Apple II

ISO01 – Compact low voltage isolated power supply

May 4, 2020 GGLABS

Project Status: work in progress While working in the lab it’s often useful to have a small isolated power supply handy. Depending on the circuit configuration, ISO01 can generate galvanically isolated unipolar and symmetric voltages from a single 3.3V or 5V rail. The circuit is based on the Texas Instruments SN6501 …

Apple II

GRAD – Micropower Geiger-Müller Counter Arduino Shield

April 7, 2020 GGLABS

Project Status: work in progressLike many other hobbyist we have always been fascinated by radioactivity and the sensors to detect it. Geiger-Müller tubes are a common and relatively inexpensive way to measure radiation. GRAD is a complete solution for radiation counting in an Arduino shield form factor. Its main features are …


CoCo DMA: All Charged Up!

April 4, 2020 RETRO Innovations

Addressing the Color Computer 3 DMA operation challenges via hardware modification, while pretty simple, limits initial adoption. It places the technique into a classic “chicken and egg” situation. The CoCo3 provides an ideal platform for DMA capabilities, but owners will only perform hardware modification if highly desired peripheral capability demands …

Apple II

GZ/80-B00 – 20MHz Z-80 PCPI compatible Apple CP/M card

April 2, 2020 GGLABS

Project Status: work in progressThe PCPI Appli-Card was the first single board computer style CP/M card for the apple II. It featured a 6MHz Z-80 CPU paired with 64KB of RAM and 2KB of ROM. Thanks to the high clock and zero wait states DRAM accesses the card performed almost 3 …

Apple II

Juiced.GS to publish bi-weekly

April 1, 2020 Juiced.GS

APRIL 1, 2020 — LEOMINSTER, MA — Gamebits, publisher of quarterly Juiced.GS magazine, is celebrating its storied magazine’s 25th volume by increasing its publishing frequency. “When Juiced.GS debuted in 1996, our readers were connecting to GEnie and Delphi on archaic dial-up modems, downloading files at a snail’s pace,” reflected …


CoCo DMA: Missing Without a Trace

March 23, 2020 RETRO Innovations

Radio Shack’s introduction of the Color Computer 3 introduced extensive changes to the Color Computer design. Gone were the 6847 VDG and 6883 SAM, functionally replaced and enhanced with the TCC1014 Advanced Color Video Chip (ACVC) which most folks reference as the GIME. Other additions included an additional 64kB of …


CoCo DMA: Invisible RAM

March 12, 2020 RETRO Innovations

Now that we’ve learned a bit about how the 6809E wants to be treated during a direct memory access (DMA) request, we can put all we’ve learned into action. But, before we launch into the details, let’s address some questions that arose during previous article discussions: Some asked why the …