58 lines
2.1 KiB
Plaintext
58 lines
2.1 KiB
Plaintext
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# Z80-MBC2
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The Z80-MBC2[1] combines a Z80 and an ATMEGA32A to provide a
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CP/m capable computing environment. It features a SD card
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bootloader which makes running Collapse OS on it rather simple.
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In this recipe, we're going to run Collapse OS on the Z80-MBC2,
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interfacing through its serial port. We're going to use the
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MBC's API to implement BLK on the SD card.
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# Gathering parts
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* A Z80-MBC2 computer with its SD card module and a properly
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flashed "IOS" on the ATMega32A.
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* A FTDI-to-TTL cable to connect to the serial port.
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# Building the binary
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Running "make" in arch/z80/z80mbc2 will yield "os.bin" which is
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what we want.
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# Running on the Z80-MBC2
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Mount the SD card on your modern computer and copy "os.bin" as
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"autoboot.bin", overwriting the binary that was previously
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there.
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We also have to copy the blkfs over. This is done by using IOS'
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drive system. Each "DSxNyy.DSK" file on the card is a drive,
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each drive has 512 track of 32 sectors of 512 bytes, so one
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drive is plenty for our needs. Collapse OS hardcodes drive 0.
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Each drive is part of a set. IOS theoretically supports up to 10
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sets, but the binary shipped by default only accepts 4. You have
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to overwrite an existing set. I used set 3. So, copy "blkfs" to
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file "DS3N00.DSK". If you want, you can change the name of the
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set by changing the contents of "DS3NAM.DAT".
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Put back the SD card in the Z80-MBC2 and power it up by
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connecting the FTDI adapter to it (red: VCC, black: GND, green:
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TX, white: RX).
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The FTDI adapter will show up as something like "ttyUSB0" (or
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"ttyU0" on OpenBSD). Connect to it with "screen" or "cu" or
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whatever you like. Baud rate of the Z80-MBC2 appears to be
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hardcoded to 115200.
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Then, enable IOS program selection by holding RESET and USER at
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the same time, wait 2 seconds, releasing RESET, wait 2 seconds,
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releasing USER. You should then be given a 1-8 choice.
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You begin by selecting the proper disk set, which is through
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choice 8, then you select the Autoboot binary through choice 4.
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You are now in Collapse OS.
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[1]: https://hackaday.io/project/159973-z80-mbc2-a-4-ics-homebrew-z80-computer
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