Difference between revisions of "I2C Registers"
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bit22: Volume slider position change | bit22: Volume slider position change | ||
bit23: ??? Register 0x0E update | bit23: ??? Register 0x0E update | ||
− | bit24: | + | bit24: GPU off |
− | bit25: | + | bit25: GPU on |
− | bit26: | + | bit26: bottom backlight off |
− | bit27: | + | bit27: bottom backlight on |
− | bit28: | + | bit28: top backlight off |
− | bit29: | + | bit29: top backlight on |
bit30: bit set by mcu sysmodule | bit30: bit set by mcu sysmodule | ||
bit31: bit set by mcu sysmodule | bit31: bit set by mcu sysmodule |
Revision as of 21:44, 31 August 2023
Registers
Old3DS | Name | Address | Width | Used by |
---|---|---|---|---|
Yes | I2C1_DATA | 0x10161000 | 1 | I2C bus 1 devices |
Yes | I2C1_CNT | 0x10161001 | 1 | I2C bus 1 devices |
Yes | I2C1_CNTEX | 0x10161002 | 2 | I2C bus 1 devices |
Yes | I2C1_SCL | 0x10161004 | 2 | I2C bus 1 devices |
Yes | I2C2_DATA | 0x10144000 | 1 | I2C bus 2 devices |
Yes | I2C2_CNT | 0x10144001 | 1 | I2C bus 2 devices |
Yes | I2C2_CNTEX | 0x10144002 | 2 | I2C bus 2 devices |
Yes | I2C2_SCL | 0x10144004 | 2 | I2C bus 2 devices |
Yes | I2C3_DATA | 0x10148000 | 1 | I2C bus 3 devices |
Yes | I2C3_CNT | 0x10148001 | 1 | I2C bus 3 devices |
Yes | I2C3_CNTEX | 0x10148002 | 2 | I2C bus 3 devices |
Yes | I2C3_SCL | 0x10148004 | 2 | I2C bus 3 devices |
I2C_CNT
BIT | DESCRIPTION |
---|---|
0 | Stop (0=No, 1=Stop/last byte) |
1 | Start (0=No, 1=Start/first byte) |
2 | Pause (0=Transfer Data, 1=Pause after Error, used with/after Stop) |
4 | Ack Flag (0=Error, 1=Okay) (For DataRead: W, for DataWrite: R) |
5 | Data Direction (0=Write, 1=Read) |
6 | Interrupt Enable (0=Disable, 1=Enable) |
7 | Start/busy (0=Ready, 1=Start/busy) |
I2C_CNTEX
BIT | DESCRIPTION |
---|---|
0-1 | ? Set to 2 normally. |
I2C_SCL
BIT | DESCRIPTION |
---|---|
0-5 | ? |
8-12 | ? Set to 5 normally. |
I2C Devices
Device id | Device bus id | Device Write Address | Accessible via I2C service | Device description |
---|---|---|---|---|
0 | 1 | 0x4a | "i2c::MCU" | Power management?(same device addr as the DSi power-management) |
1 | 1 | 0x7a | "i2c::CAM" | Camera0?(same dev-addr as DSi cam0) |
2 | 1 | 0x78 | "i2c::CAM" | Camera1?(same dev-addr as DSi cam1) |
3 | 2 | 0x4a | "i2c::MCU" | MCU |
4 | 2 | 0x78 | "i2c::CAM" | ? |
5 | 2 | 0x2c | "i2c::LCD" | ? |
6 | 2 | 0x2e | "i2c::LCD" | ? |
7 | 2 | 0x40 | "i2c::DEB" | ? |
8 | 2 | 0x44 | "i2c::DEB" | ? |
9 | 3 | 0xa6 | "i2c::HID" | Gyroscope. The device table in I2C-module had the device address changed from 0xA6 to 0xD6 with 8.0.0-18. |
10 | 3 | 0xd0 | "i2c::HID" | Gyroscope (old3DS) |
11 | 3 | 0xd2 | "i2c::HID" | Gyroscope (2DS, new3DSXL, new2DSXL) |
12 | 3 | 0xa4 | "i2c::HID" | DebugPad (slightly modified Wii Classic Controller Pro) |
13 | 3 | 0x9a | "i2c::IR" | IR |
14 | 3 | 0xa0 | "i2c::EEP" | HWCAL EEPROM (only present on dev units where SHA256 is used for HWCAL verification) |
15 | 2 | 0xee | "i2c::NFC" | New3DS-only NFC |
16 | 1 | 0x40 | "i2c::QTM" | New3DS-only QTM |
17 | 3 | 0x54 | "i2c::IR" | Used by IR-module starting with 8.0.0-18, for New3DS-only HID via "ir:rst". This deviceid doesn't seem to be supported by i2c module on 8.0.0-18(actual support was later added in New3DS i2c module). |
Notice: These device addresses are used for writing to the respective device, for reading bit0 must be set (see I2C protocol). Thus, the actual device address is >> 1.
