Category Archives: Apple II

Everything concerning the Apple II, II+, IIe, IIgs and IIc

T2A2 for everyone

While the guys over at OpenApple were speculating in their latest podcast what a Transputer actually is… well, there are about a 100 links and ways on this page to find out – but hey… just click here – and of course that box saying search would do great wonders, too.

But seriously, my bad: I should have mentioned that this page your looking at is really just one post of many… so make sure you start at a Chapter (Menu. At the Top. ↑…yes up there) and read them in the order you’d read a book 😉

After quite some years (and a handful Apple II users requests) I felt the urge to finally put the T2A2 prototype (read that post to get a more general understanding) into a real expansion card… and here it is: Say “Hello!” to the T2A2 version 1.1!

It came a long way…


…in more detail:


As you can see, the final T2A2 is much smaller than the prototype (which used an 8bit Baby one-for-all PCB) and offers many additional features

  • 2 size-1 TRAM slots (or one size-2) – double the processing power!
  • Low-power, low-profile parts used where possible (3.3V CPLD, HCT logic)
  • External Transputer-link available as edge connector – extend your network to “near infinitum
  • Jumpers for LinkSpeed and optional power to the Transputer-link connector
  • Fully buffered to be a good Apple II bus citizen
  • Works in any slot set to “your card”

Beyond this, everything said about the prototype is still true.

Most important:

a) It’s not tested in the ][ or ][+. I simply don’t own one of those.
Update: One owner reported it’s perfectly working in his IIe!
b) The T2A2 won’t instantly speed up any of your Apple II[e/gs] applications.

It’s more like a co-processor attached to it. And even then, you’ll need something really calculation-intensive to justify the time you’ll loose due to communication between the Apple and the Transputer. A single square-root for example wouldn’t make much sense – but having a complex algorithm (like the Mandelbrot fractal in my demo)  does absolutely make sense, as you just pass the parameters to the Transputer and let him do the sweating.

But on the other hand, FPU cards like the Innovative Systems FPE (using an M68881) or my even faster clone “NumberCruncher Reloaded” did just send instruction by instruction. So I somehow fancy the idea writing a SANE driver for GS/OS to integrate the T2A2 more transparently.

Want your own T2A2?

So now you’re keen to get one yourself? Please check this list first:

  • Do you have a TRAM already? (*)
  • You are aware that there’s no real software (yet) besides my little Mandelbrot demo?
  • You are keen to program something yourself – or are fine to wait until somebody else did?

While the Apple II side of coding is pretty easy, you have to get a grip about the Transputer development, too. That includes a DOS/Windows (<=XP) setup and some knowledge of C and/or OCCAM. I’ve created a little Transputer “SDK”, namely a VirtualBox image running DOS.

Plenty of Dev-Docs are available here.  
I suggest using the INMOS cross-compilers for C or OCCAM. An alternative C compiler came from LSC, which might suit you more if you don’t like the INMOS stuff.

Ok, so you’re still with me… so I have the first batch of 20 T2A2 PCBs ready which I will populate on-demand, and for 40€ (plus shipping) one of them can be yours.
(*) I might be able to offer you a TRAM, too. The price depends on available model, RAM size and CPU used.

⇒ drop me a mail tonobody likes SPAM
(Sorry, you have to type that into your mail-client – nobody likes SPAM, so do I)

Also check the T2A2 forum for current availability, shipping procedure and built status.

Some more technical details

Here’s a T2A2 with a size-1 TRAM installed in Slot-0:


The T2A2’s CPLD programming can be updated any time through a JTAG port (the lower 2×5 pin-row at the edge).
The jumper above it can be used to set the linkspeed for the TRAMs (10 or 20mbps). If you look very close, there’s a tiny LED next to that jumper. It’s the error LED controlled by the CPLD.
The next single jumper enables the VCC pins on the external Link connector, meant for (small!) external extensions. This connector is the same used on the Gerlach card and is very convenient because of its ubiquitous standard 2×5 shrouded pcb header connector. Here’s the pinout:

As said, the V1.1 T2A2 offers two size-1 TRAM slots. Before plugging in 40MIPS of raw processing power consider the amount of juice being pulled there. Depending on the amount of RAM and load a single TRAM can use up to 800mA of power!  😯
Given the max. of 4A on a standard IIgs power-supply, two TRAMs could bring your souped-up GS into trouble… it’s better to use the external connector with just one smaller TRAM or even simply bridge the Link0In/Out pins with Link3In/Out so that the T2A2 works as a TRAM-less adapter.
That said, there are size-2 TRAMs in existence which will snugly fit  and won’t hurt that much.

