Bosch Sensortec | BME680 Datasheet 1 | 53 BME680 Low power gas, pressure, temperature & humidity sensor BME680 - Datasheet Document revision 1.2 Document release date May 2019 Document number BST-BME680-DS001-02 Technical reference code(s) 0 273 141 229; 0 273 141 312 Notes Data and descriptions in this document are subject to change without notice. Product photos and pictures are for illustration purposes only and may differ from the real product appearance. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 2 | 53 BME680 Low power gas, pressure, temperature & humidity sensor The BME680 is a digital 4-in-1 sensor with gas, humidity, pressure and temperature measurement based on proven sensing principles. The sensor module is housed in an extremely compact metal-lid LGA package with a footprint of only 3.0 x 3.0 mm with a maximum height of 1.00 mm (0.93 0.07 mm). Its small dimensions and its low power consumption enable the integration in battery-powered or frequency-coupled devices, such as handsets or wearables. Typical applications * Indoor air quality * Home automation and control * Internet of things * Weather forecast * GPS enhancement (e.g. time-to-first-fix improvement, dead reckoning, slope detection) * Indoor navigation (change of floor detection, elevator detection) * Outdoor navigation, leisure and sports applications * Vertical velocity indication (rise/sink speed) Target Devices * Handsets such as mobile phones, tablet PCs, GPS devices * Wearables * Home weather stations * Smart watches * Home appliances * Navigation systems * Gaming, e.g. flying toys * IOT devices Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 3 | 53 Key features * Package * Digital interface * Supply voltage * * * * 3.0 mm x 3.0 mm x 0.93 mm metal lid LGA IC (up to 3.4 MHz) and SPI (3 and 4 wire, up to 10 MHz) VDD main supply voltage range: 1.71 V to 3.6 V VDDIO interface voltage range: 1.2 V to 3.6 V Current consumption 2.1 A at 1 Hz humidity and temperature 3.1 A at 1 Hz pressure and temperature 3.7 A at 1 Hz humidity, pressure and temperature 0.0912 mA for p/h/T/gas depending on operation mode 0.15 A in sleep mode Operating range -40+85 C, 0100% r.H., 3001100 hPa Individual humidity, pressure and gas sensors can be independently enabled/disabled The product is RoHS compliant, halogen-free, MSL1 Key parameters for gas sensor * Response time (33-63% ) * Power consumption * Output data processing < 1 s (for new sensors) < 0.1 mA in ultra-low power mode direct index for air quality (IAQ) output Key parameters for humidity sensor * Response time (0-63% ) * Accuracy tolerance * Hysteresis ~8 s 3% r.H. 1.5% r.H. Key parameters for pressure sensor * RMS Noise * Offset temperature coefficient 0.12 Pa, equiv. to 1.7 cm 1.3 Pa/K, equiv. to 10.9 cm at 1 C temperature change Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 4 | 53 Table of contents 1. Specification 7 1.1 General Electrical Specification ............................................................................................................................ 7 1.2 Gas sensor specification ....................................................................................................................................... 8 1.3 Humidity sensor specification.............................................................................................................................. 10 1.4 Pressure sensor specification ............................................................................................................................. 11 1.5 Temperature sensor specification ....................................................................................................................... 12 2. Absolute maximum ratings 13 3. Sensor usage 14 3.1 Sensor modes ..................................................................................................................................................... 14 3.2 Sensor configuration ........................................................................................................................................... 15 Quick start ........................................................................................................................................................ 15 Sensor configuration flow ................................................................................................................................. 16 3.3 Measurement flow ............................................................................................................................................... 17 Temperature measurement .............................................................................................................................. 17 Pressure measurement .................................................................................................................................... 18 Humidity measurement .................................................................................................................................... 19 IIR filter ............................................................................................................................................................. 21 Gas sensor heating and measurement ............................................................................................................ 21 3.4 Data readout........................................................................................................................................................ 22 Gas resistance readout .................................................................................................................................... 22 4. Software and use cases 24 4.1 BSEC software .................................................................................................................................................... 24 4.2 Indoor-air-quality ................................................................................................................................................. 26 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 5. Global memory map and register description 5 | 53 27 5.1 General remarks ................................................................................................................................................. 27 5.2 Memory map ....................................................................................................................................................... 28 5.3 Register description ............................................................................................................................................ 29 General control registers .................................................................................................................................. 29 Temperature, pressure and relative humidity control registers ........................................................................ 30 Gas control registers ........................................................................................................................................ 32 Data registers ................................................................................................................................................... 35 Status registers ................................................................................................................................................ 36 6. Digital interfaces 38 6.1 Interface selection ............................................................................................................................................... 38 6.2 IC Interface......................................................................................................................................................... 