First Production Version

Hurray!

This is the first production version of the L-Star kit. The files are labeled "v5" because it took me that many revisions of the printed circuit board to get it right.

Hardware and software are still subject to change, check the https://l-star.org website for the latest updates. That URL will be the main website for the project, and I will post build instructions and projects there. I may also host forums where kit owners can share their work or ask questions.

The downloadable files of this release include:

• Schematic and PCB in Kicad (4.0.4) format of L-Star Plus, see below
• Breadboard wiring diagram of the minimal version, produced with Fritzing
• Software to emulate the Apple 1 (with or without the use of the SRAM chip)
• Software to emulate the Ohio Scientific Superboard II (a.k.a. UK-101, a.k.a. OSI Challenger C1P) emulator (currently without cassette or disk emulation)
• KimStar: an experiment that I did to troubleshoot, fix and modify a Briel Computers MicroKim by connecting a Parallax QuickStart board to the 6502 bus.

L-Star Plus

L-Star Plus is the official kit version of the hardware that I designed for this project. It includes a number of extra features that aren't strictly necessary for all projects.

Features:

• Power supply that generates 5V and 3.3V (up to 1.5A total) from a 7-15V DC input. With a small modification you can also use commonly available 5V wall-warts on the power input.
• SRAM chip that can be used as RAM, ROM or a combination of the two.
• Jumper block to connect P25, P26, P27 of the Propeller to their defaults (TVOUT, KBDATA, KBCLK) or to the SRAM chip, or to one of the 65C02 pins ~IRQ, ~NMI, ~SYNC, ~SO, RDY, ~RESET.
• 50-pin 0.1" pitch expansion connector featuring all the signals you could possibly need to add expansion hardware. It has all the Propeller pins, all the 6502 control pins (except ~VPB), pins connected to the video and PS/2 connectors on the motherboard and of course power pins.
• On-board power on/off switch and tactile switches to reset the Propeller and the 65C02, combined with 2-pin headers, in case you want to put the project into an enclosure.

Buy Me

The project is open source (MIT License) so you could decide to make your own circuit board or let someone produce it for you, but if you want to support the project and keep me motivated, please buy a kit from me on Tindie. It will probably be cheaper too, because I buy the parts in bulk and I share the discount with you.

Initial pre-release

This version contains:

• Schematic and PCB of the L-Star Plus, see below
• Breadboard version of minimal version, produced with Fritzing
• Apple 1 emulator (works)
• Ohio Scientific Superboard II emulator (works partially; no cassette or disk emulation)

L-Star Plus is a version of the hardware that includes a number of extra features that aren't necessary for the current software projects, but may come in handy for future projects:

• Optional SRAM chip: 64KB or 128KB (not used by any software in this version!)
• Jumper block to connect P25, P26, P27 of the Propeller to their defaults (TVOUT, KBDATA, KBCLK) or to the RAM chip, or to one of the 65C02 pins ~IRQ, ~NMI, ~SYNC, ~SO, RDY.
• Expansion connector featuring all Propeller pins, plus ~IRQ, ~NMI, ~SYNC, ~SO and ~RESET6502.
• On-board pushbutton switches combined with 2-pin headers, in case users want to put it in an enclosure

The PDF file contains the schematic for this version of L-Star Plus
The ZIP file contains the Gerber files as sent to OSHpark on 2015-01-27