1649-1106-ND

Datasheet SPS30 Particulate Matter Sensor for Air Quality Monitoring and Control ▪ Unique long-term stability ▪ Advanced particle size binning ▪ Superior precision in mass concentration and number concentration sensing ▪ Small, ultra-slim package ▪ Fully calibrated digital output Product Summary The SPS30 Particulate Matter (PM) sensor is a technological breakthrough in optical PM sensors. Its measurement principle is based on laser scattering and makes use of Sensirion’s innovative contaminationresistance technology. This technology, together with high-quality and long-lasting components, enables precise measurements from its first operation and throughout its lifetime of more than ten years. In addition, Sensirion’s advanced algorithms provide superior precision for different PM types and higher-resolution particle size binning, opening up new possibilities for the detection of different sorts of environmental dust and other particles. With dimensions of only 41 x 41 x 12 mm3, it is also the perfect solution for applications where size is of paramount importance, such as wall-mounted or compact air quality devices. Content 1 Particulate Matter Sensor Specifications 2 2 Electrical Specifications 3 3 Hardware Interface Specifications 4 4 Functional Overview 5 5 Operation and Communication through the UART Interface 6 Operation and Communication through the I2C Interface 8 16 7 Mechanical Specifications 23 8 Shipping Package 24 9 Ordering Information 24 10 Revision History 24 11 Important Notices 25 12 Headquarters and Subsidiaries 26 www.sensirion.com Version 1.0 – D1 – March 2020 1/26 1 Particulate Matter Sensor Specifications 1.1 Specification Overview Parameter Mass concentration range Mass concentration size range ±10 Units μg/m3 μm μm μm μm μg/m3 ±10 % m.v. ±25 μg/m3 100 to 1000 μg/m3 ±25 % m.v. Maximum long-term mass concentration precision limit drift 0 to 100 μg/m3 ±1.25 μg/m3 / year 100 to 1000 μg/m3 % m.v. / year Number concentration range Number concentration size range PM0.5 PM1.0 PM2.5 PM4 PM10 0 to 1000 #/cm3 ±1.25 0 to 3’000 0.3 to 0.5 0.3 to 1.0 0.3 to 2.5 0.3 to 4.0 0.3 to 10.0 Mass concentration precision 1,2 for PM1 and PM2.5 3 Conditions PM1.0 PM2.5 PM4 PM10 0 to 100 μg/m3 100 to 1000 Mass concentration precision1,2 for PM4, PM10 4 0 to 100 Number concentration precision1,2 for PM0.5, PM1 and PM2.53 Number concentration precision1,2 for PM4, μg/m3 μg/m3 1000 to 3000 PM104 Value 0 to 1’000 0.3 to 1.0 0.3 to 2.5 0.3 to 4.0 0.3 to 10.0 0 to 1000 #/cm3 #/cm3 1000 to 3000 #/cm3 Maximum long-term number concentration precision 0 to 1000 #/cm3 limit drift2 1000 to 3000 #/cm3 Sampling interval Typical start-up time 5 Sensor output characteristics Lifetime 6 Acoustic emission level Long term acoustic emission level drift Additional T-dependent mass and number concentration precision limit drift2 Weight number concentration 200 – 3000 100 – 200 #/cm3 50 – 100 #/cm3 PM2.5 mass concentration PM2.5 number concentration 24 h/day operation 0.2 m max. 0.2 m max. temperature typ. difference to 25°C - #/cm3 ±100 #/cm3 μm μm μm μm μm #/cm3 ±10 % m.v. ±250 #/cm3 ±25 % m.v. ±12.5 #/cm3 / year ±1.25 % m.v. / year s 1±0.04 8 s 16 s 30 s Calibrated to TSI DustTrak™ DRX 8533 Ambient Mode Calibrated to TSI OPS 3330 > 10 years 25 dB(A) +0.5 dB(A) / year % m.v. / °C ±0.5 26.3 ±0.3 g 1 Also referred to as “between-parts variation” or “device-to-device variation”. For further details, please refer to the document “Sensirion Particulate Matter Sensor Specification Statement”. 3 Verification Aerosol for PM2.5 is a 3% atomized KCl solution. Deviation to reference instrument is verified in end-tests for every sensor after calibration. 4 PM4 and PM10 output values are calculated based on distribution profile of all measured particles. 5 Time after starting Measurement-Mode, until a stable measurement is obtained. 6 Lifetime is based on mean-time-to-failure (MTTF) calculation. Lifetime might vary depending on different operating conditions. 