Datasheet SGP30 (Sensirion) - 8

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6 Operation and Communication
The SGP30 supports I2C fast mode. For detailed information on the I2C protocol, refer to NXP I2C-bus specification8. All SGP30 commands and data are mapped to a 16-bit address space. Additionally, data and commands are protected with a CRC checksum to increase the communication reliability. The 16-bit commands that are sent to the sensor already include a 3-bit CRC checksum. Data sent from and received by the sensor is always succeeded by an 8-bit CRC. In write direction it is mandatory to transmit the checksum, since the SGP30 only accepts data if it is followed by the correct checksum. In read direction it is up to the master to decide if it wants to read and process the checksum.
SGP30 Hex. Code
I2C address 0x58
Table 8
I2C device address. The typical communication sequence between the I2C master (e.g., a microcontroller in a host device) and the sensor is described as follows: 1. The sensor is powered up, communication is initialized 2. The I2C master periodically requests measurement and reads data, in the following sequence: a. I2C master sends a measurement command b. I2C master waits until the measurement is finished, either by waiting for the maximum execution time or by waiting for the expected duration and then poll data until the read header is acknowledged by the sensor (expected durations are listed in
Table 10
) c. I2C master reads out the measurement result
6.1 Power-Up and Communication Start
The sensor starts powering-up after reaching the power-up threshold voltage VDD,Min specified in
Table 3
. After reaching this threshold voltage, the sensor needs the time tPU to enter the idle state. Once the idle state is entered it is ready to receive commands from the master. Each transmission sequence begins with a START condition (S) and ends with a STOP condition (P) as described in the I2C- bus specification.
6.2 Measurement Communication Sequence
A measurement communication sequence consists of a START condition, the I2C write header (7-bit I2C device address plus 0 as the write bit) and a 16-bit measurement command. The proper reception of each byte is indicated by the sensor. It pulls the SDA pin low (ACK bit) after the falling edge of the 8th SCL clock to indicate the reception. With the acknowledgement of the measurement command, the SGP30 starts measuring. When the measurement is in progress, no communication with the sensor is possible and the sensor aborts the communication with a XCK condition. After the sensor has completed the measurement, the master can read the measurement results by sending a START condition followed by an I2C read header. The sensor will acknowledge the reception of the read header and responds with data. The response data length is listed in
Table 10
and is structured in data words, where one word consists of two bytes of data followed by one byte CRC checksum. Each byte must be acknowledged by the microcontroller with an ACK condition for the sensor to continue sending data. If the sensor does not receive an ACK from the master after any byte of data, it will not continue sending data. After receiving the checksum for the last word of data, an XCK and STOP condition have to be sent (see
Figure 12
). The I2C master can abort the read transfer with a XCK followed by a STOP condition after any data byte if it is not interested in subsequent data, e.g. the CRC byte or following data bytes, in order to save time. Note that the data cannot be read more than once, and access to data beyond the specified amount will return a pattern of 1s.
6.3 Measurement Commands
The available measurement commands of the SGP30 are listed in
Table 10
. www.sensirion.com Version 1.0 – May 2020 – D1 8/19 Document Outline 1 Sensor Performance 1.1 Gas Sensing Performance 1.2 Air Quality Signals 1.3 Recommended Operating and Storage Conditions 2 Electrical Specifications 3 Interface Specifications The SGP30 comes in a 6-pin DFN package, see Table 4. 4 Absolute Minimum and Maximum Ratings 5 Timing Specifications 5.1 Sensor System Timings 5.2 Communication Timings 6 Operation and Communication 6.1 Power-Up and Communication Start 6.2 Measurement Communication Sequence 6.3 Measurement Commands 6.4 Soft Reset 6.5 Get Serial ID 6.6 Checksum Calculation 6.7 Communication Data Sequences 7 Quality 7.1 Environmental Stability 7.2 Material Contents 8 Device Package 8.1 Moisture Sensitivity Level 8.2 Traceability 8.3 Package Outline 8.4 Landing Pattern 8.5 Soldering Instructions 9 Tape & Reel Package 10 Ordering Information Revision History Important Notices Warning, Personal Injury ESD Precautions Warranty Headquarters and Subsidiaries