How to prepare SD cards for the AppleIISd

Here is how to prepare SD cards for use with my AppleIISd. Please be aware, that the AppleIISd does not use the FAT format like other SD or CF storage solutions does, it uses the ProDOS format directly. This means that you can not simply take a ProDOS image and drop it to the card in the Windows Explorer, it has to be written using CiderPress.

1. Open CiderPress in Admin mode (Right-click on Icon, "Open as Administrator").
2. Select "Volume copier" from the icon bar or select "Tools -> Volume copier (open volume)" from the menu.
3. Make sure that "Open as read-only" is deselected. Select the SD card's logical volume from the list. Triple check that you have selected the correct volume and don't come crying when your PC has only a ProDOS volume left to boot 😉

4. When you open an SD card for the first time like this it might show an MS-DOS volume with SD card's size. This gives you an opportunity to check again! Select the volume a…

Shipping the AppleIISd kits

My small run of 20 AppleIISd kits is already sold out.
It sold "like sliced bread", as we say in Germany.

In the last few days I felt like I had my own little manufacture. All parts and packaging had arrived and I packed them to ship in 14 little packages.

They will be on their way to Europe, America and Australia tomorrow. I'd like to thank everyone who trusted me and hope you will have fun with the card. Happy holidays for all of you 🎄

I know I wont be bored in the next few weeks as I am already working on integrating the Smartport protocol into the firmware to support more than two partitions. So stay tuned for updates!

Glorious Technicolor and a peek into the Mac's history

Last week I finally got my RGB monitor out of storage and now I can enjoy the nice colours the IIgs can produce. The picture is sharp and text is very legible and not as blocky as on emulators or LCDs.

I realize that it may seem blasphemous to use a Commodore monitor on a IIgs, but the 1084S is one of the most versatile CRTs ever produced. It offers Composite, S-Video, analogue RGB and digital RGB. That means I can use it with every computer or console that outputs a PAL or 15kHz type signal.
The monitor itself is from 1987, so it matches my 1987 IIgs perfectly. I will give it a good cleanup and change all capacitors, so that I can enjoy it for another 30 years.

The second item I'd like to share is a 400k external disk drive for the original Macintosh. The drive is dated May 1984 as you can see in the second picture. I got it for "free" when I bought an Apple 3.5 800k drive for use on my IIgs.
Unfortunately neither my IIgs nor my Mac Classic support this drive, but it s…

AppleIISd PCBs have arrived

The guys (and gals?) on the Applefritter forum have persuaded me to do a small run of AppleIISd kits.
Today, the 20 PCBs arrived from China and they do look fine. As I have changed only one connection from Version 1.0 to 1.1, I may safely assume that the boards work.

I have to admit I was surprised that so many of you were interested in my small exercise. The kits are already sold out!

I just corrected a small bug in the firmware that kept SD V2 cards with less than 2GB from working. Now the kits are ready to ship. With a little luck, they could arrive in time to put them under the xmas tree 🎄

How to upgrade AppleIISd V1.0 to V1.1

I needed to change a minor detail in hardware design to make the card work and I was happy to hear that some of you folks have made their own PCBs from my design.

Here are the changes that are needed to make the current ROM and CPLD work with a V1.0 card:

On the front: Remove resistor R10 and make a connection between the left pad and pin 13 (A11)

On the back: Cut the trace between pin 30 (/IRQ) and the via.

IIgs breaktrough

Last night I had a major breakthrough for my SD card interface! Not only does it work, it boots GS/OS on the Apple IIgs! 🎉

Switching the source code from Merlin-8 on the IIe to CC65 in Visual Studio and using an EEPROM sped up my development cycle quite a bit. This wasn't a fix for the issues, of course, but it helped. As usual, there were a lot of small things involved and I have learned some lessons.
First lesson: the disk status function uses the X- and Y-registers as return values. However, when you load these registers with the return values and then insert a function call that does not only save these registers but uses them for slot addressing, it will crash. There simply isn't a slot number 255 in the Apple II 😉
Second lesson: SDHC cards use block addressing, not byte addressing. Some weeks ago, my 512 MB card died and I replaced it with an 8 GB card. I knew before that it was initialized correctly, so I assumed it worked as well. The problem was block 0 was always …

Some errors are better

It has been quite a long time since I had some spare time to work on my still-not-working SD card interface for the Apple II.
After rewriting almost all of the VHDL code for the card's CPLD it still would not boot and most of the time crashed with a more ore less garbled message of "Unable to load ProDOS". The fact that this message is shown at all means that at least the first block of the volume is loaded and executed. But the messed up message indicates an issue in the transmission either from card to CPLD or from CPLD to the computer. I checked the data coming from the card and it seems fine. Thanks to Protek over at the Applefritter forum, I found a step into the right direction. He built a card from my design and uses a quite old version of my sources, that was sort of working. He swapped the 74HCT type bus transceiver for a 74LS type and instantly got better results.
I tried the same and got better results, too. Well sort of. The "Unable to load ProDOS" …