4kB of
RAMpopulation, 8kB or 20 kB. Depending to the availiable RAM on
mainboard the expansion card
should offer either 4 kB, 8 kB, 16 kB, 20 kB or 32 kB additional
RAM and it should be possible to create entirely consistent
RAMspace in one large block together.
The trouble started while examining the slot and the availiable
signals at the slot. I discovered that a lot of requested
signals for RAMtiming and RAMrefresh
are not availiable at the slot and that signals needed to make that
signals are not availiable too. From that moment i recognized
that the development of a
RAMexpansioncard would become a very tricky and difficult task. Its
one thing to generate tha requested signals for refresh and row
and column adressing
on the one side and its a complete other story to get that signals
syncronized with the signals like the databus and adressbus as
well as the CPU on the other
side.
possible Orders:
4
D) Apple1 RAMexpansioncard
( After revision and correction!
)
due to european laws and german court decision:
I hereby declare no responsibility to any "deep links"
resulting from the links in this page. I have no influence to
the pages linked hereby in this page and the
contents in those pages. I therefor canīt take any kind of
responsibility to contents in the pages, where these links
direct the readers browser to nor to the
contents resulting from following up links from those pages.
The reference to contents by this links is dependent ro the
status of the date when the links have
been set ( April 2013 ) and it might occur that references and
contents may change by the fact that domains may have been
discontinued from their former owners.
In such cases i canīt take any kind of responsibility to the
changed contents. this is specialy valid to banners,
advertisements or merchandising links in the targeted
pages.
