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**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

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**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

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