Assembling an Apple-1 computer – Part 4

My Apple-1 computer needs a parallel ASCII keyboard to work. My S-100 systems could use a parallel ASCII keyboard as well. AFAIK parallel ASCII keyboards have not been made for a couple of decades.

I have a NOS parallel ASCII keyboard however it will require some work to get it setup correctly; this got me to wondering if I could use a more modern PS/2 style keyboard; this lead to me reinstalling my MikroE c compiler (for PICs) and digging out my EasyPIC5 development board.

I am sitting here astonished at how east this was to put together; the MikroE c compiler supplies a number of libraries including a 4-Bit LCD driver and a PS/2 Keyboard driver.

It took perhaps 30 minutes to write a short c program to read the PS/2 keyboard; decode the scan code, write the code to the LCD and to set the ASCII bits on PORTD of my 16F877A PIC. I’ll be able to use PORTC to control the strobe, clear and reset bits for the Apple-1 very easily.

This got me to thinking; there are a number of small readily available programs for the Apple-1, most exist as a HEX file (Apple BASIC Example here) you type in and/or as a cassette tape you load. I can store these either in a serial FLASH or perhaps even in the FLASH within the PIC, a bit of coding and the function keys of a PS/2 keyboard will clear/reset the Apple-1, then send the key strokes to enter and run the program. For Basic programs it could even load up BASIC, run it, then enter the BASIC program.

Of course this project creates a PS/2 to Parallel ASCII keyboard encoder in the process, there are several already on the web, I simply wanted to create on myself.

Another fun project to add to my project list.

Assembling an Apple-1 computer – Part 3

It’s Alive!

My Apple-1 is up and running. I’m still short one of the transformers so I used one of my triple output bench power supplies to provide the +10VDC and +/-16VDC by tying directly to the filter caps.

I built out the video cable per the original Apple-1 manual and plugged it into the 30+ year old monitor I have.

I stuffed out the parts required to drive the video stream, checked the parts several times and hit the power. I had video, the ‘@’s are blinking as expected. When jumping the ‘Clear’ input to +5VDC the screen clears with a single ‘@’ blinking in the upper left corner.

Next I stuffed out the parts for the CPU group, placing a solder bridge on the jumper points for 6502, no DMA, and the chip selects for the 4K DRAM. Again I checked every part for orientation, bent pins, correct part in the socket etc.

I powered up and again got the random start up screen with the ‘@’s blinking. I jumped ‘Clear’ and the screen cleared. I then jumped ‘Reset’ to VSS and the CPU group reset. The video acted correctly when reset with an active CPU displaying:

 

\
@

The fact that the ‘@’ sign is below the ‘\’ and not along side it is the indication the CPU group is running, this is how subtle these old machines are.

“It’s Alive” was exclaimed loudly as I sat back and smiled.

I still have a lot of work left to finish this project.

• Install the additional 4K of DRAM so I can run Apple Basic
• Jumper the board for the additional 4K
• Create an adapter for the parallel ASCII keyboard I have
• Build out the cassette interface so I can save/load programs
• Build some kind of case for it

The project list grows…….

Assembling an Apple-1 computer – Part 2

Well crud, all of the pictures I tool are out of focus. Here is where I currently stand:

All IC sockets and components have been soldered up, I’ve tested the basic power supply section and see the proper output voltages (+5, –5, +12 and –12VDC).

I spent a few minutes with a brush and flux remover to clean off the solder flux, current the board is near the space heater in my shop drying off.

I started out using some 0.1uF ceramic disc caps I bought just for this project, they are about 1 inch across. I was trying to make it look like the caps on Woz’s board in the original post. In the end I really hated how they looked and went with some reclaimed 0.1uF caps from old PCBs from the 1970s and early 80s.

I’ve modified the edge connector I had to look more like the original (removed the ears) and have soldered it up. I was surprised to find several connectors in my stock that I could have used, this one looked unused so I used it. I actually have some prototyping boards that will work with this connector as well, one of them has a 1976 date code, sweet!!!!!!!

The PROMs arrived along with a 6820 from 1976, it’s a purple ceramic unit so it will look great. Having an actual 6820 instead of the later 6821 is another touch that will result in a more period accurate board.

I was digging for transformers for the system and actually found one of the suggested ones on an old power supply from a scrapped bit of gear form several decades ago, again a lucky find.

Many of the parts I collected for the project are show above, not shown is the TTL logic, the PROMs, the 8220, the 0.1uF and the final 22uF caps I used (I didn’t like the look of the orange ones I originally planned to use).

About a third of the of the IC sockets have been soldered in this picture.