2 www.sensirion.com Version 1.0 – D1 – March 2020 2/26 Laser wavelength (DIN EN 60825-1 Class 1) typ. 660 nm Table 1: Particulate matter sensor specifications. Default conditions of 25±2 °C, 50±10% relative humidity and 5 V supply voltage apply unless otherwise stated. ‘max.’ means ‘maximum’, ‘typ.’ means ‘typical’, ‘% m.v.’ means ‘% of measured value’. 1.2 Recommended Operating Conditions The sensor shows best performance when operated within recommended normal temperature and humidity range of 10 to 40 °C and 20 to 80 % RH, respectively. 2 Electrical Specifications 2.1 Electrical Characteristics Parameter Supply voltage Supply current Input high level voltage (VIH) Input low level voltage (VIL) Output high level voltage (VOH) Output low level voltage (VOL) Conditions Sleep-Mode Idle-Mode Measurement-Mode Measurement-Mode, first 200ms (fan start) - Min 4.5 300 45 2.31 0 2.9 0 Typ 5.0 38 330 55 3.3 0 Max 5.5 50 360 65 80 5.5 0.99 3.37 0.4 Unit V µA mA V Table 2: Electrical specifications at 25°C. 2.2 Absolute Minimum and Maximum Ratings Stress levels beyond those listed in Table 3 may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these conditions cannot be guaranteed. Exposure to the absolute maximum rating conditions for extended periods may affect the reliability of the device. Parameter Supply voltage VDD Interface Select SEL I/O pins (RX/SDA, TX/SCL) Max. current on any I/O pin Operating temperature range Storage temperature range Operating humidity range Min -0.3 -0.3 -0.3 -16 -10 -40 0 Max 5.5 4.0 5.5 16 60 70 95 Unit V mA °C % RH Table 3: Absolute minimum and maximum ratings. www.sensirion.com Version 1.0 – D1 – March 2020 3/26 2.3 ESD / EMC Ratings Immunity (Industrial level) Description Electro Static Discharge Power-Frequency Magnetic Field Radio-Frequency EM-Field AM-modulated Radio-Frequency EM-Field AM-modulated Standard IEC 61000-4-2 IEC 61000-4-8 IEC 61000-4-3 IEC 61000-4-3 Rating ±4 kV contact, ±8 kV air 30A/m, 50Hz and 60Hz 80MHz - 1000MHz, 10V/m, 80% AM @1kHz 1.4GHz – 6GHz, 3V/m, 80% AM @1kHz Standard IEC/CISPR 16 IEC/CISPR 16 IEC/CISPR 16 IEC/CISPR 16 Rating 40dB(µV/m) QP @3m 47dB(µV/m) QP @3m 70dB(µV/m) P, 50dB(µV/m) AP @3m 74dB(µV/m) P, 54dB(µV/m) AP @3m Emission (Residential level) Description Emission in SAC for 30MHz to 230MHz Emission in SAC for 230MHz to 1000MHz Emission in SAC for 1GHz to 3GHz Emission in SAC for 3GHz to 6GHz 3 Hardware Interface Specifications The interface connector is located at the side of the sensor opposite to the air inlet/outlet. Corresponding female plug is ZHR-5 from JST Sales America Inc. In Figure 1 a description of the pin layout is given. Pin 1 Pin Name Description Comments 1 VDD Supply voltage 5V ± 10% UART: Receiving pin for communication 2 I C: Serial data input / output TTL 5V and LVTTL 3.3V compatible UART: Transmitting pin for communication 2 I C: Serial clock input TTL 5V and LVTTL 3.3V compatible 2 Pin 5 3 Figure 1: The communication interface connector is located at the side of the sensor opposite to the air outlet. RX SDA TX SCL 4 SEL Interface select Leave floating to select UART Pull to GND to select I2C 5 GND Ground Housing on GND Table 4 SPS30 pin assignment. The SPS30 offers both a UART 7 and an I2C interface. For connection cables longer than 20 cm we recommend using the UART interface, due to its intrinsic robustness against electromagnetic interference. Note, that there is an internal electrical connection between GND pin (5) and metal shielding. Keep this metal shielding electrically floating in order to avoid any unintended currents through this internal connection. If this is not an option, proper external potential equalization between GND pin and any potential connected to the shielding is mandatory. Any current though the connection between GND and metal shielding may damage the product and poses a safety risk through overheating. 