MAXI000 initial bring-up and some workbench improvements

The bring-up of MAXI000 is still in the very early stages, despite the relatively large amount of bench-time that’s gone by since the boards and other parts arrived. I ended up using in the end, as they were a fair amount cheaper then The bare boards look great: And the back: The reasons for the slowness in getting… Read more »

A PS/2 interface and PCB routing progress

Routing the MAXI000 board has been a slog. A mostly enjoyable slog, but a slog all the same. Before actually getting to the PCB design, the first task was to associate footprints with each schematic symbol. I always dread this task; you are presented with an intimidating list of symbols from the schematic and must pick the correct footprint for… Read more »

More prototyping and a description of the MAXI000 schematic

In the post which first discussed the MAXI000 board I plan to build, the idea of using a programmable oscillator to generate the pixel clock for video output was brought up. A programmable pixel clock would have a big advantage: video modes would not be fixed by the choice of pixel clock oscillator. It would be possible to experiment with… Read more »

Keyboard finished and PCM sound output prototyping

The bring-up of the keyboard controller board was a protracted affair. The first problem was obtaining an RJ10 cable. When drawing up the schematics for the IO board and the keyboard controller board I had naively assumed that the RJ10 cable I had salvaged from an old telephone was wired straight through with pin 1 connected to pin 1 etc…. Read more »

Keyboard controller construction and a DRAM controller

Receiving deliveries of brand new electronic components is exciting! The order from Mouser included a part for the keyboard controller board and multiple parts for MAXI000. On the same day I also received the previously described PCBs from Here’s the front of a keyboard controller board: As usual they look great. A quick test of the updated RJ10 socket… Read more »

A mini-review of a microscope, a keyboard controller, and a SIMM adapter

When building PCBs with small Surface Mount components, it helps to be able to view the board with some magnification. This is useful for both the actual placing and soldering of components, and for inspection of the board after the fact. With the practice boards I made up previously I did have a look at them, after the soldering, with… Read more »

The switch back to Linux

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I’ve previously written about my dissatisfaction with modern Apple Macs after being a big fan of them for more then a decade. In summary, the machines are over priced, have had the useful ports removed, and further, the OS appears to no longer be improving in any meaningful way. I’ve not been using a Mac laptop since my 2013 Macbook… Read more »

Adventures with Surface Mount construction

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I’ve been putting off learning how to build PCBs with Surface Mount Devices for many years. For the most part, I’ve had very little reason to look into SMD/SMT. Most, but not all, of my electronics projects involves the use of 80s and 90s parts which are usually available in through-hole packages; indeed many are only available in through-hole. But… Read more »

VGA improvements

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After trying to make some small improvements to my VGA implementation I’ve come to the conclusion that it is deeply flawed. Whilst I can produce a working video controller that appears to operate reliably, if I make an even insignificant change to the VHDL code then corruption when doing writes into the video memory usually occurs. It’s also clear, from… Read more »

Thoughts on the MAXI000 and other things

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Before getting to the MAXI000, a brief discussion on some unrelated things. First up, I’ve finally bought an oscilloscope, specifically a RigolĀ  DS1054Z. This is a fairly low end 50Mhz DSO (Digital Storage Oscilloscope), which should nonetheless be perfectly adequate for my needs for the foreseeable future. One nice feature: it has four inputs. I must admit that a lot… Read more »