The many projects floating in my head

I have so many projects in various states that I’ve decided to try off the top of my head to list them and their current status, I have 320 minutes so here goes:

1. FEZ .NETMF based NIXIE (BDC) clock written in C#
   1. Basic BCD conversion / driver code is written and working
   2. Interface to a set of NUMITRON tubes is working
   3. Internal RTC is working
   4. Network interface is functional
      1. I’ve created a mini web server that delivers the time/date via a web page
      2. I’m having issues with UDP, I can’t seem to query an NTP server
2. FEZ .NETMF based Lobby Counter using NIXIEs, written in C#
   1. Very much in the early planning stages, will use code from the BCD clock project
3. Conway’s Life sculpture, using an early plasma display, PIC16 based, written in c
   1. Electronics and programming are complete, it runs well and is really fun
   2. It plays Conway’s Life starting with a random pattern
   3. It recognizes repeating patterns up to 17 levels deep (ran out of RAM)
   4. It used an external RTC and is also a digital clock
   5. It implements Raymond Weisling’s 4 letter word algorithm from 1973 to generate and display random 4 letter words.
   6. It is menu driven and has a ton of user options.
   7. I need a case to house it, then I can call it complete.
4. S-100 Computer
   1. I have a running S-100 system that I am slowly updating.
   2. Designed and wire wrapped a 64K memory card with serial and parallel I/O, updated CP/M 1.4 for the UARTs and memory size on the card. A Centronic’s Parallel part is partially implemented using an 8255.
   3. Soldered a video card from a 30 year old kit and got it working. Wrote a custom ‘driver’ for in and built the driver into CP/M 1.4
   4. Soldered an RTC card from a 30 year old kit and got it working.
   5. Custom built a backplane and card cage for it.
   6. Custom built a linear power supply for it.
   7. I still need too:
      1. Convert from CP/M 1.4 to 2.x
      2. Get the Z-80 based CPU card I assembled running at 4MHz
      3. Convert from the TARBELL Single Density floppy controller to one that handles double density, I have a couple DD cards here, just need to patch CP/M for them.
   8. I have a number of 30 year old blank PCBs, Z-80 CPU, I/O cards, memory cards etc. that I want to stuff out and build another standalone system, I have two NOS 8-inch floppy drives waiting for this system.
   9. I have several modern design cards for it I want to get assembled
      1. Front Panel
      2. CPU card
      3. I/O card
      4. ???????
5. N8VEM Computer
   1. Basic computer up and running, boots CP/M from floppy, IDE harddisk or flashdrive.
   2. Video card working.
   3. Designed a custom sound (AY-3-8510) and speech (SPO256) card for it, lots of fun hearing it talking.
   4. Custom build a card cage for it.
   5. I started working with the graphics card project for it then got sidetracked.
   6. I have a stack of cards for it waiting to be assembled.
6. Pro-80
   1. I have one of two working example that are know in the world, I have restored it and it runs well. I want to add memory to it using the S-100 card connector built into it.
7. MARK-8 Computer
   1. I have my second set of Obtronix provided PCBs, I had to sell the first unit 1/2 assembled some time ago. I have the PCBs, an 8008 CPU and LEDs from the era it was designed. Just need to find the remaining parts and get it built.
8. Apple-1 Computer
   1. This is making excellent progress, it has my full attention. I am blogging about it as I go.
   2. About 1/3 of the sockets are soldered in
   3. I believe I have all the parts (except for the transformers) required
   4. I hope to spend a few hours working on it today (including photos)
9. Replica-1 Apple-1 Clone
   1. It is running again, the S-RAM had failed, now to lean the WOZ monitor using it.
10. Parallel ASCII keyboard
    1. I have a NOS early 1970s parallel ASCII keyboard made by Cherry. It is of the correct vintage for my APPLE-1 project.
    2. It uses RTL logic and uses negative logic (meaning the bits are inverted from what I need).
       1. I need to add an inverting latch and a latch pulse signal to it so that the Apple-1 can use it.
    3. The proper edge connector for it has been found in one of my boxes of old computer stuff, this was the last obstacle to getting this usable.
11. SCOM Status Application for Windows Phone 7
    1. I need and want to do this for work, it will help me learn how to program the phone
    2. In the very early planning stages
12. A game for Windows Phone 7
    1. Currently just a dream, thinking I will port SPIN, we’ll see….
13. LED Light bar for my CNC Mill
    1. I don’t have nearly enough light at the mill head on my mill, this is a bar with a number of high intensity LEDs that is flexible. I want to create a mount (or mounts) to hold it out of the way but in a place where the mill end, tool and material being milled are well lit.
14. CNC Mill
    1. The issues with run out on the mill end have been solved (bought a new palm router to use as a mill end).
    2. I’ve cut a new set of wooden clock gears with very acceptable results.
    3. Current issue is I need to mill parts longer then the 18 inch max length on the mill, there are several mechanical solutions. I’m however stuck in the design software as it wants all the vertices to be closed loops, how I do this and not cut the part in half has my stumped?
15. Conversion of hundreds of photos to digital format with cataloging
    1. Making slow progress, this was easier before MOM died as I was doing it for her.
16. Photos and blogs – I need to document and share everything above.
17. Windows Media Center computer
18. Ripping all my DVDs to the media center
    1. Not pirating or stealing, just making copies for convenience, I will keep the original DVDs
    2. How do I RIP HD DVDs, I have an X-Box 360 HD player and lots of HD media, I just can’t find the right software to rip them now that HD is dead.
19. HP-65 Calculator
    1. I do love this calculator, the restoration when very well, it’s beautiful. I have so many items along with it, I need to document it.
20. HP-41CV calculator – alas I should sell you for my heart has been stolen by another
    1. I have probably 100 items I need to get on EBAY and get sold
21. PIC32 – Mikroe has released the beta c compiler for you, I want to upgrade and see what cool things I can do with you. You have the power to bring multimedia, multi-touch and so many other fun things to life within the Mikroe world, these are still the best tools for the price you can find.
22. FlushList – my web idea, you are still there in my mind, someday… someday…
23. I want to dog through all the ancestry work my extended family has done, there is so much waiting for me to learn about my family, I just need to find the time.
24. Ah, my Valkyrie. I love you girl, your green and ivory paint is so beautiful. I will ride you again some day, I will wash and polish you. One day soon, you, I and Karen will ride again. The wind in my face, the woman I love pressed tight behind me.
25. The PONG project
    1. So many antique PONG chips in my stock, anyone up for a game of PONG 1975 style?
26. The Heathkit project
    1. I need to get one system fully operational, of the two I still have both still have issue
27. The Radio Shack Model IV project
    1. You my friend are complete, I have recreated as best I could the development system I built for myself in the early 80s. Now I need to use you, you can run CP/M, you should be able to help with my S-100 work.
28. A Bikers Journal – my book about two brothers finding each others, finding their way, finding a life. You have been completed for years yet you sit, unpublished. I need to take the next step with you.
29. Learning to self publish for the Kindle, I could publish my book; more important I could publish Karen’s Novels. Must learn to self publish for the Kindle.
30. Dad’s book, I need to finish reading it. I need to mail his original manuscript back to him now that I have it safely scanned into the computer.