Device 3
ro = read-only (writing is no-op) rw = read-write wo = write-only (reading will yield 00, FF, or unpredictable data)
d* = dynamic register (explaination below this table) s* = shared register (explaination below this table) ds = dynamic shared (explaination below this table)
Reading or writing multiple bytes from/to single-byte registers increments the register ID along with it. For example reading two bytes from reg 0x00 reads regs 0x00 and 0x01.
This is not the case for multibyte regs (0x29, 0x2D, 0x4F, 0x61 and 0x7F), plus reg 0x60.
REGISTER | WIDTH | INFO | DESCRIPTION | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0x00 | s | ro | Version high | ||||||||||||||||
0x01 | s | ro | Version low | ||||||||||||||||
0x02 | d | rw | For bit0 and 1 values, writing will mask away/"acknowledge" the event, set to 3 by mcuMainLoop on reset if reset source is Watchdog
bit0: RTC clock value got reset to defaults bit1: Watchdog reset happened bit5: TWL MCU reg: volume mode (0: 8-step, 1: 32-step) bit6: TWL MCU reg: NTR (0) vs TWL mode (1) bit7: TWL MCU reg: Uses NAND | ||||||||||||||||
0x03 | ds | rw | Top screen Vcom | ||||||||||||||||
0x04 | ds | rw | Bottom screen Vcom | ||||||||||||||||
0x05
- 0x07 |
s | rw | Danger zone - MCU unlock sequence is written here. | ||||||||||||||||
0x08 | s | ro | Raw 3D slider position | ||||||||||||||||
0x09 | s | ro | Volume slider state (0x00 - 0x3F)
This is the same value returned by MCUHWC:GetSoundVolume | ||||||||||||||||
0x0A | s | ro | Battery temperature (in Celcius?) | ||||||||||||||||
0x0B | s | ro | Battery percentage | ||||||||||||||||
0x0C | s | ro | Battery percentage, fractional part (seems to have a resolution of around 0.1% according to tests) | ||||||||||||||||
0x0D | s | ro | System voltage | ||||||||||||||||
0x0E | s | ro | ? | ||||||||||||||||
0x0F | s | ro | Flags: bit7-5 are read via mcu::GPU. The rest of them are read via mcu::RTC.
