Makers and classic computing fanatics Michael Wessel, Jason T. Jacques, and Decle have constructed the primary Busch Microtronic because the Eighties, operating a duplicate of the recently-recovered unique ROM in emulation: the Microtronic Phoenix.
“In a earlier effort we’ve got efficiently recovered the unique firmware ROM of the [Busch] Microtronic,” Wessel explains of the crew’s work. “With the unique firmware obtainable, it’s now time to let it fly once more on fashionable {hardware}, ensuing within the first absolutely genuine re-implementation of the Busch Microtronic from 1981! Rise out of your ashes, Microtronic!”
Bought a hankering for somewhat four-bit retro computing? Construct your self a Microtronic Phoenix. (📷: Michael Wessel)
Launched in 1981, the Busch 2090 Microtronic Pc System — to present the system its correct title — was an uncommon microcomputer coach constructed by Busch Modellbau, an organization based as a fireworks producer earlier than pivoting to plastic fashions. The unique used a Texas Devices TMS1600 four-bit processor operating at simply 500kHz and with a mere 576 bytes of RAM and 4kB of ROM — and it is the contents of that ROM, lengthy thought misplaced, that Wessel and buddies had been in a position to recuperate.
Whereas there are hard- and software program emulators of the machine obtainable, none of them had been operating the unique ROM — till the launch of the Microtronic Phoenix, a {hardware} recreation operating an emulator on a Microchip ATmega644P-20U microcontroller — and eight-bit half operating at a significantly quicker 20MHz. Elsewhere on the board is a 24LC256 EEPROM as a non-volatile storage system and a 74LS244 to guard the microcontroller’s pins from the machine’s enter/output ports and vice-versa. “In precept,” Wessel explains, “the Phoenix is a one-chip design — the whole lot is pushed by the ATmega644P-20U, even the show. The 24LC256 EEPROM is elective; the machine can even work with out it.”
The emulator, which incorporates the selection of utilizing six-digit seven-segment LED or bubble LED show or fashionable equal, features a bodily keyboard, buzzer, and silkscreen instruction set reference, and no fewer than three firmware choices: Neo Mode, a reimplementation of the firmware; Phoenix Mode, which runs the unique Busch ROM; and Mixed, which permits both to be chosen on startup.
The recreation even consists of practical general-purpose enter/output pins, appropriate with unique Microtronic equipment. (📷: Michael Wessel)
“In Neo Mode,” Wessel explains, “the {hardware} emulator has entry to the extra {hardware} options on the board: a speaker for sound output, a 256kBit 24LC256 EEPROM for mass-storage of Microtronic RAM dumps, as an alternative of the 2095 cassette interface; [and a] seven-segment standing show.”
The venture is documented in full on Hackaday.io; board Gerber recordsdata and firmware supply code can be found on GitHub underneath the reciprocal GNU Normal Public License 3.
