Atari SDrive Max

I got an SDrive Max for my Atari 800 and I really like it. It took a little doing to get it working for me. Hopefully you won’t have the same troubles I did. If you are, hopefully what helped me will help you. Let’s take a look at the Atari SDrive Max and what it does for you.

SDrive Max is a modern storage solution for vintage Atari 8-bit computers that uses SD cards. By storing images on the card, the Atari can boot off the image as if it were a floppy drive.

How the Atari SDrive Max works

Atari SDrive Max
The Atari SDrive Max boots this nice menu, from which you can select a disk image to load.

The Atari SDrive Max is just an Arduino at heart, with custom software loaded to emulate an Atari disk drive and enough hardware to connect to the Atari’s SIO port, use an SD card for storage, and a display for feedback. You can assemble one yourself, but with no source for some of the necessary parts, I bought mine off Ebay. You can then load your Atari disk images (in .ATR or .XEX format) onto the SD card. The seller I bought mine from helpfully provided a card with a few images loaded on it, which made it pretty obvious how to add more.

The Atari 8-bit computers autoboot, but this can be a problem. The SDrive Max can have its own power supply, or it can take power from the SIO port. The power on the SIO port doesn’t come online fast enough for the SDrive Max to boot off SIO power. To solve that, you have two options.

Powering from external power

To power the SDrive Max from its own external power supply, change a switch or jumper on the SDrive Max to enable external power, then plug in a suitable power source for an Arduino, such as a USB A-B cable and a phone charger. Don’t forget this step, because if you run off both external power and SIO power, you can damage your SDrive Max, your Atari computer, or both.

This should be the easy option. Unfortunately mine didn’t like that much.

Powering from a disk drive

If you have an Atari 810 or 1050 disk drive, you can plug the SDrive Max into that. The drive, as long as it’s functioning correctly, should provide SIO power to the unit so the computer can boot off it. Just make sure your drive isn’t set to drive ID 1, or the two devices will fight, and you’ll get a boot error.

But more on that in a second.

Booting the Atari SDrive Max

Having an SDrive Max connected to a vintage Atari feels like this fanciful magazine cover from 1985. No one I knew had that much software in 1985. But today you can.

When the SDrive Max boots, it provides a nice menu that you can navigate with the arrow keys and use the return key to make your selections. The left and right arrow keys serve as page up and page down keys, which is helpful

The SDrive Max can emulate up to four drives, so you can load four disk images if you want. After you make your selection, you can hit the system reset button, and the system boots the disk image off the emulated drive. The speed is comparable to a floppy drive. It may be a little bit faster, but not dramatically so.

It is super convenient, since everything ever written for the Atari 8-bit line easily fits on even the smallest of SD cards, and the SD card is much more reliable than decades-old floppy disks.

How I got my SDrive Max working

My SDrive Max didn’t want to work off external power. And since I had to import mine from England due to a lack of domestic sellers at the time I got mine, I didn’t want to send it back. There’s nothing right about this hacky way I got mine working, but it might help you.

I have two broken 1050 drives. One tries to boot and just fails every time. The other doesn’t seem to acknowledge the computer exists. I accidentally figured out that if I have both the drive that fails to boot and the SDrive Max plugged in at the same time, and the drive that fails to boot is set to ID 1, I get a boot error. But if I then turn off the floppy drive, the SDrive Max kicks in and boots. Furthermore, once I have a disk image mounted, I can hit the system reset button and the disk image boots.

That’s not how any of this is supposed to work. But it lets me play Lode Runner and Mr. Robot and his Robot Factory, so I’m not complaining.

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