38 IC write ............................................................................................................................................................ 39 IC read ............................................................................................................................................................ 39 6.3 SPI interface ........................................................................................................................................................ 40 SPI write ........................................................................................................................................................... 40 SPI read ........................................................................................................................................................... 41 6.4 Interface parameter specification ........................................................................................................................ 41 General interface parameters .......................................................................................................................... 41 IC timings ........................................................................................................................................................ 42 SPI timings ....................................................................................................................................................... 43 7. Pin-out and connection diagram 44 7.1 Pin-out ................................................................................................................................................................. 44 7.2 Connection diagrams .......................................................................................................................................... 45 7.3 Package dimensions ........................................................................................................................................... 46 7.4 Landing pattern recommendation ....................................................................................................................... 47 7.5 Marking ................................................................................................................................................................ 48 Mass production devices.................................................................................................................................. 48 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 6 | 53 Engineering samples ........................................................................................................................................ 48 7.6 Soldering guidelines and reconditioning recommendations ............................................................................... 49 7.7 Mounting and assembly recommendations ........................................................................................................ 49 7.8 Environmental safety ........................................................................................................................................... 50 RoHS ................................................................................................................................................................ 50 Halogen content ............................................................................................................................................... 50 Internal package structure................................................................................................................................ 50 8. Legal disclaimer 51 8.1 Engineering samples ........................................................................................................................................... 51 8.2 Product use ......................................................................................................................................................... 51 8.3 Application examples and hints ........................................................................................................................... 51 9. Document history and modifications Modifications reserved |Data subject not change without notice | Printed in Germany 52 Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 7 | 53 1. Specification If not stated otherwise, * * * * * * all values are valid over the full voltage range, all minimum/maximum values are given for the full accuracy temperature range minimum/maximum values of drifts, offsets and temperature coefficients are 3 values over lifetime, typical values of currents and state machine timings are determined at 25 C, minimum/maximum values of currents are determined using corner lots over complete temperature range, and minimum/maximum values of state-machine timings are determined using corner lots over 0+65 C temperature range. Besides the general electrical specifications, the following tables are separated for the gas, pressure, humidity and temperature functions of the BME680. 1.1 General Electrical Specification Table 1: Electrical parameter specification OPERATING CONDITIONS BME680 1 Parameter Symbol Condition Min Typ Max Unit Supply Voltage Internal Domains 1 VDD ripple max. 50 mVpp 1.71 1.8 3.6 V Supply Voltage I/O Domain VDDIO 1.2 1.6 3.6 V Sleep current IDDSL 0.15 1 A Standby current (inactive period of normal mode) IDDSB 0.29 0.8 A Current during humidity measurement IDDH Max value at 85 C 340 450 A Current during pressure measurement IDDP Max value at -40 C 714 849 A Current during temperature measurement IDDT Max value at 85 C 350 Start-up time tstartup Time to first communication after both VDD > 1.58 V and VDDIO > 0.65 V 2 ms Power supply rejection ratio (DC) PSRR full VDD range 0.01 5 %r.H./V Pa/V Standby time accuracy tstandby 25 % 5 A The power efficiency, performance and heat dissipation scales with the applied supply voltage. The BME680 is optimized for 1.8 V. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 8 | 53 1.2 Gas sensor specification Table 2 lists the gas sensor specification. All the parameters are deduced from lab measurements under controlled environmental conditions, which are compliant to the ISO16000-29 standard "Test methods for VOC detectors". Detailed procedure to measure the gas sensor is available in the Application Note AN012: Measurement Instructions for Lab Environment. Referring to Chapter 4, a software solution (BSEC: Bosch Software Environmental Cluster) is available for the BME680. The software is carefully engineered to seamlessly work with the 4-in-1 integrated sensors inside the BME680. Based on an intelligent algorithm, the BSEC provides an index for air quality (IAQ) output. In principle, this output is in an index that can have values between 0 and 500 with a resolution of 1 to indicate or quantify the quality of the air available in the surrounding. Table 4 lists the IAQ system specification. The detailed classification and color coding of the IAQ index is described in Table 4. Furthermore, the BSEC solution supports different operation modes for the gas sensor to address the necessary power budget and update rate requirements of the end-application. Unless mentioned otherwise, the specifications are deduced from new sensors that have been operated for at least five days mainly in ambient air and consequently have the same history (i.e. same power mode and exposed to the same environment). Besides ethanol (EtOH) as a target test gas, the sensors are also tested with breath-VOC (b-VOC). The b-VOC mixture, as listed in Table 5, represents the most important compounds in an exhaled breath of healthy humans. The values are derived from several publications on breath analysis studies. The