Archive for the ‘Apple II’ Category

A Conversation with PCB designer Howard Cantin

Monday, April 2nd, 2012

We live in an unique age where important people engaged in the early days of the personal electronics industry are often accessible and willing to talk about the “old days”. Today I had the good fortune to have a telephone conversation with Howard Catin. Howard is the PCB (printed circuit board) layout designer responsible for early Atari and Apple PCBs. I was interested in talking to Howard because of my reproductions of his work have created a large amount of curiosity about how the original PCBs were created. I was also interested in his relationship to Steve Jobs and Steve Wozniak.

At that time, PCBs were laid out on a transparent film on drafting boards. Tape and preprinted images of each ICs footprint were transferred to the film in order to make the image of the board. The film was photographed and the photographic films of each layer were provided to the PCB manufacturer in order to fabricate the actual PCBs.

What follows are taken from notes taken during the call with Howard. The call was not recorded, so words are mine. Footnotes, denoted by brackets are additional information that Howard did not relate, but add context to the story.

Background
Howard worked from his house for clients including Atari and Apple. Howard says he laid out all the boards for the first four years at Atari, until Nolan Bushnel sold the business [1]. He also laid out first boards of other electronics startups in valley that became major players. Though he couldn’t remember the names of others, he says he did the first PCB for Intel. Howard says he was well connected to insiders in the valley electronics community and was the person to go to, when a PCB layout was needed. Howard related how he set many of the standards in PCB layout that were followed by others.

Nolan Bushnell of Atari was often in a hurry and pushed Howard to hurry along a design. Howard says he was a fast designer, partly because of working under the pressure provided by Nolan. He could add a chip to a layout in hour.

Steve Wozniak
Regarding Steve Wozinak, Howard related to me, the often retold story about how Woz created a game design that used 60 parts instead of the 100 in the design that preceded it [2]. Howard related that engineers at Atari couldn’t understand the design. Because they couldn’t understand it, Atari ended up not using it.

How Howard Worked
Most designs had an edge connector, so he would start with that and then add parts that connected to the edge connector. Then he would connect those parts to the parts that connected to those parts and so on. Vias were expensive and to be avoided, and would take up the space need for 3 traces. Howard provided his original artwork and photographic transparencies ready for the PCB manufacturer to his clients. Howard often didn’t negotiate price before taking on a job, but a typical cost was 6 to 8 dollars per chip. Howard worked directly from customers schematics, and is still proud of his ability to produce a result that matched the schematic perfectly.

The Hobby Computer
The first board that Howard did for Jobs and Wozniak was a computer to be sold to the hobbyists at the local computer club [3]. Howard says that this computer was the board that provided the financing to start Apple Computer. Howard refers to this as a hobby computer, not an Apple Computer. [4]. Howard says the two Steve’s always were together and they conducted their discussions with him together. To pay for this computer, the Steve’s tried to trade an old Fiat Station Wagon for services rendered [5]. Howard asked for cash, so the Fiat was sold and proceeds used to pay Howard. As some point, stock was offered, but this was also refused.

The First Apple Computer
Steve Jobs appeared to be a perfectionist to Howard. During the layout of the first Apple Computer [6], Howard had three proposed layouts with different form factors. There apparently was a lot of back and forth figuring out the form factor. Finally, Howard suggested one of the layouts happened to exactly match the size of a piece of legal paper (8.5×14) and Jobs selected that one [7]. The proto area in the corner of this computer was empty and it was Howard’s idea to put pads for a chip and an array of pads that became the proto area.

Though Howard did the main chip placement on this second layout, Howard paid a woman to lay the tape for traces. She was not very good and the traces she laid were not very straight. Jobs wasn’t satisfied and took the design and had it redone digitally. Jobs later told Howard that this re-layout cost Apple three months [8]. Howard asked Steve why he needed to redo the layout and Steve said he was only going to do it once in his life.

Howard did not use that woman for laying traces again. Howard told me that after that project, that he would have refused more work from Apple. In any case, Apple didn’t come back to him.

PIRACY
Howard also mentioned that he thought that the one of the Steve’s took a picture of an Atari board that he happened to be working on as the same time he was working for them. He thought that the Steve’s might have used this picture to duplicate an Atari design in some way. Howard did not have any specific details about what exactly was done with the image. Howard also said he talked on the phone with someone in England that might have been investigating another pirated Atari design. At one point, Nolan Bushnel asked Howard to pirate another design, but Howard refused. Howard now thinks that this was Nolan’s way of checking Howard’s honesty.

