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 … Continue reading A portable CP/M machine

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 … Continue reading A dual-ported RAM for the MC6847