TSU Meeting MONDAY — June 5, 2023
David Anderson, Jeff Burrell, Jeff Cave, Adam Trionfo, Tim Swenson, Larry Lorenson, Bob, John Tolverken, Willie Jones, Alan, Keith, Joe, Ingo Truppel, Ryan Gray
David Anderson hosted a freewheeling Monday meeting with no set agenda. Jeff Burrell gave the headline update on his TS2068 FPGA video board: the design is essentially complete, with two simultaneous VGA outputs, a 256x192 256-color high-res mode, a 128x192 16-color mode, a 256x192 4-color mode, a TMS9918 VDP core in the FPGA, an extended 64-column mode that supports per-cell attributes, and the ability to overlay the high-res screen with the standard Timex display. The remaining work is signal-compatibility with the Wednesday group's board (extra daughter-board lines) and a memory-chip re-spin to drop the awkward SOJ package. Jeff wrote the demo in C via Z88DK in about six hours; that triggered a side discussion with Tim Swenson and Jeff Cave on Z88DK targeting the TS2068 vs. ZX81, including a compiler switch for the native 32-column mode that Jeff B. agreed to post to the io.groups list.
David walked through a large batch of recent archive.org uploads (around 20 items so far) -- Sound Design (an AY-3-8910 register editor with bomb/crash example loops), MScript word processor, Wes Brzozowski's 64-column BASIC, Tom Wood's screen-eating 'virus' demo, Harry Peters' dog animation, and more -- pulled mostly from Paul Bingham's box of Syncware News contest cassettes. He's adopted the TOSEC naming convention (with Adam Trionfo's nudge to prefix 'TS2068' / 'TS1000' to avoid Amiga-1000 collisions). On the timexsinclair.com side, David demoed a new chip-style tag filter on the Sync article index (filter by 2068 / type-in / hardware project) and pointed Adam at the 'what's new' / 'updated' pages and RSS feeds as the best way to keep up with the firehose of new scans. There was also a longer thread about library/Syncware tape archiving methodology -- using FUSE to load WAV captures and re-save as both TAP and TZX, and the 'GOTO 9999 to save' trick built into many Zebra-era programs.
Willie Jones joined for a detailed comparison of the period TS2068 disk systems. He bought his JLO around 1987 and beta-tested ROM revisions for John Oliger; he praised JLO for using existing 2068 BASIC tokens with just a leading forward-slash, its built-in Centronics printer interface, and the fact that the JLO cartridge can also drive Larken drives if you know the Larken commands. He contrasted that with Larken (RANDOMIZE USR 100 / PRINT #4 style, which motivated Bob Swoger's Logicall menu front-end) and AERCO (asterisk-prefixed, like Interface 1 / Zebra FDD-3000). Alan added that AERCO is arguably the easiest because it auto-hooks the error vector on power-up, but it isn't compatible with OS64 or the Spectrum ROM without a ROM rewrite. Ryan Gray (calling in from an Amtrak break in Gallup en route to Disneyland) asked about emulating these disk systems; consensus was that the mainstream Spectrum-focused emulator authors aren't aware of the Timex disk hardware. There was also extended discussion of LROS vs AROS cartridge image formats, jumper settings on David's cartridge board, and Jeff Burrell's Python BASIC-to-cart-image tool (posted to the io.groups list, not on GitHub).
Other threads: new attendee Bob introduced himself -- he repaired an eBay ZX81 (composite-video mod, then a full keyboard-replacement PCB using NimbleSloth's Adobe Illustrator key artwork, fabbed at JLCPCB, similar to Ingo Truppel's design). Joe showed his Charlie Robinson ZX-Spand (5th edition, recently bought via eBay from Poland) -- AY-3-8910 sound, 9-pin joystick, SD-card storage, working on every modified ZX81 he owns; Adam noted his Back Bit by contrast is hit-or-miss across machines. Larry Lorenson talked through power-supply choices for his ZX81 NVRAM project (LM338 19V->9V pre-regulator, 7805 on-board) and started learning EasyEDA + JLCPCB ($19.50 for five boards including shipping). John Tolverken recapped his Albuquerque/VCF-Midwest road trip and the VCF Midwest venue's growing pains. David announced he'll list his duplicate books, Spectrum tapes, 2040 printers, prototype SCLDs and Timex/Sinclair ROMs on andertone.com (separate mailing list, not the group, to avoid spamming). Next meeting (June 18) will feature Richard Booth on his complex-math book for the ZX81/TS1000/TS2068; David and Tim will type in sample programs in advance. A future meeting is also lined up with Jeff Street (OS64 cartridge author), tracked down via Bruno Florindo.
Highlights
- Jeff Burrell's TS2068 FPGA video board is feature-complete: dual VGA, 256x192 256-color high-res, TMS9918 core, attribute-capable 64-column mode, demo written in Z88DK in ~6 hours.
- David uploaded ~20 vintage TS2068/TS1000 programs to archive.org from Paul Bingham's Syncware News contest cassettes, using TOSEC-style naming.
- Willie Jones gave a detailed JLO vs Larken vs AERCO disk-system comparison; AERCO judged easiest to use but incompatible with OS64/Spectrum ROM.
- New attendee Bob showed his ZX81 keyboard-replacement PCB (NimbleSloth keycaps, JLCPCB-fabbed) and composite-video mod.
- Joe demoed a Charlie Robinson ZX-Spand (5th ed., AY-3-8910 + joystick + SD card) and contrasted its reliability with the Back Bit across modified ZX81s.
Projects discussed: FPGA "Advanced 2068" · Library Tape Archiving Process · TAP-to-Cart — TS2068 Cartridge Conversion Topics: TS2068 / TC2068 · Disk & floppy systems (Larken, AERCO, Oliger) · Hardware projects & new boards · Tape & library archiving (TAP/TZX) · TS1000 / ZX81 / TS1500 · Pico / modern interfaces (UnoDos, etc.)
Summary generated from the meeting recording; the full transcript is kept in the group's private archive.