Table of Contents
/* Imported from Wayback Machine
Original URL : https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:epm240dev:3vz80:3vz80rev0 Snapshot date: 2025-06-14 Generator : wayback-archiver
*/
Table of Contents
Z80 Rev0 Mezzanine Board for EPM240 Dev Board
Note, Rev0 of Z80 Mezzanine board is superceded by rev1.1 of 3V Z80 Mezzanine board
Introduction
While Z80 is specified for 5V operation, selected CMOS Z80 are capable of running at 3.3V. This mezzanine board hosts such Z80 plus a 512K RAM and plugs on top of the EPM240 development board. The two-board Z80 computer can run RomWBW.
Features
CMOS Z80 selected for 3.3V operation
512K RAM
512 byte flash embedded in EPM240 can boot RomWBW
ACIA emulation in EPM240
SD card interface
RTC module based on DS1302
I2C interface
RomWBW capable
Theory of Operation
Boot from embedded 512-byte flash, etc, etc…place holder.
Design Files
Gerber photoplot files
RomWBW SD bootstrap code resided in EP240's embedded flash
EPM240 design files with fast SD bootstrap (6 seconds), but no RAM disk at drive A
Software
RomWBW image for 3VZ80. The RomWBW will be booted at power up. It takes 23 seconds to load and boot RomWBW from reset.