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 👨‍🦳

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