INES Mapper 019

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Namco 129/163
Company Namco
Games 20 in NesCartDB
Complexity ASIC
Boards 11xF0, 111F0S
PRG ROM capacity 512K
PRG ROM window 8Kx3 + 8K fixed
PRG RAM capacity 8K
PRG RAM window 8K
CHR capacity 256K
CHR window 1Kx8 (PT) + 1Kx4 (NT)
Nametable mirroring arbitrary, up to 226 source nametables
Bus conflicts No
IRQ CPU cycle counter
Audio Yes
iNES mappers 019

iNES Mapper 019 is used to denote Famicom boards bearing the Namco 129 and Namco 163 ASICs. These chips contain 128 bytes of internal RAM that can be used either for expansion audio or, together with a battery, for 128 bytes of save RAM. Games may also come with the regular 8 KiB of additional battery-backed WRAM mapped into CPU address space at $6000-$7FFF.

In NES 2.0, the 128 bytes of internal chip RAM are not included in the PRG-RAM and PRG-NVRAM fields. NES 2.0 Mapper 19 ROM images therefore either have:

  • no battery and no WRAM: battery bit clear, PRG-RAM/PRG-NVRAM both set to zero.
  • a battery but no WRAM: battery bit set, PRG-RAM/PRG-NVRAM both set to zero. The game writes its save data into the 128 byte internal RAM.
  • a battery and WRAM: battery bit set, PRG-RAM set to zero and PRG-NVRAM set to 8192.

The NES 2.0 submapper is used to specify the mixing resistor that determines the relative volume of the expansion audio channels against the APU's audio channels:

INES Mapper 019 submapper table
Submapper # Meaning Note
0 Default Expansion sound volume unspecified
1 Deprecated Internal 128b RAM is battery backed, no external PRG-RAM is present.

No expansion sound. (Equivalent to submapper 2 with 0 in PRG-NVRAM field.)

2 No expansion sound
3 N163 expansion sound: 11.0-13.0 dB louder than NES APU
4 N163 expansion sound: 16.0-17.0 dB louder than NES APU
5 N163 expansion sound: 18.0-19.5 dB louder than NES APU


Game list

Name Chip Battery WRAM Expansion Audio NES 2.0 Submapper
Battle Fleet 163 Yes No No 2
Digital Devil Story: Megami Tensei II 163 Yes Yes Yes 3
Dokuganryuu Masamune 163 Yes No No 2
Erika to Satoru no Yume Bouken 163 No No Yes 5
Famista '90 163 Yes No No 2
Final Lap 163 No No Yes 3
Hydlide 3: Yami kara no Houmonsha 163 Yes No No 2
Juvei Quest 163 Yes Yes No 2
Kaijuu Monogatari 163 Yes No No 2
King of Kings 163 Yes Yes Yes 5
Mappy Kids 163 No No Yes 5
Mindseeker 163 Yes No No 2
Namco Classic 163 No No No 2
Namco Classic II 163 No No Yes 3
Rolling Thunder 163 No No Yes 4
Sangokushi: Chuugen no Hasha 163 Yes Yes Yes 5
Sangokushi II: Haou no Tairiku 163 Yes Yes Yes 3
Star Wars 129 No No No 2
Youkai Douchuuki 163 No No Yes 5

Banks

  • CPU $6000-$7FFF: 8 KB PRG RAM bank, if WRAM is present
  • CPU $8000-$9FFF: 8 KB switchable PRG ROM bank
  • CPU $A000-$BFFF: 8 KB switchable PRG ROM bank
  • CPU $C000-$DFFF: 8 KB switchable PRG ROM bank
  • CPU $E000-$FFFF: 8 KB PRG ROM bank, fixed to the last bank
  • PPU $0000-$03FF: 1 KB switchable CHR bank
  • PPU $0400-$07FF: 1 KB switchable CHR bank
  • PPU $0800-$0BFF: 1 KB switchable CHR bank
  • PPU $0C00-$0FFF: 1 KB switchable CHR bank
  • PPU $1000-$13FF: 1 KB switchable CHR bank
  • PPU $1400-$17FF: 1 KB switchable CHR bank
  • PPU $1800-$1BFF: 1 KB switchable CHR bank
  • PPU $1C00-$1FFF: 1 KB switchable CHR bank
  • PPU $2000-$23FF: 1 KB switchable CHR bank
  • PPU $2400-$27FF: 1 KB switchable CHR bank
  • PPU $2800-$2BFF: 1 KB switchable CHR bank
  • PPU $2C00-$2FFF: 1 KB switchable CHR bank

These ASICs have the unusual ability to select the internal 2 KB nametable RAM as a CHR bank page, allowing it to be used as CHR RAM in combination with the existing CHR ROM.

Registers

The 163 has 19 registers within $4800-$5FFF and $8000-$FFFF. Each register occupies a range of $800 bytes, so $4800-$4FFF all refers to one register, $5000-$57FF all refers to another register, and so on.

