Archive for the ‘Apple 1’ Category

PS/2 Adapter Software and Hardware CAD Files Now Available for Free Download

Monday, December 26th, 2016

Go to my PS/2 adapter web page to find the links.

http://www.willegal.net/appleii/appleii-kb-int.htm

Support will be very limited. The firmware is actually rather sophisticated for what this device does. Understand that it is completely in assembler, and if you desire to make changes, it would be best if you were familiar with coding in assembler for micro-controllers.

Some scripts are included in the software package that are used to download the firmware, calibrate the built in RC oscillator and burn the fuses using a USB programmer called AVRdude. Fuses and EEprom must be programmed correctly or the micro-controller may not function correctly. The A version of the Atmel at tiny 2313 has not been tested. I have been using ATTINY2313V-10PU.

The CAD program I used to create the PCB is called Osmond PCB. I have also included GERBER and Postscript files. You must accept all risk associated with creating PCBs using any of these files.

End of an Era for Me

Saturday, December 17th, 2016

As look back at some of the blog postings I made during the early days of the Mimeo project, the excitement I felt, could be easily discerned. For better or worse, after nearly 7 years, that excitement is no longer there, and it’s time to move the project over to someone who has a strong passion for that landmark system.

I’ve transitioned Mimeo 1 sales to Corey Cohen. I’m sure he will do a great job selling and supporting people interested in building reproduction Apple 1 Computers.

Since first making them available in March of 2010, I’ve sold 167 Mimeo PCBs, the first few as part of a kit, even a few that were completely assembled and tested. I have greatly enjoyed the entire process from creating the PCBs in the first place, to fixing a few boards that customers needed help with. Especially gratifying, has been the great relationship that I have established with all the people that I have made contact with over the years. One thing that I never expected, when starting this project, was the amazing contacts I made with so many people associated with Apple during those early years.

However, the learning part of the process, which is one of things that keeps me interested in my hobbies, has not been there over the past few years. It is time to move the sales over to Corey, who has unbelievable enthusiasm and knowledge for and about those milestone computers.

SCELBI PCBS

I will continue to sell SCELBI PCBs, as I am still excited about working on that system and learning a lot, while doing it. Blog followers will know that the Oscilloscope Interface PCBs, the last SCELBI boards that need to be reproduced, will soon become available to interested parties. I have some ideas for some even more obscure reproduction vintage computer projects. However, the Oscilloscope interface must be completed, before I move on to those projects.

Other Products

Other products I have sold in the past, will only be continue to be sold if I have remaining inventory in stock.

I presently have stock of the following

  • Brain Boards
  • Swift Cards
  • I am sold out of the following:

  • Apple II, rev 0 boards
  • SuperProto boards
  • PS/2 keyboard adapters.
  • Datanetics Keyboard PCB
  • The PS/2 Keyboard Adapter

    The PS/2 keyboard adapter is a little bit of a special item to me. When I had those PCBs made, because of economies of scale, I had 150 fabricated. I never thought I’d sell all of them. In the end, I sold over 140 those little dongles, using the others for a number of my own special projects. Though they probably exist, I have never heard of a PS/2 keyboard that it didn’t work with. It was designed to operate with Apple 1 and Apple II computers. As I originally hoped, people adapted the design to a number of systems beyond that. The firmware has had minor firmware features and improvements made over the years, but the basic design hasn’t changed over all these years.

    There have been a number of other PS/2 keyboard to parallel ASCII keyboard adapters designed over the years, some coming before, and inspiring my adapter. Though it could certainly be improved further, I sincerely believe my version is currently the best of the breed.

    When I get the time to add them to my web site, I will be releasing to the public domain, with no restrictions, all design files, including firmware and PCB CAD files. You will be able to do what you want with it, make copies for sale, improve it, or just study the design for your own purposes.

    Using an Apple Powerbook as a Cassette Tape Recorder

    Sunday, September 13th, 2015

    During my debug of the SCELBI cassette tape interface, I decided I needed to get better visibility to the actual output of the cassette interface. There are a couple of ways to do this. One way was to use a DSO (digital storage oscilloscope) or logic analyzer to capture and analyze the signal. I don’t have either, so I had to resort to a second method. That is to capture the cassette output as an audio clip using an audio recorder and editor on a personal computer. One such application is Audacity, which is a free download.

    The only trouble with using a modern personal computer is getting the audio clip into the PC. Apple Powerbooks include a headphone port that includes speaker out and microphone in. Wendell Sander has an Apple 1 site that includes directions on connecting an Apple 1 to an iPod’s headphone port. I did a bit of research and determined that the Powerbook headphone port is basically the same.

    I constructed a dongle based on Wendells directions and hooked it up to an Apple IIe for testing. Unfortunately, I found that the Powerbook didn’t recognize the microphone input. After some more web searches I found a couple of sites that indicated that a 1600 ohm resistor between microphone in and ground would cause the microphone to be recognized. I hooked up a 1500 ohm resistor and found that it worked most of the time. The next larger size resistor in my stash was 2K ohms, so I switched to that and found that it worked reliably. I tested with the Apple IIe and found I could read and write reliably. I also decided to add a .1 uF capacitor on the microphone input line to decouple it.

