CompactFlash Adapter for Tandy 1400 Laptops
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The CompactFlash Adapter for Tandy 1400 Laptops is a system specific XT-CF variant for Tandy 1400 Series Laptops.
The board is programatically identical to the XT-CF-lite and is therefore powered by the XT-IDE Universal BIOS, provided through an in-system re-programmable 32KB (addressible) flash-based ROM. Since the BIOS is only 8KB, 24KB is available for other purposes, and is byte-programmable.
To buy this and other PCBs, please visit the lo-tech shop.
Specifications
General
- 8-bit Tandy 1400 Series Expansion Slot Card with CompactFlash header
- Entirely 5V CMOS logic
- Low-cost flash memory chip for boot ROM, with 32KB usable
- Port-mapped IO; supports both 8- and 16-bit instructions (via partial address decoding)
- Utilises XT-IDE Universal BIOS (XTplus build; adapter type: 'XT-CF')
- Fixed resource allocation - IO ports 300-31Fh, ROM 32KB at C800h
- Compatible with any CompactFlash card (microdrives are not supported due to power budget limitation from the Tandy 1400 expansion slot)
PCB
Bill of Materials
| Part | Device | Package | Qty | Farnell | Mouser |
|---|---|---|---|---|---|
| IC1, IC2 | 74HCT688D | SOIC-20W | 2 | 1085321 | - |
| IC3 | 74HCT139D | SOIC-16 | 1 | 9591834 | - |
| IC4 | AMIC - A29010-70F | DIP-32 | 1 | 1907092 | - |
| R1, R2, R4 | 10k Resistor | 0603 | 3 | 1469748 | - |
| R3 | Do not populate | - | - | - | - |
| R5* | 1k6 Resistor | 0603 | 1 | 2138367 | - |
| C1..5 | 0.1uF Ceramic Capacitor | 0603 | 5 | 1414610 | - |
| C6 | 10uF Electrolytic Capacitor | E2-5 | 1 | 8767084 | - |
| CF1 | 3M NE750-Q516RB-50 CompactFlash Header | - | 1 | 1267444 | - |
| IC Socket | - | DIL32 | 1 | 1654375 | 571-1-390263-2 |
| JP1, LED* | AMP - 826629-2 | 1x2 Pin Header | 2 | 3418285 | - |
*Components only needed if activity LED is required
- Board design permits the use of a range of DIP-32 flash chips (1, 2 or 4Mb):
- SST39SF0x0A (SST39SF010A, SST39SF020A, SST39SF040A)
- AMIC A29010
- Regardless of the chip used, 32KB is presented commencing C800h
Configuration
- JP1: ROM enable (closed = enabled)
- An external LED can be attached to the 2-pin LED header, but a low-current type must be used (approx 2mA available).
- The IO port address (300h - 31Fh) is fixed, as is the ROM address (32KB at C800h) - note therefore the board cannot co-exist with the Tandy 1400HD MFM disk controller
- Pre-configured BIOS based on XTIDE Universal BIOS r567 is available here
- The flash ROM can be programmed with the Lo-tech XT-CF flash utility