This year our staff decided to enter the retrochallenge competition. Our goal is to reverse engineer the Berkely softworks geoRAM and publish what we discover under the GPL. The geoRAM is a 512KB memory expansion for the Commodore 64 and 128. Unlike the Commodore 1750 REU, which contain a custom chip, the geoRAM is built completely out of standard TTL chips.
GLINKUSB-LT is a modern variation of the Commodore VIC-1011. Instead of providing a legacy 12V RS232 connection, it provides a USB Virtual Com Port (VCP) suitable for direct connection to any modern PC. The adapter is fully supported by the standard Commodore BASIC at up to 2400 baud. Jumpers allow the card to be configured as a UP9600 for 9600 baud operation in Novaterm and Striketerm. A reset button is also provided for added convenience.
The 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/512S is a geoRAM compatible cartridge based on a single 512Kx8 SRAM.
The 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 CGA2RGB 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.
The 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 CGA2RGB 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.
The 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 CGA2RGB 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.
GLINK-LT is a modern clone of the Commodore VIC-1011A RS232 User Port adapter for Commodore 8-bit computers. The adapter is fully supported by the standard Commodore BASIC at up to 2400 baud. Jumpers allow the card to be configured as a UP9600 for 9600 baud operation in Novaterm and Striketerm. A reset button is also provided for added convenience.
Both the commodore 64 and the 128 have a software UART implementation that limits the useful speed to 2400 bauds. To work around this limitation Dr. Evil Labs and later CMD produced the SwiftLink232 and Turbo232 cartridges based on the 6551 ACIA chip. Both of these have been out of production for a very long time. GLINK232 is a modern replacement for the swiftlink232 allowing the commodore 64/128 to communicate at speeds up to 38400 bauds.