Differences

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--- pmic [2024/12/17 13:18] – created arisotura
+++ pmic [2025/04/03 20:30] (current) – arisotura
@@ Line 4: / Line 4: @@
 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.
+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     | ?? |
+| 0x01     | Charge status -- bit6=AC, bit7=USB (1=connected) |
 | 0x02     | ?? |
 | 0x03     | ?? |
@@ Line 20: / Line 75: @@
 | 0x07     | ?? |
 | 0x08     | ?? -- seemingly accessed after 0x07 |
-| 0x09     | ?? |
+| 0x09     | Battery level LSB (format/bounds unknown) |
+| 0x0A     | Battery level MSB |
 | 0x0D     | ?? |
 | 0x0F     | ?? |
-| 0x18     | Backlight related |
+| 0x18     | Backlight related -- 0x90=on 0x10=off |
-| 0x19     | Backlight related |
+| 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):
+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)
+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.