bit01: ShellState bit03: AdapterState bit04: BatteryChargeState bit05: Bottom screen backlight on bit06: Top screen backlight on bit07: GPU on(?) | ||||||||||||||||
0x10
- 0x13 |
s | ro | Received interrupt bitmask, see register 0x18 for possible values
If no interrupt was received this register is 0 | ||||||||||||||||
0x14 | s | ro | Unused and unwritable byte :( | ||||||||||||||||
0x15
- 0x17 |
s | rw | Unused and unreferenced free RAM! Good for userdata. | ||||||||||||||||
0x18
- 0x1B |
s | rw | Interrupt mask for register 0x10 (0=enabled,1=disabled)
bit00: Power button press (for 27 "ticks") bit01: Power button held (for 375 "ticks"; the 3DS turns off regardless after a fixed time) bit02: HOME button press (for 5 "ticks") bit03: HOME button release bit04: WiFi switch button bit05: Shell close bit06: Shell open bit07: Fatal hardware condition(?) (sent when the MCU gets reset by the Watchdog timer) bit08: Charger removed bit09: Charger plugged in bit10: RTC alarm (when some conditions are met it's sent when the current day and month and year matches the current RTC time) bit11: ??? (accelerometer related) bit12: HID update bit13: Battery percentage status change (triggered at 10%, 5%, and 0% while discharging) bit14: Battery stopped charging (independent of charger state) bit15: Battery started charging Nonmaskable(?) interrupts bit16: ??? bit17: ??? (opposite even for bit16) bit22: Volume slider position change bit23: ??? Register 0x0E update bit24: GPU off bit25: GPU on bit26: bottom backlight off bit27: bottom backlight on bit28: top backlight off bit29: top backlight on bit30: bit set by mcu sysmodule bit31: bit set by mcu sysmodule | ||||||||||||||||
0x1C
- 0x1F |
s | rw | Unused and unreferenced free RAM! Good for userdata. | ||||||||||||||||
0x20 | d | wo | System power control:
bit0: power off bit1: full reboot (unused). Discards things like CFG9_BOOTENV - Asserts RESET1 via PMIC command (?) (deasserts nRESET1). This could be the reset that controls some CFG9 registers - Asserts RESET2 (P0.1 = 0, PM0.1 = 0 (output)) (deasserts nRESET2) - Asserts FCRAM_RESET (P3.0 = 0) (deasserts nFCRAM_RESET) bit2: normal reboot. Preserves CFG9_BOOTENV, etc. - Asserts RESET2 (P0.1 = 0, PM0.1 = 0) - If in NTR emulation mode (see reg 0x02), asserts FCRAM_RESET (P3.0 = 0) - Resets TWL MCU i2c registers bit3: FCRAM reset (present in by LgyBg. Unused because a system reboot does the same thing & a PDN reg also possibly implements this function) - Asserts FCRAM_RESET (P3.0 = 0) bit4: signal that sleep mode is about to be entered (used by PTM) Bit 4 sets a bit at a RAM address which seems to control the watcdog timer state, then this bit is immediately unmasked. This field has a bitmask of 0x0F. If any of the reset bits is set, the MCU waits for 5ms, then deasserts RESET1 (via PMIC), RESET2 (PM0.1 = 1 (input)) and FCRAM_RESET (P3.0 = 1), and reinitializes some other various registers after a 100ms delay. | ||||||||||||||||
0x21 | d | wo | Used in legacy mode to signal events for TWL MCU "emulation" (written to REG[0x5D])? Software then asserts the TWL MCU IRQ pin via Legacy I/O registers.
bit0: Signal TWL POWER button click bit1: Signal TWL reset bit2: Signal TWL power off bit3: Signal TWL battery low bit4: Signal TWL battery empty bit5: Signal TWL volume button click | ||||||||||||||||
0x22 | d | wo | Used to set LCD states
bit0: don't push to LCDs bit1: push to LCDs bit2: bottom screen backlight off bit3: bottom screen backlight on bit4: top screen backlight off bit5: top screen backlight on Bits 4 and 5 have no effect on a 2DS because the backlight source is the bottom screen. The rest of the bits are masked away. | ||||||||||||||||
0x23 | d | wo | Writing 0x72 ('r') resets the MCU, but this is stubbed on retail? | ||||||||||||||||
0x24 | s | rw | Watchdog timer. This must be set *before* the timer is triggered, otherwise the old value is used. Value zero disables the watchdog. | ||||||||||||||||
