[Joshua Coleman] likes to structure his very own desktops. Occasionally, that implies drawing up bus architectures, memory maps and I/O port pinouts. Other occasions, he can aim his attempts far more on the common aesthetics, as effectively as on setting up a excellent established of peripherals, as he demonstrates in his most up-to-date ColemanZ80 venture. Many thanks to the RC2014 architecture defining most of the crucial features of a typical Z80 computing system, [Joshua] was ready to structure a modern-day retrocomputer that is not only truly handy, but also seems to be as if it arrived off a creation line yesterday.
The exterior design is a sight to behold: brilliant red laser-cut acrylic pieces type a neat, semi-transparent scenario with air flow slots on the sides and tons of blinkenlights on the front. Impressed by 1970s classics like the Altair 8800, the front panel offers the user a immediate perspective of the machine’s interior state and will allow straightforward command inputs by means of a collection of tumbler switches. The CPU, RAM and other fundamental equipment are housed in just one case, with all the enlargement modules in a next one particular, joined to the mainboard by means of a 40-wire flatcable.
Even though the mainboard carefully follows the RC2014 style, [Joshua] went as a result of a great deal of effort and hard work to tune the system to his particular demands. The expansion boards he constructed contain an NS16550 UART to swap the default 68B50, a battery-backed real-time clock, a YM2149-based seem card and even a speech synthesizer module crafted all-around the common SP0256 chip, of Converse & Spell fame. An even extra unusual feature is the existence of an AM9511, one particular of the earliest math coprocessors at any time built, to speed up floating-place calculations. All of these modules had been developed totally by hand on prototype boards: we can hardly visualize how a great deal time this have to have taken.
Output products include a VGA adapter courtesy of a Raspberry Pi Pico as perfectly as a common 4-digit 7-phase LED exhibit and a set of vintage HP “bubble” LEDs. [Joshua] runs quite a few demos in his online video (embedded beneath), ranging from computing the Mandelbrot established to enjoying chiptunes on the YM2149. There is loads of scope for even more enlargement, too: [Joshua] plans to construct a lot more peripherals such as a floppy generate interface and a module to operate a robotic motor vehicle.
This is not the initial Coleman Z80 pc: the preceding model ran on an architecture [Joshua] developed all by himself. We’ve seen numerous other extraordinary RC2014 derivatives, like a little micro version and this Altair-impressed scenario.