[1] Atari was sold to Warner Communciations in 1976
[2] This must be the Breakout game
[3] Homebrew Computer Club
[4] In my opinion, this computer is actually the Apple 1
[5] Is this the source for the often heard van story?
[6] Actually the Apple 2
[7] I often wondered if the size of an Apple 2 matching a legal page size was a coincidence
[8] Though the Apple 1 layout is very consistent, I could tell that the Apple 2 layout is quite a bit more consistant – now I know why

A2 proto board update

Friday, March 30th, 2012

After an email exchange with Vince Briel where Vince casually indicated that the A2 community really needs a prototyping board, I’ve decided to raise priority and get a batch of these prototype cards built.

I’m a little concerned about timing, especially with the 6522. The Mockingbird board, which also uses the 6522, does some strange stuff with clock timing and I need to really investigate what is going on with a real board. So, before doing the production build, I need to get a prototype proto board working.

Normally, I would just etch a prototype PCB at home, but a proto card needs a bunch of holes drilled in it which would take a long time to do manually and besides, I might need to make some significant changes, which is easy to do with wirewrap. In addition I had on hand an Apple Hobbyboard, which is ideal for this project. The Hobbyboard had been used before for a simple temperature sensor project that I did in the 80’s, but the old circuit had been removed from the board a few years ago. So in the last week, I have wirewrapped the new circuit onto the old Hobbyboard.

prototype proto board

prototype proto board

I haven’t gone very far in debugging because I keep frying the 16V8 GAL chips I’m using to cut down on chip count (and leave more prototyping space). Could be something to do with the ancient Data I/O Pal programmer I”m using. Anyway, there is real progress being made on this project and I hope to get things squared away so I can make a build this spring or summer.

VCF EAST – May 5th and 6th – Wall, New Jersey

Friday, March 16th, 2012

There are going to be some great speakers this year. Make an effort to join the festivities – it’s a great time.

VCF EAST 2012 flyer

Wozanium fix for new Apple 1 Program/Hack

Saturday, February 18th, 2012

It’s been a while since I found an Apple 1 program that didn’t run on the Brain Board/Wozanium, but there is a new program out for the Apple 1 that uses the ACI for audio out.

http://www.applefritter.com/content/8k-apple-i-ascii-graphics-lunar-lander-aci-audio-hack-0

Copied here, is my post on the Applefritter forum, describing the fix.

This program will not work as is, with versions Brain Board/Wozanium pack firmware less than version 5.2. There is an issue with the the gosubs 750s in the 900 range (at the end of the program). Those gosubs call directly into the original Cassette interface driver to generate sound. This driver is still present in the Wozanium PROM, but is incompatible with Apple II hardware and will crash the system.

There are several fixes available.

1) remove the call 750s at the end of the program. LInes 900 and 910.

2) Change the pokes in line 999 to call the Wozanium A2 cassette Driver at 0xd0d7:
999 POKE 750,169:POKE 752,32:POKE 753,215:POKE 754,208:POKE 755,96:RETURN

3) If you have a PROM burner, fix the Wozanium cassette driver to work with the A2 hardware by erasing a bit in the PROM – change location 0x01EA in PROM from 0xBC to 0xAC.

4) If you don’t have a PROM burner, send your board or prom back to me and I’ll erase the bit for you.

With fixes 2, 3 or 4 in place, you can attach a preamp to the cassette output of the Apple 2 and get the same sounds as if you were running on an actual Apple 1. It’s kind of funky because the A2 has a built in speaker, which is bypassed, but it works.

If you are running a Wozanium PROM image in an Apple II emulator either:
1) remove the call 750s at the end of the program. Lines 900 and 910.

2) change line 999 to call the Wozanium ACI driver at 0xd1d7:
999 POKE 750,169:POKE 752,32:POKE 753,215:POKE 754,209:POKE 755,96:RETURN

Finally if you don’t have a preamp for the cassette output, there is an inexpensive design on my website that will work for this application.

http://www.willegal.net/preamp/preamp.htm

Complete Information on MM5740 Keyboard Decoder Found!

Tuesday, February 14th, 2012

I’ve done several online searches for a complete MM5740 data sheet over the last several years. There is a version that can be found on many of the data sheet archive search engines, but it is missing at least one page, containing crucial information. I knew it was part of National’s MOS/LSI data book from the mid ’70s, but I couldn’t locate an online version of that book, and I really didn’t want to buy a physical copy. One of the key questions that couldn’t be answered with the existing online data sheet, is what exactly is the difference between the AAC/AAD/AAE/AAF versions.