Times up, 30 minutes, 30 items called out. I wonder how many I’ve missed? This list was created in a single session totally from the top of my head.

Assembling an Apple-1 computer – Part 1

An Apple-1 – What is that?

The Apple-1 computer is the first computer designed and sold by the company that today is known as Apple Computer. The design itself represents everything in the early microcomputer ethos. Steve Wozniak designed it for the sure pleasure of designing it; for the sure pleasure of being able to attend a meeting of an early microcomputer enthusiasts group to show off what he had created. Steve Jobs saw the potential in the humble Apple I to build a computer and to bring it to market. Today we have the Mac, the iPad, the iPhone and the iPod. All stand as direct decedents of the engineering and business savvy of the two Steve’s.

In building a clone of the original Apple-1 I am paying homage to the two Steve’s and to the early microcomputer industry that lead to the computerized world we have today.

I had the pleasure of meeting Woz several years ago and getting to chat with him for a bit. He is full of light and energy; his easy smile; the glint in his eyes; his humbleness; his willingness to reach out, shake my hand, smile a HUGE smile and ask my name has stuck with me.

Neil Breeden and Steve Wozniak

Neil Breeden and Steve Wozniak. I’m 7 foot tall resulting
in Steve looking very short next to me. In my hand is a
Replica 1 computer (emulates the Apple-1) which Woz
has just signed. It was also signed by the designer of
the Replica 1, Vince Briel. Steve and I are showing our
Nixie Tube watches, a true sign we are both technology geeks.

The Apple-1 represents what was state of the art in 1975. An 8-bit microprocessor (SY6502), 4K of RAM upgradable to 8K, use of 74xxx series TTL logic, composite video output and the use of simple PROMs to store a monitor program. A double sided printed circuit board was laid out for it. Apple sold about 200 of these systems. I can say with absolute certainty that had I been able to buy one I would have.

An original Apple-1 signed by Steve Wozniak. The picture
was taken by the author during avisit to the
Computer History Museum.

Update for the weekend of Feb-19, 2011

I’ve got a few weeks tied up in the preliminary work for this build.

• I obtained a reproduction PCB from Obtronix, I’ve studied it thoroughly, and I’ve read over the few documents to be found about the Apple-1. Obtronix supplied the blank PCBs, the rest was left up to me.
• Finding the Mimeo Apple-1 project website has been super helpful; he has also created a clone of the Apple-1 which has provided me many resources to keep this project moving.
• I’ve found sources for the hardest to find components. Some of the parts are very rare and have not been manufactured for decades. Three shipments of parts arrived last week; I am waiting for two more to arrive so I have a complete ‘hard to find’ part set.
• Many of the parts I already have in my cache of old electronics and computer parts. The SY6502, a 6821 which I can use as a replacement for the 6820 chip, the TTL logic chips, the IC sockets, many of the capacitors, all but one of the resistors.
• I found a source for 4K 4096 style DRAM chips, at $0.85 each they were a bargain. I needed 16, I ordered 20. In my personal stock I have lots of 16K, 64K and 256K DRAMs. I’ve been collecting these parts since the late 1970s, the 4K parts are older than my collection contains.
• My collection of TTL logic covers parts produced over many decades. I hope to find parts with mid 1970 date codes to help add an air of authenticity to the build. I have literally tens of thousands of TTL parts to screen to find the most appropriate ones.
• I have an open frame composite video monitor from the mid 1970s, perfect for this project.
• I recently acquired a parallel ASCII keyboard from the early 1970s, it’s NOS (New Old Stock). It will require some work to adapt for the APPLE-1.