0x25 | s | rw | ? | ||||||||||||||||
0x26 | s | rw | ? | ||||||||||||||||
0x27 | sd | rw | Raw volume slider state | ||||||||||||||||
0x28 | s | rw | Brightness of the WiFi/Power LED | ||||||||||||||||
0x29 | sd(5) | rw | Power mode indicator state (read-write)
1 = forced default blue 2 = sleep mode animation 3 = "power off" mode 4 = disable blue power LED and turn on red power LED 5 = disable red power LED and turn on blue power LED 6 = animate blue power LED off and flash red power LED anything else = automatic mode The other 4 bytes (32bits) affect the pattern of the red power LED (write only) | ||||||||||||||||
0x2A | s | rw | WiFi LED state, non-0 value turns on the WiFi LED, 4 bits wide | ||||||||||||||||
0x2B | s | rw | Camera LED state, 4bits wide,
0, 3, 6-0xF = off 1 = slowly blinking 2 = constantly on 3 = "TWL" mode 4 = flash once 5 = delay before changing to 2 | ||||||||||||||||
0x2C | s | rw | 3D LED state, 4 bits wide | ||||||||||||||||
0x2D | 0x64 | wo | This is used for controlling the notification LED (see MCURTC:SetInfoLEDPatternHeader as well), when this register is written. It's possible to write data here with size less than 0x64, and only that portion of the pattern data will get overwritten. Reading from this register only returns zeroes, so it's considered write-only. Writing past the size of this register seems to do nothing. | ||||||||||||||||
0x2E | s | ro | This returns the notification LED status when read (1 means new cycle started) | ||||||||||||||||
0x2F | s | wo? | ??? The write function for this register is stubbed. | ||||||||||||||||
0x30
- 0x36 |
ds | rw | RTC time (system clock). 7 bytes are read from this. The upper nibble of each byte encodes 10s (BCD), so each byte is post-processed with (byte & 0xF) + (10 * (byte >> 4)).
byte 0: seconds byte 1: minutes byte 2: hours byte 3: current week (unused) byte 4: days byte 5: months byte 6: years | ||||||||||||||||
0x37 | s | rw | RTC time byte 7: leap year counter / "watch error correction" register (unused in code) | ||||||||||||||||
0x38
- 0x3C |
s | rw | RTC alarm registers
byte 0: minutes byte 1: hours byte 2: day byte 3: month byte 4: year | ||||||||||||||||
0x3B | s | rw | Could be used on extremely old MCU_FIRM versions to upload MCU firmware if reg 0xF == 0 and reg 0x10 == 1 (presumably major and minor version fields for mcufw 0.1 which largely predates factory firm). | ||||||||||||||||
0x3D
0x3E |
ds | ro | RTC tick counter / "ITMC" (when resets to 0 the seconds increase)
Only reading 0x3D will update the in-RAM value | ||||||||||||||||
0x3F | d | wo | 2 bits
bit0: Asserts RESET1 (P0.0 = 0, PM0.0 = 0 (output)) but does NOT deassert it (wtf?). This seems to kill the entire SoC: is it because it doesn't deassert it, or does it not deassert it because the SoC hangs anyway? This is the pin that controls some security-critical regs like CFG9_BOOTENV! bit1: turns on a prohibited bit in an RTC Control register and turns P12 into an output | ||||||||||||||||
0x40 | s | rw | Tilt sensor sampling mode. Bits 0 and 1 control the mode. If bits 0 or 1 are set then the tilt sensor is enabled and sampled. | ||||||||||||||||
0x41 | s | rw | Index selector for register 0x44 | ||||||||||||||||
0x42 | s | rw | Unused? | ||||||||||||||||
0x43 | s | rw | Unused???, accelometer related | ||||||||||||||||
0x44 | s | rw | ???, pedoometer related(?) | ||||||||||||||||
0x45
- 0x4A |
s | ro | Tilt sensor 3D rotation from the 12bit ADC, left shifted 4 to fit in a 16bit signed short, relative to the 3DS bottom screen
| ||||||||||||||||
0x4B | s | rw | PedometerStepCount (for the current day) | ||||||||||||||||
0x4C
0x4D |
?? | ?? | ?? | ||||||||||||||||
0x4E | d | rw | ??? this = (0xFFE9E & 1) ? 0x10 : 0 | ||||||||||||||||
0x4F | d(6) | ro | |||||||||||||||||
0x50 | s | rw | ??? | ||||||||||||||||
0x51 | s | rw | ??? | ||||||||||||||||
0x52
- 0x57 |
s | rw | ? | ||||||||||||||||
