Talk:NES 2.0: Difference between revisions
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An observation: it would've made more sense for the TV system byte to use bit 0 to mean "Supports NTSC" and bit 1 to mean "Supports PAL", since it would've made it trivial to support Dendy timing by just adding another bit. --[[User:Quietust|Quietust]] 04:52, 14 January 2011 (UTC) | An observation: it would've made more sense for the TV system byte to use bit 0 to mean "Supports NTSC" and bit 1 to mean "Supports PAL", since it would've made it trivial to support Dendy timing by just adding another bit. --[[User:Quietust|Quietust]] 04:52, 14 January 2011 (UTC) | ||
== Zero CHR ROM == | |||
Observation: if a ROM is marked as NES 2.0 and has zero banks of CHR ROM, it must set the CHR RAM size field to a nonzero value (ideally 0x07, for 8KB non-batteried), otherwise it technically doesn't have anything at all connected to the PPU bus. --[[User:Quietust|Quietust]] 02:20, 26 August 2011 (UTC) | Observation: if a ROM is marked as NES 2.0 and has zero banks of CHR ROM, it must set the CHR RAM size field to a nonzero value (ideally 0x07, for 8KB non-batteried), otherwise it technically doesn't have anything at all connected to the PPU bus. --[[User:Quietust|Quietust]] 02:20, 26 August 2011 (UTC) | ||
:Good point. I'll mention 0x07 as the most common CHR RAM size in the article. But I do know of two ways to make a cart with no CHR ROM or CHR RAM. The Game Genie uses one way: wire CHR address lines to data lines through a mux to make 4x4 pixel squares. The other way, which I've talked about before on the forum but have never seen used in a game, involves always enabling CIRAM and wiring PA13 to CIRAM A10, which gives 1-screen mirroring (all banks at $400-$7FF) plus 64 tiles of CHR RAM (at $000-$1FF). --[[User:Tepples|Tepples]] 10:57, 26 August 2011 (UTC) | |||
Revision as of 10:57, 26 August 2011
- "Kevin Horton reports that Nintendulator supports NES 2.0."
No it doesn't - it detects them (and the mapper interface has room for them), but it doesn't actually read any of the fields. --Quietust 01:58, 5 January 2010 (UTC)
- ...though now it at least handles larger ROM images (including "Super 8-in-1 99 King Fighter (Unl).nes", which should actually be Mapper 45 with 1MB PRG and 2MB CHR, but with the 256KB CHR blocks 0/1/2/3/4/5/6/7 rearranged to be 0/2/3/1/4/5/6/7). --Quietust 03:30, 5 January 2010 (UTC)
An observation: it would've made more sense for the TV system byte to use bit 0 to mean "Supports NTSC" and bit 1 to mean "Supports PAL", since it would've made it trivial to support Dendy timing by just adding another bit. --Quietust 04:52, 14 January 2011 (UTC)
Zero CHR ROM
Observation: if a ROM is marked as NES 2.0 and has zero banks of CHR ROM, it must set the CHR RAM size field to a nonzero value (ideally 0x07, for 8KB non-batteried), otherwise it technically doesn't have anything at all connected to the PPU bus. --Quietust 02:20, 26 August 2011 (UTC)
- Good point. I'll mention 0x07 as the most common CHR RAM size in the article. But I do know of two ways to make a cart with no CHR ROM or CHR RAM. The Game Genie uses one way: wire CHR address lines to data lines through a mux to make 4x4 pixel squares. The other way, which I've talked about before on the forum but have never seen used in a game, involves always enabling CIRAM and wiring PA13 to CIRAM A10, which gives 1-screen mirroring (all banks at $400-$7FF) plus 64 tiles of CHR RAM (at $000-$1FF). --Tepples 10:57, 26 August 2011 (UTC)
