Commodore.ca: The PET, VIC, 128, 64 & More Forum

Hi there,

I'm new to this forum, so hello everyone.
I am a vintage computer hobbyist living in northern California, and recently started building some hardware for my PET. I wanted to find a simple way to load and save programs onto the PET, since I did not have any working IEEE-488 drives with the computer, nor did I have a working datasette. I started out by building a simple cassette cable which connects to the audio in/out of another computer's sound card to load and save programs. After that worked, I wanted something a bit faster. After reading up on the IEEE-488 standard, I built a device which used an Atmel microcontroller and a micro-SD card to function as a simple PET storage device.
I'd like to introduce the PETdisk:

The PETdisk (on left) is about the size of a business card, and connects directly to the IEEE-488 port on a PET without needing a cable. It has a passthrough connector to attach additional IEEE-488 drives, and the drive number is selectable with a jumper. The PETdisk is powered with a standard USB cable connected to the secondary board (on right) which attaches to the PET's cassette port. The cable carries +5v power to the main PETdisk board. In addition, the secondary cassette board functions as a cassette interface which lets you load and save cassette programs using another computer's sound card.

If you're looking for a simple and convenient way to transfer programs to and from your PET, this may be interesting to you. I'm selling the PETdisk as a kit at:
http://bitfixer.com/PETdisk

If you have access to a programmer for Atmel microcontrollers, you can build your own version of the PETdisk from scratch, as I will be posting the full code and schematics to this as well.

Hope this is interesting to the PET folks! Thanks.

bitfixer wrote:I wanted to find a simple way to load and save programs onto the PET, since I did not have any working IEEE-488 drives with the computer, nor did I have a working datasette.

I could have dug out a datasette for you.

If you're looking for a simple and convenient way to transfer programs to and from your PET, this may be interesting to you.

It is very, very interesting! Can you tell what its limitations are?

Truly,

Thanks for the interest,

The PETdisk can load and save individual programs in .prg format. It supports just 3 basic commands:
LOAD "<filename>",9
SAVE "<filename>",9
and
LOAD "$",9

While I use device number 9 in this example, you can set it to 8,9,10,or 11 via jumpers.
One of the main limitations is that it does not support disk images such as .d64, just individual .prg files.
The files are stored on the SD card formatted with a FAT32 file system. Basically just format the microSD card and copy .prg files onto it, and then they can be loaded onto your PET.
Currently it does not support wildcards like LOAD "*",9 or LOAD "partialname*",9 with the current firmware, but this and other additional features are slated for future firmware updates.

I have a couple of videos showing the basic operation of the PETdisk. They won't win any filmmaking awards, but will give you an idea of what the gadget can do.
PETdisk, part 1: http://www.youtube.com/watch?v=0YZ4iEvR92g
PETdisk, part 2: http://www.youtube.com/watch?v=bBaM-jOukT8

The PETdisk I used in the video is an earlier revision, I have since changed the USB connector to a vertically mounted one, used a 90 degree pin header for the uSD adapter for ease of card replacement, and have changed the layout of the cassette board slightly. The latest version can be seen at http://bitfixer.com/PETdisk.

Thanks for the added information. I've found out that there are less network errors getting to your site when the following address is used --

http://www.bitfixer.com/bf/PETdisk

Truly,

Bitfixer says "other users [report] that the PETdisk works on C64 and 128 with an IEEE-488 cartridge interface".

Truly,

bitfixer wrote:Thanks for the interest,


PETdisk, part 1: http://www.youtube.com/watch?v=0YZ4iEvR92g
PETdisk, part 2: http://www.youtube.com/watch?v=bBaM-jOukT8

This videos are pure gold, plentiful useful info right here folks. Good job and thanks for sharing your knowledge!

Jacob