#nabupc — Public Fediverse posts

Looks up EF9367. Ooo, ahh, it can do 512 pixel wide scan lines. That means 80 column text!

My current project #NthPongEars for the #NabuPC uses a 4 year older TMS9918A video chip that just does 256 pixels per line.

I didn’t know much about Gould, other than they were the only one with a computer system fast enough to run the head end of the #NABU cable TV data network in 1982, pumping out 6 megabits per second to a city of #NabuPC home computers.
https://en.wikipedia.org/wiki/NABU_Network

@AGMS00 Ohh awesome. When I saw the theme of #VCFMontreal this year was “Canadian Computing”, I immediately thought #NabuPC!

@pierrenick I had a good time at #VCFMontreal. Lots of chats, interesting talks and I even got to ask CuriousMarc (YouTuber restoring Apollo computing and digital radio equipment) a NASA atomic clock question (they used the same HP clocks he is working on, for measuring Doppler speed changes in the radio signal from the space craft). But for me, mostly #NabuPC stories and history and meeting people.

I'm planning on going to the #VCF Vintage Computer Federation's Montreal convention (January 24, 25 2026), to see a couple of #NabuPC talks by Leo Binkowski and D.J. Sures. https://vcfed.org/vcf-montreal has show info.

I hope to be in the audience, since I'm writing #NthPongWars initially for the #Nabu. I might be able to demo it.

I also hope to see CuriousMarc of Apollo guidance computer restoration fame demoing his recreation of the space radio data transmission system.

Looks like a fun weekend!

Maybe I should make a video about my attempt to allow bigger programs on the Z80 #NabuPC by switching off the 4K boot ROM to access the underlying RAM? :-) Technically it’s just a relocating loader.

Had fun adding the first power-ups to #NthPongWars, a game for the Z80 #NabuPC. Of course, got many more ideas. The challenge is fitting them in 64K of memory, and making overall game-play coherent.

Details, discussion and video script in the longer blog post at http://web.ncf.ca/au829/WeekendReports/20240207/NthPongWarsBlog.html#2025.09.03

I spent more time on #NthPongWars today, looking into sound effects on the #NabuPC using the AY-3-8910 sound chip. I also converted some old assembler Pac-man sound code to C to get the hang of it, and found an abandoned sound experiment in the wacka-wacka code.

Longer story and technical details and code on my blog at https://web.ncf.ca/au829/WeekendReports/20240207/NthPongWarsBlog.html#2025.03.04

#NthPongWars continues on the #nabupc now with signs of game-play, after a difficult time figuring out Manhattan vector rotation math.

I added tile power! Every time you run over your own tiles, they gain in strength. Then when you switch to harvest mode, you get accelerated when you consume your tiles, more speed obtained for stronger tiles.

More details on the blog at https://web.ncf.ca/au829/WeekendReports/20240207/NthPongWarsBlog.html#2025.02.23

#NthPongWars continues on the #NabuPC. Today's head banging brought to you by #Z88DK / #SDCC compiler system for the Z80, where itoa() indirectly causes a crash or mysterious glitches as local variables suddenly change on their own.

Turns out the underlying utoa() assembler code uses more than the usual registers, including ix and the alternate set. And when compiling for speed, ix is the stack frame pointer! Hilarity ensues when you use a local variable pointer to write to memory :-)

More work on the #NABUPC Adaptor signal generation. Seems like I need to up my SPI game and learn how the DMA block works. The gaps between the bytes are almost as long as the bytes themselves.
I was obsessing over the inter-packet delays when the buffers were switched, but this is much more likely to be causing the issues I'm having with packets timing out and the NPC throwing "Adaptor failure" (which is a timeout or data corruption).

Good news! I've got the #NABUPC #NABU Adaptor's QPSK scrambler figured out and reimplemented in C. Next up, the packet format.
#retrocomputing

Z80 ICE acquired! The #NABU #nabupc won't know what's hit it. Thanks again, @rc2014 !

Since I’m targeting the 1982 #NabuPC, fixed point math is essential. I was going to use 16 bits with a 6 bit fraction, but on the Z80 that involves 6 slow shift instructions to get the integer portion. At least 68000 and 8086 have shift-n-times instructions (though no barrel shifter). So putting the fraction point at a byte boundary is desirable.

