Over time, and particularly in recent times, we’ve observed lots of single-board retrocomputer builds. That’s wonderful with us — the extra, the merrier. However all of them begin to run in combination a little bit, with little to differentiate between them. Now not so this about-as-compact-as-possible 6502 pc that matches on a unmarried breadboard.
Now, whilst you do the mathematics, it kind of feels like there’s no means that [Anders Nielsen] would had been ready to suit even a minimum chipset onto a typical solderless breadboard. The 40-pin 6502 by myself takes up just about two-thirds of the connections to be had; upload in similarly massive however vital chips just like the 6522 interface adapter, ROM and RAM chips, and a few toughen ICs, and one breadboard isn’t going to chop it. Fortuitously, some frugal engineers at MOS again within the 70s got here up with the 6507, a variant at the 6502 in a 28-pin DIP. The opposite key to this construct is the 6532 RAM-I/O-timer chip or RIOT, which places a tiny quantity of RAM and a few IO strains on a unmarried 40-pin DIP. Together with a 28-pin ROM, a 14-pin hex inverter, and a bit crystal oscillator, all of the chipset simply slightly suits on a unmarried breadboard.
However what can this minimalist 6502 in reality do? As you’ll see within the video underneath, the rest a 555 timer can do, and perhaps a bit bit extra. That’s now not a dig, after all — [Anders] in reality calls out his preliminary blinkenlight software as a bit greater than a glorified 555, and in reality comes up with a slightly extra complicated software simply to end up the purpose. The fascinating section this is coping with the limitations imposed through the restricted sources to be had in this device.
We’re having a look ahead to no matter comes subsequent for this suave construct. It’s arduous to look how one of the plans [Anders] has for it’s going to nonetheless are compatible on a unmarried breadboard, even though — these items have a tendency to unfold out as they move.
