ROMulator 6502 Kit


RAM/ROM Replacement and Debug console for 6502-based computers
August 18, 2021:
The ROMulator is available again! For now only available in kit form (through hole soldering only), fully assembled units will be available again in a few weeks.



August 18, 2021:
Happy to announce the ROMulator is available again! There are a couple of changes, though – for the moment I am only offering the ROMulator as a kit, with only through-hole soldering required. All surface mount parts are pre-assembled and the assembly requires about 15 minutes. I still have a number of orders for fully assembled units in the queue, and until those are completed I can only offer the kit version.
Second, because of general price increases in parts, assembly, PayPal fees, and shipping as well as prep time for each unit, I had to increase the price from the previous $30USD. The price for the kit version of the ROMulator is now $35 USD. There will be a new price for the assembled version as well when it’s available again.

About the ROMulator:
The ROMulator is a RAM and ROM replacement and diagnostic board for the Commodore PET, Apple II, and other 6502 based microcomputers. The ROMulator connects to the 6502 socket in your computer, and the ROMs to use are selected by a dip switch on the board. It allows you to view the memory of a running 6502 machine using the replacement RAM by halting the CPU and sending the memory contents over an SPI connection to a Raspberry Pi.

The ROMulator comes as a Kit as shown, and requires only through hole soldering, all surface mount parts are pre-assembled. It takes about 15 minutes to build and requires just a soldering iron and solder. A pair of snips is useful as well.

Assembly Instructions

If you are interested in the programming cable to connect this to a Raspberry PI for programming/debug (not required, but convenient), that is available as a kit here:

Raspberry Pi SPI/UART Breakout

The ROMulator is open source, and the schematics and Verilog code for the ROMulator’s onboard FPGA are available at:

Check out my video using the ROMulator to help fix a PET 2001-N here:

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