/* Imported from Wayback Machine
Original URL : https://retrobrewcomputers.org/doku.php?id=builderpages:mastmees:start Snapshot date: 2025-11-17 Generator : wayback-archiver
*/
Z-One
http://www.nomad.ee/micros/z-one/
Z80 running at up to 4.6Mhz, changeable in MCU firmware
Memory address space filled with 64K RAM
CP/M running, with maxed out storage on SD card (16x8MB drives). You need at least 256MB card.
ATMega1284P as system controller:
Provides system clock for Z80
Contains and serves bootloader, monitor, and CP/M binaries
At startup, patches Z80 bootloader into first 128 bytes of RAM
SD card interface and initialization
Console port for Z80-ChibiTerm connection, using UART at 115200
Heathkit H19 terminal emulation, with special keymappings for WordStar
Software implemented auxiliary serial port connected to FTDI based USB-Serial converter, up to 19200
Interval timer with 10ms resolution
Integrated ChibiTerm
80×30 character text with analog VGA connector
Inverse text and line drawing characters
PS/2 keyboard, US layout only
Boots into system monitor if no SD card, that has
Commands to examine and change memory
Built in Z80 disassembler
SD card read/write sector commands
Can read/write I/O ports
Can run code, examine registers
Download Intel Hex file from auxiliary port
Wait logic for adding 2nd MCU
Runs from 5V, with modern CMOS Z80 and HCT series logic chips uses less than 70mA
Z-Two
http://www.nomad.ee/micros/z-two/
Like Z-One, but without physical Z80.
ATMega1284P, running at 18.432MHz is the brains of the operation
Emulates Z80
All documented Z80 instruction set, at about 110000 instructions/sec at 18.482MHz ATMega clock
Enough undocumented ones to pass all Frank Cringle's yaze tests
Does not emulate undocumented flags 5 and 3
No external interrupt capabilities
Can physically address all 512K of memory, although currently only uses 64K for Z80 emulator
Contains and provides boot loader, monitor, and CP/M binaries
SD card interface and initialization
Console port for Z80-ChibiTerm connection, using UART at 115200
Heathkit H19 terminal emulation, with special key mappings for WordStar
Auxiliary serial port connected to FTDI based USB-Serial converter
SD card interface and initialization
Provides interval timer with 10ms resolution
CP/M 2.2 running, with maxed out storage on SD card (16x8MB drives). You need at least 256MB card.
Integrated ChibiTerm
The whole system runs from 3.3V, regulated down from 5V supply voltage. Uses less than 10mA
