I2C Services

I2C Service Names

Service names	Accessible deviceIDs	Service used by sysmodule
"i2c::MCU"	0, 3	MCU
"i2c::CAM"	1, 2, 4	Camera
"i2c::LCD"	5, 6	GSP
"i2c::DEB"	7, 8	dmnt
"i2c::HID"	9, 10, 11, 12	HID
"i2c::IR"	13, and additionally for New3DS i2c module: 17	IR
"i2c::EEP"	14	Cfg
New3DS-sysmodule specific services:
"i2c::NFC"	15	New3DS NFC
"i2c::QTM"	16	New3DS QTM

Each I2C service can only access certain I2C device(s).

Commands

Command Header	Description	Available since system-version
0x00010100	ReplaceRegisterBits8	All
0x000200C0	SetRegisterBits8	All
0x000300C0	ClearRegisterBits8	All
0x00040102	MultiReplaceRegisterBits16	All
0x000500C0	WriteRegister8	All
0x00060080	WriteDeviceRaw8	All
0x000700C0	WriteRegister16	All
0x000800C2	MultiWriteRegister16	All
0x00090080	ReadRegister8	All
0x000A0080	ReadRegister16	All
0x000B00C2	WriteRegisters8	All
0x000C00C2	WriteRegisters16	All
0x000D00C0	ReadRegisters8	All
0x000E00C2	WriteRegisters8_2	All
0x000F00C0	LegacyReadRegisters8	All
0x001000C0	ReadRegisters16	All
0x001100C2	WriteRegistersBuffer8	All
0x001200C2	ReadRegistersBuffer8	All
and, for the New3DS-specific version of the sysmodule (though technically the Old3DS supports these commands as well):
0x00130040	ReadDeviceRaw8	8.0.0-18
0x00140082	WriteDeviceRaw	8.0.0-18
0x00150080	ReadDeviceRaw	8.0.0-18

Commands 0x00140082 and 0x00150080 are used by NFC module.

Command 0x00150080 is also used for reading ZL, ZR, and C-stick data by IR Services.

Common Result Values

Result code	Description
0xE0A02FEA	The current session is not permitted to access the specified device ID.
0xF9602FEF	Communication error. Device may not be connected.