The Timex FDD (Floppy Disk System), was launched in December 1984. It have 3 boxes and a Interface. The first box is the power supply, the second box is the controller and the other box is a 3" drive. The FDD is almost a complete computer: It have it's own processor (Z80A @ 4Mhz), have it's own RAM (16K. Can be upgraded to 64K) and 2 serial ports.
The connection between the Timex
and the controller is made by a high velocity channel. This controller and the interface
was totally made by Timex Portugal, Lda.
The drive units, made by Hitachi, accept 2 types of disks. One with 40 tracks and 160K/side capacity; and other with 80 tracks with 640K capacity. A maximum of 4 drives can be connected to the controller and if we have the 4 drives, we would have access to 2.4MB of data on a 48K RAM computer!
The FDD system uses TOS as OS. It uses normal Sinclair Basic commands with a *, which make them more easy to use than the microdrives. TOS uses the tree system that MS-DOS have. TOS is booted when you turn FDD on or when you press the reset button
A silver version has been sold in USA by Zebra Systems as Zebra FDD System. Zebra imported the Timex FDD system and erased all references about Timex in the FDD manual and in the controller.
It's possible to connect a PC 3,5" DSDD drive or a PC 5,23" DSHD drive. Disks have 640K capacity and a maximum of four drives can be connected to the same controller.
Along the Timex and Zebra versions of the FDD system, a Polish version has existed too:
-Unipolbrit's FDD 3
Small cover, three parts : -Controller, PSU, 3" Drive.
Small PCB. Totally different. No ULA's , one or two PLA's. Done by normal chips, not SMD.
Interface at totally other basis, better. 2* PLA for adress decoding (16V8) with one on additional board (plugged like chip) with 74109) 2116 SRAM, 2732 EPROM. 2* 74 series line drivers.
Eprom require standard programming.
16k of RAM 2k of ROM
All FDD machines have Z80 chip onboard and 16K of
All FDD's are build on FDC WD1770 (HOOKED INTRQ TO _INT IN Z80) UART WD2123 (RS232. NO INTERRUPTS) Special helping port (FM/MFM, HEAD LOAD, SIDE SELECT, ROM OFF)
This page was uptaded at 07-07-2001