There’s not been as much progress over the last few, actually six, months as I would have liked. The good news is that I now have a whole load more time available to work on my projects, including MAXI09-related things. So expect many more blog posts in the coming months! There has been some progress on the OS which I… Read more »
I have restructured the source code tree for MAXI09OS. Source files are now grouped in directories, with a directory for drivers, another one for the core of the OS, etc. The assembly source files are no longer stuck in a single directory. The makefiles are, by necessity, a little more complex as a result. After toying with using make in… Read more »
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 »
The last few month’s free time has been spent knee deep in the Operating System for my 8 bit micro. The main area of attack has been on implementing a console (screen and keyboard) driver, but I’ve been working on a few other things as well. Up until recently I have not tried linking the code that makes up the… Read more »
This past few months has been spent thinking about, and prototyping, ideas for the Operating System I want to write for the computer. But before talking about that, a summary of the other little pieces of hardware progress. Anyone who has viewed the video will be familiar with most of this.First up SPI. I have implemented a trivial SPI controller… Read more »
Physical construction of the MAXI09 PCB is now complete. A final, 3 hour, session with the soldering iron completed that task. Here is a picture of the top of the board: I have also found a solution to the problem of unwanted flux residue. After trying out various things including isopropyl alcohol, it seems that the best approach is good old… Read more »
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 »
After a wait of only about a week and a half, I have now received five MAXI09 PCBs from Botech. Here they are in the wallet: I was surprised at how much they all weigh! And the bottom: As you can see, they look great. Especially noticeable is the silk screen which is beautifully crisp and clear. After doing some… Read more »
Two more bits of prototyping work have been completed recently. The first is the keyboard controller portion. Since the MAXI09 now includes a new Amiga 600 keyboard, and because this keyboard has many more connections then the old C64 one, I have mocked up the controller on breadboard. I was able to establish the pining on the 30 way flex… Read more »
I have been busy the last few weeks prototyping up the remaining untested parts of MAXI09. The first thing I wanted to do was to confirm the functioning of the AD8013 (PDF) video amplifiers. This did not go well at all. After attaching one to a SOIC-14 breakout adapter and plugging it into the circuit on the breadboard, I was… Read more »