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TC2144

Upgrade for Timex Computer 2048 and Timex Computer 2068 to 144kB RAM with compatibility to ZX Spectrum 128K. The project was based on two ideas. First: use PLCC sockedt placed over ULA to reduce number of wires. Second: simplify design by living 16kB RAM in section C (as Timex has separate /CAS line for each section).

The prototipe was build in 1998 and presented in September 1999 on ZX Party 2 in Lubañ ¦l. (Poland). It hahe taken too much space, so the case cannot be closed and was not fixed so sometimes it jumped out of the ULA.

In 2000 a board v003 was designed. Some time later the prototype was disassembled and replaced with upgrade based on v003 board. After years it appeard that the solution was not best: the resistance in ULA contacts grows with time and afer 2-3 years the upgrade needs to be manually pushed to get work back.

W 2006 was realised an idea to solder the upgrade with wires, in place of the PLCC socket. This requires at least 18 wires, but will work better than PLCC socket.

Next step in upgrading Timex Computer 2048 and Timex Computer 2068 will be made board mounted under Z80CPU with all the logic required for 4MB RAM.

Memory map

SectionMemory bank
D
(#C000..#FFFF)
RAM0RAM1RAM2RAM3RAM4RAM5RAM6RAM7
C
(#8000..#BFFF)
RAM8
B
(#4000..#7FFF)
RAM5
A
(#0000..#3FFF)
ROM0ROM1
RAM8 - extra 16kB in section C, that is not copy of RAM2 like in ZX Spectrum 128K.

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Files for download

0007-bot.jpg 514.0kB (2006-05-14 16:20)
Timex Computer 2048 upgraded with TC2144 board. Bottom view.
0007-top.jpg 372.3kB (2006-05-14 16:09)
Timex Computer 2048 upgraded with TC2144 board connected with wires. Also changed polarity of Kempston Joystick, mounted AY-3-8910, FlashD0, 2 colors LED and reset button. Top view.
0007-toq.jpg 376.1kB (2006-05-14 16:11)
Timex Computer 2048 upgraded with TC2144 board connected with wires. 8pin slot is disconnected and the board opened. Top view.
pl-tc2144.html 9.4kB (2005-10-25 01:04)
[pl] Upgrade technical details.
tc2144v1.jpg 90.0kB (2005-04-01 02:18)
Timex Computer 2048 with TC2144 mounted.
memory.txt 4.5kB (2002-08-22 00:24)
[en] TC2144 and using Dock and Exrom banks - description.

Links to other pages



See also

4MB RAM upgrade : ZX Spectrum
ZX Spectrum memory upgrade - 4MB RAM (DRAM).
Sinclair ZX Spectrum+ 128K
Technical notes and simple upgrades for Sinclair ZX Spectrum+ 128K model.
Dock bank : Timex
The 64kB memory bank known from Timex computers. Timex memory map.
ZXVGS FD0 - FlashD0 (128kB PEROM)
ZXVGS for FlashD0 (128kB PEROM) for ZX Spectrum. Works with 128kB, TC2144 and 4MB RAM. Supports many IDE and floppy interfaces.

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CPC
4MB RAM
Flash ROM
To 128
Sam Coupé
SAM512
Portfix
YABUS.Z80RTC
Z80JOY
MSX
Mapper 4MB
MSX-2 SVI738
Spectrum
FlashD0
8251
AY
Eniac'owe
Dock
Gama 192
Keyboard
ROM replacer
SamRam
TC2144
To 128K
To +3
Wonder RAM
Z80JOY
ZX 4MB
ZXMUX
Timex
Memory
Timex FDD
YABUS.TF
YABUS.TF3
TI-of-TTL
ZX81
Memory

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© 2009-12-28 21:50 Jarek Adamski, http://8bit.yarek.pl