0x58 | s | rw | Register-mapped ADC register
DSP volume slider 0% volume offset (setting this to 0xFF will esentially mute the DSP as it's the volume slider's maximum raw value) | ||||||||||||||||
0x59 | s | rw | Register-mapped ADC register
DSP volume slider 100% volume offset (setting both this and the above to 0 will disable the volume slider with 100% volume, setting this to a lower value than the above will make the volume slider have only 2 states; on and off) | ||||||||||||||||
0x5A | s | ro/rw | Invalid, do not use! On newer MCU_FIRM versions this is unused, but on older MCU_FIRM versions this is a read-only counter. | ||||||||||||||||
0x5B
- 0x5F |
s | - | These registers are out of bounds (0xFFC00 and up), they don't exist, writing is no-op, reading will yield FFs. | ||||||||||||||||
0x60 | d | rw | Free register bank address (index) select
Selects the index to read from in the free register bank, up to 200. Used in conjunction with reg 0x61. byte 0: bit0 = "WirelessDisabled", bit1 = "SoftwareClosed", bit2 = "PowerOffInitiated", bit3 = "LgyNativeResolution", bit4 = "LegacyJumpProhibited" byte 1: Legacy LCD data bytes 2 and 3: Local Friend Code counter bytes 4 and 5: UUID clock sequence bytes 6 and 7: Unused bytes 8 to 175: Playtime data for legacy titles bytes 176 to 188: Playtime data bytes 188 to 199: Unused | ||||||||||||||||
0x61 | d(200) | rw | Free register bank, data is read from/written to here.
Accessing N bytes of this register increments the selected index by N. | ||||||||||||||||
0x62 - 0x7E | s | - | These registers don't exist, writing is no-op, reading will yield FFs. | ||||||||||||||||
0x7F | d(9-0x13) | ro | Various system state information (debug pointer table)
byte 0x00: Console type, see here byte 0x01: PMIC vendor code byte 0x02: Battery vendor code byte 0x03: MGIC version (major?) byte 0x04: MGIC version (minor?) byte 0x05: RCOMP(?) byte 0x06: battery related? (seems to decrease while charging and increase while discharging) byte 0x09: system model (see Cfg:GetSystemModel for values) byte 0x0A: Red Power LED mode (0 = off, 1 = on) byte 0x0B: Blue Power LED intensity (0x00 - 0xFF) byte 0x0D: RGB LED red intensity byte 0x0E: RGB LED green intensity byte 0x0F: RGB LED blue intensity byte 0x11: WiFi LED brightness byte 0x12: raw button states? bit0: unset while Power button is held bit1: unset while HOME button is held bit2: unset while WiFi slider is held bit5: unset while the charging LED is active bit6: unset while charger is plugged in On MCU_FIRM major version 1 the size of this is 9, reading past the 9th byte will yield AA instead of FF. | ||||||||||||||||
0x80
- 0xFF |
s | - | These registers don't exist, writing is no-op, reading will yield FFs. |
Shared register: the letter "s" means that the given register is in a "shared register pool", meaning the resgister is in the register pool in RAM at address 0xFFBA4 + registernumber
.
Dynamic register: these registers aren't in the shared pool, they just "pretend" to be there. These registers often don't retain their set value, change rapidly, or control various hardware.
Non-shared (dynamic) register: it's a register whose contents separate from the shared register pool. Messing with these registers will not affect the shared register pool at all.
On old versions of MCU_FIRM none of the invalid registers are masked away by the read handler function, but are still read-only. Newer MCU_FIRM versions return the hardcoded value FF instead.
Device 5 & 6
LCD controllers for main/sub displays, most likely.
Register | Width | Name | Description |
---|---|---|---|
0x1 | 8 | ? | |
0x11 | 8 | ? | |
0x40 | 8 | CMD_IN/CMD_RESULT1 | Write to trigger a command? Seen commands: 0xFF=Reset?, 0x62=IsFinished?. Result is stored in CMD_RESULT1:CMD_RESULT0. |
0x41 | 8 | CMD_RESULT0 | Read result |
0x50 | 8 | ? | |
0x60 | 8 | ? | |
0xFE | 8 | ? |
Device 10
See the datasheet linked to on the Hardware page for reference.
