WiiU Gamepad Technical Documentation

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====== PMIC ======

The gamepad's power management IC is a Texas Instruments SN1010007. So far no datasheet has been found.

It is connected to the [[UIC]]'s I2C bus, where its device ID is 0x48.


===== Pinout =====

^ Pin ^ Desc. ^
| 1   | ?? |
| 2   | ?? |
| 3   | ?? |
| 4   | ?? |
| 5   | Battery pin 1 (red) |
| 6   | Battery pin 1 (red) |
| 7   | ?? |
| 8   | ?? |
| 9   | ?? |
| 10  | 4.75V input from AC adapter |
| 11  | Battery pin 2 (gray) (through 510ohm resistor) |
| 12  | ?? |
| 13  | ?? |
| 14  | ?? |
| 15  | ?? |
| 16  | ?? |
| 17  | Ground |
| 18  | ?? |
| 19  | Vcc1 - 3.2V (UIC voltage?) |
| 20  | Vcc1 feedback |
| 21  | ?? |
| 22  | Vcc2 feedback |
| 23  | Vcc2 - 1.24V (SoC core voltage) |
| 24  | Power button output - to UIC pin 64 |
| 25  | Power button |
| 26  | CPU/etc active - to UIC pin 19 |
| 27  | UIC I2C - SDA |
| 28  | UIC I2C - SCL |
| 29  | Vcc3 - 2.8V output for peripherals (CPU, Flash, etc) |
| 30  | Ground |
| 31  | Vcc3 feedback |
| 32  | ?? |
| 33  | ?? |
| 34  | ?? |
| 35  | ?? |
| 36  | ?? |
| 37  | ?? |
| 38  | ?? |
| 39  | ?? |
| 40  | System active? - to UIC pin 17, with 100k pull-up resistor |
| 41  | ?? |
| 42  | Ground |
| 43  | Battery pin 4 (white) |
| 44  | ?? |
| 45  | ?? |
| 46  | ?? |
| 47  | ?? |
| 48  | ?? |

The gamepad is rated for 4.75V 1.6A. In practice, the PMIC accepts an input voltage of up to 5.2V (as often delivered by third-party AC adapters) without problem. This makes USB chargers a viable substitute for the proprietary AC adapter, as long as they can deliver enough current.


===== I2C communications =====

Communications to the PMIC always start by writing one byte, which is likely a register ID/address. Then further bytes are written or read in order to access the registers themselves.

The UIC firmware has code for accessing the following registers:

^ Register ^ Description ^
| 0x01     | Charge status -- bit6=AC, bit7=USB (1=connected) |
| 0x02     | ?? |
| 0x03     | ?? |
| 0x04     | ?? |
| 0x06     | ?? |
| 0x07     | ?? |
| 0x08     | ?? -- seemingly accessed after 0x07 |
| 0x09     | Battery level LSB (format/bounds unknown) |
| 0x0A     | Battery level MSB |
| 0x0D     | ?? |
| 0x0F     | ?? |
| 0x18     | Backlight related -- 0x90=on 0x10=off |
| 0x19     | Backlight related -- maybe timeout/delay? |

Which battery level is read out of registers 0x09/0x0A seems to depend on settings in register 0x07.

Writes to register 0x07 (and 0x08):

90 06 - to turn on the CPU

D9 - to read current battery level

D0 - to read maximum battery level

D5 - ?? to read minimum battery level?? (unused)

00 07 - to turn off the CPU

Seems register 0x0D is set to 0xA0 after turning the CPU on/off?

Bit 5 in register 0x07 is some sort of ready bit that is checked after changing register 0x07 and before reading battery levels.