    I next switched to the SCELBI to capture the output of the SCELBI write card. This proved very helpful and with the help of the Audacity audio editor, I was able to zero in on the problem I was having. During the examination of the SCELBI cassette signal I noticed that the high frequency tone was greatly attenuated. This was due to the .33uF capacitor suggested in Wendell’s notes. The SCELBI uses much higher frequencies than the Apple. I needed to change the capacitor to .01uF so it didn’t attenuate the 2700 Hz high frequency signal used in the SCELBI cassette interface. The resulting circuit is depicted below.

    powerbook cassette adapter circuit

    powerbook cassette adapter circuit

    Here is a picture of the dongle. Note that I took a 4 conductor patch cord and cut it in two for the plug end. The reason is that the small clearances in 4 conductor plugs are difficult to solder cleanly. It was much easier to cut the wire and solder the wires and components together.

    Powerbook Cassette Interface Dongle

    Powerbook Cassette Interface Dongle

    And here is a screen shot of the Audacity application showing a piece of SCELBI cassette audio out. The higher frequency portions represent ones, and the lower frequency are zeros. It takes 2 cycles of low frequency or 4 cycles of high frequency to represent a single bit. This encoding method is called frequency shift keying or FSK.

    SCELBI Cassette Clip

    SCELBI Cassette Clip

    An Apple with a Very Interesting History

    Friday, August 21st, 2015

    My web site doesn’t draw the number of hits that many more popular sites do, but my site occasionally attracts some emails that turn into very interesting stories. The discovery of John Draper’s Apple II is one of them, and I need to put together a few more posts in order to describe his system and it’s history. However, right on the heels of the discovery of Draper’s Apple II, another very interesting system has just surfaced which is housed in this enclosure.

    Apple Case

    Apple Case

    The story is that it was taken out of Steve Jobs office by Apple employee and manufacturing engineer, Don Hutmacher, after Steve was fired in the mid 80s. The story goes that Don was allowed by his boss to go into Steve Job’s office take anything that was left over. It had been picked clean by the time that he got there. He noticed this computer and a bag of Starbucks coffee, and that is how he ended up with it.

    More to come…

    Apple 1 Registry Updated – One of Which May be Myth Destroying

    Sunday, June 14th, 2015

    This update is way past due, I had knowledge of some of the new units since last fall. Three new Apple 1’s are listed. The most interesting is number 1-0052,owned by James Coble. His story seems to shatter the myth that the Byte Shop, not Apple, added the serial numbers on the units in the first batch. There were some issues with that story before, but this information seems to completely shatter it. I have a sent a query out to some experts to see if they can comment on what James has to say. Stay tuned for an update.

    Another interesting note is that the unit that was sold on ebay is reported to be going to Germany. The world-wide market for Apple 1 continues to be stronger than the domestic US market. I think the Ford Museum purchase might have been an anomaly.

    Lastly, I’m pretty skeptical about the report from the bay area about an Apple 1 being given to a recycler. That unit is not going to get mention in the registry until far more concrete details (like a picture) are revealed.

    fixed 6502/Apple 1 Cheat Sheet

    Friday, February 6th, 2015

    Apple 1 6502, cheat sheet, v.98

    I fixed the definition of the ROL and ROR instructions.

    6502 memory test gotcha – 6502 cheat sheet error

    Friday, February 6th, 2015

    One of the more popular programs that I’ve written is this 6502 memory test. One person using this test to checkout his Mimeo, recently discovered that it doesn’t work with his early white 6502. Turns out that that particular 6502 is a nice collectors piece, without a functioning ROR instruction. I used the ROR instruction at the end of the third test, so the program hangs when run on an early 6502 with the missing ROR functionality.

    ;
    ;
    ; all test 2 passes complete – prepase for test 3
    ;
    LDA #$7F
    BNE NX_TEST ;always branch

    CHK_TEST3 ;floating zeros in progress or done
    CPY #3
    BNE CHK_TEST4
    ;
    ; pass of test 3 complete – 8 passes in all with 0 in each bit position
    ;
    SEC
    ROR TEST_PATRN ; rotate right – Carry to MSB, LSB to Carry
    BCS NX_PASS2 ; keep going until zero bit reaches carry

    I haven’t checked it, but I think the following code will accomplish the same basic test without using the ROR instruction.

    ;
    ;
    ; all test 2 passes complete – prepase for test 3
    ;
    LDA #$FE
    BNE NX_TEST ;always branch

    CHK_TEST3 ;floating zeros in progress or done
    CPY #3
    BNE CHK_TEST4
    ;
    ; pass of test 3 complete – 8 passes in all with 0 in each bit position
    ;
    SEC
    ROL TEST_PATRN ; rotate left – MSB TO Carry, LSB = Carry
    BCS NX_PASS2 ; keep going until zero bit reaches carry

    I recently discovered that my 6502 cheat sheet has an egregious error. The ROL and ROR instructions move the Carry bit into the LSB and MSB (respectively), not the MSB and LSB. In other words the instructions are rotate through carry instructions.

