A Z80 Computer With Switches And Blinkenlights

While most people who build their own computer from chips want the finished product to do something useful, there’s something to be said about a huge bank of switches and a bunch of blinkenlights. They’re incredibly simple – most of the time, you don’t even need RAM – and have a great classic look about them.

[Jim] wanted to build one of these computers and wound up creating a minimal system with switches and blinkenlights. It’s based on the Z80 CPU, has only 256 bytes of RAM, and not much else. Apart from a few extra chips to output data and address lines to LEDs and a few more to read switches, there are only two major chips in this computer.

With the circuit complete, [Jim] laser cut a small enclosure big enough to house his stripboard PCB, the switches and LEDs, and a few buttons to write to an address, perform a soft reset, and cycle the clock. One of the most practical additions to this switch/blinkenlight setup is a hand crank. There’s no crystal inside this computer, and all clock cycles are done manually. Instead of pushing a button hundreds of times to calculate something. [Jim] added a small hand crank that cycles the clock once per revolution. Crazy, but strangely practical.

[Jim] made a demo video of his computer in action, demonstrating how it’s able to calculate the greatest common divisor of two numbers. You can check that video out below.

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Multi-target IDE For 8-Bit CPUs

A long time ago, [Martin] played with old 8-bit computers. Recently, he’s been honing his assembly skills again, and the idea of an IDE for a boatload of old systems came to him. After a year of work, he announced a multitarget IDE for 8-bit computers that works in your browser.

The project is called ASM80, and includes a code editor, a workspace to put all your code, compilers for the 8080/8085, Z80, 6502, 6800 and 6809 CPUs, emulators for all these CPUs, and emulators for a few Czech computers, the ZX Spectrum, and a few of [Grant Searle]’s single board computers.

What makes this project interesting is the syntax for all the different CPUs is pretty much the same. It’s a real, modular code editor that supports macros and everything you would expect for a code editor for ancient computers.

You can check out an assembler description here. [Martin] also has an offline, desktop-based version of ASM80 called IDE80, with a video demo of that below.

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