Inspired by the amazing RunCPM, eCPM is a CP/M 2.2 emulator, developed mainly fo the ESP8266 microcontroller. This is a far from perfect emulation, just like RunCPM, it's just enough to run a lot of old CP/M programs, notably office applications, program- ming environments and, obviously, games. Mostly text adventure games.
BIOS and BDOS are completly reimplemented in C++, running on 32 bits, with barely a dozen of "hooks" to interface with the 8-bit environment. CCP is not emulated, it is the old i8080 compatible Digital Research version, reassambled.
The major goal of the project was to run on the ESP8266 microcontroller, a cheap and disposable device, and, why not, on any other Arduino device. The added benefit is the wireless connectivity of the ESP, allowing us not only to connect to, let's say, a network printer, but to remotely connect to the CP/M prompt via telnet. The downside of using an ESP8266 is the small amount of on-chip RAM, around 96kb, which might seem enough, and it eally is, if you don't use the full SDK, providing WiFi connectivity. If you need WiFi, do not hope for more than 48kb of CP/M memory. That's why we have experimented with SPI RAM. It works, but it's slower. We tried buffered RAM and multi-buffered RAM. It worked faster, but not faster than on-chip RAM.
Another goal was to emulate the filesystem too, like RunCPM does, to place your files directly on SD card (organized in a directory structure), and not inside disk images. It is easier to work this way, but you need to provide the translation inside the emulated BDOS.
This way, we don't emulate a machine, but the operating system, therefore the CP/M 2.2 compatibility level is all you can get. No CP/M 3, no MP/M. There are a lot of projects out there doing this sucessfully. They inspired us: cpm8266, Z80pack, cpmish, Altair8800, imsai8080esp, TeensyBoardZ80 and, of course, RunCPM, this project evolved from. I would like to thank you all. You are the giants on whose shoulders we stand.
Keep in mind this is work in progress, a lot might change. Or not.
This README was typed on eCPM, with WordStar 3.3, VT100 patched.