Wonder why they needed 10 fractional bits. Also 3 physics frames per video frame suggests a max ball speed. I was going to try dynamic physics.

Got a bit more work done on my #NABUPC game. This time getting a prototype of Nth Pong Wars using ncurses to work. Shows that my fixed point math is working, and I now have a testbed to write code on for the non- #NABU parts of the game (makes for easier debugging).

Blog post and source code at https://web.ncf.ca/au829/WeekendReports/20240207/NthPongWarsBlog.html

Look what showed up on my doorstep today!

Volume 89 of Make Magazine is all about retro tech and features an article I wrote about the #nabupc as well as many other retro related articles including one written by @polpo about his awesome picoGUS card.

#NABU #NABUPC says Hellorld!, thanks to a DIY printer cable.
I made it from a modified PC printer cable. Just had to swap the DE25 plug for a DA15.

I've made some pretty good progress with the #NABUPC Adaptor reverse engineering, but I've got this unshakable feeling that I'll need to write an emulator and single-step the 6805 ROM code to see what the heck it's doing and figure out what the flags are...

edit: if you want to take a look at the work so far, it's on github: https://github.com/philpem/NABU-Adaptor/

Nth Pong Wars...

I had a productive evening and came up with lots of ideas (game and code) for my #NabuPC learning to program game. It's just the usual bouncing ball and bricks (inspired by browser version https://pong-wars.koenvangilst.nl/ in Javascript), but with N balls and N players. Possibly some network play. Hope to make it portable so it can run on other computers, but if it can do #NABU, it should work almost anywhere else.

My continuing blog post about it:
https://www.agmsmith.ca/WeekendReports/20240207/NthPongWarsBlog.html

This evening I'm playing Wingwar on the #nabu #nabupc. Just finished assembling a much nicer RS422 cable from an FTDI adapter and a DIN plug

Not long before I've got a complete #NABU #NABUPC Nabu Adaptor receiver board schematic...

This is the first part of the #NABU #NABUPC Adaptor (cable TV receiver) schematic - it's the bit the last bits of the RF can talk to.
This looks like an LFSR-based 22- or 23-stage self-synchronising descrambler, followed by an 8-bit pattern detector. The tap sequence is odd. x^22 + x^3 + 1?

A little casual #NABU #NABUPC reverse engineering. I'm taking the chips off one by one and transcribing the tracks underneath onto the PCB scan.
It's a little like how @tubetime does it, but doesn't leave me with a pile of assorted chips...

Someone found 2200 NABU PC’s in a #barnfind. Z80 based, circa 1982. Of course I bought one. Should arrive mid-month! I’ll be setting up the adapter emulator and getting it “online”.

#nabu #nabupc #z80 #retrocomputing

https://www.vice.com/en/article/ak3k34/2200-forgotten-vintage-computers-are-being-liberated-from-a-barn-in-massachusetts

Fascinating stuff - never heard of the #NABUPC until now :-)

https://www.vice.com/en/article/ak3k34/2200-forgotten-vintage-computers-are-being-liberated-from-a-barn-in-massachusetts

#vintagecomputing

I'm quite fond of this little machine! #nabu #nabupc

I'm really tempted to try making a #NABU #NABUPC floppy controller card which combines the Option Card and floppy card, and uses a WD1772 instead of the 1797 and separate data separator. It's also tempting to add a clock doubler for high-density...

As much as I was tempted to pick up a #NABUPC Adapter, the idea of figuring out a T2-rate OQPSK protocol with no information but the modulation and data rate seems a bit like a fool's errand :(

Parcels are like buses. None for days then three turn up at once. #NABUPC

NABU PC – A 1984 Z-80 Computer You Can Buy Today - Want to hack on brand new 8-bit 1980s hardware? Until recently you needed a time m... - https://hackaday.com/2022/11/28/nabu-pc-a-1984-z-80-computer-you-can-buy-today/ #retrocomputing #cablemodem #auction #nabupc #news #nabu