EXDOS by pear

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EXDOS card (compact version)

Brief information

It is a clone card EXDOS. Compact version designed by pear. It includes the Bus Bridge on-board.

Jumper J9 (PWR in version 2) near a power socket:

  • Short: card and a EP powered with a common power supply connected to the card,
  • Open: card and a computer powered with separate power supplies.
Do not connect the interface to the computer when the power is on !
The original Enterprises power supply does not have enough power to both the computer and the card !

If you want to use a single, common AC adapter should provide 9V voltage and current of about 3 - 4A. In the case of the power supply connected direct to the card's polarity can be any (the card has a diode bridge).

EXDOS v2.0 Compact

EXDOS card v2.0 Compact

Refreshed the EXDOS project. It is more compact, more configurable and more compatible with newer floppy disk drives.

Futures

  • power switch with two color LED,
  • provides power for two drives (only +5V for 3,5" drives),
  • two modes of connect floppy drives - XT or AT style,
  • PC full compatible floppy drive connector,
  • possibility of powering the Enterprise from one common power supply,
  • possibility to change the order of A/B-B/A drives by jumpers,
  • support for many types of memory chip.

Configuration

The chip 240B is optional. It is only needed in two situations:

  • if you want to connect the original Enterprise drive,
  • there are connect more than 2 floppy drives.

When connecting the original Enterprise drive and 5.25 "drives, an additional 12V power supply is required.

Modes of drives connection

XT Up to 4 drives can be connected (straight tape, drive setup by jumpers)
AT Two drives can be connected (interlaced tape, fixed DS1 drives)

In both modes, for proper operation, DD or HD floppy drives with a DD/HD switch are required.
Some new HD drives aren't has a switch by factory and do not support DD disks.

A/B-B/A switch

AB standard order DS0=A, DS1=B
BA reverse order DS0=B, DS1=A

240B jumpers

Use only in XT mode. Do not short them in AT mode !

Label Purpose
DCR Disk Change Reset used only with original EP drive
InUse used only with original EP drive
Sel3 select drive C
Sel2 select drive D