7 Universal Asynchronous Receiver Transmitter. www.sensirion.com Version 1.0 – D1 – March 2020 4/26 4 Functional Overview 4.1 Operating Modes Power on / Reset Measurement 45 - 65 mA 1s Start Measurement Stop Measurement Idle ~ 330 µA Sleep Wake-Up Sleep < 50 µA Idle • • • • After power on or reset the module is in Idle-Mode. Most of the internal electronics switched off /reduced power consumption. Fan and laser are switched off. The module is ready to receive and process any command. Measurement • • • • The Measurement-Mode can only be entered from Idle-Mode. All electronics switched on / max. power consumption. The measurement is running and the module is continuously processing measurement data. New readings are available every second. Sleep • • • • • • The Sleep-Mode can only be entered from Idle-Mode. Most of the internal electronics switched off / reduced power consumption. Fan and laser are switched off. Microcontroller is in Sleep-Mode. To minimize power consumption, the UART / I2C interface is also disabled. A wake-up sequence is needed to turn the module back on. See Wake-up command in the interface description. 4.2 Fan Auto Cleaning When the module is in Measurement-Mode an automatic fan-cleaning procedure will be triggered periodically following a defined cleaning interval. This will accelerate the fan to maximum speed for 10 seconds in order to blow out the dust accumulated inside the fan. • • • • • • • Measurement values are not updated while the fan-cleaning is running. The default cleaning interval is set to 604’800 seconds (i.e., 168 hours or 1 week) with a tolerance of ±3%. The interval can be configured using the Set Automatic Cleaning Interval command. Set the interval to 0 to disable the automatic cleaning. Once set, the interval is stored permanently in the non-volatile memory. If the sensor is switched off, the time counter is reset to 0. Make sure to trigger a cleaning cycle at least every week if the sensor is switched off and on periodically (e.g., once per day). The cleaning procedure can also be started manually with the Start Cleaning command. www.sensirion.com Version 1.0 – D1 – March 2020 5/26 4.3 Measurement Output Formats The measurement results can be read with the “Read Measured Values” command. The returned data structure depends on the selected output format. The output format must be specified when stating the measurement with the “Start Measurement command”. IEEE754 float values Byte # SHDLC I2C 0..3 0..5 4..7 6..11 8..11 12..17 12..15 18..23 16..19 24..29 20..23 30..35 24..27 36..41 28..31 42..47 32..35 48..53 36..39 54..59 Datatype Description big-endian float IEEE754 Mass Concentration PM1.0 [µg/m³] Mass Concentration PM2.5 [µg/m³] Mass Concentration PM4.0 [µg/m³] Mass Concentration PM10 [µg/m³] Number Concentration PM0.5 [#/cm³] Number Concentration PM1.0 [#/cm³] Number Concentration PM2.5 [#/cm³] Number Concentration PM4.0 [#/cm³] Number Concentration PM10 [#/cm³] Typical Particle Size 8 [µm] Unsigned 16-bit integer values 9 Byte # SHDLC I2C 0..1 0..2 2..3 3..5 4..5 6..8 6..7 9..11 8..9 12..14 10..11 15..17 12..13 18..20 14..15 21..23 16..17 24..26 18..19 27..29 Datatype Description big-endian unsigned 16-bit integer Mass Concentration PM1.0 [µg/m³] Mass Concentration PM2.5 [µg/m³] Mass Concentration PM4.0 [µg/m³] Mass Concentration PM10 [µg/m³] Number Concentration PM0.5 [#/cm³] Number Concentration PM1.0 [#/cm³] Number Concentration PM2.5 [#/cm³] Number Concentration PM4.0 [#/cm³] Number Concentration PM10 [#/cm³] Typical Particle Size8 [nm] 8 The typical particle size (TPS) gives an indication on the average particle diameter in the sample aerosol. Such output correlates with the weighted average of the number concentration bins measured with a TSI 3330 optical particle sizer. Consequently, lighter aerosols will have smaller TPS values than heavier aerosols. 