The Number Cruncher – FPU for the Apple II

This is a post I’d like to write since 2006… so 15 years after I’ve put all the Transputer, MIPS, i860 and-what-not stuff aside and made some room for my other (late) love: The Apple IIgs

You might have stumbled about my post/project connecting a Transputer to the Apple II called the T2A2… well, what I did not mention was, that the inspiration to this came from another card built in 1988, called the FPE made by Innovative Systems. That’s a small card featuring just a buffer, an old XILINX FPGA (actually the first of its kind) and the Motorola 68881 floating point co-processor.

Co-pro-ces-sor! I was hooked!  😯

After more research I learned that the FPE was actually a diva like this newsgroup post says:

“The FPE is suffering from a major problem, namely the coproc is crashing internally and has to be reset in software. This happens in a non deterministic way, and software written for that engineering junk must be adapted to that. “

But a bit later there was something better available: The Number Cruncher (NC for short). Fine German engineering  😉 And the newsgroup post was quite nice to it:
“The Number Cruncher is compatible with the FPE but is actually what the FPE was supposed to be – a math coproc that works. It perfoms very well.”

This is the “marketing blurb” from back then

  • totally compatible with the FPE from Innovative Systems
  • much less sensible to heat, voltage problems etc.
  • supports the FPE SANE patch for speeding up any program that does floating point calculations
  • you can compile ORCA/Pascal and C programs to use it directly with the special floatlib for the FPE provided by The Byte Works
  • works in any slot (slot 3 & 4 without need for setting it to “Your Card”)
  • works with TransWarp GS and Zip GS accelerators and RamFAST SCSI card
  • comes with lots of mathematical software and an enhanced SANE patch by Albert Chin-A-Young

I directly contacted the creators of the NC, Dirk and Andreas, but both of them hadn’t had a tiny bit of the NC left. No schematic, no HDL, no nothing 🙁

During looooong and wild eBay raids I managed to get my hands onto an FPE as well as on an NumberCruncher. Woohoo! They both work with the same driver and yes, the NC is much more robust than the FPE.
But it seems that there are only a handful of them survived, if anymore at all. So I thought it might be interesting for me and others to make a re-release…

Let’s re-animate the Number Cruncher!

So, again, it’s up to me to save the world… reverse-engineering time again!
This job consists of two parts – dissect the hardware and to get a better understanding of this, the software/driver, too.


Well, you could simply rebuild the card, copy the bitstream from the serial PROM for the FPGA and you’re done.
But it’s not so easy, as the FPGA which has been used, the XILINX XC2064 is long time EOL’ed and if you buy old stock, they’re more expensive than a comparably recent CPLD – if they’re not Chinese fakes and/or broken… not mentioning that a simple copy-paste job is not really manly 😉

The XC2064 is a 5V FPGA (the first of its kind actually), has 600-1000 logical gates and 58 user IO pins of which 32 are used. It is getting its bitstream fed by an external 12K serial PROM. I’ve pulled the bitstream in a file available here, but because XILINX never documented that format, it’s pretty much useless.

The rest is all standard stuff. A ‘245 transceiver, an oscillator (~12MHz)  and some chicken feed.

Revving it up

To prove that I got everything right and having a better attack analysis vector I designed the “NumberCruncher Reloaded v0.1“… more or less a 1:1 clone but bringing out all FPGA signals to pin-headers to have a convenient access for my logic analyzer.
Also I used a PLCC version of the 68881, because I have more of those.

Then, out went the logic analyzer and weeks and weeks of looking/listening to the the FPGAs conversation to the the FPU and Apple bus while having the 68881 manual on my lap, I got an idea of what’s going on.


Later I found the original floppy which came with the NumberCruncher containing  just the init-files for GS/OS patching SANE to use the FPU instead of the 65c816  (download the ShrinkIt archive here) – well, at least something!

Next came my ol’ buddy Mr. disassembler… a lot. About a year on-and-off… and here’s my initial, slightly commented disassembly of the SANE patch.

Again, some years down the road I found the floppies which were delivered with the FPE and those are quite helpful with code examples, assembler macros and libs etc. – that would have been quite helpful during the disassembly  😕 Anyhow, it’s good to see that most of my interpretations were correct.
Also, the FPE came with quite a nice manual – which actually was more valuable than the card 😉
It very well describes the basic functionality, the FPU registers used and the programming side of things – even the most important parts from the 68881 manual are cited. Very good job on that Innovative Systems!

Having all this at my hands I was prepared to start and after some huffing and puffing the NumberCruncher Reloaded v.1.0 was born.

