The Z80 softcard is somewhat of a curiosity. Released in 1980, it added a Z80 CPU to the Apple II, allowing CP/M (a popular business operating system) to be ran.

With CP/M gave the ability to run programs like WordStar, dBase, programming languages like PASCAL, and interactive adventures, such as...

I had previously programmed an ATmega328P using AVRDude - this was some time ago, and I was not even sure what program I had applied.

When I attempted to overwrite the program using the Arduino IDE, I hit a dead end. I got the error message:

stk500_recv(): programmer is not responding

It was c...

As part of the repair process for the Apple II Europlus, I have been testing each IC on the motherboard, to ensure it is working correctly. I have been able to test many of the 74 series ICs with my Xgemu 866 Universal Programmer, but there are some ICs that require more complex circuits to test tha...

These disks have been converted with c2t, and can be used in the same way as the Apple II Disk Server. Connect to the audio input of your Apple II, and at the basic ] prompt, type LOAD and press enter. Then play the chosen file below. The disk image will be written to a blank floppy, inser...

As part of diagnosing the issues with my Disk II interface card, I thought I would see whether there were any issues with the PROM, as this would definitely cause issues with reading or writing disks.

The card itself is made up of a number of ICs:

  • SN74LS14N - Hex/6 Way Inverter
  • SN74LS132N -...

While cleaning the keyboard here I noticed a strange problem.

After I had cleaned the keyboard, the machine consistently did not boot correctly. Instead, it would boot to the internal self-test routine. This is usually invoked by pressing solid apple-control-reset. However, instead of displaying...