    I’m not sure how I managed to mess this one up or why it took so long for me to notice this or why no one else noticed it. Perhaps the functionality of these instructions are so well known that most people don’t need to refer to a cheat sheet to understand functionality. Clearly, I knew how they worked (or were supposed to work in the case of the early chips) when I wrote the 6502 memory test.

    Brain Boards Sold Out – summary of pending projects

    Friday, January 9th, 2015

    I built and tested the last two kits over the holiday break and sold them on eBay. I made 59 PCBs, and kept 1 for myself, so there are 58 that were sold, either as kits or fully assembled.

    Once the initial interest passed, they were very slow sellers, so I’m not expecting to make any more. I have some ideas for an enhanced version, but that is very far down my list of things to do, so I don’t know if or when I’ll take the time to work on that.

    Here are just a few projects on my backlog that are ahead of the enhanced Brain Board. These will easily keep me busy for a couple of years or more.

  • Finishing all the SCELBI I/O Boards
  • Getting Apple II RTTY on the air – reception is working – transmission software is coded, but needs lab testing prior to actual “on air” tests
  • Getting vintage computer Morse code encoder/decoder on the air – Jack Rubin sent me an early Byte Magazine article with a 8008 software package for this, so I’ll probably do this on the SCELBI
  • Fabricating SCELBI Chassis Components
  • Putting together the VCF East 10 display and “Fix It” lecture
  • Hack together a Mimeo with 20K DRAM
  • Move Apple II RTTY application to the Mimeo/Apple 1
  • I have identified another board that is rare, of historical significance and worthy of replication
  • I have other ideas, that are even further out, such as doing a Mark-8. If I did a Mark-8, I would probably etch my own boards. This would probably be pretty easy to do, as the artwork was published and there was no solder mask and the holes were not plated through. I don’t think I would make batches of boards for sale, as this has been done already, and some of the parts are in the harder to find category.

    I also really need to do a manual/book on the SCELBI and I have made some half hearted attempts to start this. The main obstacle is that I’d want to scan and OCR the original docs and that is a very laborious process.

    Brain Board Inventory Down to Two Kits

    Thursday, December 4th, 2014

    I have two Brain Board Kits left and don’t think I’ll do a rerun anytime in the near future.

    I had a total of 59 made in early 2011 and it’s taken a while to sell the last few kits after a fair level of initial interest. Given the numbers made, these are likely to be hard to come by in the future. If you don’t already have one, this may be your last opportunity to get one for some time.

    Bob Bishop’s Apple 1 Trade In Deal – and just when did Apple II’s first ship

    Monday, November 17th, 2014

    Apple 1 and Apple II programmer, Bob Bishop recently passed away. Though I didn’t know Bob Bishop, I did exchange a few emails with him in June of 2013. From the few emails I exchanged with him, I got the impression that Bob was a good guy, and I feel it’s unfortunate that I never got to meet him in person.

    Back in June of 2013, while refining the Apple 1 Registry, I noticed that at one time, that Bob had an Apple 1. I sent him an email, asking if he still had his unit. Bob replied, saying that he had traded it in. This was about the time that Fred Hatfield’s Apple 1 was sold at auction. There was much in the press about Fred’s Apple 1, which included a letter from Jobs, offering a trade in deal. This was a deal which Fred had refused. Bob was a little concerned that the trade he made, wasn’t as good as what Fred and others were offered.

    Here is the story of that trade in, in Bob’s words. The article he mentions, was a New York Times article that included some mention about how aggressively Apple pursued the Apple 1 trade in program.

    When I read that article, I was a little upset (and said so on my weekly radio show) to discover that the company had “an aggressive trade-in program, offering Apple II’s and sometimes cash incentives in exchange for Apple-1’s.” When I wanted to do MY trade-in, I had to go to apple and ask THEM if they would be willing to do it. They said YES… but only if I paid THEM some additional money! But I guess that was before they had fully started their trade-in program. So it may be that I have the dubious distinction of having been the very first person to trade-in my Apple-I for an Apple-II (since the serial no. of the Apple-II that I got was 0013). 🙂

    But now that you’ve showed me the original letter from Fred, It looks like the NY Times article may have gotten their information a little mixed up. According to the letter, it appears that Fred had to pay THEM the $400 — and not the other way around (just as in my case).

    I don’t remember exactly how much I had to pay when I made my trade-in, but I think it was about the same amount ($400). And I made the trade-in around late June of 1977, but Apple didn’t ship the computer to me until July. (I remember that they said it would be delivered to my home in the next few days. So on July third, I sat around anxiously waiting for delivey. The next day was going to be the Fourth of July, and if it didn’t come today, I would have to wait two more days to get it! Well, it didn’t come… so I had a very miserable Fourth of July that year. But around 10AM on July fifth, it finally arrived! 🙂

    – Bob –

    By the way, surviving evidence indicates that though Apple 1 trade ins occurred, it wasn’t a real great deal. Several surviving Apple 1’s that came through the hands of early Apple employees, were probably trade-in’s, but there aren’t that many of them. The only person that I know of, that actually acknowledged that he traded in an Apple 1, was Bob Bishop.