Two small Apple II cards: Hemi-Disk II and Grappler Minus V2
Neither of these cards is new technology. Both are projects I've had sitting on the bench for a while, and I finally got them to where I'm happy with them. They're simple and they're easy to use. That was the whole point.
Hemi-Disk II
Hemi-Disk II is a replacement for Apple's Disk II controller card. Same drives, same disks, same commands. If you know how to use a Disk II card, you already know how to use this one.
Why another Disk II card?
The original Disk II card uses two small PROMs, and they're over 40 years old now. Some of them are going bad. You can put an EEPROM in their place with an adapter, but it doesn't always work. If the part you end up with isn't fast enough, the card can't keep up and you're back where you started.
So I wanted to build a proper stand-in for the card itself. I asked my friend Wing Yeung (MFA2 WorkShop) about it, and it turned out he'd already done the hard part. His mini Apple II Plus clone has a Disk II controller running inside a CPLD, and he told me the code wouldn't be much work.
I really liked that design. It's simple and clean, and I wanted a card that would last as long as possible. Wing handed me a working starting point, and the two of us went back and forth, trying things and fixing things, until it turned into this card.
These days you can put almost anything on one card. Merge three cards into one, add Wi-Fi, whatever you like. I went the other way on purpose. A plain Disk II replacement keeps the classic 5.25" Disk II drives in use, and to me that's worth more than one more feature. Keeping those drives running is the real reason this card exists.
What's on the board
The Disk II logic lives in a CPLD. The boot ROM is an AT28C16. It's easy to find, easy to flash, and I expect it to hold up for a very long time.
There are two drive connectors, a drive select switch and an LED for each drive.
Features
You get Drive 1 and Drive 2 connectors, just like the original card. With two drives hooked up you can copy disks with the DOS 3.3 System Master, and a few games want both drives anyway.
The two connectors face different directions, and that's deliberate. One is a horizontal header, so you can plug the cable in from the top the way you always did on a Disk II card. Anyone who's used an Apple II for a long time does it that way without thinking. The other is a vertical header. If you'd rather run the ribbon cable out the back of the machine, that one will probably suit you better.
Because of that, there's a 6-pin slide switch that sets which connector is Drive 1 and which is Drive 2. The LEDs show you which drive is active, so you're never guessing.
Put it in the same machine as a Grappler Minus and you can use SmartPort too (more on that below).
Hemi-Disk II is sold fully assembled for $36. Hemi-Disk II in the store
Grappler Minus V2
This one is an older project of mine, but V2 is a new board. The four logic ICs from the old version are now one PLD, so the whole card is two chips. Wing wrote the CPLD code for Hemi-Disk II. The PLD logic on this one is mine.
If you've seen it before you can skip this paragraph. The Grappler started life as a printer interface card (the Orange Micro Grappler Plus). Wing wrote a ROM called SoftSP DIY for it, and with that ROM a Grappler plus a Disk II card gives you SmartPort. Grappler Minus keeps only the logic that job needs and drops the rest. The SoftSP DIY ROM is used with Wing's permission.
Wing also makes his own SoftSP card, sold fully assembled through Chris Torrence's CT6502 Store. Grappler Minus is closer to a kit. It's for enthusiasts who like to solder and want the fun of building the card and then watching their own machine use it. Every part is through-hole DIP, and there are only six of them. The full parts list is on the store page.
It doesn't take long, and it's a nice little build.
A few other things changed in V2. There's an ACT LED that only lights up when SmartPort is actually in use. If you boot the drive as a plain Disk II with PR#6, it stays dark, which is handy when you're not sure which mode you're in. The board is smaller and has the old Apple "shell" shape, so front and back are obvious. And the ROM socket now takes a 28C64, the 2764 and 2732 can also be used.
The kit is $20 and an assembled card is $25. It works in the Apple IIe (including Platinum and Euro Platinum) and the II Plus, Europlus and J-plus.
Using them together
Hemi-Disk II goes in slot 6. Grappler Minus goes in slot 5 (any slot except 6 works, just change the number). Power on, press Control-Reset, type PR#5 and hit Return. A SmartPort drive such as SPIISD V2 on the Hemi-Disk II then runs as a SmartPort device.
Or leave the Grappler out and use Hemi-Disk II as an ordinary Disk II card with your old floppy drives. That's what it was built for.
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