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.

note

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.

info

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

Examples of I²C bus usage in TOWER:

• Temperature Tag
• Humidity Tag
• Climate Module

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

note

All addresses are provided in a 7-bit format.

info

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

Address	Chip	TOWER product	Remark
0x08	NT3H2011	NFC Tag	Changed from default to avoid collision
0x19	LIS2DH12	Core Module	Channel I2C0
0x20	TCA9534	IQRF Module
0x21	TCA9534	GPS Module
0x22	TCA9534	RFID Module
0x23	TCA9534	Infragrid Module
0x24	TCA9534	Ethernet Module
0x25	TCA9534	Audio Module
0x26	TCA9534		Reserved
0x27	TCA9534		Reserved
0x38	TCA9534A	CO2 Module
0x39	TCA9534A		Reserved
0x3a	TCA9534A		Reserved
0x3b	TCA9534A	Relay Module	Default address
0x3c	TCA9534A	LCD Module
0x3d	TCA9534A		Reserved
0x3e	TCA9534A	Sensor Module	Default address
0x3f	TCA9534A	Relay Module	Alternate address
0x40	SHT20	Humidity Tag (R3.x+) Climate Module
0x40	HDC2080	Humidity Tag (R2.x)	Default address
0x41	HDC2080	Humidity Tag (R2.x)	Alternate address
0x44	OPT3001	Lux Meter Tag Climate Module	Default address
0x45	OPT3001	Lux Meter Tag	Alternate address
0x48	TMP112	Temperature Tag Climate Module	Default address
0x49	TMP112	Temperature Tag	Alternate address
0x49	TMP112	Core Module	Channel I2C0
0x4b	TLA2021	RS-485 Module ADC	Channel I2C0
0x4d	SC16IS740	CO2 Module I2C to UART bridge	Channel I2C0
0x4e	SC16IS750	RS-485 Module I2C to UART bridge	Channel I2C0
0x4f	SC16IS750	RS-232 Module I2C to UART bridge	Channel I2C0
0x58	SGP30	VOC Tag	Default address
0x5f	HTS221	Humidity Tag (R1.x)
0x60	MPL3115A2	Barometer Tag Climate Module
0x64	ATSHA204A	Radio Dongle	Channel I2C0
0x64	ATSHA204A	Radio Dongle	Channel I2C1