composition does not contain species which would chemically react to ensure that the mixture is stable for at least 6 months. Furthermore, the composition is also limited to species which can be manufactured in one mixture. Table 2: Gas sensor parameter specification Parameter Symbol Condition Operational range1 Supply Current during heater operation Peak Supply Current Average Supply Current (VDD 1.8 V, 25C) Response time 2 (brand-new sensors) Typ Max Unit -40 85 C 10 95 % r.H. IDD Heater target temperature 320 C, constant operation (VDD 1.8 V, 25C) 9 12 13 mA IPeak Occurs within first ms of switching on the hotplate 15 17 18 mA Ultra-low power mode 0.09 mA Low power mode 0.9 mA Continuous mode 12 mA 33-63% Ultra-low power mode 92 s 33-63% Low power mode 1.4 s 33-63% Continuous mode 0.75 s IDD,IAQ Resolution of gas sensor resistance measurement Noise in gas sensor resistance (RMS) Min 0.05 NR 0.08 1.5 0.11 % % 1 The sensors are electrically operable within this range. Actual performance may vary. Response time of unsoldered, brand-new sensors extracted from the sensors' resistance change in response to a 0.6-60 ppm step of EtOH and a 0.5-15 ppm step of b-VOC at 20 C, 50% r.H. and atmospheric pressure. 2 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 9 | 53 Table 3: IAQ system parameter specification 3 Parameter Symbol Condition Min Accuracy status 4 AXIAQ Android compatible 0 IAQ Resolution IAQrs IAQ Range IAQrg Sensor-to-sensor deviation 5 IAQS2S All operation modes 15% 15 IAQS2S Sensor-to-sensor deviation 15% 15 IAQdrift Drift at low & high concentrations 1% 4 Durability to siloxanes 6,7,8 Typ Max Unit 3 1 0 500 Table 4: Index for Air Quality (IAQ) classification and color-coding 9 IAQ Index 0 - 50 Air Quality Impact (long-term exposure) Suggested action Excellent Pure air; best for well-being No measures needed 51 - 100 Good No irritation or impact on well-being No measures needed 101 - 150 Lightly polluted Reduction of well-being possible Ventilation suggested 151 - 200 Moderately polluted More significant irritation possible Increase ventilation with clean air 201 - 2509 Heavily polluted Exposition might lead to effects like headache depending on type of VOCs optimize ventilation Severely polluted More severe health issue possible if harmful VOC present Contamination should be identified if level is reached even w/o presence of people; maximize ventilation & reduce attendance Extremely polluted Headaches, additional neurotoxic effects possible Contamination needs to be identified; avoid presence in room and maximize ventilation 251 - 350 > 351 3 IAQ parameters only apply for the combination of BME680 together with the Bosch Software Environmental Cluster (BSEC) solution (available separately, see Chapter 4) The accuracy status is equal to zero during the power-on stabilization times of the sensor and is equal to 3 when the sensor achieves best performance 5 Tested with 0.6-90 ppm of EtOH at 5-40 C, 20-80% r.H. and atmospheric pressure. Condition is valid after the calibration period of the BSEC algorithm. 6 Siloxanes are present in a typical indoor environment and can in principle perturb the metal-oxide-based gas sensor performance. 7 220 hours of 700 mg/m3 of octamethylcyclotetrasiloxane (D4) in ambient conditions (i.e. 20 C and 50% r.H.) simulates the amount of siloxanes in a typical indoor environment over more than 10 years. 4 8 9 Tested with 0.5-15 ppm of b-VOC at 20 C and 50% r.H. using continuous operation mode for 220 hours of 700 mg/m3 of octamethylcyclotetrasiloxane (D4). According to the guidelines issued by the German Federal Environmental Agency, exceeding 25 mg/m3 of total VOC leads to headaches and further neurotoxic impact on health. The BSEC software auto-calibrates the low and high concentrations applied during testing to IAQ of 25 and 250, respectively. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 10 | 53 Table 5: bVOC mixture with Nitrogen as carrier gas Molar fraction Compound Production tolerance Certified accuracy 5 ppm Ethane 20 % 5% 10 ppm Isoprene /2-methyl-1,3 Butadiene 20 % 5% 10 ppm Ethanol 20 % 5% 50 ppm Acetone 20 % 5% 15 ppm Carbon Monoxide 10 % 2% 1.3 Humidity sensor specification Table 6: Humidity parameter specification Parameter Symbol Condition Operating Range 10 Full accuracy range 1 Hz forced mode, temperature and humidity measurement Min Typ Max Unit -40 25 85 C 0 100 % r.H. 0 65 C 10 90 % r.H. 2.8 A 2.1 Supply Current IDD,H Absolute Accuracy AH 2080 % r.H., 25 C, including hysteresis 3 % r.H. Hysteresis 11 HH 109010 % r.H., 25C 1.5 % r.H. Nonlinearity 12 NLH 1090 % r.H., 25C 1.7 % r.H. Response time to complete 63% of step 13 0-63% N2 (dry) 90 % r.H., 25C 8 s Resolution RH 0.008 % r.H. Noise in humidity (RMS) NH Highest oversampling 0.01 % r.H. Long-term stability Hstab 1090 % r.H., 25C 0.5 % r.H./ year 10 When exceeding the operating range (e.g. for soldering), humidity sensing performance is temporarily degraded and reconditioning is recommended as described in Section 7.7. Operating range only for non-condensing environment. 11 For hysteresis measurement the sequence 0103050709070503010 % r.H. is used. The hysteresis is defined as the maximum difference between measurements at of the same humidity up / down branch and the averaged curve of both branches. 12 Non-linear contributions to the sensor data are corrected during the calculation of the relative humidity by the compensation formulas described in Section Error! Reference source not found.. 13 The air-flow in direction to the vent-hole of the device has to be dimensioned in a way that a sufficient air exchange inside to outside will be possible. To observe effects on the response time-scale of the device an air-flow velocity of approximately 1 m/s is needed. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 11 | 53 1.4 Pressure sensor specification Table 7: Pressure parameter specification Parameter Symbol Condition Min Typ Max Operating temperature range TA Operating pressure range operational -40 25 85 full accuracy 0 65 P full accuracy 300 1100 hPa Supply current IDD,LP 1 Hz forced mode, pressure and temperature, lowest power 4.2 A Temperature coefficient of offset 14 TCOP 2540 C, 900 hPa Ap, full 3001100 hPa 065C Absolute accuracy pressure Arel Relative accuracy pressure Resolution of pressure output data Noise in pressure 15 700900hPa, 2540 C, at constant humidity 9001100hPa C 1.3 Pa/K 10.9 cm/K 0.6 hPa 0.12 hPa Arel 2540 C, at constant humidity 0.12 hPa RP Highest oversampling 0.18 Pa Full bandwidth, highest oversampling 1.4 Pa 11 cm Reduced bandwidth, highest oversampling 0.2 Pa 1.7 cm NP,fullBW Solder drift 14 3.1 Unit Minimum solder height 50m Long-term stability 15 Pstab per year Possible sampling rate fsample_P Lowest oversampling, see chapter 3.3.2 -0.5 157 1.2 +2.0 hPa 1.0 hPa 182 Hz When changing temperature from 25 C to 40 C at constant pressure / altitude, the measured pressure / altitude will change by (15xTCOP). Long-term stability is specified in the full accuracy operating pressure range 065 C Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 12 | 53 1.5 Temperature sensor specification Table 8: Temperature parameter specification Parameter Symbol Condition Min Typ Max Unit Operating temperature range TA operational -40 25 85 C IDD,T 1 Hz forced mode, temperature measurement only 1.0 A AT,25 25 C 0.5 C AT,full 065 C 1.0 C Output resolution RT API output resolution 0.01 C RMS noise NT Lowest oversampling 0.005 C Supply current Absolute accuracy temperature 16 Temperature measured by the internal temperature sensor. This temperature value depends on the PCB temperature, sensor element self-heating and ambient temperature and is typically above ambient temperature. 