Modern IC replacements for retro computers by Jani Laatikainen


J-CIA64 Available

Product
FPGA replacement for MOS 6526 & 8521 CIAs.

Complete logic and all features of the original IC's implemented.

Some tested hardware: WifiModem, Ultimate-II+, SD2IEC, Pi1541, TapeCart, 1531-mouse, all original C64 mainboards, SX-64, EVO64, Commodore 128, 1570 & 1571 drives.

More info.

J-CPU64 Available

Product
Modern FPGA replacement for MOS 6510 or 8500 CPU / processor used in Commodore 64 / SX-64

Complete logic and all features of the original IC implemented, including illegal opcodes.

More info.

J-VIC Not actively developed

Product
Replacement for C64 / SX-64 VIC-II video chip
(6569, 8565, 6567, 8562)

About 90% complete, not currently actively developed, but project is not abandoned.

More info.

J-CPU264 Available

Product
FPGA replacement for MOS 7501 & 8501 CPUs in Commodore 264-series computers.

Complete logic and features implemented, including illegal opcodes.

Tested on C16, C116 and Plus/4

Lots of demanding demos and games tested, no known compatibility problems.

Some tested hardware: pi1541, Ultimate II+, TCBM2SD, real 1551 Drive, 1531 Datassette.

J-CPU02 In development

Product
6502 & SALLY CPU replacement

Works as a replacement for 6502 CPU and Atari Sally CPU (sometimes referred as 6502C)

Some already tested systems and devices include: VIC-20, Atari 600XL, Atari 800XL, Atari XE GS, Atari 130XE, Micro-Professor II, Salora Manager, 1541 Disk Drive

J-CIA500 In development

Product
Replacement for 8520 CIA (DIP40-version) used Commodore Amiga 500, 1000, 2000, 3000, CDTV and Commodore 1581 disk drive.

Work in progress...
Already tested on Amiga 500. CIA-tests fully passed on Diagrom, Amiga Test Kit and Versatile Amiga Testprogram

J-CPU128 In development

Product
8502 CPU replacement for Commodore 128.

Complete logic and features implemented, including illegal opcodes.

Already tested with a lot of software and harware. Works in C64 & C128 -mode.

J-CPU07 In development

Product
Replacement for 6507 (CO10745) CPU used in Atari devices.

Complete logic and features implemented, including illegal opcodes.

Works as a CPU replacement for Atari 2600 & 2600jr (not "one chip" -version), Coleco Gemini, Atari 810 and 1050 disk drives and 850 Serial & Parallel interface.

So far tested on several different version Atari 2600 consoles, over 100 original cartridges and UnoCart 2600. No compatibility issues found.

J-CPU04 In development

Product
Replacement for 6504 CPU used for example in Commodore 2040, 3040 and 4040 disk drives and some printers.

Complete logic and features implemented, including illegal opcodes.

Currently tested with Commodore 4040 dual drive and MPS-802 printer, working perfectly.

J-CPU09 Planned

Replacement for 6509 CPU used in CBM II -series computers.

J-PLA In production

Product
CPLD based replacement for Commodore 64 PLA.

New version of well known replacement with same compatibility as before.

Replaces the following original C64/SX-64 PLAs: 82S100, 93459PC, 7700, 8700, 906114-01, 251064-01.

Compatible (and tested) with 251102(SX-64), 326298, KU-14194HB, 250407, 250425 and 250466 -mainboards. NTSC and PAL -versions.
250469 uses different kind of PLA and this replacement is not compatible with it.

J-SRAM Ready (not currently available)

Product
C64 RAM replacement for 250466 and 250469.




Finland 2020-2025 Jani Laatikainen