On 5/4/2020 11:09 AM, Ruud_at_Baltissen.org wrote: > Hallo allemaal, > > But what is so "dynamic" on the 6502? AFAIK it doesn't use > capacitors like a DRAM. Better AFAIK it only uses transistors, > something that has been proofed by this guy that built a 100% > compatible 6502 using only transistors. MOS transistors have a capacitance. In fact, the designer of the Monster 6502 (the project you noted), talks about it: "No; it's relatively slow. The MOnSter 6502 runs at about 1/20th the speed of the original, thanks to the much larger capacitance of the design. The maximum reliable clock rate is around 50 kHz. The primary limit to the clock speed is the gate capacitance of the MOSFETs that we are using, which is much larger than the capacitance of the MOSFETs on an original 6502 die." The original NMOS design relies on the fact that the charge on a wire will continue to live there for 300nS or so, as part of the operation of the 6502. On the 65C02, such things were dumped into flops, to avoid the issue. JimReceived on 2020-05-30 01:37:57
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