Mar 152014

Hackaday’s Brian Benchoff introduced his new project – a 68000 based computer named Hackaday 68k. It contains backplane, 68000 CPU, 4MB RAM, Yamaha V9939 VDP (as seen in MSX2), Ethernet, Compact Flash, PS/2 keyboard and (maybe) SID for sound.

EasyEDA – a web based design tool

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Mar 152014

 EasyEDA is an EDA, schematic capture, spice circuit simulation and PCB layout designer in one online tool. Not first, we’ve seen it before. But EasyEDA provides full cycle, from idea and schematic through simulation to PCB design and manufacturing. You can use a rich library of circuits, you can share your design as well as export / import data.

Jan 032014

8080js is Yet Another 8080 Emulator. But why?

Chris Double’s js8080 emulator is pretty good if you want to play around. But it has a really big issues – some instructions simply don’t work, some instructions set the flags totally bad and DAA instruction is probably guessing rather than computing. Stephan Tramm did a pretty good work with his i8080 CP/M emulator. But it is still slightly differrent from original (“silicon”) CPU.

The biggest challenge were two testing software: so-called “Kelly Smith Test” and – the greatest one – 8080 Exerciser (a.k.a. Sunhillow). The first one does some basic tests, it checks known border states and simply says: OK, or Error at… The second one does a lot of combinations of data manipulating instructions, and the result is a set of CRC codes (one for each test case). They are compared with CRCs from real “silicon” CPUs. It checks all non-standard states very well and deeply.

My emulator passed Kelly Smith test a long time ago. But Exerciser was a really big issue. It takes a lot of changes and tests and fixes, but – it works!

So I keep my promise and release this JS emulator as open source library. Here it is: 8080js

PS: Big thanks to Roman Borik for his help.