Ruud's Commodore Site: An IDE hard disk drive for your C64/128 Home Email

C64IDE-2: another IDE hard disk drive for your C64/128

What is it

Add an IDE hard disk drive to your C64 or 128 without additional ICs. This project was meant as a kind of joke: just to proof it was possible at all!

The IDE bus has 16 data lines and 7 control lines. I already found out that you can bit-bang the bus. During a conversation I joked about the fact that the two ports used for the keyboard could handle the data and the userport could serve the control lines.

The big advantage of the above proposal is that there is much less soldering to do then when building a real IDE interface. But you need an additional power supply for the HD itself.
The disadvantage is that it will be completely incompatible to any existing system. So any software circumventing the Kernal for loading/saving data won't see the hard disk drive at all.
What ever other disadvantages you can think of, don't forget the two big advantages:
- the huge amount of data you can store on the hard disk drive (and maybe CDROM)
- the higher speed with which you can load/save data comparing to an original 1541

The hardware

Remark: When revising various pages, I found out that the hardware part of this page was missing. I have no idea at all what happened with it or that I just simply forgot to write it. The problem: I don't know any detail anymore.

What I DO know is that, as said above, I connected the seven lines of the control bus of the IDE interface to the userport and the 16 data lines to the keyboard connector.


I built it and it worked. That is, I proved that I could turn the motor of the hard disk drive on and off again. Doesn't sound great but it proved in a simple way that the interface as so worked.


No software. The program I used to start or stop the motor was written in Basic and contained only a few peeks and pokes.

The future...

None. The reason: the complete incompatibility mentioned above.


I developed this interface before I started to use the IDE drives with 8 bits only. Working with this interface meant that one could not use the keyboard when using the drive: by pushing a key one certainly shortens two data lines.
Using only 8 bits and particularly the A port means that shorting two data lines by pushing a key is avoided. But I don't know what the risk is when pushing more than one key at the time.
And don't forget, using only 8 data lines means even less soldering :)

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