the difference that is no difference makes no difference
So I had an Amiga 500 in my late teens/early twenties. I had the 512K RAM expansion (actually a home brew one) and one external floppy drive. I wrote a heap of 68000 assembly back then using that setup. Hard drives were around but they were the ‘stuff of dreams’. They were so so expensive […]
So in the previous article I upgraded my SV-318 from 16KB of CPU RAM to 64KB of CPU RAM. But I really wanted to emulate the floppy disk controller on the Spectravideo. If you are familiar with the early Spectravideo’s you may assume that this is a silly goal. More on that later.
So I was given this Spectravideo SV-318 quite some time ago (thanks Bryce). It’s quite a cool looking computer. The red joystick knob on the right is an interesting feature.
So that Galaksija I made up was quite fun to build and get going. And I’ve found a few other homebrew projects like that. Recently I’ve built an Amiga 500++ (thanks Rob), and then I came across the Omega MSX2 . Sergey has designed a set of boards that make up an MSX2 home computer […]
A few months back I came across an ebay ad for a circuit board for a Galaksija. I had never heard of it before. The original Galaksija came out in 1983 in Yugoslavia. The Galaksija wikipedia page has a lot more info and the spetsialist-mx.ru site has a big section on it (in Russian). That […]
This is really part 2 of Emulating a hardware ROM in real time with an STM32F4. In that post I used a cheap STM32F407 board to emulate some ROMs and some IO ports for an Acorn Electron. ie. The Electron thinks it has a bunch of hardware attached, but it’s simply the STM32F407 board pretending to be […]
The Acorn Archimedes A3000 came out in 1989. My vague recollection of the era is that the Amiga 500 was really popular around then, and even though the A3000 was a lot more powerful, it was in a price bracket that made it a lot more expensive. I probably didn’t know how much more powerful […]
So in part 1 (Amstrad CPC ROM emulation using an STM32F4) the code I had for emulating a ROM (and some IO) with a cheap STM32F4 board for the Amstrad CPC 464 ran in a continuous polling loop. The code just watched _ROMEN and _IORQ going high and low, and acted appropriately. The (sort of […]
UPDATE: There is a ‘part 2‘ to this article. In that I use interrupts, instead of the polling technique shown below So, in emulating a hardware ROM in real time with an STM32F4 I hooked up a cheap US$10 STM32F4 board to my Acorn Electron to act as both a sideways ROM board and a sort of […]
UPDATE (20190523). There is a ‘Part 2’ of this article in Acorn Electron ROM Emulation with an STM32F4 that describes using interrupts to emulate ROMs. The article below involves using ‘polling’ to perform a similar function. I remember reading dhole’s Emulating a GameBoy Cartridge with an STM32F4 some time ago thinking that it had a lot […]
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