It was about to go in the recycling pile when I thought, “I wonder if I can save it.” There’s no telling how old this lovely Casio fx-590 calculator is, because in spite of deploying my best Google-fu I can find very little information on it. One source suggested that maybe it came out at the beginning of the 1990s…. Read more »
In a previous post, I detailed how I’m having to shift voltage levels on signals running between a 65C22 VIA chip and the GPIO pins of a Raspberry Pi. The solution I settled on was to go for simple voltage dividers using pairs of resistors. And that’s been working fine. I mean, you’d expect it to work with the 5V… Read more »
Let’s be clear about this, I have no idea how you write an operating system. I just know you need to have one. When I first started writing ROM code for the Zolatron 64 (Z64) 6502-based homebrew computer all that really mattered was getting things to work. And I was amazed when they did. I was following in the footsteps… Read more »
As I mentioned before, the Zolatron 64 6502-based homebrew computer (Z64) needs some kind of persistent storage. And these days there is no shortage of options. If you search around the interwebz for homebrew projects you’ll discover a treasure trove of clever solutions. But many of these involve implementing some form of existing technology. For example, you can employ a… Read more »
Pretty much every computer needs persistent storage. And these days we’re spoiled for choice – everything from hard drives down to micro SD cards being capable of holding more information than I can comfortably imagine. With clever interfaces, these options are also open to builders of homebrew computers, like the 6502-based Zolatron 64 (Z64). But it does mean grappling with… Read more »
There’s no getting away from it. The 6522 Versatile Interface Adapter (VIA) is, well, versatile. Alongside giving you two 8-bit general purpose I/O ports – much like the GPIO pins on a Raspberry Pi, Arduino and the like – it also has a bunch of handy extra features. These include a shift register and control lines that you can employ… Read more »