Retrocomputing

Commodorino - Use arduino shields on the Commodore 64

CommodorinoArduino shields are ubiquitous and provide a wide range of sensors and interfaces. Commodorino allows their use on a Commodore 64. The interface provides good compatibility with the Arduino Uno platform. Digital I/O, Analog In, SPI, I2C and limited interrupt and Serial port are implemented and additional Micro SD card socket is available for future expansion.

GRAM/4D - 4MB geoRAM Compatible RAM Expansion for Commodore 64/128

geoRAMThe geoRAM is a 512KB memory expansion for the Commodore 64 and 128 designed by Berkeley Softworks for use with GEOS. While not as fast as the Commodore REU due to its lack of DMA capabilities, it still provides a significant performance boost. GRAM/4D is a 4MB geoRAM compatible cartridge based on a two 4Mx4 DRAM devices.

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RAMGS/4 - 4MB memory expansion for the Apple IIgs

ramgsThe apple IIgs is the most advanced computer in the Apple II series. Equipped with a 65c816 8/16-bit CPU with 24-bit address space it could address up to 16MB of memory. The original rom 01 model shipped with 256KB of fast RAM, the revised rom 3 shipped with 1MB (both had an additional 128KB of standard RAM and 64KB of sound RAM). RAMGS/4 is a newly designed 4MB memory expansion card for this great classic computer.

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CGA2RGBv2 - Digital RGBI to analog RGB for C128 and IBM PC MDA/CGA/EGA

CGA2RGBThe 80 column output of the Commodore 128 is the same digital RGBI used by the original IBM CGA graphics adapter. Unfortunately nowadays is quite difficult to find a monitor with the suitable RGBI input. The CGA2RGBv2 adapter will convert the TTL RGBI to analog RGB suitable to be connected directly to a 15KHz capable RGB monitor or to the popular Gonbes GBS-8200 VGA converter.

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M10MEM - 8KB SRAM Module for Tandy Model 100

M10MEMBeing nostalgic for the birth of laptop computers we recently acquired an Olivetti M10. The M10, like many of the KC-85 derivatives like the Tandy TRS-80 Model 100 and the NEC PC8201A, uses custom modules for their system RAM. These modules contained four 2Kx8 SMD SRAMS mounted on a ceramic substrate with a non standard DIP footprint. Needless to say, these modules have become increasingly hard to find. M10MEM is a modern replacement for the memory modules using 8Kx8 SRAMS.

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GZ/80S - 20MHz Z-80 PCPI Applicard compatible Apple CP/M card

GZ80 B00The 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 times as fast as the Microsoft SoftCard. The GZ/80-B00 is a new implementation of the PCPI card with a 20MHz Z-80 CPU and 512KB of static RAM.

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GTERM25 - DB25 Active SCSI Terminator with diagnostics LEDs

GTERMActive termination is required to get newer high performance drives working on vintage computers. Unfortunately both the Amiga and older Apple computers use a DB25 SCSI connector which makes finding a suitable terminator quite difficult. GTERM25 solves this problem providing a high performance active terminator with a DB25 connector and SCSI diagnostic LEDs.

GZ/80-A03 - Zilog Z80 turbo card for Apple II computers

A new version of this project is available here

gz80The Microsoft Softcard was the first card to allow CP/M software to run on the Apple II. It was originally developed to simplify the porting of Microsoft Basic to the Apple II. It turned out to be a great success and at some point in time it was the most popular CP/M platform in use.
This success prompted the development of many compatible cards. Some exact copies, some enhanced or cost reduced. The GZ/80 is a modern implementation of a Softcard compatible card with an additional turbo mode with approximately double the speed of the original card.

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GS2HD - Apple IIgs RGB to HDTV Component Adapter

GS2HD D00The apple IIgs, like many computers from the 80's and early 90's, has a analog RGB output at a 15KHz horizontal frequency (same as NTSC/PAL). The majority of modern monitors and TVs will not sync to anything below 31.5KHz on their VGA input. If you have a TV with a SCART connector it is possible to wire the RGB directly to the TV. Most TVs in USA, however, use the YPbPr component instead of SCART making a direct connection not possible.

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