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UNISDISK - A DISK II / SmartPort Emulator for Apple II Series -

pic1cable DB19cable 20 pin
UNISDISK unitDB19 Cable20 pin Cable

Order page.


Now you can use a UNISDISK with a Toshiba FlashAir, an SD card with WiFi. See UNISDISK with FlashAir for details.


Please update the firmware.

Firmware Update is here.


UNISDISK is a DISK II / SmartPort drive emulator for Apple II series.

UNISDISK will be able to used with any Apple II. With an Apple II / II Plus / IIe with a DISK II interface card, you can only use DISK II mode. With an Apple IIc Plus / GS, you can use both modes. With an Apple IIc, you will only be able to use a drive 2 in DISK II mode. But there is a cable to connect a DB19 Cable with the internal drive connector of an Apple IIc to use a drive 1. I've not tested SmartPort mode with a IIc.


DISK II mode

You can convert a .DSK file to a .NIC file manually by a tool called nic2dsk here.

If you write data to an image on an Apple II, and you want to use the resulting image with an Apple II emulator on a PC, you have to write back the NIC file into the DSK/PO file. For this, push the "func" button while pushing "enter" button after the Apple II writes to the image.

SmartPort mode

You can also use larger images created by CiderPress. I succeeded mounting 32MB images.

You cannot unmount an image when used with a IIc/Plus. You cannot eject the SD card, nor select images when Apple II DeskTop is running.

Selecting An Image



version 2014.12.19
version 2015.02.18
version 2015.04.20
version 2015.04.30

The license is GPL version 3.
See the Bootloader section below to update the firmware

This firmware archive also include another firmware source code of SDISK II.

The SmartPort part is based on a project by Robert Justice.


UNISDISK has a bootloader program on the bootloader area of the flash rom in the microcontroller. You can program the firmware yourself from an SD card without a writer. You can improve the firmware yourself and you can even make your own firmware.

To program the firmware, follow the instruction below.

The hex file must be generated with Atmel Studio, and the addresses in the hex file should be continuous.

Pin Connection

DIK35 and HDSEL are for the future project.

DB19 Cable has resistors to adjust logic levels. Please use a DB19 cable when you use a UNISDISK with an Apple II which has a DB19 floppy connector. Don't use a 20 pin cable with a DB19 adapter for SDISK II

Connecting a UNISDISK with the internal floppy port of an Apple IIc (non Plus)

You have to open the cover of the Apple IIc. To see how to open the cover, see this page.

IIc Cable
IIc Cable
IIc Cable 3
IIc Cable
This is a IIc Internal Cable (up: old version, down: new version). Unplug the floppy connector from the internal floppy port,
and connect it with the IIc Internal Cable.
IIc Cable 4
IIc Cable
IIc Cable 5
Plug the IIc Internal Cable in the internal floppy port. Let the 2 pin connector through a hole of the cover,
and close the cover.
IIc Cable 6 IIc Cable 7
Plug the DB19 Cable in the external floppy port,
and connect the IIc Internal Cable with the DB19 Cable
so that the yellow (or red) line of the 2 pin connector is upper.
Connect the DB19 Cable with the UNISDISK.

When Something Is Wrong...

Future Plan

I'm interested in creating an Apple 3.5 emulator.


I thank to everyone in the Apple II community of the world.