Finally while exploring the possibility of using an AVR as a replacement decoder for the MM5740, I did another search and the data book turned up as a PDF at bitsavers.org. The last page of the data sheet show that the AAE version has N-key rollover and the AAF version has 2-key rollover. Otherwise they are the same. This means that the AAF version should be usable in the Apple/Datanetics keyboards, only with the loss of the n-key rollover feature. Also, in this data book are some app notes, that provide information on the AAC and AAD versions. Those versions decode the matrix differently, in order to make using an external PROM decoder simpler. They will not be compatible with Apple/Datanetics keyboards.

Once I figure out the best way to cut it out of the complete data book, I’ll put a copy of the complete MM5740 data sheet and associated app notes up on one of my web pages. For now, you can try to download the complete National MOS/LSI data book from bitsavers.org. Recently, I’ve have trouble accessing that site, but if you are persistant, you should be able to get through.

Apple II ebay starting auction price 4,995

Tuesday, February 14th, 2012

This is NOT a rev 0 system. Is there really a chance Dan could sell this?

http://www.ebay.com/itm/1978-Apple-II-Computer-Integer-BASIC-Steve-Jobs-and-Wozniak-Collector-Quality/120860101174?ssPageName=WDVW&rd=1&ih=002&category=80075&cmd=ViewItem#ht_31541wt_1047

Banner day for my retro-computing hobby – historic images added to website

Friday, February 3rd, 2012

An image of an original SCELBI stock certificate was sent to me about a week ago, by early SCELBI employee, Frank Zawacki. More about Frank and the image can be found on my SCELBI page.

http://www.willegal.net/scelbi/the8008andScelbi.html

Wendell Sander sent me an incredible scan of an original photo used in an early Apple 1 ad. A lower res image of this scan has been added to my registry page.

http://www.willegal.net/appleii/apple1-originals.htm

Also, earlier today, I was lucky enough to have a brief chat with Jon Titus of Mark-8 fame about an Apple ][ project I have had in the works for a while. Jon seems like a great guy and was very accommodating. Hopefully I’ll have time to make more headway on this Apple ][ project, so I can share the details with readers.

“Retro 1″ Systems

Friday, January 27th, 2012

Marty Ewer is now selling “Retro 1″ systems on ebay for $249. They are fully tested Apple IIe computers equiped with my Brain Board. If you are looking for the easiest, least expensive way to an authentic Apple 1 experience, this may be it. In addition, you get a working Apple IIe in the bargain. Search for “Retro 1″ under user “shockwavetechnologies” on ebay.

http://www.ebay.com/sch/shockwavetechnologies/m.html?_nkw=%22Retro+1%22&_sacat=0&_odkw=retro+1&_osacat=0&_trksid=p3911.c0.m270.l1313

Brain Board 74LS244 Grounding Issue

Tuesday, October 25th, 2011

The Brain Board review in Juiced GS included a description of a bad 74LS244. I have had one other report of problems with the Brain Board in an Apple IIe. In that second case, I had that person send back his board, twice. Though I wasn’t able to reproduce the problem in my Apple IIe with his board, I tried two different repairs, the second of which seems to be successful. The first was a simple swap of the 74LS244, which helped, but didn’t completely eliminate the problem.

After further analysis, I determined that the grounding of the 74LS244 is less than optimal on the Brain Board and switching on of the 74LS244 causes a lot of noise on the ground. Apple boards that use a similar data bus driver circuit (Apple FW card & Super Serial) also exhibit this switching noise. The stock Brain Board is somewhat worse in this regard. I found that adding an additional ground wire on the 74LS244 reduces noise to levels lower than the Apple FW board and appears to solve the problem.

This intermittent operation is typically seen as random characters input while at the console prompt, while not actually typing on the keyboard. If you notice this problem, add a wire between the ground pin of the 74LS244 and the ground lead of the decoupling cap near the other end of the edge connector.

Here is an image of a board with the fix applied.

brainboard 74LS244 ground wire fix

brainboard 74LS244 ground wire fix

One more word about this problem. Though I didn’t know of any issue with the ground, when laying out the production Brain Board, I considered shortening the ground connection to the 74LS244, running it across the center of the board, instead of the top. This change might have prevented this issue. However, I decided that, since, in several years of operation of the prototype “Brain Board”, I had seen no issues, that it was unnecessary. This is a case where the “if it ain’t broke, don’t fix it” approach, was the wrong approach. For now, the one wire fix will have to do. If I make another run of these boards, the ground trace will be widened and rerouted using the shortened path I considered before.

Also because of this issue, I’m going to have to make major changes to the layout of the protoboard that I have described earlier in this blog.

Brain Board Review in Juiced GS

Saturday, October 1st, 2011

Peter Neubauer wrote up an excellent review of the Brain Board and it is printed the in September, 2011 edition of Juiced GS.