Merge branch 'master' of github.com:ClusterM/coolgirl-famicom-multicart

1 files changed, 233 insertions, 1 deletions

diff --git a/README.md b/README.md
index a669a88..c48f106 100644
--- a/README.md
+++ b/README.md
@@ -2,5 +2,237 @@
 
 The goal of the project is to create a open source Famicom cartridge that will not be too expensive and can contain up to ~700 games of various mappers.
 
-Documentation coming soon.
+## Registers
+Range: 5000-$5FFF
 
+Mask: $5007
+
+All registers are $00 on power-on and reset.
+
+### $5xx0
+```
+ 7  bit  0
+ ---- ----
+ PPPP PPPP
+ |||| ||||
+ ++++-++++-- PRG base offset (A29-A22)
+```
+
+### $5xx1
+```
+ 7  bit  0
+ ---- ----
+ PPPP PPPP
+ |||| ||||
+ ++++-++++-- PRG base offset (A21-A14)
+```
+
+### $5xx2
+```
+ 7  bit  0
+ ---- ----
+ AMMM MMMM
+ |||| ||||
+ |+++-++++-- PRG mask (A20-A14, inverted+anded with PRG address)
+ +---------- CHR mask (A18, inverted+anded with CHR address)
+```
+
+### $5xx3
+```
+ 7  bit  0
+ ---- ----
+ BBBC CCCC
+ |||| ||||
+ |||+-++++-- CHR bank A (bits 7-3)
+ +++-------- PRG banking mode (see below)
+```
+
+### $5xx4
+```
+ 7  bit  0
+ ---- ----
+ DDDE EEEE
+ |||| ||||
+ |||+-++++-- CHR mask (A17-A13, inverted+anded with CHR address)
+ +++-------- CHR banking mode (see below)
+```
+
+### $5xx5
+```
+ 7  bit  0
+ ---- ----
+ CDDE EEWW
+ |||| ||||
+ |||| ||++-- 8KiB WRAM page at $6000-$7FFF
+ |+++-++---- PRG bank A (bits 5-1)
+ +---------- CHR bank A (bit 8)
+```
+
+### $5xx6
+```
+ 7  bit  0
+ ---- ----
+ FFFM MMMM
+ |||| ||||
+ |||+ ++++-- Mapper code (bits 4-0, see below)
+ +++-------- Flags 2-0, functionality depends on selected mapper
+```
+
+### $5xx7
+```
+ 7  bit  0
+ ---- ----
+ LMTR RSNO
+ |||| |||+-- Enable WRAM (read and write) at $6000-$7FFF
+ |||| ||+--- Allow writes to CHR RAM
+ |||| |+---- Allow writes to flash chip
+ |||+-+----- Mirroring (00=vertical, 01=horizontal, 10=1Sa, 11=1Sb)
+ ||+-------- Enable four-screen mode
+ |+-- ------ Mapper code (bit 5, see below)
+ +---------- Lockout bit (prevent further writes to all registers)
+```
+
+## Mapper codes
+```
+| Code   | iNES mapper number(s) and name(s)  | Flags meaning                         | Notes                                     |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000000 | 0 (NROM)                           |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000001 | 2 (UxROM)                          | 0 - enable "Fire Hawk" mirroring for  | Mapper 2 is fully compartible with mapper |
+|        | 71 (Codemasters)                   |     mapper 71 (Codemasters)           | 71 but "Fire Hawk" only uses mirroring    |
+|        | 30 (UNROM-512)                     | 1 - Enable one screen mirroring       | control. UNROM-512 self-writable feature  |
+|        |                                    |     select for mapper 30 (UNROM-512)  | is not supported                          |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000010 | 2 (CNROM)                          |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000011 | 78 (Irem)                          |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000100 | 97 (Irem's TAM-S1)                 |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000101 | 93 (Sunsoft-2)                     |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000110 | 163 (Nanjing)                      |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 000111 | 18 (Jaleco SS 88006)               |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001000 | 7 (AxROM)                          | 0 - disable mirroring control, used   | iNES Mapper 034 is used to designate both |
+|        | 34 (BNROM, NINA-001)               |     to select mapper 34 instead of 7  | the BNROM and NINA-001 boards but only    |
+|        |                                    |                                       | BNROM is supported                        |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001001 | 228 (Action 52)                    |                                       | Only Cheetahmen II is supported           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001010 | 11 (Color Dreams)                  |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001011 | 66 (GxROM)                         |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001100 | 87                                 |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001101 | 90 (J.Y. Company)                  |                                       | Partical support only, can be used for    |
+|        |                                    |                                       | "Aladdin" game only                       |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001110 | 65 (Irem's H3001)                  |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 001111 | 5 (MMC5)                           |                                       | Experimental partically support, can be   |
+|        |                                    |                                       | used for "Castlevania 3 (U)" only         |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010000 | 1 (MMC1)                           | 0 - enable 16KiB of WRAM              |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010001 | 9 (MMC2)                           |                                       |                                           |
+|        | 10 (MMC4)                          | 0 - 0=MMC2, 1=MMC4                    |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010010 | 152                                |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010011 | 73 (VRC3)                          |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010100 | 4 (MMC3/MMC6)                      | 0 - use TxROM                         |                                           |
+|        | 118 (TxROM)                        | 1 - use mapper 189                    |                                           |
+|        | 189                                | 2 - use mapper 206                    |                                           |