Chip RAM Data Port ($4800-$4FFF) r/w

See Namco 163 audio.

IRQ Counter (low) ($5000-$57FF) r/w

7  bit  0
---- ----
IIII IIII
|||| ||||
++++-++++- Low 8 bits of IRQ counter

IRQ Counter (high) / IRQ Enable ($5800-$5FFF) r/w

7  bit  0
---- ----
EIII IIII
|||| ||||
|+++-++++- High 7 bits of IRQ counter
+--------- IRQ Enable: (0: disabled; 1: enabled)

CHR and NT Select ($8000-$DFFF) w

Value CPU writes Behavior
$00-$DF Always selects 1KB page of CHR-ROM
$E0-$FF If enabled by bit in $E800, use the NES's internal nametables (even values for A, odd values for B)
Write to CPU address 1KB CHR bank affected Values ≥ $E0 denote NES NTRAM if
$8000-$87FF $0000-$03FF $E800.6 = 0
$8800-$8FFF $0400-$07FF $E800.6 = 0
$9000-$97FF $0800-$0BFF $E800.6 = 0
$9800-$9FFF $0C00-$0FFF $E800.6 = 0
$A000-$A7FF $1000-$13FF $E800.7 = 0
$A800-$AFFF $1400-$17FF $E800.7 = 0
$B000-$B7FF $1800-$1BFF $E800.7 = 0
$B800-$BFFF $1C00-$1FFF $E800.7 = 0
$C000-$C7FF $2000-$23FF always
$C800-$CFFF $2400-$27FF always
$D000-$D7FF $2800-$2BFF always
$D800-$DFFF $2C00-$2FFF always

It is believed, but untested, that a game could add a normal SRAM and use it in lieu of the nametable RAM; if so, a game would be able to get 4-screen mirroring and many more pages of CHR-RAM.

PRG Select 1 ($E000-$E7FF) w

7  bit  0
---- ----
.MPP PPPP
 ||| ||||
 |++-++++- Select 8KB page of PRG-ROM at $8000
 +-------- Disable sound if set

PRG Select 2 / CHR-RAM Enable ($E800-$EFFF) w

7  bit  0
---- ----
HLPP PPPP
|||| ||||
||++-++++- Select 8KB page of PRG-ROM at $A000
|+-------- Disable CHR-RAM at $0000-$0FFF
|            0: Pages $E0-$FF use NT RAM as CHR-RAM
|            1: Pages $E0-$FF are the last $20 banks of CHR-ROM
+--------- Disable CHR-RAM at $1000-$1FFF
             0: Pages $E0-$FF use NT RAM as CHR-RAM
             1: Pages $E0-$FF are the last $20 banks of CHR-ROM

PRG Select 3 ($F000-$F7FF) w

7  bit  0
---- ----
..PP PPPP
  || ||||
  ++-++++- Select 8KB page of PRG-ROM at $C000

Write Protect for External RAM AND Chip RAM Address Port ($F800-$FFFF) w

7  bit  0
---- ----
KKKK DCBA
|||| ||||
|||| |||+- 1: Write-protect 2kB window of external RAM from $6000-$67FF (0: write enable)
|||| ||+-- 1: Write-protect 2kB window of external RAM from $6800-$6FFF (0: write enable)
|||| |+--- 1: Write-protect 2kB window of external RAM from $7000-$77FF (0: write enable)
|||| +---- 1: Write-protect 2kB window of external RAM from $7800-$7FFF (0: write enable)
++++------ Additionally the upper nybble must be equal to b0100 to enable writes

Any value outside of the range $40-$4E will cause all PRG RAM to be read-only.

Also see Namco 163 audio.

IRQ Operation

The IRQ is a 15-bit CPU cycle up-counter. $5000 and $5800 provide direct access to the counter itself (i.e., this isn't a reload value). Games can read and write to these registers in realtime.

The IRQ counter increments on each CPU cycle. Upon reaching $7FFF, an IRQ is fired, and it stops counting. Writing to $5000 or $5800 will acknowledge any pending IRQs.

Notes

  • Many older programs incorrectly identify this mapper by the name Namco 106. Some sources use the name Namcot instead of Namco, as some games and PCBs use this variation on the company name.
  • The N163 supports 8k of PRG-RAM but also has 128 bytes of internal memory. If there is a battery, then both will be battery backed. The internal memory is battery backed for several games that have no additional PRG-RAM.
  • The only known difference between the Namco 129 and 163 is the 129's faulty implementation of expansion audio. The only known game (Star Wars) using the Namco 129 can also be found in later runs with a Namco 163 ASIC.
  • Many INES Mapper 210 games are incorrectly set to Mapper 019.
  • Dokuganryuu Masamune is often thought as having WRAM. Tests have indicated however that the fourth glob is not SRAM but a protection circuit for the chip-internal RAM.

See also

All of the below are in Japanese: