INES Mapper 019

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 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: 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

• 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 fauly 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

• Namcot 106 by goroh, fix by ZW4 and nori, english translation by nori.
• Comprehensive NES Mapper Document by \Firebug\, information about mapper's initial state is inaccurate.

All of the below are in Japanese:

• Namco mapper by goroh
• Naruko's post to the forum
• Wiki on same
• Naruko's blog's post on mirroring on the 340
• Naruko's blog's post on the write protect register at $F800