Cameron's Closet

Vintage Mimeo Ad

cameron — Fri, 13 Jul 2012 15:06:09 +0000

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?

A Common Apple 1 Emulation Bug

cameron — Sun, 19 Feb 2012 15:08:02 +0000

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 0×00 to 0xFF and prints each byte as an ASCII character. Here is the program:

0000 LDA #0 0002 TAX 0003 JSR ECHO 0006 INX 0007 TXA 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.

Disk II

cameron — Mon, 06 Jun 2011 12:41:22 +0000

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.

Apple 1 Software Library for iOS

cameron — Mon, 06 Jun 2011 04:13:44 +0000

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.

Mimeo Apple Cassette Interface

cameron — Mon, 06 Jun 2011 04:07:08 +0000

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.

Brain Board Demo Video

cameron — Fri, 27 May 2011 11:56:59 +0000

Here is a video demoing Mike Willegal‘s Brain Board. In the demo I load Blackjack for the Apple 1 from cassette.

Vintage Ceramic DRAMs

cameron — Fri, 27 May 2011 01:24:22 +0000

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.

Brain Board – Turning the Apple II Into an Apple 1

cameron — Thu, 26 May 2011 17:24:34 +0000

This week I received a beta Brain Board from Mike Willegal. This board came with the Wozanium pack which will cause an Apple II to function like an Apple 1. This a great way to get the Apple 1 experience without having to build a replica. The assembly took me about 40 minutes and it works great!

Applesoft ROM Card

cameron — Wed, 17 Nov 2010 04:03:21 +0000

I’ve added a ROM card to my Apple II containing Applesoft ROMs. Thanks a bunch to Mike Willegal for suppling the card.

Apple II Serial #133

cameron — Wed, 17 Nov 2010 04:01:05 +0000

I recently acquired a rev 0 Apple II motherboard numbered #133. I’ve done a full restoration on this board using the earliest components I could find including the keyboard and power supply.