Zac67 wrote:
Well, even the C64 had two CIAs, (older) 6526 (same with C128). 8520s even work in C64s, they're just faster and have additional timer(s).
The 1541's 6522s were just called VIAs (simpler, but very similar still).
Are 8520s hard to get? Vesalia has them in stock for 6.90€ (DIL) or 3.90 (PLCC) - no way to beat that price with an FPGA!
The difference between the 6526 and 8520 is the TOD (time of day) counter.
It is a 24-bit counter on the 8520 and a BCD counter on the 6526.
The ECS/OCS Amigas have a 1 MHz capable 8520 (running at 0.7 MHz) and the AGA Amigas have a 2 MHz capable 8520 (running at 1.4 MHz).
