SUBOR: Difference between revisions

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[[Category:ASIC_mappers]]
[[Category:ASIC_mappers]]
'''SUBOR''' is a Russian or Chinese mapper used in NES clones with keyboards. It may be the base for the playpower.org project
'''Subor''' is a company in Zhongshan, China, making NES clones with keyboards.
Subor famiclones are reportedly the second most popular famiclone brand in Russia next to Dendy, and one may be the base for the playpower.org project.


It uses a glob that provides 16KB PRG banks swappable at $8000 and $C000
A mapper used in Subor releases uses a glob that provides 16KB PRG banks swappable at $8000 and $C000.
The [[iNES]] format assigns #166 and #167 to these boards.
The [[iNES]] format assigns '''mappers 166 and 167''' to these boards.


== Overview ==
== Overview ==
Line 11: Line 12:
== Registers ==
== Registers ==


=== Bank select ($8000-$FFFF) ===
Nestopia and FCEUX implement mappers 166 and 167 as follows:
 
=== Outer bank ($8000-$9FFF) ===
7  bit  0
...B ....
    |
    +------ XORed with B from Mode below, selects 512KiB outer bank
 
=== Mode ($A000-$BFFF) ===
7  bit  0
...B MM..
    | ||
    | ++--- Banking mode:
    |        0- 512 KiB UNROM
    |        4- 512 KiB inverted UNROM (mapper 180)
    |        8,C- 32 KiB NROM
    +------ XORed with B from Outer bank above, selects 512 KiB outer bank
 
The source of the fixed bank '''ignores the outer bank''', and varies depending on mapper number:
{| class="tabular"
| colspan=2| || colspan=2|Mode
|-
| colspan=2| || 0 || 4
|-
| rowspan=2|Mapper # || 166 || upper bank fixed to 7 || rowspan=2|lower bank fixed to 0x1F
|-
| 167 || upper bank fixed to 0x20
|}
 
The 32 KiB NROM mode ignores the LSB of the 6 bit sum of inner and outer banks, selecting one of 32 different possible slices. However, for mapper 167, the upper and lower halves are '''reversed'''.
 
=== Inner bank 1 ($C000-$DFFF) ===
  7  bit  0
  ...b bbbb
    | ||||
    +-++++- XORed with Inner bank 2 below, selects 16KiB inner bank
 
=== Inner bank 2 ($E000-$FFFF) ===
  7  bit  0
  ...b bbbb
    | ||||
    +-++++- XORed with Inner bank 1 above, selects 16KiB inner bank
 
== References ==
*[http://bootleggames.wikia.com/wiki/Subor Subor on BootlegGames Wiki]

Latest revision as of 06:01, 5 May 2014

Subor is a company in Zhongshan, China, making NES clones with keyboards. Subor famiclones are reportedly the second most popular famiclone brand in Russia next to Dendy, and one may be the base for the playpower.org project.

A mapper used in Subor releases uses a glob that provides 16KB PRG banks swappable at $8000 and $C000. The iNES format assigns mappers 166 and 167 to these boards.

Overview

Banks

Registers

Nestopia and FCEUX implement mappers 166 and 167 as follows:

Outer bank ($8000-$9FFF)

7  bit  0
...B ....
   |
   +------ XORed with B from Mode below, selects 512KiB outer bank

Mode ($A000-$BFFF)

7  bit  0
...B MM..
   | ||
   | ++--- Banking mode:
   |        0- 512 KiB UNROM
   |        4- 512 KiB inverted UNROM (mapper 180)
   |        8,C- 32 KiB NROM
   +------ XORed with B from Outer bank above, selects 512 KiB outer bank

The source of the fixed bank ignores the outer bank, and varies depending on mapper number:

Mode
0 4
Mapper # 166 upper bank fixed to 7 lower bank fixed to 0x1F
167 upper bank fixed to 0x20

The 32 KiB NROM mode ignores the LSB of the 6 bit sum of inner and outer banks, selecting one of 32 different possible slices. However, for mapper 167, the upper and lower halves are reversed.

Inner bank 1 ($C000-$DFFF)

 7  bit  0
 ...b bbbb
    | ||||
    +-++++- XORed with Inner bank 2 below, selects 16KiB inner bank

Inner bank 2 ($E000-$FFFF)

 7  bit  0
 ...b bbbb
    | ||||
    +-++++- XORed with Inner bank 1 above, selects 16KiB inner bank

References