Talk:NES 2.0 Mapper 268

Official documentation

I added files shared by the original developer of this mapper. There is some interesting info that can be added to the article. Cluster (talk) 00:15, 30 July 2021 (UTC)

Submapper 8/9

Why do we need a submapper for this? As I see it, it's merely submapper 2/3 with A20/A21/A22 in a different order. NewRisingSun (talk) 20:03, 7 December 2022 (UTC)

So, it's not compatible with 2/3 because of A20/A21/A22 in a different order. There are ROMs which can't be emulated using existing submappers. I see no reason why they shouldn't be added. Also, AFAIK from the developer, all new ASICs will use this submapper. Cluster (talk) 15:19, 8 December 2022 (UTC)

The reason is that there can only be sixteen submappers, or eight pairs of two, so I don't want to waste them. It must be investigated whether the address order of 2 and 8, respectively are indeed correct, or one is based on misordered ROM files. Misordered ROM files should be correctly ordered instead of adding submappers for incorrectly-ordered ROM files. What is the source for the submapper 8 address line order? NewRisingSun (talk) 18:01, 8 December 2022 (UTC)

This is info from the ASIC developer from China. He says that it's ASIC version "23b" and all new chips will be this version now. I have multiple dumps from the desoldered flash chips and multiple binary files sent by the developer. Cluster (talk) 18:17, 8 December 2022 (UTC)

Also, please note that this submapper is really needed by people who making their own multigame ROMs for cartridges. They need to emulate them somehow. Cluster (talk) 18:27, 8 December 2022 (UTC)

There is only a single multicart ("Ultimate NES Remix - Super 154-in-1" from "GameJoy") using submapper 3 at the moment, and none that use submapper 2. It uses the SMD172C-L1 PCB. The current dump was produced by trial-and-error using the Tengu dumper, so it may be that its correct PRG bank order is actually that of what you described as submapper 8/9. If that is so, submapper 2/3 actually does not exist, so what you described as submappers 8/9 should be moved to submappers 2/3, and the current ROM image of "Ultimate NES Remix - Super 154-in-1" should have its address lines reordered. The ASIC markings have been sanded off, but the SMD172C-L1 PCB has a date code of 20210830. NewRisingSun (talk) 19:27, 8 December 2022 (UTC)

Yep, we can move it to 2/3, i think. I'll fix fceux code to match it. Cluster (talk) 19:31, 8 December 2022 (UTC)

Not so fast; I must research first if the 154-in-1 is really that new ASIC version. When did that ASIC version come out? Can you ask the developer if it was already used on the SMD172C-L1 PCB from 2021? NewRisingSun (talk) 19:39, 8 December 2022 (UTC)

Ok, i'll ask. Cluster (talk) 19:56, 8 December 2022 (UTC)

He hasn't answered yet but i uploaded datasheet for the AA6023B. Those bits are labelled as PX0 and PX1 pins, so their functionality depends on a PCB layout. PX0=A22 and PX1=A21 on submappers 0/1. PCB looks the same for all revisions, but we need to make sure. Can "Ultimate NES Remix - Super 154-in-1" owner check PX0 and PX1 pins connectivity corresponding to this pinout: https://www.nesdev.org/wiki/SMD133_(AA6023)_pinout ? Also, note that this mapper revision uses $5xxx/$7xxx registers, not $5xxx/$6xxx! Cluster (talk) 21:44, 11 December 2022 (UTC)