9 Requires at least firmware version 2.0 www.sensirion.com Version 1.0 – D1 – March 2020 6/26 4.4 Device Status Register The Device Status Register is a 32-bit register that contains information about the internal state of the module. 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 res. res. res. res. res. 3 2 1 0 res. res. res. res. Warning res. res. res. res. res. res. res. res. res. res. 15 14 13 12 11 10 9 8 7 6 res. res. Note: res. res. res. res. res. res. res. res. SPEED 5 4 Error Error LASER FAN All “res.” bits are reserved for internal use or future versions. These bits can be both 0 and 1 and should therefore be ignored. Bit 21 SPEED: Fan speed out of range 0: Fan speed is ok. 1: Fan speed is too high or too low. • During the first 3 seconds after starting the measurement (fan start-up) the fan speed is not checked. • The fan speed is also not checked during the auto cleaning procedure. • Apart from the two exceptions mentioned above, the fan speed is checked once per second in the measurement mode. If it is out of range twice in succession, the SPEED-bit is set. • At very high or low ambient temperatures, the fan may take longer to reach its target speed after start-up. In this case, the bit will be set. As soon as the target speed is reached, this bit is cleared automatically. • If this bit is constantly set, this indicates a problem with the power supply or that the fan is no longer working properly. Bit 5 LASER: Laser failure 0: Laser current is ok. 1: Laser is switched on and current is out of range. • The laser current is checked once per second in the measurement mode. If it is out of range twice in succession, the LASER-bit is set. • If the laser current is back within limits, this bit will be cleared automatically. • A laser failure can occur at very high temperatures outside of specifications or when the laser module is defective. Bit 4 FAN: Fan failure, fan is mechanically blocked or broken. 0: Fan works as expected. 1: Fan is switched on, but the measured fan speed is 0 RPM. • The fan is checked once per second in the measurement mode. If 0 RPM is measured twice in succession, the FAN bit is set. • The FAN-bit will not be cleared automatically. • A fan failure can occur if the fan is mechanically blocked or broken. www.sensirion.com Version 1.0 – D1 – March 2020 7/26 5 Operation and Communication through the UART Interface VDD The following UART settings have to be used: • Baud Rate: 115’200 bit/s • Data Bits: 8 • Parity: None • Stop Bit: 1 VDD (1) Master TX RX (2) Master RX TX (3) NC SPS30 Connector SEL (4) GND (5) Figure 2: Typical UART application circuit. 5.1 Physical Layer The SPS30 has separate RX and TX lines with unipolar logic levels. See Figure 3. Bit Time (1/Baudrate) Start Bit Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Stop Bit Figure 3: Transmitted byte. 5.2 SHDLC Frame Layer On top of the UART interface, the SPS30 uses the very powerful and easy-to-implement SHDLC 10 protocol. It is a serial communication protocol based on a master/slave architecture. The SPS30 acts as the slave device. Data is transferred in logical units called frames. Every transfer is initiated by the master sending a MOSI 11 frame. The slave will respond to the MOSI frame with a slave response, or MISO 12 frame. The two types of frames are shown in Figure 4. Frame Content MOSI Frame Start (0x7E) L ADR CMD (1 Byte) (1 Byte) (1 Byte) TX Data 0...255 Bytes CHK (1 Byte) Stop (0x7E) Frame Content MISO Frame Start (0x7E) ADR CMD State L (1 Byte) (1 Byte) (1 Byte) (1 Byte) RX Data 0...255 Bytes CHK (1 Byte) Stop (0x7E) Figure 4: MOSI and MISO frames structure. 10 Sensirion High-Level Data Link Control. Master Out Slave In. Frame direction from master to slave. 12 Master In Slave Out. Frame direction from slave to master. 