Device 11
See the datasheet linked to on the Hardware page for reference.
Device 12
REGISTER | WIDTH | DESCRIPTION |
---|---|---|
0x0 | 21 | DebugPad state. |
This is a Wii Classic Controller Pro which was slightly modified to have an encrypted device type of 0xF0 instead of 0xFD.
See here for the HID shared memory report format.
Device 13
Raw I2C register address | Internal register address | Width | Description |
---|---|---|---|
0x0 | 0x0 | 0x40 | RHR / THR (data receive/send FIFO) |
0x8 | 0x1 | 0x1 | IER |
0x10 | 0x2 | 0x1 | FCR/IIR |
0x18 | 0x3 | 0x1 | LCR |
0x20 | 0x4 | 0x1 | MCR |
0x28 | 0x5 | 0x1 | LSR |
0x30 | 0x6 | 0x1 | MSR/TCR |
0x38 | 0x7 | 0x1 | SPR/TLR |
0x40 | 0x8 | 0x1 | TXLVL |
0x48 | 0x9 | 0x1 | RXLVL |
0x50 | 0xA | 0x1 | IODir |
0x58 | 0xB | 0x1 | IOState |
0x60 | 0xC | 0x1 | IoIntEna |
0x68 | 0xD | 0x1 | reserved |
0x70 | 0xE | 0x1 | IOControl |
0x78 | 0xF | 0x1 | EFCR |
See the datasheet linked to on the Hardware page for reference. From that datasheet, for the structure of the I2C register address u8: "Bit 0 is not used, bits 2:1 select the channel, bits 6:3 select one of the UART internal registers. Bit 7 is not used with the I2C-bus interface, but it is used by the SPI interface to indicate a read or a write operation."
Device 14
Used by Cfg-sysmodule via the i2c::EEP service. This is presumably EEPROM going by the service name.
The Cfg-module code which loads the CCAL(nandro:/sys/{HWCAL0.dat/HWCAL1.dat}) file from NAND will load it from I2C instead, if a certain state flag is non-zero. Likewise for the function which writes CCAL to NAND. HMAC/hash verification after loading is skipped when the CCAL was loaded from I2C.
Device 15
This the New3DS NFC controller "I2C" interface. This device is accessed via the WriteDeviceRaw/ReadDeviceRaw I2C service commands.
Since the *Raw commands are used with this, this device has no I2C registers. Instead, raw data is transfered after the I2C device is selected. Hence, WriteDeviceRaw is used for sending commands to the controller, while ReadDeviceRaw is for receiving responses from the controller. Certain commands may return multiple command responses.
Command request / response structure:
Offset | Size | Description |
---|---|---|
0x0 | 0x1 | Normally 0x10? |
0x1 | 0x1 | Command source / destination. |
0x2 | 0x1 | CmdID |
0x3 | 0x1 | Payload size. |
Following the above header is the payload data(when payload size is non-zero), with the size specified in the header. The command response payload is usually at least 1-byte, where that byte appears to be normally 0x0. For command requests the payload data is the command parameters.
For command requests sent to the NFC tag itself, Cmd[1]=0x0 and CmdID=0x0. The command request payload data here is the actual command request data for the NFC tag, starting with the CmdID u8 at payload+0.
During NFC module startup, a certain command is sent to the controller which eventually(after various cmd-reply headers etc) returns the following the payload after the first byte in the payload:
000000: 44 65 63 20 32 32 20 32 30 31 32 31 34 3a 35 33 Dec 22 201214:53 000010: 3a 35 30 01 05 0d 46 05 1b 79 20 07 32 30 37 39 :50...F..y .2079 000020: 31 42 35 1B5
Or that is: "Dec 22 201214:53:50<binary>20791B5". Therefore, this appears to return the part-number of the NFC controller(other command request(s) / response(s) use this part-number value too).
NFC controller commands
CmdRequest[1] | CmdID | Payload data for parameters | Description |
---|---|---|---|
0x2E | 0x2F | Firmware image for this chunk, size varies. | This is used during NFC module startup to upload the firmware image to the NFC controller. This is used repeatedly to upload multiple chunks of the image. |