16 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 13 | 53 2. Absolute maximum ratings The absolute maximum ratings are determined over the complete temperature range using corner lots. The values are provided in Table 9. Table 9: Absolute maximum ratings Parameter Condition Min Max Unit Voltage at any supply pin VDD and VDDIO pin -0.3 4.25 V -0.3 VDDIO + 0.3 V -45 +85 C 0 20 000 hPa HBM, at any pin 2 kV Machine model 200 V Voltage at any interface pin Storage temperature 65% r.H. Pressure ESD Condensation No power supplied Modifications reserved |Data subject not change without notice | Printed in Germany Allowed Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 14 | 53 3. Sensor usage 3.1 Sensor modes The sensor supports low-level power modes: sleep and forced mode. These modes can be selected using the mode<1:0> control register (see Section 5.3.1.3). The key differences between the modes are summarized in Table 10. After a power-up sequence, the sensor automatically starts in sleep mode. If the device is currently performing a measurement, execution of mode switching commands is delayed until the end of the currently running measurement period. It is important to note that, further mode change commands or other write commands to the control registers are ignored until the mode change command has been executed. All control registers should be set to the desired values before writing to the mode register. Table 10: Low-level operation modes Operation mode mode<1:0> Key features Sleep 00 * * No measurements are performed Minimal power consumption Forced mode 01 * * * Single TPHG cycle is performed Sensor automatically returns to sleep mode afterwards Gas sensor heater only operates during gas measurement In forced mode, temperature, pressure, humidity and gas conversion are performed sequentially. Such a measurement cycle is abbreviated as TPHG (Temperature, Pressure, Humidity and Gas) in the following descriptions. Up to 10 temperature setpoints and heating durations for the gas sensor hot plate can be stored in the sensor registers. In the following, these setpoints and the corresponding measurements are identified as G0 - G9.Figure 1 illustrates the handling of these measurement sequences and the gas sensor hot plate is heated for the forced mode. Figure 1: Sequence of ADC and gas sensor heater operation Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 15 | 53 3.2 Sensor configuration Quick start The sensor is configured by writing to a set of control registers (see Chapter 5 for a detailed list of all available registers and their descriptions). This section illustrates, with the help of a basic step-by-step example, how to configure the sensor for simple forced mode measurements with a single heater set-point. For a more detailed description of the measurement flow, please refer to Section 3.3. In this example, the sensor will be configured to use 2x oversampling for its temperature measurements, 16x oversampling for the pressure signal, and 1x oversampling for humidity. Moreover, the gas sensor hot plate will be configured to be heated for 100 ms at 300 C before the gas measurement is performed. First, the user must configure the oversampling settings for temperature, pressure and humidity by setting the control registers osrs_t<2:0> and osrs_h<2:0>, respectively. Supported settings range from 16x oversampling down to 0x, which is equivalent to skipping the corresponding sub-measurement. See Section 5.3.2 for further details. 1. Set humidity oversampling to 1x by writing 0b001 to osrs_h<2:0> 2. Set temperature oversampling to 2x by writing 0b010 to osrs_t<2:0> 3. Set pressure oversampling to 16x by writing 0b101 to osrs_p<2:0> It is highly recommended to set first osrs_h<2:0> followed by osrs_t<2:0> and osrs_p<2:0> in one write command (see Section 3.3). Next, the user shall set at least one gas sensor hot plate temperature set-point and heating duration. Up to 10 heating duration can be configured through the control registers gas_wait_x<7:0>, where x ranges from 0 to 9. See Section 5.3.3 for definition of register content. The corresponding heater set-points are stored in the registers res_heat_x<7:0>. Section 3.3.5 explains how to convert the target heater temperature, e.g. 300 C, into a register code. For forced mode operation, the used heater set point is selected by setting the control register nb_conv<3:0> to the heater profile to be used, e.g. to use gas_wait_0<7:0> and res_heat_0<7:0>, nb_conv<3:0> shall be set to 0x0. Finally, gas functionality shall be enabled by setting the run_gas_l bit to 1. 4. 5. 6. 7. Set gas_wait_0<7:0> to 0x59 to select 100 ms heat up duration Set the corresponding heater set-point by writing the target heater resistance to res_heat_0<7:0> Set nb_conv<3:0> to 0x0 to select the previously defined heater settings Set run_gas_l to 1 to enable gas measurements Now, a single forced mode measurement with the above settings can be triggered by writing 0b01 to mode<1:0>. For more details on data readout, please see Section 5.3.1.3. 8. Set mode<1:0> to 0b01 to trigger a single measurement. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 16 | 53 Sensor configuration flow Picture 2 illustrates which control registers must be set. For details on the individual control registers, please refer to Chapter 5. Moreover, details on the measurement flow for the individual modes can be found in Section 3.3. Forced Mode Select oversampling for T, P and H * Set osrs_x<2:0> Select IIR filter for temperature sensor * Set filter<2:0> Enable gas coversion * Set run_gas to 1 Select index of heater set-point * Set nb_conv <3:0> (indexing is zero-based) Define heater-on time * Convert duration to register code * Set gas_wait_x<7:0> (time base unit is ms) Set heater temperature * Convert temperature to register code * Set res_heat_x<7:0> Set mode to forced mode * Set mode<1:0> to 0b01 Picture 2: Sensor configuration flow Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 17 | 53 3.3 Measurement flow Referring to Figure 1, the BME680 measurement period consists of a temperature, pressure and humidity measurement with selectable oversampling. Moreover, it contains a heating phase for the gas sensor hot plate as well as a measurement of the gas sensor resistance. After the measurement period, the pressure and temperature data can be passed through an optional IIR filter, which removes short-term fluctuations. For humidity and gas, such a filter is not needed and has not been implemented. Temperature measurement Temperature measurement can be enabled or skipped. Skipping the measurement is typically not recommended since temperature information is used to compensate temperature influences in the other parameters. When enabled, several oversampling options exist. The temperature measurement is controlled by the osrs_t<2:0> setting which is detailed in Section 5.3.2.2. For the temperature measurement, oversampling is possible to reduce the noise. The resolution of the temperature data depends on the IIR filter (see Section 5.3.2.4) and the oversampling setting: * When the IIR filter is enabled, the temperature resolution is 20 bit * When the IIR filter is disabled, the temperature resolution is 16 + (osrs_t - 1) bit, e.g. 18 bit when osrs_t is set to `3' Using the variables listed in Table 11, the following code will calculate the compensated temperature value (in degrees Celsius). It is, however, recommended to use the sensor API available on github (Chapter 4) for a friendlier user experience. Floating point: var1 = (((double)temp_adc / 16384.0) - ((double)par_t1 / 1024.0)) * (double)par_t2; var2 = ((((double)temp_adc / 131072.0) - ((double)par_t1 / 8192.0)) * (((double)temp_adc / 131072.0) - ((double)par_t1 / 8192.0))) * ((double)par_t3 * 16.0); t_fine = var1 + var2; temp_comp = t_fine / 5120.0; Integer: var1 = ((int32_t)temp_adc >> 3) - ((int32_t)par_t1 << 1); var2 = (var1 * (int32_t)par_t2) >> 11; var3 = ((((var1 >> 1) * (var1 >> 1)) >> 12) * ((int32_t)par_t3 << 4)) >> 14; t_fine = var2 + var3; temp_comp = ((t_fine * 5) + 128) >> 8; where * par_t1, par_t2 and par_t3 are calibration parameters, * temp_adc is the raw temperature output data, * temp_comp is the compensated temperature output data in degrees Celsius. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 18 | 53 Table 11: Variable names and register addresses for temp_comp calculation Variable name Register address (LSB / MSB) par_t1 0xE9 / 0xEA par_t2 0x8A / 0x8B par_t3 0x8C temp_adc 0x24<7:4> / 0x23 / 0x22 Pressure measurement Pressure measurement can be enabled or skipped. When enabled, several oversampling options exist. The pressure measurement is controlled by the osrs_p<2:0> setting which is detailed in Section 5.3.2. For the pressure measurement, oversampling is possible to reduce noise. The resolution of the pressure data depends on the IIR filter (see Section 5.3.2.4) and the oversampling setting: * When the IIR filter is enabled, the pressure resolution is 20 bit * When the IIR filter is disabled, the pressure resolution is 16 + (osrs_p - 1) bit, e.g. 18 bit when osrs_p is set to `3' Using the variables listed in Table 12, the following code will calculate the compensated pressure value (in Pascal). It is, however, recommended to use the sensor API available on github (Chapter 4) for a friendlier user experience. Floating point: var1 var2 var2 var2 var1 = = = = = ((double)t_fine / 2.0) - 64000.0; var1 * var1 * ((double)par_p6 / 131072.0); var2 + (var1 * (double)par_p5 * 2.0); (var2 / 4.0) + ((double)par_p4 * 65536.0); ((((double)par_p3 * var1_p * var1) / 16384.0) + ((double)par_p2 * var1_p)) / 524288.0; var1 = (1.0 + (var1 / 32768.0)) * (double)par_p1; press_comp = 1048576.0 - (double)press_adc; press_comp = ((press_comp - (var2_p / 4096.0)) * 6250.0) / var1; var1 = ((double)par_p9 * press_comp * press_comp) / 2147483648.0; var2 = press_comp * ((double)par_p8 / 32768.0); var3 = (press_comp / 256.0) * (press_comp / 256.0) * (press_comp / 256.0) * (par_p10 / 131072.0); press_comp = press_comp + (var1_p + var2_p + var3_p + ((double)par_p7 * 128.0)) / 16.0; Integer: var1 var2 var2 var2 var1 = = = = = ((int32_t)t_fine >> 1) - 64000; ((((var1 >> 2) * (var1 >> 2)) >> 11) * (int32_t)par_p6) >> 2; var2 + ((var1 * (int32_t)par_p5) << 1); (var2 >> 2) + ((int32_t)par_p4 << 16); (((((var1 >> 2) * (var1 >> 2)) >> 13) * ((int32_t)par_p3 << 5)) >> 3) + (((int32_t)par_p2 * var1) >> 1); Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 19 | 53 var1 = var1 >> 18; var1 = ((32768 + var1) * (int32_t)par_p1) >> 15; press_comp = 1048576 - press_raw; press_comp = (uint32_t)((press_comp - (var2 >> 12)) * ((uint32_t)3125)); if (press_comp >= (1 << 30)) press_comp = ((press_comp / (uint32_t)var1) << 1); else press_comp = ((press_comp << 1) / (uint32_t)var1); var1 = ((int32_t)par_p9 * (int32_t)(((press_comp >> 3) * (press_comp >> 3)) >> 13)) >> 12; var2 = ((int32_t)(press_comp >> 2) * (int32_t)par_p8) >> 13; var3 = ((int32_t)(press_comp >> 8) * (int32_t)(press_comp >> 8) * (int32_t)(press_comp >> 8) * (int32_t)par_p10) >> 17; press_comp = (int32_t)(press_comp) + ((var1 + var2 + var3 + ((int32_t)par_p7 << 7)) >> 4); where * par_p1, par_p2, ..., par_p10 are calibration parameters, * press_adc is the raw pressure output data, * press_comp is the compensated pressure output data in Pascal. Table 12: Variable names and register addresses for press_comp calculation Variable name Register address (LSB / MSB) par_p1 0x8E / 0x8F par_p2 0x90 / 0x91 par_p3 0x92 par_p4 0x94 / 0x95 par_p5 0x96 / 0x97 par_p6 0x99 par_p7 0x98 par_p8 0x9C / 0x9D par_p9 0x9E / 0x9F par_p10 0xA0 press_adc 0x21<7:4> / 0x20 / 0x1F Humidity measurement The humidity measurement can be enabled or skipped. When enabled, several oversampling options exist. The humidity measurement is controlled by the osrs_h<2:0> setting, which is described in detail in Section 5.3.2.1. For the humidity measurement, oversampling is possible to reduce noise. The resolution of the humidity measurement is fixed at 16 bit ADC output. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 20 | 53 Using the variables listed in Table 13, the following code will calculate the compensated humidity value (in percent). It is, however, recommended to use the sensor API available on github (Chapter 4) for a friendlier user experience. Floating point: var1 = hum_adc - (((double)par_h1 * 16.0) + (((double)par_h3 / 2.0) * temp_comp)); var2 = var1 * (((double)par_h2 / 262144.0) * (1.0 + (((double)par_h4 / 16384.0) * temp_comp) + (((double)par_h5 / 1048576.0) * temp_comp * temp_comp))); var3 = (double)par_h6 / 16384.0; var4 = (double)par_h7 / 2097152.0; hum_comp = var2 + ((var3 + (var4 * temp_comp)) * var2 * var2); Integer: temp_scaled = (int32_t)temp_comp; var1 = (int32_t)hum_adc - (int32_t)((int32_t)par_h1 << 4) - (((temp_scaled * (int32_t)par_h3) / ((int32_t)100)) >> 1); var2 = ((int32_t)par_h2 * (((temp_scaled * (int32_t)par_h4) / ((int32_t)100)) + (((temp_scaled * ((temp_scaled * (int32_t)par_h5) / ((int32_t)100))) >> 6) / ((int32_t)100)) + ((int32_t)(1 << 14)))) >> 10; var3 = var1 * var2; var4 = (((int32_t)par_h6 << 7) + ((temp_scaled * (int32_t)par_h7) / ((int32_t)100))) >> 4; var5 = ((var3 >> 14) * (var3 >> 14)) >> 10; var6 = (var4 * var5) >> 1; hum_comp = (var3 + var6) >> 12; hum_comp = (((var3 + var6) >> 10) * ((int32_t) 1000)) >> 12; where * par_h1, par_h2, ..., par_h7 are calibration parameters, * hum_adc is the raw humidity output data, * hum_comp is the compensated humidity output data in percent. Table 13: Variable names and register addresses for hum_comp calculation Variable name Register address (LSB / MSB) par_h1 0xE2<7:4> / 0xE3 par_h2 0xE2<7:4> / 0xE1 par_h3 0xE4 par_h4 0xE5 par_h5 0xE6 par_h6 0xE7 par_h7 0xE8 hum_adc 0x26 / 0x25 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 21 | 53 IIR filter The environmental pressure is subject to many short-term changes, caused external disturbances. To suppress disturbances (e.g. slamming of door or wind blowing into the sensor) in the output data without causing additional interface traffic and processor work load, the BME680 features an internal IIR filter (see Section 5.3.2.4). It effectively reduces the bandwidth of the temperature and pressure output signals and increases the resolution of the output data to 20 bit, noting that the humidity and gas values inside the sensor does not fluctuate rapidly and does not require low pass filtering. The output of a next measurement step is filtered using the following formula: [] = [ - 1] ( - 1) + [ - 1] is the data coming from the current filter memory, and is the data coming from current ADC acquisition. [] denotes the new value of filter memory and the value that will be sent to the output registers. The IIR filter can be configured to different filter coefficients, which slows down the response to the sensor inputs. Note that the response time with enabled IIR filter depends on the number of samples generated, which means that the data output rate must be known to calculate the actual response time. When writing to the register filter, the filter is reset. The next ADC values will pass through the filter unchanged and become the initial memory values for the filter. If temperature or pressure measurements are skipped, the corresponding filter memory will be kept unchanged even though the output registers are set to 0x80000. When the previously skipped measurement is re-enabled, the output will be filtered using the filter memory from the last time when the measurement was not skipped. If this is not desired, please write to the filter register in order to re-initialize the filter. Gas sensor heating and measurement The operation of the gas sensing part of BME680 involves two steps: 1. Heating the gas sensor hot plate