INES Mapper 101: Difference between revisions
From NESdev Wiki
Jump to navigationJump to search
("erroneously"? I'm more likely to think "room for expansion") |
m (→Bank Select ($6000-$7FFF): Formatting.) |
||
| (4 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
[[Category:iNES Mappers | {{DEFAULTSORT:101}}[[Category:iNES Mappers]][[Category:CNROM-like mappers]][[Category:Bad iNES Mappers]] | ||
This mapper | This mapper was allocated for a naïve misdumping of the [//nescartdb.com/profile/view/1547 JF-10] board that contains ''Urusei Yatsura - Lum no Wedding Bell'', which assumed the bank bits were reversed. Otherwise, it is entirely identical to [[iNES Mapper 087|J87]]. | ||
== Registers == | |||
=== Bank Select ($6000-$7FFF) === | |||
This will select an 8 KB CHR ROM bank for PPU $0000-$1FFF. | |||
7 bit 0 | |||
---- ---- | |||
CCCC CCHL | |||
--------------- | |||| |||| | ||
|||| |||+- (Normal) Low CHR bit | |||
|||| ||+-- (Normal) High CHR bit | |||
++++-++--- (Oversize only) Extra CHR bits | |||
This | This is the same as J87 but with the bits in order, and so has a better defined [[oversize]] extension; or the same as [[CNROM]] without bus conflicts. | ||
Latest revision as of 10:17, 25 October 2023
This mapper was allocated for a naïve misdumping of the JF-10 board that contains Urusei Yatsura - Lum no Wedding Bell, which assumed the bank bits were reversed. Otherwise, it is entirely identical to J87.
Registers
Bank Select ($6000-$7FFF)
This will select an 8 KB CHR ROM bank for PPU $0000-$1FFF.
7 bit 0 ---- ---- CCCC CCHL |||| |||| |||| |||+- (Normal) Low CHR bit |||| ||+-- (Normal) High CHR bit ++++-++--- (Oversize only) Extra CHR bits
This is the same as J87 but with the bits in order, and so has a better defined oversize extension; or the same as CNROM without bus conflicts.
