Lo-tech ISA CompactFlash Adapter — XT-IDE Storage Solution
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
Floppy Controller ISA Lab - Engineering Application
Legacy floppy controller integration, diagnostics, and data recovery profiles for 360KB, 720KB, 1.2MB, and 1.44MB workflows.
- Interface
- 8-bit and 16-bit ISA controller variants
- Drive Modes
- 360KB, 720KB, 1.2MB, 1.44MB verified
- BIOS Pairing
- XT and AT BIOS compatibility tables
- Signal Checks
- Index, step, direction, ready, and write gate diagnostics
- Recovery Toolkit
- Read-retry and sector salvage operation notes
- Test Harness
- Head alignment and media condition scripts
Multi-I/O Serial/Parallel Cards - Engineering Application
COM/LPT/FDC multi-function ISA cards configured for deterministic IRQ and DMA behavior in restoration and industrial control systems.
- Interfaces
- COM1-COM4, LPT1-LPT3, optional game port and floppy
- IRQ Mapping
- 2, 3, 4, 5, 7 selectable profiles
- Address Ranges
- 3F8h/2F8h/3E8h/2E8h and custom map options
- UART Coverage
- 8250, 16450, 16550A compatibility paths
- Tooling
- Loopback and parity stress diagnostics
- Deployment
- Field profile templates for mixed adapter stacks
Qualification Matrix
Long-run soak tests alternate DMA and serial traffic to expose marginal timing behavior.