11 www.sensirion.com Version 1.0 – D1 – March 2020 8/26 Start/Stop Byte and Byte-Stuffing The 0x7E character is sent at the beginning and at the end of the frame to signalize frame start and stop. If this byte (0x7E) occurs anywhere else in the frame, it must be replaced by two other bytes (byte-stuffing). This also applies to the characters 0x7D, 0x11 and 0x13. Use Table 5 for byte-stuffing. Original data byte Transferred data bytes 0x7E 0x7D, 0x5E 0x7D 0x7D, 0x5D 0x11 0x7D, 0x31 0x13 0x7D, 0x33 Table 5 Reference table for byte-stuffing. Example: Data to send = [0x43, 0x11, 0x7F]  Data transmitted = [0x43, 0x7D, 0x31, 0x7F]. Address The slave device address is always 0. Command In the MOSI frame the command tells the device what to do with the transmitted data. In the MISO frame, the slave just returns the received command. Length Length of the “TX Data” or “RX Data” field (before byte-stuffing). State The MISO frame contains a state byte, which allows the master to detect communication and execution errors. b7 Error-Flag b6 Execution error code b0 Figure 5: Status byte structure. The first bit (b7) indicates that at least one of the error flags is set in the Device Status Register. The “Execution error code” signalizes all errors which occur while processing the frame or executing the command. The following table shows the error codes which can be reported from the device. Note that some of these errors are system internal errors which require additional knowledge to be understood. In case of a problem, they will help Sensirion to localize and solve the issue. Error Code dec hex 0 0x00 1 0x01 2 0x02 3 0x03 4 0x04 40 0x28 67 0x43 Meaning No error Wrong data length for this command (too much or little data) Unknown command No access right for command Illegal command parameter or parameter out of allowed range Internal function argument out of range Command not allowed in current state Table 6 Reference table for error codes. www.sensirion.com Version 1.0 – D1 – March 2020 9/26 Data The data has a usable size of [0…255] bytes (original data, before byte-stuffing). The meaning of the data content depends on the command. Checksum The checksum is built before byte-stuffing and checked after removing stuffed bytes from the frame. The checksum is defined as follows: 1. Sum all bytes between start and stop (without start and stop bytes). 2. Take the least significant byte of the result and invert it. This will be the checksum. For a MOSI frame use Address, Command, Length and Data to calculate the checksum. For a MISO frame use Address, Command, State, Length and Data to calculate the checksum. Example (MOSI frame without start/stop and without byte-stuffing): Adr CMD L Tx Data 2 Bytes CHK 0x00 0x00 0x02 0x01, 0x03 0xF9 The checksum is calculated as follows: Adr CMD L Data 0 Data 1 0x00 0x00 0x02 0x01 0x03 Sum 0x06 Least Significant Byte of Sum 0x06 Inverted (=Checksum) 0xF9 5.3 SHDLC Commands The following table shows an overview of the available SHDLC commands. CMD 0x00 0x01 0x03 0x10 0x11 0x56 0x80 0xD0 0xD1 0xD2 0xD3 Command Start Measurement Stop Measurement Read Measured Value Sleep Wake-up Start Fan Cleaning Read/Write Auto Cleaning Interval Device Information Read Version Read Device Status Register Reset Read / Write / Execute Execute Execute Read Execute Execute Execute Read / Write Read Read Read Execute max. Response Time 20 ms 20 ms 20 ms 5 ms 5 ms 20 ms 20 ms 20 ms 20 ms 20 ms 20 ms min. required Firmware V1.0 V1.0 V1.0 V2.0 V2.0 V1.0 V1.0 V1.0 V1.0 V2.2 V1.0 Table 7 Reference table for SHDLC commands. www.sensirion.com Version 1.0 – D1 – March 2020 10/26 5.3.1 Start Measurement (CMD: 0x00) Starts the measurement 13. After power up, the module is in Idle-Mode. Before any measurement values can be read, the Measurement-Mode needs to be started using this command. MOSI Data: Byte # Datatype 0 uint8 1 uint8 Description Subcommand, this value must be set to 0x01 Measurement Output Format: 0x03: Big-endian IEEE754 float values 0x05: Big-endian unsigned 16-bit integer values MISO Data: No data. Example Frames: Start measurement with output format “Big-endian IEEE754 float values”: 0x7E 0x00 0x00 