Nanokit board layout from manual

The NANOKIT (Or NANO-KIT) is a National SC/MP II based single board computer with 256 bytes of RAM. You have eight switches to select the memory address and eight switches for the data which you then deposit (DMA!) using a momentary switch. This you do as many times as there are bytes in your program (which you had carefully hand-assembled before, of course).

Then you give the processor control and off it goes.

Unsurprisingly (it's right there in the NAME!), the NANOKIT came as a kit, produced by a company (or maybe just some guys in a garage) calling themselves "Microsystems / Mikrostelsels". Since the manual claims to have been printed in Cape Town, that's probably where they were based. And that explains why you've probably never heard of it (assuming you're not here because of the googles, like Stephen, see further down).

I bought the NANOKIT secondhand and prebuilt. Well, my parents bought it for me. It came with a set of ROMs piggybacked onto / underneath the RAM chips, containing a program to play "Die Stem" (The old South African Anthem) through one of the output pins.

The manual contains quite a few errors, and looking back I can see why I had such a hard time wrapping my brain around this stuff. OK, the fact that I was twelve at the time might have had something to do with it.

If you have more info, please contact me. This might be the only existing NANOKIT?

2002-09-23: Received email from Stephen Davies, who says that he also has one, which he got in 1977 or so. Stephen says he knew Andre Wagner who knew the designer.

NANOKIT small image - click for larger image

I took my NANOKIT apart, I needed the switches for another project (yea, I was young). But I have since put it back together. I have also reverse engineered the schematic, although this is still a work in progress: PDF, KiCad.

Somewhere along the way, the 2111 RAM chips went missing (this is strange, I never throw anything away). And of course by now, 2111s are unobtanium. Completely unobtanium. Fortunately, one can substitute a 6116, and I have plenty of those.

Also, the space between the two 2111 sockets is exactly one 6116. Now to fire up VeeCAD to optimise the design.

Other SC/MP Stuff

The SC/MP came in two flavours, namely P-MOS (INS 8050 ISP-8A/500 SC/MP-1, 1976) and N-MOS (INS 8060 ISP-8A/600 SC/MP-2, 1977).

The P-MOS SC/MP-1 is kind of strange in that it needs the standard +5V but also -7V. Well, it's actually not that strange -- if you call the +5V rail zero, then the voltages are -5V and -12V, the opposite of the +5V and +12V the Intel 8080 needs to run (OK, the 8080 also needs -5V, and to this day your PC power supply probably has a -5V rail even though there's nothing using it).

SC/MP Demonstration Kit

National Semiconductors offered a "SC/MP Demonstration Kit" (PCB 5514879/B, ISP-8K/200) (Manual dated March 1976) which consisted of a SC/MP processor, 256 bytes of RAM and a 512 byte Mask ROM. The ROM contained KITBUG which allowed the user to interact with the Demonstration Kit using a Teletype.

In October 1976 they added a keyboard and display, consisting of basically a calculator body on a ribbon cable. A replacement ROM with "SCMPKP" firmware and a whole bunch of TTL was required.

The National Semiconductors Introkit (PCB 551305229) is slightly bigger than the Demonstration Kit it closely followed (in time and in design -- actually I suspect the schematics are identical). The instructions for the SC/MP Keyboard Kit cover both PCBs.

The Sinclair MK14 is very similar to these kits, which is pretty much the point of Demonstration Kits.

National SC/MP Keyboard Kit Schematic

Sinclair MK14 Schematic. Compare the right hand half of the schematic with the Keyboard Kit Schematic. GO MEM ABORT TERM all in the same place even.

My SC/MP Demonstration and Keyboard Kits

81ls97 3 ls95 2 3 x 81LS97 8-bit bus driver 4 x 74193 Synchronous 4-bit binary counter 1 x 2111 256 x 4 RAM 1 x 7402 quad NOR gate 1 x 7410 triple 3-input AND gate 2 x 74LS08 quad AND gate 2 x 7495 4-bit shift register

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