NumberCruncher Reloaded Details

Because the main page of the NumberCruncher Reloaded grew bigger and bigger, I’ve split the FAQ and programming stuff in this separate post.


Q: Which Apple computers are compatible with the NC-R?
I’ve tested the NC-R in my IIgs and IIe. Those work for sure.
The original FPE was communicated as being compatible with the II and II+, too. I don’t have those machines and while the compatibility is highly possible, it has yet to be proven.

Q: I’m experiencing crashes and instant lock-ups starting programs which are supposed to use the NC-R
A: Most likely your software is expecting the FPE/NC-R in another slot.
For speed sake, most current programs naively supporting an FPU card, expect the card in a certain slot. Especially the SANE INIT.
So please check if your NC-R is installed in the correct slot and try other programs if they are crashing, too.
I recommend the Mandelbrot program provided on the NC-R Tools disk. This program scans all slots for a FPE/NC-R by itself.

Q: What are these LEDs for?

  • The green BUSY LED blinks at every access to the FPU.
  • The yellow INFO LED doesn’t have a proper job yet. Currently it’s connected to DEVSEL, so you can see it blink very briefly, when your Apple II scans its bus.
  • The red ERROR LED will be lit when the FPU encounters a so-called ‘protocol violation’, i.e. there’s some problem in the communication between the Apple and the 68881/2.
    See page 30 in the manual for more details.

Q: And for what use is that 5×2 pin-row at the cards back-edge?
A: That’s the connector to update the firmware if that should ever be nesseccary. For now there’s just the one version which is installed.

Q: Can I make the NC-R go faster? What about overclocking?
A: Not really. See the ‘Benchmark‘ section further down.

Q: On the pictures of the NC-R I can identify a 40MHz Motorola 68882. Do all NC-R have such fast FPU?
A: No. I use whatever 68882 is available on the market. Strangely enough, sometimes a 40MHz version is cheaper than say a 16MHz.
So whichever version is installed in your NC-R, it’ll be fast enough and always clocked at 16MHz anyhow.

Q: How can I write programs using the NC-R?
A: This is an extensive question which can’t be answered satisfyingly in an FAQ. Refer to chapter 3 of the manual to learn how the NC-R works internally and how to program it in assembler, C or even Basic.
But I’m also thinking about a dedicated post about just that matter.

Q: I wrote a small program to test the NC-R and it’s not really faster than using SANE on my IIgs
A: There’s a certain amount of calculations need to be done until the NC-R shows its performance. A single addition probably takes longer than it would need on e.g. a stock Transwarp GS because all the communication overhead.
This dramatically changes if you have lots of floating-point calculations in one stream, optimally using the 68881/2 internal registers.

Q: Are you writing software for the NC-R
A: Well, maybe in the future but currently I’m busy with other projects.
But so much can be revealed: Brutal Deluxe has its NC-R already 😲

Q: How can I ask you a question / get help / praise / complain / rant about the NC-R?
A: I reactivated my little Forum on this page. Therefore it got its own Apple II board.
This way everybody can participate in your question or complaint… speaking of complains: Do not complain that you have to register and that it took so long for the approval! This is a one-man show, there are time-zones and despite other rumors, I do have a job 😀

Q: Why did you chose green for the PCBs colo(u)r?
A: It’s a remake. So  it should at least somewhat resemble the original look. Also given there are translucent lid/case options available today I personally don’t like the idea of a motley bunch of green/blue/red/white cards standing out of my Apple II… yeah, I’m old-school 👨‍🦳

NumberCruncher Reloaded Software

“Real” applications for your NumberCruncher Reloaded

I prepared an archive, containing all applications (I was able to find) supporting an Apple II FPU accelerator card in some manner, i.e. natively or via SANE.
These were commercial programs back in the days and were not provided with the card itself – to learn more about the basic tools which came with the card, visit the NumberCruncher Reloaded main post.

You can Download all presented applications as ShrinkIt archive or ZIP file

Obviously, they’re mainly math packages… and sad but true, as for now they’re all Apple IIgs programs:

GSnumerics (by Spring Branch Software)


Symbolix (by Henrik Gudat of Bright Software)

Screen Shot

jazGraph (by Jason Perez)

MathGraphics (by Dirk Fröhling)

saneglue (by Söhnke Behrens)

From the README: “lsaneglue is a library that contains code to let you call SANE funtions directly from ORCA/C”.
This lib provides convenient functions like findfpcp() and most calls to floating-point operations.

I hope that due to the availability of the NumberCruncher Reloaded this software collection will get some new addition by enthusiasts of the vivid Apple II retro scene.