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I²C Bus

I²C (Inter-Integrated Circuit) is a synchronous, multi-controller/multi-target bus used for communication between sensors, chips, etc.

TOWER uses I²C Bus for a lot of sensor communication. Down below, you can find a list of I²C addresses that TOWER uses.


Most of the sensors work with their specific SDK modules so you will most likely not encounter I²C-specific functions if you don't develop some driver for a new sensor or a chip.


There is a separate chapter on how to work with I²C SDK Module

Examples of I²C bus usage in TOWER:

I²C Buses on the Core Module

There are two buses on the Core Module. They are called:

  • TWR_I2C_I2C0 - Using SDA0 and SCL0 (17, 18) pins in the bottom right corner of the Core Module
  • TWR_I2C_I2C1 - Using SDA1 and SCL1 (27, 28) pins in the top right corner of the Core Module

TOWER I²C Address Space

The following table lists the I²C addresses used across the TOWER


All addresses are provided in a 7-bit format.


Addresses 0x00-0x07 and 0x78-0x7F are I²C reserved addresses and cannot be used.

AddressChipTOWER productRemark
0x08NT3H2011NFC TagChanged from default to avoid collision
0x19LIS2DH12Core ModuleChannel I2C0
0x20TCA9534IQRF Module
0x21TCA9534GPS Module
0x22TCA9534RFID Module
0x23TCA9534Infragrid Module
0x24TCA9534Ethernet Module
0x25TCA9534Audio Module
0x38TCA9534ACO2 Module
0x3bTCA9534ARelay ModuleDefault address
0x3cTCA9534ALCD Module
0x3eTCA9534ASensor ModuleDefault address
0x3fTCA9534ARelay ModuleAlternate address
0x40SHT20Humidity Tag (R3.x+)
Climate Module
0x40HDC2080Humidity Tag (R2.x)Default address
0x41HDC2080Humidity Tag (R2.x)Alternate address
0x44OPT3001Lux Meter Tag
Climate Module
Default address
0x45OPT3001Lux Meter TagAlternate address
0x48TMP112Temperature Tag
Climate Module
Default address
0x49TMP112Temperature TagAlternate address
0x49TMP112Core ModuleChannel I2C0
0x4bTLA2021RS-485 Module ADCChannel I2C0
0x4dSC16IS740CO2 Module
I2C to UART bridge
Channel I2C0
0x4eSC16IS750RS-485 Module I2C to UART bridgeChannel I2C0
0x4fSC16IS750RS-232 Module I2C to UART bridgeChannel I2C0
0x58SGP30VOC TagDefault address
0x5fHTS221Humidity Tag (R1.x)
0x60MPL3115A2Barometer Tag
Climate Module
0x64ATSHA204ARadio DongleChannel I2C0
0x64ATSHA204ARadio DongleChannel I2C1