0x02 0x01 0x03 0xF9 0x7E Empty response frame: 0x7E 0x00 0x00 0x00 0x00 0xFF 0x7E MOSI MISO 5.3.2 Stop Measurement (CMD: 0x01) Stops the measurement 14. Use this command to return to the initial state (Idle-Mode). MOSI Data: No data. MISO Data: No data. Example Frames: MOSI 0x7E 0x00 0x01 0x00 0xFE 0x7E Empty response frame: 0x7E 0x00 0x01 0x00 0x00 0xFE 0x7E MISO 5.3.3 Read Measured Values (CMD: 0x03) Reads the measured values from the module. This command can be used to poll for new measurement values. The measurement interval is 1 second. MOSI Data: No data. MISO Data: If no new measurement values are available, the module returns an empty response frame. If new measurement values are available, the response frame contains the measurement results. The data format depends on the selected output format, see 4.3 Measurement Output Formats. Example Frames: MOSI 13 14 0x7E 0x00 0x03 0x00 0xFC 0x7E This command can only be executed in Idle-Mode. This command can only be executed in Measurement-Mode. www.sensirion.com Version 1.0 – D1 – March 2020 11/26 Empty response frame: 0x7E 0x00 0x03 0x00 0x00 0xFC 0x7E MISO Or response frame with new measurement values: 0x7E 0x00 0x03 0x00 0x28 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0xD4 0x7E 5.3.4 Sleep (CMD: 0x10) 15 Enters the Sleep-Mode with minimum power consumption. This will also deactivate the UART interface, note the wakeup sequence described at the Wake-up command. MOSI Data: No data. MISO Data: No data. Example Frames: MOSI MISO 0x7E 0x00 0x10 0x00 0xEF 0x7E 0x7E 0x00 0x10 0x00 0x00 0xEF 0x7E 5.3.5 Wake-up (CMD: 0x11) Use this command to switch from Sleep-Mode to Idle-Mode. In Sleep-Mode the UART interface is disabled and must first be activated by sending a low pulse on the RX pin. This pulse is generated by sending a single byte with the value 0xFF. If then a Wake-up command follows within 100ms, the module will switch on again and is ready for further commands in the Idle-Mode. If the low pulse is not followed by the Wake-up command, the microcontroller returns to Sleep-Mode after 100ms and the interface is deactivated again. The Wake-up command can be sent directly after the 0xFF, without any delay. However, it is important that no other value than 0xFF is used to generate the low pulse, otherwise it’s not guaranteed the UART interface synchronize correctly. MOSI Data: No data. MISO Data: No data. Example Frames: MOSI MISO Send 0xFF to generate a low pulse in order to wake-up the interface: 0xFF Wake-up command, within 100ms: 0x7E 0x00 0x11 0x00 0xEE 0x7E 0x7E 0x00 0x11 0x00 0x00 0xEE 0x7E Alternatively, if the software implementation does not allow to send a single byte with the value 0xFF, the Wake-up command can be sent twice in succession. In this case the first Wake-up command is ignored, but causes the interface to be activated. 15 This command can only be executed in Idle-Mode. www.sensirion.com Version 1.0 – D1 – March 2020 12/26 First Wake-up command (just, activates the interface): 0x7E 0x00 0x11 0x00 0xEE 0x7E Second Wake-up command, within 100ms (this finally wakes up the module): 0x7E 0x00 0x11 0x00 0xEE 0x7E 0x7E 0x00 0x11 0x00 0x00 0xEE 0x7E MOSI MISO 5.3.6 Start Fan Cleaning (CMD: 0x56) Starts the fan-cleaning manually 16. For more details, note the explanations given in 4.2 Fan Auto Cleaning. MOSI Data: No data. MISO Data: No data. Example Frames: MOSI MISO 0x7E 0x00 0x56 0x00 0xA9 0x7E 0x7E 0x00 0x56 0x00 0x00 0xA9 0x7E 5.3.7 Read/Write Auto Cleaning Interval (CMD: 0x80) Reads/Writes the interval [s] of the periodic fan-cleaning. For more details, note the explanations given in 4.2 Fan Auto Cleaning. MOSI Data: Read Auto Cleaning Interval: Byte # Datatype 0 uint8 Description Subcommand, this value must be set to 0x00 Write Auto Cleaning Interval: Byte # Datatype 0 uint8 1..4 uint32 Description Subcommand, this value must be set to 0x00 Interval in seconds as big-endian unsigned 32-bit integer