to a target temperature (typically between 200 C and 400 C) and keep that temperature for a certain duration of time. 2. Measuring the resistance of the gas sensitive layer. Up to 10 different hot plate temperature set points can be configured by setting the registers res_heat_x<7:0>, where x = 0...9 .The internal heater control loop operates on the resistance of the heater structure. Hence, the user first needs to convert the target temperature into a device specific target resistance before writing the resulting register code into the sensor memory map. Using the variables listed Table 14: Variable names and register addresses for res_heat_x calculation, the following code will calculate register code that to be written to res_heat_x<7:0>. It is, however, recommended to use the sensor API available on github (Chapter 4) for a friendlier user experience. Floating point: var1 = ((double)par_g1 / 16.0) + 49.0; var2 = (((double)par_g2 / 32768.0) * 0.0005) + 0.00235; var3 = (double)par_g3 / 1024.0; var4 = var1 * (1.0 + (var2 * (double) target_temp)); var5 = var4 + (var3 * (double)amb_temp); res_heat_x = (uint8_t)(3.4 * ((var5 * (4.0 / (4.0 + (double)res_heat_range)) * (1.0/(1.0 + ((double)res_heat_val * 0.002)))) - 25)); Integer: var1 = (((int32_t)amb_temp * par_g3) / 10) << 8; var2 = (par_g1 + 784) * (((((par_g2 + 154009) * target_temp * 5) / 100) + 3276800) / 10); var3 = var1 + (var2 >> 1); var4 = (var3 / (res_heat_range + 4)); var5 = (131 * res_heat_val) + 65536; res_heat_x100 = (int32_t)(((var4 / var5) - 250) * 34); res_heat_x = (uint8_t)((res_heat_x100 + 50) / 100); Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet where * * * * * * * 22 | 53 par_g1, par_g2, and par_g3 are calibration parameters, target_temp is the target heater temperature in degree Celsius, amb_temp is the ambient temperature (hardcoded or read from temperature sensor), var5 is the target heater resistance in Ohm, res_heat_x is the decimal value that needs to be stored in register, where `x' corresponds to the temperature profile number between 0 and 9, res_heat_range is the heater range stored in register address 0x02 <5:4>, and res_heat_val is the heater resistance correction factor stored in register address 0x00 (signed, value from -128 to 127). Table 14: Variable names and register addresses for res_heat_x calculation Variable name Register address (LSB / MSB) par_g1 0xED par_g2 0xEB/0xEC par_g3 0xEE res_heat_range 0x02 <5:4> res_heat_val 0x00 For each of the 10 temperature set-points, the heating duration must be specified. Referring to Figure 1, the heating phase starts after the temperature, pressure and humidity measurements are complete. This means there is no heating in parallel to these measurements, which is desirable to minimize undesired cross-influences between the various sensor components. The heating duration is specified by writing to the corresponding gas_wait_x<7:0> control register. Heating durations between 1 ms and 4032 ms can be configured. In practice, approximately 20-30 ms are necessary for the heater to reach the intended target temperature. 3.4 Data readout The procedure goes as follows, the new_data_x bit (see Section 5.3.5.1) can be checked to see if a new data is generated. If gas measurements are performed the gas_valid_r (see Section 5.3.5.5) and heat_stab_r (see Section 5.3.5.6) status bits of the respectively field should be checked to ensure that the gas measurement was successful. If heat_stab_r is zero, it indicates that either the heating time was not sufficient to allow the sensor to reach to configured target temperature or that the target temperature was too high for the sensor to reach. After the uncompensated values of temperature, pressure and humidity have been read, the actual humidity, pressure and temperature need to be calculated using the compensation parameters stored in the device. Please refer to the BME6xy API for more details. Gas resistance readout Readout of gas resistance ADC value and calculation of gas resistance consists of 3 steps 1. Read gas ADC value (gas_adc) and gas ADC range (gas_range) (see Section 5.3.4) 2. Read range switching error from register address 0x04 <7:4> (signed 4 bit) 3. Convert ADC value into gas resistance in ohm Using the variables listed in Table 15 and Table 16, the conversion is done as follows: Floating point: var1 = (1340.0 + 5.0 * range_switching_error) * const_array1[gas_range]; gas_res = var1 * const_array2[gas_range] / (gas_adc - 512.0 + var1); Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 23 | 53 Integer: int64_t var1 = (int64_t)(((1340 + (5 * (int64_t)range_switching_error)) * ((int64_t)const_array1_int[gas_range])) >> 16); int64_t var2 = (int64_t)(gas_adc << 15) - (int64_t)(1 << 24) + var1; int32_t gas_res = (int32_t)((((int64_t)(const_array2_int[gas_range] 1)) / var2); where * * * * * (int64_t)var1) >> 9) + (var2 >> gas_adc is the raw gas resistance output data (i.e. ADC value), gas_range is the ADC range of the measured gas resistance, range_switching_error is a calibration parameter, gas_res is the compensated gas resistance output data in Ohms. Table 15: Variable names and register addresses for gas_res calculation Variable name Register address (LSB / MSB) gas_adc 0x2B<7:6> / 0x2A gas_range 0x2B<3:0> range_switching_error 0x04 Table 16: List of gas ranges and corresponding constants used for the resistance calculation Constants to be integrated into the driver gas_range_r Floating point Integer const_array1 const_array2 const_array1_int const_array2_int 0 1 8000000 2147483647 4096000000 1 1 4000000 2147483647 2048000000 2 1 2000000 2147483647 1024000000 3 1 1000000 2147483647 512000000 4 1 499500.4995 2147483647 255744255 5 0.99 248262.1648 2126008810 127110228 6 1 125000 2147483647 64000000 7 0.992 63004.03226 2130303777 32258064 8 1 31281.28128 2147483647 16016016 9 1 15625 2147483647 8000000 10 0.998 7812.5 2143188679 4000000 11 0.995 3906.25 2136746228 2000000 12 1 1953.125 2147483647 1000000 13 0.99 976.5625 2126008810 500000 14 1 488.28125 2147483647 250000 15 1 244.140625 2147483647 125000 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 24 | 53 4. Software and use cases 4.1 BSEC software BME680 sensor is intended to be used together with Bosch Software Environmental Cluster (BSEC) solution and BME6xy sensor API to unlock its full potential. The BSEC software features intelligent algorithms which enable use cases such as indoor-air-quality monitoring using the BME680. Bosch Sensortec BSEC software is available as a closed source binary which will be made available via a Software License Agreement (SLA) on the Bosch Sensortec website (https://www.bosch-sensortec.com/bst/products/all_products/BSEC). Sensor API covers basic sensor communication and data compensation functions and is available as open-source code from Github (https://github.com/BoschSensortec/BME680_driver). The key features of the hardware-software system are: * * * Calculation of ambient air temperature outside of the device (e.g. phone) Calculation of ambient relative humidity outside of the device Calculation of index for air quality (IAQ) level outside of the device Moreover, the software algorithms handle humidity compensation, baseline as well as long-term drift correction of the gas sensor signal. Different power modes for the gas sensor and corresponding data rates are supported by the software solution: * * * * Ultra low power (ULP) mode is designed for battery-powered and/or frequency-coupled devices over extended periods of time. This mode features an update rate of 300 seconds and an average current consumption of <0.1 mA Quick Ultra-low power (q-ULP) has a 3 s data rate for Temprature, pressure and humidity w/o significantly increasing the power consumption compared to ULP. Low power (LP) mode that is designed for interactive applications where the air quality is tracked and observed at a higher update rate of 3 seconds with a current consumption of <1 mA Continuous (CONT) mode provides an update rate of 1 Hz and shall only be used short-term for use cases that incorporate very fast events or stimulus. Table 17: BSEC gas sensor power-modes BSEC power mode Update rate Average current consumption Ultra-low power mode (ULP) 3.3 mHz 0.09 mA quick Ultra-low power mode (q-ULP) 0.33 Hz (T, p, h) / 3.3 mHz (IAQ) 0.1 mA Low power mode (LP) 0.33 Hz 0.9 mA Continuous mode (for testing purposes only) 1 Hz 12 mA The BSEC software suite can be downloaded from the Bosch Sensortec website: https://www.bosch-sensortec.com/bst/products/all_products/BSEC The following table describes the available outputs of BSEC. Full descriptions of the outputs and the available interfaces are available in the integration guide shipped together with the BSEC software. