INES Mapper 019
| Company | Namco |
| Games | 20 in NesCartDB |
| Complexity | ASIC |
| Boards | 11xF0, 111F0S |
| Pinout | Namcot 163 family pinout |
| 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 |
| Dragon Ninja | 163 | No | 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 ---- ---- AMPP PPPP |||| |||| ||++-++++- Select 8KB page of PRG-ROM at $8000 |+-------- Disable sound if set +--------- Pin 22 (open collector) reflects the inverse of this value, unchanged by the address bus inputs.
If not battery backed, the internal sound RAM powers on in a random state, and similarly the N163 may power on with sound enabled. A short burst of sound due to these random settings may be heard at first power-on, before the game software manages to disable it.
PRG Select 2 / CHR-RAM Enable ($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 ---- ---- B.PP PPPP | || |||| | ++-++++- Select 8KB page of PRG-ROM at $C000 +--------- Pin 44 reflects this value.
Write Protect for External RAM AND Chip RAM Address Port ($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.
- If it is not battery backed, the internal RAM state will be undefined at power-on[1].
- The only known difference between the Namco 129 and 163 is the 129's subtly different design 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.
- An IC labelled "160" has been found with a copy of Dokuganryuu Masamune: [1]
- 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 the write protect register at $F800