value. MISO Data: Read Auto Cleaning Interval: Byte # Datatype 0..3 uint32 Description Interval in seconds as big-endian unsigned 32-bit integer value. Write Auto Cleaning Interval: No data. Example Frames: MOSI MISO 16 Read Auto Cleaning Interval: 0x7E 0x00 0x80 0x01 0x00 0x7D 0x5E 0x7E Write Auto Cleaning Interval to 0 (disable): 0x7E 0x00 0x80 0x05 0x00 0x00 0x00 0x00 0x00 0x7A 0x7E Response frame for “Read Auto Cleaning Interval”: 0x7E 0x00 0x80 0x00 0x04 0x00 0x00 0x00 0x00 0x7B 0x7E Response frame for “Write Auto Cleaning Interval”: 0x7E 0x00 0x80 0x00 0x00 0x7F 0x7E This command can only be executed in Measurement-Mode. www.sensirion.com Version 1.0 – D1 – March 2020 13/26 5.3.8 Device Information (CMD 0xD0) This command returns the requested device information. It is defined as a string value with a maximum length of 32 ASCII characters (including terminating null character). MOSI Data: Byte # Datatype 0 uint8 Description This parameter defines which information is requested: 0x00: Product Type 0x01: Reserved 0x02: Reserved 0x03: Serial Number MISO Data: Byte # Datatype 0…n string Description Requested Device Information as null-terminated ASCII string. The size of the string is limited to 32 ASCII characters (including null character). Example Frames: Product Type: Recommended to use as product identifier, returns always the string “00080000” on this product. MOSI 0x7E 0x00 0xD0 0x01 0x00 0x2E 0x7E 0x7E 0x00 0xD0 0x00 0x09 0x30 0x30 0x30 0x38 0x30 0x30 0x30 0x30 0x00 0x9B 0x7E MISO Serial Number: MOSI 0x7E 0x00 0xD0 0x01 0x03 0x2B 0x7E 0x7E 0x00 0xD0 0x00 0x15 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x30 0x00 0x5A 0x7E MISO 5.3.9 Read Version (0xD1) Gets version information about the firmware, hardware, and SHDLC protocol. MOSI Data: No data. MISO Data: Byte # 0 1 2 3 4 5 6 17 Datatype uint8 uint8 uint8 uint8 uint8 uint8 uint8 Description Firmware major version Firmware minor version 17 Reserved: always 0 Hardware revision Reserved: always 0 SHDLC protocol major version SHDLC protocol minor version Firmware minor version may change without notice, given full backwards compatibility. www.sensirion.com Version 1.0 – D1 – March 2020 14/26 Example Frame: MOSI 0x7E 0x00 0xD1 0x00 0x2E 0x7E Firmware V2.1, Hardware V6, SHDLC V2.0: 0x7E 0x00 0xD1 0x01 0x07 0x02 0x01 0x00 0x06 0x00 0x02 0x00 0x1C 0x7E MISO 5.3.10 Read Device Status Register (0xD2) Use this command to read the Device Status Register. For more details, note the explanations given in 4.4 Device Status Register. Note: If one of the device status flags of type “Error” is set, this is also indicated in every SHDLC response frame by the Error-Flag in the state byte. MOSI Data: Byte # Datatype 0 uint8 Description 0: Do not clear any bit in the Device Status Register after reading. 1: Clear all bits in the Device Status Register after reading. MISO Data: Byte # Datatype 0…3 big-endian, uint32 4 uint8 Description Device Status Register Reserved for future use Example Frame: MOSI MISO 0x7E 0x00 0xD2 0x01 0x00 0x2C 0x7E 0x7E 0x00 0xD2 0x00 0x05 0x00 0x00 0x00 0x00 0x00 0x28 0x7E 5.3.11 Device Reset (CMD: 0xD3) Soft reset command. After calling this command, the module is in the same state as after a Power-Reset. The reset is executed after sending the MISO response frame. Note: To perform a reset when the sensor is in sleep mode, it is required to send first a wake-up sequence to activate the interface. MOSI Data: No data. MISO Data: No data. Example Frames: MOSI MISO 0x7E 0x00 0xD3 0x00 0x2C 0x7E 0x7E 0x00 0xD3 0x00 0x00 0x2C 0x7E www.sensirion.com Version 1.0 – D1 – March 2020 15/26 6 Operation and Communication through the I2C Interface Usage: • I2C address: 0x69 • Max. speed: standard mode, 100 kbit/s • Clock stretching: not used VDD Rp Rp SDA VDD (1) SDA (2) SCL SPS30 Connector SCL (3) SEL (4) GND (5) Both SCL and SDA lines are open drain I/Os. They should be connected to external pull-up resistors (e.g. Rp = 10 