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 25 | 53 Table 18: BSEC outputs Output Description Raw pressure Raw data from sensor API bypassed to BSEC output Raw temperature Raw data from sensor API bypassed to BSEC output Raw relative humidity Raw data from sensor API bypassed to BSEC output Raw gas resistance Raw data from sensor API bypassed to BSEC output Sensor-compensated temperature (C) Temperature which is compensated for internal crossinfluences caused by the BME sensor Sensor-compensated relative humidity (%) Relative humidity which is compensated for internal crossinfluences caused by the BME sensor Sensor-compensated gas resistance (Ohm) Raw gas resistance compensated by temperature and humidity influences. IAQ (0-500) Index for Air Quality, especially recommended for mobile devices, since the auto-trim algorithm automatically adopts to different environments. Static IAQ ("s-IAQ") "Static" Index for Air Quality, especially recommended for stationary devices (w/ o auto-trimming algorithm) CO2 equivalents (ppm) Estimation of the CO2 level in ppm. The sensor does not directly measure CO2, but derives this from the average correlation between VOCs and CO2 in human's exhaled breath. b-VOC equivalents (ppm) Conversion into breath-VOC equivalents in ppm concentration. The scaling is derived from lab tests with the b-VOC gas mixture described in Table 5. Accuracy status (0-3) Accuracy status of IAQ Stabilization time status Indicates if the sensor is undergoing initial stabilization during its first use after production Run in status Indicates when the sensor is ready after switch-on Gas (%) Alternative indicator for air pollution which rates the current raw gas resistance value based on the individual sensor history: 0% = "lowest air pollution ever measured" 100% = "highest air pollution level ever measured" Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 26 | 53 4.2 Indoor-air-quality BME680 is a metal oxide-based sensor that detects VOCs by adsorption (and subsequent oxidation/reduction) on its sensitive layer. Thus, BME680 reacts to most volatile compounds polluting indoor air (one exception is for instance CO2). In contrast to sensors selective for one specific component, BME680 is capable of measuring the sum of VOCs/contaminants in the surrounding air. This enables BME680 to detect e.g. outgassing from paint, furniture and/or garbage, high VOC levels due to cooking, food consumption, exhaled breath and/or sweating. As a raw signal, BME680 will output resistance values and its changes due to varying VOC concentrations (the higher the concentration of reducing VOCs, the lower the resistance and vice versa). Since this raw signal is influenced by parameters other than VOC concentration (e.g. humidity level), the raw values are transformed to an index for air quality (IAQ) by smart algorithms inside BSEC. The IAQ scale ranges from 0 (clean air) to 500 (heavily polluted air). During operation, the algorithms automatically calibrate and adapt themselves to the typical environments where the sensor is operated (e.g., home, workplace, inside a car, etc.). This automatic background calibration ensures that users experience consistent IAQ performance. The calibration process considers the recent measurement history (typ. up to four days) to ensure that IAQ ~ 25 corresponds to "typical good" air and IAQ ~ 250 indicates "typical polluted" air. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 27 | 53 5. Global memory map and register description 5.1 General remarks Communication with the device is performed by reading from and writing to registers. Registers have a width of 8 bits. If I2C is used, 8-bit addressing is utilized. If SPI is used, 7-bit address is only available for register access. For details on the interface, consult Chapter 6. In SPI mode complete memory map is accessed using page 0 and page 1. Register spi_mem_page is used for page selection. After power-on, spi_mem_page is in its reset state and page 0 (0x80 to 0xFF) will be active. Page 1 (0x00 to 0x7F) will be active on setting spi_mem_page to 1. Global memory map consists of calibration registers, control registers, data registers, status registers and reserved registers. There are, however, several registers which are reserved. Accordingly, they should not be written to and no specific value is guaranteed when they are read. Table 19: Memory map page selection Digital Interface Register address range Register spi_mem_page Memory Page I2C 0x00 to 0xFF Not Applicable Not Applicable SPI 0x80 to 0xFF 0 (default; power on state) Page 0 SPI 0x00 to 0x7F 1 Page 1 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 28 | 53 5.2 Memory map The memory map is given in Table 20, noting that not all reserved registers are depicted. Table 20: Memory map Register name I2C SPI Bit 7 Adr Adr Bit 6 Bit 5 Bit 4 Bit 3 Bit2 Bit 1 Bit 0 Reset state Pg status 73h 73h 1 Reset E0h 60h 0 reset<7:0> 00h Id D0h 50h 0 chip_id<7:0> 61h Config 75h 75h 1 Ctrl_meas 74h 74h 1 osrs_t<2:0> Ctrl_hum 72h 72h 1 spi_3w_int_en Ctrl_gas_1 71h 71h 1 Ctrl_gas_0 70h 70h 1 Gas_wait_x 6Dh...64h 6Dh...64h 1 gas_wait_9<7:0> downto gas_wait_0<7:0> 00h Res_heat_x 63h...5Ah 63h...5Ah 1 res_heat_9<7:0> downto res_heat_0<7:0> 00h Idac_heat_x 59h...50h 59h...50h 1 idac_heat_9<7:0> downto idac_heat_0<7:0> 00h gas_r_lsb 2Bh 2Bh 1 gas_r_msb 2Ah 2Ah 1 gas_r<9:2> 00h hum_lsb 26h 26h 1 hum_lsb<7:0> 00h hum_msb 25h 25h 1 hum_msb<7:0> 80h temp_xlsb 24h 24h 1 temp_lsb 23h 23h 1 temp_lsb<7:0> 00h temp_msb 22h 22h 1 temp_msb<7:0> 80h press_xlsb 21h 21h 1 press_lsb 20h 20h 1 press_lsb<7:0> 00h press_msb 1Fh 1Fh 1 press_msb<7:0> 80h eas_status_0 1Dh 1Dh 1 spi_mem_page 00h filter<2:0> spi_3w_en osrs_p<2:0> mode<1:0> 00h osrs_h<2:0> run_gas 00h nb_conv<3:0> 00h heat_off gas_r<1:0> gas_valid_r measuring Modifications reserved |Data subject not change without notice | Printed in Germany gas_range_r 0 press_xlsb<7:4> new_data_0 gas_measuring 00h heat_stab_r temp_xlsb<7:4> 0 00h 0 0 00h 0 0 0 0 gas_meas_index_0<3:0> 00h 00h 00h Registers Color/Type Reserved Do not change Status register Read only Data register Read only Control register Read/write Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 29 | 53 5.3 Register description General control registers 5.3.1.1 SPI 3 wire interrupt enable - spi_3w_int_en Register Name ctrl_hum Address Content<bit position> 0x72 spi_3w_int_en <6> Description New data interrupt can be enabled if the device is in SPI 3 wire mode and pi_3w_int_en=1. The new data interrupt is then indicated on the SDO pad. 5.3.1.2 SPI 3 wire enable - spi_3w_en Register Name config Address Content<bit position> 0x75 spi_3w_en<0> Description Enable SPI 3 wire mode 5.3.1.3 Mode Selection - mode The operation modes of the sensor can be controlled by the register mode as specified below. Register Name Address Content<bit position> Description ctrl_meas mode<1:0> 0x74 mode<1:0> Select sensor power