The Apple IIe “Mini”, the Mega IIe, works

2023-12-16 12:00:50

About a year ago (give or take a few days), we told you regarding James Lewis. He had begun trying to make an Apple IIe “Mini”, a compact version of one of Apple’s first computers. And he decided to start with an interesting chip: the Mega-II. Integrated into the Apple IIgs (16-bit variant of the Apple II) and into a Macintosh expansion card, it was a system-on-chip that contained many of the components of the Apple IIe. And a year later he successful.

He is trying to make an Apple IIe “mini” with an Apple chip

His idea was to create a modular computer. On one side a card equipped with the Mega-II chip, the CPU (which is not integrated into the chip in question) and RAM. On the other, a card which acts as a cradle for the expansion cards of the Apple II “Mini”, renamed Mega IIe. One of the expansion cards does not exist in a real Apple IIe: it manages the keyboard. James gives the reasons in detail in his video, but one thing must be remembered: the keyboard controller is not integrated into the Mega-II chip and he therefore had to create a card dedicated to this use, equipped with a card Raspberry Pi Pico. This choice allows you to use a USB keyboard, through the USB port on the card.

The card is equipped with the CPU and Mega-II.

For access to disks (floppy disks, the backup icon ???? for the youngest among you), he created a card with an IWM chip (Integrated Woz Machinein reference to a Serbian well known in the Apple world) and modified the ROM to take the chip into account.

VGA (RGB) gives a much cleaner image.

After finding a bug in the Mega-II chip and successfully running Apple II programs through the composite video output, he decided to design a video card with (pretty much) modern video output. For various reasons, including the complexity of the HDMI standard, he chose VGA, which dates from 1987 but which has the advantage of being well supported by monitors, even in 2023.

A compact version

After validating the functions with separate expansion cards, he chose to design a third version. This v3 is integrated on a single printed circuit, and required some adjustments, notably to the contents of the ROM, but it works. The last step, in the video, is the design of a miniature case, printed in 3D.

The final map.

Let us also remember that this Apple IIe “Mini” has an interest (the diagrams are available): there is little chance that Apple will one day offer its own version, given the lack of attraction for nostalgia among managers. So you will probably never find the equivalent of “ C64 Mini ” or ” The A500 Mini » in the stalls. And the names are in quotes because both devices are not licensed to use the Commodore name…

The printed case.

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