kΩ). Important notice: in order to correctly select I2C as interface, the interface select (SEL) pin must be pulled to GND before or at the same time the sensor is powered up. Figure 6: Typical I2C application circuit. Some considerations should be made about the use of the I2C interface. I2C was originally designed to connect two chips on a PCB. When the sensor is connected to the main PCB via a cable, particular attention must be paid to electromagnetic interference and crosstalk. Use as short as possible (< 10 cm) and/or well shielded connection cables. We recommend using the UART interface instead, whenever possible: it is more robust against electromagnetic interference, especially with long connection cables. For detailed information on the I2C protocol, refer to NXP I2C-bus specification 18. 6.1 Transfer Types Set Pointer Sets the 16-bit address pointer without writing data to the sensor module. It is used to execute commands, which do not require additional parameters. P P P P P P P P 7 6 5 4 3 2 1 0 ACK P P P P P P P P 15 14 13 12 11 10 9 8 ACK A6 A5 A4 A3 A2 A1 A0 ACK SDA Pointer Address Write I2C Header SCL 1 S 18 9 I2C Address W A 1 9 Pointer MSB 1 A 9 Pointer LSB A P http://www.nxp.com/documents/user_manual/UM10204.pdf www.sensirion.com Version 1.0 – D1 – March 2020 16/26 Set Pointer & Read Data Sets the 16-bit address pointer and read data from sensor module. It is used to read sensor module information or measurement results. The data is ready to read immediately after the address pointer is set. The sensor module transmits the data in 2-byte packets, which are protected with a checksum. D D D D D D D D 7 6 5 4 3 2 1 0 ACK A6 A5 A4 A3 A2 A1 A0 ACK Read Data 0 Read P P P P P P P P 7 6 5 4 3 2 1 0 ACK P P P P P P P P 15 14 13 12 11 10 9 8 ACK A6 A5 A4 A3 A2 A1 A0 ACK SDA I2C Header Pointer Address Write I2C Header ... ... SCL D D D D D D D D 7 6 5 4 3 2 1 0 9 Read Data (n-2) C C C C C C C C 7 6 5 4 3 2 1 0 ... ... 9 1 Read Data (n-1) D D D D D D D D 7 6 5 4 3 2 1 0 D D D D D D D D 7 6 5 4 3 2 1 0 Checksum C C C C C C C C 7 6 5 4 3 2 1 0 ... 1 S 1 Checksum ACK ... 9 NACK Read Data 1 1 ACK 9 ACK 1 ACK 9 1 9 I2C Address ... W A 1 9 Pointer MSB Data 1 A A 9 Pointer LSB Checksum 0 A A P ... S 1 9 Slave Address R A A Data (n-1) Data (n-2) 1 9 Data 0 A A ... Checksum A P It is allowed to read several times in succession without setting the address pointer again. This reduces the protocol overhead for periodical reading of the measured values. Set Pointer & Write Data Sets the 16-bit address pointer and writes data to the sensor module. It is used to execute commands, which require additional parameters. The data must be transmitted in 2-byte packets which are protected by a checksum. D D D D D D D D 7 6 5 4 3 2 1 0 C C C C C C C C 7 6 5 4 3 2 1 0 ACK D D D D D D D D 7 6 5 4 3 2 1 0 Checksum ACK P P P P P P P P 7 6 5 4 3 2 1 0 Write Data 1 ACK Write Data 0 ACK P P P P P P P P 15 14 13 12 11 10 9 8 ACK A6 A5 A4 A3 A2 A1 A0 ACK SDA Pointer Address Write I2C Header ... ... SCL 9 1 1 9 1 9 1 ... D D D D D D D D 7 6 5 4 3 2 1 0 1 Write Data (n-1) ACK Write Data (n-2) 9 D D D D D D D D 7 6 5 4 3 2 1 0 9 Checksum C C C C C C C C 7 6 5 4 3 2 1 0 ACK 9 ACK 1 ... 1 S Slave Address W A Pointer MSB A Pointer LSB ... www.sensirion.com A 9 1 9 1 9 ... Data 0 A Data 1 A Checksum A Data (n-2) A Data (n-1) A Checksum A P Version 1.0 – D1 – March 2020 17/26 6.2 Checksum Calculation The Read and Write Commands transmit the data in 2-byte packets, followed by an 8-bit checksum. The checksum is calculated as follows: Property Name Protected Data Width Polynomial Initialization Reflect Input Reflect Output Final XOR Example Value CRC-8 read and/or write data 8 bit 0x31 (x^8 + x^5 + x^4 + 1) 0xFF false false 0x00 CRC(0xBEEF) = 0x92 uint8_t CalcCrc(uint8_t data[2]) { uint8_t crc = 0xFF; for(int i = 0; i < 2; i++) { crc ^= data[i]; for(uint8_t bit = 8; bit > 0; --bit) { if(crc & 0x80) { crc = (crc