+|        | 206 (Namco, Tengen, others)        |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010101 | 112                                |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010110 | 33 (Taito)                         | 0 - 0=33, 1=48                        |                                           |
+|        | 48 (Taito)                         |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 010111 | 42 (FDS conversions)               | 0 - switch   A0 and A1 lines:         |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011000 | 21 (VRC2/VRC4)                     |     0=A0,A1 like VRC2b (mapper #23),  |                                           |
+|        | 22 (VRC2/VRC4)                     |     1=A1,A0 like VRC2a(#22),          |                                           |
+|        | 23 (VRC2/VRC4)                     |       VRC2c(#25)                      |                                           |
+|        | 25 (VRC2/VRC4)                     | 1 - divide CHR bank select by two     |                                           |
+|        |                                    |     (mapper #22, VRC2a)               |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011001 | 69 (Sunsoft FME-7)                 |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011010 | 32 (IREM G-101)                    |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011011 | 79 (NINA-03/06)                    |                                       |                                           |
+|        | 146 (Sachen 3015)                  |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011100 | 133 (Sachen)                       |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011101 | 36 (TXC's PCB 01-22000-400)        |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011110 | 70                                 |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 011111 | 184 (Sunsoft-1)                    |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 100000 | 38                                 |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 100001 | Reserved                           |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 100010 | 75 (VRC1)                          |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 100011 | 83                                 |                                       | Submapper 0 only                          |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 100100 | 67 (Sunsoft-3)                     |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| 100101 | 89 (Sunsoft-2 on Sunsoft-3 PCB)    |                                       |                                           |
+| ------ + ---------------------------------- + ------------------------------------- + ----------------------------------------- |
+| ...... | Reserved                           |                                       |                                           |
+
+```
+
+## PRG banking modes
+```
+| Code | $8000 | $A000 | $E000 | $C000 | Notes                                    |
+| ---- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 000  |       A       |       C       | UxROM, MMC4, MMC1 mode #3, etc.          |
+| ---- + ------------- + ------------- + ---------------------------------------- |
+| 001  |       C       |       A       | Mapper 97 (TAM-S1)                       |
+| ---- + ------------- + ------------- + ---------------------------------------- |
+| 010  |           Reserved            |                                          |
+| ---- + ----------------------------- + ---------------------------------------- |
+| 011  |           Reserved            |                                          |
+| ---- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 100  |   A   |   B   |   C   |   D   | Universal, used by MMC3 mode 0, etc.     |
+| ---- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 101  |   C   |   B   |   A   |   D   | MMC3 mode #1                             |
+| ---- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 110  |               B               | Mapper 163                               |
+| ---- + ----------------------------- + ---------------------------------------- |
+| 111  |               A               | AxROM, MMC1 modes 0/1, Color Dreams      |
+```
+Power-on/reset state: A=0, B=~2, C=~1, D=~0
+
+## CHR banking modes
+```
+| Code | $0000 | $0400 | $0800 | $0C00 | $1000 | $1400 | $1800 | $1C00 | Notes                                    |
+| ---- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 000  |                               A                               | Used by many simple mappers              |
+| ---- + ------------------------------------------------------------- + ---------------------------------------- |
+| 001  |                          Spetial mode                         | Used by mapper 163                       |
+| ---- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 010  |       A       |       C       |   E   |   F   |   G   |   H   | Used by MMC3 mode 0                      |
+| ---- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 011  |   E   |   F   |   G   |   H   |       A       |       C       | Used by MMC3 mode 1                      |
+| ---- + ----- + ----- + ----- + ----- + ------------- + ------------- + ---------------------------------------- |
+| 100  |               A               |               E               | Used by MMC1                             |
+| ---- + ----------------------------- + ------------- + ------------- + ---------------------------------------- |
+| 101  |              A/B              |              E/F              | MMC2/MMC4, switched by tiles $FD or $FE  |
+| ---- + ------- ----- + ------------- + ------------- + ------------- + ---------------------------------------- |
+| 110  |       A       |       C       |       E       |       G       | Used by many complicated mappers         |
+| ---- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ----- + ---------------------------------------- |
+| 111  |   A   |   B   |   C   |   D   |   E   |  F    |   G   |   H   | Used by very complicated mappers         |
+```
+Power-on/reset state: A=0, B=1, C=2, D=3, E=4, F=5, G=6, H=7