Prebuilt AppleIISD V1.2.1 finally available

I haven't posted for a very long time now, but I'm up and well during those strange days (future readers just google the year 2020 😷). The even better news is that since last year I teamed up with Jens who persuaded me to make a new batch of AppleIISD cards, as reported in my previous post. The cards are available preassembled for 59€ excl. shipping. We are trying to get a website online where you can buy the cards. Meanwhile, you can contact me at the Applefritter Forum.


I still have not found a solution to the EEPROM problem erasing the first byte every now and then. That is why there still is a jumper to enable writing to the chip. However, this needs to be changed only when changing the card's firmware. I am very pleased with this feature as it gives the user a chance to upgrade to a newer firmware version without the need of an EPROM burner. It has been a huge help in development, too when you don't have to extract the chip every minute to burn a new version with just one byte fixed. I'm sure the slots in the Apple will thank me for this, too.

I have been working on a couple of improvements for some time now: The first one is to get the 6502 version working to (theoretically) support every Apple II down to the original ][ model. Currently, I'm stuck at the SD card initialization. For whatever reason, the card refuses to answer after one of the initial commands, which is strange because I did not change anything there (I know everybody says that...). I will have to hook up a logic analyzer to the SPI bus and see what the card is doing. This reminds me I'd better design some test points onto the card next time 😏.

The second feature I'm working on is support for eight partitions as is available in the current ProDOS 2.5 Alpha 8. This should not be a big change as it only needs to extend the offset table for the raw addresses.

After seeing the video of John Brooks talking about ProDOS 2.5 at Kansasfest 2018, I'd like to get xHD going. This is supposed to be a virtual drive for the IIgs that can stay in RAM even when the 8-bit part reboots. This should come in very handy when developing a new firmware image so that I can put it into a folder on my modern computer and have it available instantly for flashing.

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