A portable CP/M machine

Some time ago I found FabGL, which is a fantastic library implementing a VGA controller and a PS/2 keyboard controller for the ESP32. It means you can use Arduino IDE to create a sketch that talks directly to a real VGA display and a real PS/2 keyboard. For VGA,  Red, Green and Blue signals and …

A dual-ported RAM for the MC6847

My CZ80 computer design requires a dual-ported RAM between the Z80 and the MC6847, to solve the memory contention problem. Now that the RAMs have arrived, I modified the MC6847 test circuit to try them out. The MC6847 was set to text mode. I removed the EEPROM from the circuit and replaced it with the …

Integrating prc-tools with Visual Studio Code

This is a follow-up to the last post, where we have set up prc-tools to work on a modern Windows 10 machine. Now we will see how to configure the Visual Studio Code IDE (vscode) to work with prc-tools to edit and compile PalmOS applications. For this purpose, I have copied my PalmOS projects folders …

Installing prc-tools on a modern Windows 10 machine

A common way to develop PalmOS applications back in the day was using the prc-tools SDK. There was even a port that ran on Windows, with the help of cygwin. The problem is that this solution does not work on a modern Windows machine anymore. The pre-compiled prc-tools binaries use an old 32-bits cygwin version …

CZ80: emulation

With a working MC6847 circuit, the CZ80 computer now has a viable video output option. But before tackling the hardware, I would like to test the concept in software, that is, build an emulated CZ80. I grabbed the NASCOM Basic Z80 source code I got from the internet and adapted it to my purposes: added …