The Lo-tech ISA CompactFlash Adapter is an open-source 8-bit ISA card that enables modern CompactFlash storage on IBM PC XT, AT, and compatible systems. Paired with the XTIDE Universal BIOS, it provides silent, reliable mass storage for vintage computers using inexpensive CF cards. The design uses only five through-hole ICs, making it accessible for home assembly. Originally designed by James Pearce at Lo-tech, with hardware schematics and BIOS source code freely available.

Bus Interface

8-bit ISA (fits any PC/XT/AT 8-bit slot)

Storage Media

CompactFlash Type I/II via 40-pin IDE header

I/O Address Range

300h–31Fh (300h–30Fh active)

ROM Address

C800h (32 KB window, directly flashable in-system)

Flash ROM

SST39SF010A 128KB (32 KB used) — in-system programmable

Compatible Flash ICs

SST39SF010A, SST39SF020A, SST39SF040, AMIC A29010

Supply Voltage

5V from ISA bus

IC Count

5 through-hole DIP ICs (basic build)

PCB

2-layer, ISA form factor, through-hole only

BIOS

XTIDE Universal BIOS — GPLv2, supports up to 4 IDE controllers

Transfer Modes

PIO-8 (standard), PIO-8 BIU Offload, PIO-16 BIU Offload

Max Drive Capacity

Unlimited with MS-DOS 7.x/FreeDOS; 8.4 GB limit on DOS 3–6

The Amstrad PC1640 was the successor to the hugely popular PC1512, launched in 1987 with 640KB RAM and an EGA-compatible graphics chipset from Paradise Systems integrated on the motherboard. The 1640DD variant shipped with two 360KB 5.25-inch floppy disk drives. Also marketed as the PC6400 in the United States and sold under the Schneider brand in Germany, it was one of the most successful IBM PC compatibles in Europe and helped open the consumer PC market.

CPU

Intel 8086 @ 8 MHz

Co-processor Socket

Intel 8087 math co-processor (optional)

RAM

640 KB (on-board)

Storage

Dual 360 KB 5.25-inch floppy disk drives (DD model)

Graphics

EGA-compatible (Paradise Systems chipset), CGA and Hercules modes supported

Display

Colour (ECD) or monochrome monitor; ECD model supports full EGA modes

Sound

PC speaker with physical volume control

Expansion

Three full-length 8-bit PC/XT ISA expansion slots, supports optional VGA board

I/O Ports

RS-232C serial, Centronics parallel, light pen connector

Input Devices

Full QWERTY keyboard with Atari joystick port, two-button Amstrad mouse

Dimensions

372 x 284 x 135 mm

Weight

7.75 kg (DD model)

Power Supply

Integrated into monitor housing

Operating System

MS-DOS 3.2, Digital Research DOS Plus (CP/M compatible)

Bundled Software

GEM Desktop, GEM Paint, Locomotive BASIC 2

Manufacturer

Amstrad plc (Brentwood, Essex, UK)

Released

1987

Also Known As

Schneider PC1640, Sinclair PC500, PC6400 (US)