Convert an Apple II into an Apple 1 using MCL65+

This project uses the MCL65+ to convert an Apple II into an Apple 1!

Project code is on GitHub:

The MCL65+ is a drop-in replacement the computer’s MOS 6502 which can emulate the microprocessor and much more.

​The Apple II BIOS is replaced by the Woz’s Monitor, so the machine is quite effectively running as an Apple 1.

The MCL65+ uses a Teensy 4.1 to emulate the 6502, the Apple I PROMs which contain the famous 256 byte Woz Monitor, 8 KB of RAM, and a few conversion routines for differences in video display and keyboard handling,

All keyboard and video I/O are also echoed to the Teensy’s UART so that code could be downloaded to the Apple 1 by simply cutting and pasting it into a terminal program.

Here is the MCL65+ inside of the Apple II Plus:

Here is a short video demonstration of the project:

To save time I pre-populated BASIC into memory location 0xE000 and also the Apple I anniversary program into 0x0280.

Here is a short BASIC programs which I downloaded over the UART:

The Apple I Operation Manual contained a small program to print ASCII character across the screen, so of course this was the first thing I tried when bringing the system up!

We cant forget to add a picture of Steve!

Convert an Apple II into an Apple 1 using MCL65+

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