Category Archives: Programmable Logic

Thoughts on future projects (68K!)

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This blog post does not document what I’ve done in my hobbies, except for some small projects, but rather what I plan to work on next. Before getting to that though, I should finish my description of the progress I’ve made with the VGA controller. I have attached the  EPF10K10 (PDF) FPGA to the 68000 CPU bus, and have had… Read more »

VGA signal generation with an EPF10K10 FPGA

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This post has been a long time in the making. I’ve been distracted by various things: work, family, and CNC related projects. I will create a short post describing my first successfully completed CNC project after this one, since I’m pretty proud of it. But onto the topic at hand. The road to a video display began with a stand-alone breadboard… Read more »

Being sensible: a 68008 computer on breadboard

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After writing about building a 68020 computer I feel slightly silly for going back on my word: I have built up a 68008-based computer on breadboard. For one thing going right to a 68020 felt a bit like I’d be missing out; the pleasure is in exploring not the end result. I’d have left out on the other MPUs in… Read more »

An analogue joystick and implementing an SPI controller

It’s been a while since my last post. The main reason being a house move. On the plus side this is good for my projects as I now have lots more room to work on them. On the negative side, at least as far as my hobbies are concerned I’ve, somewhat unexpectedly, found myself doing some work for my old company…. Read more »

More progress…. Lots of different areas

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Looking again at the VHDL for my interrupt router, I realised that adding a priority encoder was fairly simple: Instead of being the masked and active interrupt lines, ROUTED is now the number (bit position plus one) of the active line. 0 is used as a special case: no interrupt lines, which are exposed by the mask, are active. This… Read more »

Sound, video, DMA; more bring up

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Construction of the MAXI09 is continuing. With each part soldered onto the board comes a limited amount of testing with the monitor. Enough to exercise the very basic level of functionality, nothing more. Proper testing, and actually making the part do cool things, will come later. The first part added was the OPL2: Since this was previously prototyped on breadboard… Read more »

MuDdy and DISCo progress, and system reset generation

I have finally solved the issue with holding multiple FPGA designs inside a single configuration flash. It seems there is a special tool just for the purpose of creating complex program files (.pof files). The details are buried in this document. So this is great news, though since I only have one PLCC84 adapter made up I won’t be able… Read more »