Mapper emulation accuracy on N8 PRO

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Mapper emulation accuracy on N8 PRO

Post by wincloud » Mon Apr 05, 2021 9:12 am

How accurate is the FPGA emulation of most mappers these days? Are there any specific timing quirks/differences between the N8 PRO and original carts? I've heard there's issues with the MMC3 implementation, particularly related to the IRQ counter, but I'm not sure how true/relevant that is to the latest firmware. It would be nice to have a 1:1 match to original hardware for most games, though I don't have the wealth of NES technical knowledge some of you here have to know how easy or difficult a task that is.

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Re: Mapper emulation accuracy on N8 PRO

Post by aquasnake » Mon Apr 05, 2021 11:19 pm

At present, FPGA emulation is mostly based on behavior level, rather than circuit netlist and gate level
The combinational logic based on signal interconnection is more accurate than the sequential logic based on SRAM look-up and latch, and the sequential logic will add more duplicated/redundant registers

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