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This is an emulator to run the ROM and disk images prepared for the Just4Fun's Z80-MBC2. The Z80-MBC2 is an easy to build Z80 single board computer with just 4 ICs. SeeZ80-MBC2: a 4 ICs homebrew Z80 computer. This emulator can be used to test the SD content on a Linux, MacOS or Windows computer.

The emulator is based on the S220718-R240620 version of the Z80-MBC2 firmware. It can run Forth, CP/M 2.2, QP/M 2.71, CP/M 3.0, UCSD Pascal and Collapse OS.

Extract thelatest zip for Linux, MacOS or Windows.

The Z80-MBC2 SD contents must be extraced to a directory namedsd. You can rundownload.sh ordownload.bat to automatically download and extract the files fromhttps://cdn.hackaday.io/files/1599736844284832/SD-S220718-R290823-v2.zip .

To list the boot options available, executez80-mbc2-emu without parameters:

$ ./z80-mbc2-emu Usage: z80-mbc2-emu IMAGE  IMAGE can be:    basic for Basic using sd/basic47.bin    forth for Forth using sd/forth13.bin    autoboot for Autoboot using sd/autoboot.bin    cpm22 for CP/M 2.2 using sd/cpm22.bin    qpm for QP/M 2.71 using sd/QPMLDR.BIN    cpm3 for CP/M 3.0 using sd/CPMLDR.COM    pascal for UCSD Pascal using sd/ucsdldr.bin    collapse for Collapse OS using sd/cos.bin    fuzix for Fuzix OS using sd/fuzix.binDownload the images from https://cdn.hackaday.io/files/1599736844284832/S220718-R240620_IOS-Z80-MBC2.zip into the 'sd' directory.

To boot any of the available environments, executez80_mbc2_emu with the code of the environment. For example:

$ ./z80-mbc2-emu cpm22z80-mbc2-emu https://github.com/ivanizag/iz-cpmEmulation of the Z80-MBC2, https://hackaday.io/project/159973Press ctrl-c to return to hostZ80-MBC2 CP/M 2.2 BIOS - S030818-R140319CP/M 2.2 Copyright 1979 (c) by Digital ResearchA>DIRA: ASCIART  BAS : ASM      COM : AUTOEXEC SUB : AUTOEXEC TXTA: D        COM : DDT      COM : DUMP     COM : ED       COMA: GENHEX   COM : GPELED   BAS : GPIO     BAS : HELLO    ASMA: HELLO    COM : LOAD     COM : MAC      COM : MBASIC   COMA: MBASIC85 COM : PEG      COM : PIP      COM : RTC      BASA: STARTREK BAS : STAT     COM : SUBMIT   COM : TREKINST BASA: USERLED  BAS : XMODEM   CFG : XMODEM   COM : XSUB     COMA: ZDE16    COM : ZDENST16 COMA>

Press control-c to exit the emulation.

The Z80-MBC2 has a clever design based on a Z80 and a memory IC, both controlled by an Atmega microcontroller. The Atmega is able to put bytes on the data bus and can inject content to the RAM IC by generating code on the fly. It can also respond to IN and OUT ports with 1 bit adressing. It uses that as the interface with the Z80 programs. Via this interface it provides services related with the serial port, the SD card storage, the real time clock, the user led and button, and the GPIO.

This emulator emulates the Z80 and provides the same services given by the Atmega using the same IN and OUT ports. Instead of the serial port, it uses the terminal. Instead of the SD, it uses a directory namedsd with the same contents.

• Change the way to exit to host to allow control-c to be used on the emulation.
• User led, button and GPIO are not connected to anything
• Save the printer output to a file
• Tick based interrupts