CompactFlash Adapter for Tandy 1400 Laptops

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CompactFlash Adapter for Tandy 1400 Laptops

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.

Contents

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

CompactFlash Adapter for Tandy 1400 Laptops 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):
  • 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

See Also