When I set out to build my Apple 1 Replica I wanted to recreate the one from the first advertisement. How do you think I did?
Recently I was bringing up an Apple 1 and I did the first thing I always do to do an initial checkout, which is run the Test Program from the Apple-1 Operation Manual. This is a very simple program that runs a loop that counts from 0x00 to 0xFF and prints each byte as an ASCII character. Here is the program:
0000 LDA #0
0003 JSR ECHO
0008 JMP $0002
This time when I brought up the Apple 1 I saw the following output:
The last time I had run this program, I had run it on an emulator and seen the following:
Remembering how the output looked I thought there was a problem with my Apple 1. After further investigation I found the answer in the Apple 1 schematics.
It turns out that character output is tied to RD6 or RD7. This was overlooked in every Apple 1 emulator that I have looked at.
In 1977 Mike Markkula, like many users, was unhappy with the time it took to load data from the cassette interface. He made it a company goal to develop a disk system for the Apple II. After studying the Shugart documentation Woz found that he could avoid much of the complex circuitry needed to control a disk head by doing more work in software. In addition, by doing the board layout himself, Woz was able to reduce chip count even further. My Disk II card is an early production unit which is visible by the tin fingers on the card. The Disk II drive is serial #7461 and includes the rainbow ribbon cable that came with the early production units.
Recently I wrote an Application for iOS devices that can be used to load Apple 1 software through the cassette interface. One key benefit to this application is that is shows load and verify instructions for each program. I’m currently in the process of getting this added to the App Store.
Today I built up Mike Willegal‘s Apple Cassette Interface for the Apple 1. Previously I was using the Obtronix interface, however Mike’s board is a more accure reproduction.
Here is a video demoing Mike Willegal‘s Brain Board. In the demo I load Blackjack for the Apple 1 from cassette.
When I first restored my Rev 0 Apple II, I used DRAM chips from an Apple II plus. While this worked fine, I wanted something a little more authentic to the machine. I was looking at Geoff Harrison’s Apple II #97 and noticed some nice NEC uPD416’s so I pick up a set and put them in.