Timex Cartridge

Some Timex models, like Timex Sinclair 2068 and Timex Computer 2068 provided slot for cartridges.

The slot has following 36 lines:

• power: GND and +5V,
• address lines - A0..A15 and separately A7 with 7th refresh bit - A7R,
• data lines - D0..D7,
• Z80CPU control signals: /RD, /WR, /MREQ, /IORQ, /M1,
• active low chip select signal for Dock bank - /ROSCS,
• active low chip select signal for EXROM bank - /EXROM - useless, as there's no easy way to disable internal EXROM memory,
• in TS2068: memory refresh signal - /RFSH of Z80, or
  in TC2068: active low chip select signal for Home ROM - /ROMCS (also useless),
• in TS2068: active low memory access disable - /BE of ULA, or
  in TC2068: active high input that disables both internal ROM and also forces high state on both /ROMCS and /EXROM in the slot.

Due to the incompatibility and useless signals placed in the slot, the safest way is to build Dock cartridges (using /ROSCS) and I/O cartriges only.

Design of safe Home or EXROM cartridge would require a duplication of #F4 and #FF ports. Anyway, in each 2068 model the memory is disabled in other way (low or high state).

Universal Memory Cartridge Board

The UMCB is kind of universal board that can be used to build wide range of memory cartridges. Memory is seen in Dock only for Timex Sinclair 2068. For Timex Computer 2068 it is also possible to build Home ROM cartridge. It is not possible to make an EXROM cartridge without internal changes.

Amount of memory accessible by Z80 is limited to 64kB, as the board doesn't support bankswitching. An extra board with bankswitching can be installed under the memory chip (e.g. FlashD0 or 512kB SRAM upgrade).

Two memory chips mode

The UCMB can contain also two memory chips, as long as one of them is in 0.3" case - in most cases this is 62256 SRAM (32kB, used as cache in PC). Such cardrige can be used to run ZXVGS FD0 (with extra FlashD0 board) or CPM22QED UPB.

The decoder used is 74*253 or 74*153, so provides two /CS signals for each chip separately. In some special case it can be replaced with 74*138 (e.g. only 4kB of Home ROM replaced in Timex Computer 2068).

UMCB version v001

This is first suggestion for the board. Dimensions 48mm × 48mm (below the horizontal dashed line) are taken from original board used in Spectrum Emulator for Timex Computer 2068. The round hole (10mm) is made to give a chance to remove the board when no case is used. There are two problems with insertion into TS2068: the cartridge slot has limited hight and it could be hard to remove the 48mm board from the cased slot. So, to locate the memory chip outside the limiter, a 30mm lengthener was added (over the horizontal dashed line). It can be cuted out, giving a 48mm × 48mm board. In this case a female slot can be mouted on the cuted part, giving a free lengthener or cartridge splitter.

UMCB version v003

These boards have more options than v001. There's place for reset button, pads for signals like /EXROM, /IORQ, etc. Without modifications (just by soldering chips), the board can be used as:

• ZX Spectrum Emulator in Dock - 16kB PROM, seen in first 16kB (use OUT 244,3 to select it),
• 32kB LROS - 27128 or 27256, seen in first 32kB of Dock,
• 32kB RAM - 0.3" case 62256, seen in second 32kB of Dock,
• 32kB RAM - 0.6" case 62256, seen in first 32kB of Dock,
• 64kB RAM - two 62256, cases 0.3" and 0.6", seen in whole Dock,
• 32kB RAM + 32kB ROM - 0.3" case 62256 (second 32kB of Dock) and 27256 (first 32kB of Dock).

Pliki do pobrania

0006a.jpg 165.0kB (2006-11-15 16:06), uploaded by Jarek Adamski

Cartridge z 64kB SRAM w Dock dla Timex 2068. Górne 32kB jest w podstawce, co można użyć do czytania EPROMów albo programowania EEPROM 28C64.

umcb-zx2.jpg 31.2kB (2006-08-02 16:57)

Dwa zmontowane cartridge "Emulator ZX Spectrum". Widok 2. Użyty oryginalny PROM z ZX Spectrum.

umcb-zx1.jpg 31.5kB (2006-08-02 16:57)

Dwa zmontowane cartridge "Emulator ZX Spectrum". Widok 1. Użyty oryginalny PROM z ZX Spectrum.

900505.zip 29.5kB (2006-05-12 04:43)

Płytka Spectrum Emulator dla Timex Computer 2068. Pliki danych Eagle.

spectrum.jpg 82.0kB (2004-07-14 01:27)

Oryginalny cartridge Spectrum Emulator dla Timex Sinclair 2068. Widok z góry na obudowę.

zebra.jpg 29.0kB (2004-07-14 01:27)

Spectrum ROM dla TS2068 firmy Zebra Systems. Widok z góry na płytkę.

Linki do innych stron

Zobacz również

Timex 2068 : 128kB ROM + 512kB RAM

Wewnętrzne rozszerzenie pamięci dla Timex Sinclair 2068, Timex Computer 2068 oraz Unipolbrit Komputer 2086. 128kB ROM, dodatkowe 512kB RAM.

Dock bank : Timex

Bank 64kB pamięci znany z komputerów Timex. Mapa pamięci Timex.