Original Website: https://gitlab.com/NF6X_Retrocomputing/ts2068cart

This board allows many 28-pin EPROMs, EEPROMs and mask ROMs to be used in the cartridge slot of the Timex Sinclair 2068 computer. The installed memory may be mapped into any or all of the 8k banks of the dock space. Write access is supported for EEPROM memories.

Video of the card on YouTube

Supported Memory Chips

Chip Size (bytes) Type Notes

2764 8k EPROM

27128 16k EPROM

27256 32k EPROM

27512 64k EPROM

23128 16k Mask ROM i.e. Spectrum ROM chip

23256 32k Mask ROM 2864 8k EEPROM Read/write (see datasheet for algorithm)

28256 32k EEPROM Read/write (see datasheet for algorithm)

One or two jumpers need to be installed at JP1 to configure the memory type. A summary table is provided on the back side of the board:

Also install one or more jumpers at JP2 to map the memory chip into the desired 8k dock space banks.

Suggested Parts (not including memory chip)

Refs Manufacturer Part Number Comments

U1 Texas Instruments SN74LS32N No socket: limited vertical clearance

U2 Texas Instruments SN74LS156N No socket: limited vertical clearance

U3 3M 4828-6000-CP Socket for memory chip

C1-C3 Kemet C320C104M5R5TA

R1-R2 Stackpole Electronics CF14JT10K0

JP1-JP2 Sullins PBC36DAAN Cut to length; 2.5 boards per strip

Jumpers Sullins QPC02SXGN-RC

About the Design

This board was designed in Kicad 2014-12-16 BZR 5324 on a Mac. Design rules are 6 mil line, 6 mil trace, 13 mil via hole. It is suitable for fabrication at OSH Park.

ts2068cart is a public domain open source hardware design by Mark J. Blair nf6x@nf6x.net, created in August, 2015.

It is offered with no license restrictions, and no warranty.

Use it at your own risk.