mode as shown in the following table Mode 00 Sleep mode 01 Forced mode 5.3.1.4 SPI memory map page selection - spi_mem_page In SPI mode complete memory page is accessed using page 0 & page 1. Register spi_mem_page is used for page selection. After power-on, spi_mem_page is in its reset state and page 0(0x80 to 0xFF) will be active. Page1 (0x00 to 0x7F) will be active on setting spi_mem_page. Please refer Table 19 for better understanding. Register Name status Address Content<bit position> Description 0x73(Page 0/1) spi_mem_page <4> Selects memory map page in SPI mode Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 30 | 53 5.3.1.5 Reset - reset Writing 0xB6 to this register initiates a soft-reset procedure, which has the same effect like power-on reset. The default value stored in this register is 0x00. Register Name Address Content<bit position> Description reset 0x60 (Page 0 in SPI mode) 0xE0 in I2C reset<7:0> Resets the device Address Content<bit position> Description 0x50(Page 0 in SPI mode) 0xD0 in I2C chip_id<7:0> Chip id of the device 5.3.1.6 Chip id - chip_id Register Name Id Temperature, pressure and relative humidity control registers 5.3.2.1 Humidity sensor over sampling control - osrs_h Register Name ctrl_hum Address Content<bit position> Description 0x72 osrs_h<2:0> Controls over sampling setting of humidity sensor as described in the following table osrs_h<2:0> Humidity oversampling 000 Skipped (output set to 0x8000) 001 oversampling x1 010 oversampling x2 011 oversampling x4 100 oversampling x8 101, Others oversampling x16 5.3.2.2 Over sampling setting - Temperature data - osrs_t Register Name ctrl_meas Address Content<bit position> Description 0x74 osrs_t<7:5> Temperature oversampling settings as shown in the following table osrs_t<2:0> Temperature oversampling 000 Skipped (output set to 0x8000) 001 oversampling x1 010 oversampling x2 011 oversampling x4 100 oversampling x8 101, Others oversampling x16 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 31 | 53 5.3.2.3 Over sampling setting - Pressure data - osrs_p Register Name ctrl_meas Address Content<bit position> Description 0x74 osrs_p<4:2> Pressure oversampling settings as shown in the following table osrs_p<2:0> Pressure oversampling 000 Skipped (output set to 0x8000) 001 oversampling x1 010 oversampling x2 011 oversampling x4 100 oversampling x8 101, Others oversampling x16 5.3.2.4 IIR filter control - filter IIR filter applies to temperature and pressure data but not to humidity and gas data. The data coming from the ADC are filtered and then loaded into the data registers. The temperature and pressure result registers are updated together at the same time at the end of the measurement. IIR filter output resolution is 20 bits. The result registers are reset to value 0x80000 when the temperature and/or pressure measurements have been skipped (osrs_x="000). The appropriate filter memory is kept unchanged (the value from the last measurement is kept). When the appropriate OSRS register is set back to nonzero, then the first value stored to the result registers are filtered. Register Name config Address Content<bit position> Description 0x75 filter<4:2> IIR filter settings as shown in the following table filter<2:0> Filter coefficient 000 0 001 1 010 3 011 7 100 15 101 31 110 63 111 127 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 32 | 53 Gas control registers The sensor can have 10 programmable gas sensor heater set-points. A set-point consists of a target heater resistance, heater-on time and optionally an initial heater current. 5.3.3.1 Heater current - idac_heat_x BME680 contains a heater control block that will inject enough current into the heater resistance to achieve the requested heater temperature. There is a control loop which periodically measures heater resistance value and adapts the value of current injected from a DAC. The heater operation could be speeded up by setting an initial heater current for a target heater temperature by using register idac_heat_x<7:0>. This step is optional since the control loop will find the current after a few iterations anyway. The current injected to the heater in mA can be calculated by: (idac_heat_7_1 + 1) / 8, where idac_heat_7_1 is the decimal value stored in idac_heat<7:1> (unsigned, value from 0 to 127). Heater setpoint 0...9 Register name idac_heat_x x is from 0 to 9 Address 0x50...0x59 Content idac_heat_x<7:0> x is from 0 to 9 Description idac_heat of particular heater set point 5.3.3.2 Target heater resistance - res_heat_x Target heater resistance is programmed by user through res_heat_x<7:0> registers. The definition of res_heat_x is given in Section 3.3.5. Heater set-point 0...9 Register name res_wait_x x is from 0 to 9 Address 0x5A...0x63 Modifications reserved |Data subject not change without notice | Printed in Germany Content res_heat_x<7:0> x is from 0 to 9 Description Decimal value that needs to be stored for achieving target heater resistance Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 33 | 53 5.3.3.3 Gas Sensor wait time - gas_wait_x Referring to Figure 1, the time between the beginning of the heat phase and the start of gas sensor resistance conversion depends on gas_wait_x setting as mentioned below. Heater set-point Register name Address Content Description 0...9 gas_wait_x x is from 0 to 9 0x64...0x6D gas_wait_x<5:0> x is from 0 to 9 64 timer values with 1 ms step sizes, all zeros means no wait 0...9 gas_wait_x x is from 0 to 9 0x64...0x6D gas_wait_x<7:6> x is from 0 to 9 Please refer to the table below for settings gas_wait_x<7:6> Gas sensor wait time multiplication factor 00 1 01 4 10 16 11 64 5.3.3.4 Heater off - heat_off Register Name ctrl_gas_0 Address 0x70 Content<bit position> heat_off <3> Modifications reserved |Data subject not change without notice | Printed in Germany Description Turn off current injected to heater by setting bit to one Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 34 | 53 5.3.3.5 Heater profile selection - nb_conv nb_conv is used to select heater set-points of the sensor. The different heater set-points are described in the sections above. Register Name Address Content<bit position> Description ctrl_gas_1 0x71 nb_conv<3:0> nb_conv<3:0> Indicates index of heater set point that will be used in forced mode as describe in below table Heater profile set-point 0000 0 0001 1 0010 2 0011 3 0100 4 0101 5 0110 6 0111 7 1000 8 1001 9 5.3.3.6 Run Gas - run_gas Register Name ctrl_gas_1 Address 0x71 Content<bit position> run_gas<4> Modifications reserved |Data subject not change without notice | Printed in Germany Description The gas conversions are started only in appropriate mode if run_gas = `1' Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 35 | 53 Data registers In this section, the data registers for the temperature, pressure, humidity and gas sensors are explained. Shadowing registers are utilized to buffer the data and to ensure stable data in case an update of the data registers occurs simultaneously with the serial interface reading out. 5.3.4.1 Pressure data Register Name Address Content<bit position> Description press_msb 0x1F press_msb<7:0> Contains the MSB part [19:12] of the raw pressure measurement output data. press_lsb 0x20 press_lsb<7:0> Contains the LSB part [11:4] of the raw pressure measurement output data press_xlsb 0x21 press_xlsb<7:4> Contains the XLSB part [3:0] of the raw pressure measurement output data. Contents depend on pressure resolution controlled by oversampling setting. Content<bit position> Description 5.3.4.2 Temp data Register Name Address temp_msb 0x22 temp_msb<7:0> Contains the MSB part [19:12] of the raw temperature measurement output data. temp_lsb 0x23 temp_lsb<7:0> Contains the LSB part [11:4] of the raw temperature measurement output data. temp_xlsb 0x24 temp_xlsb<7:4> Contains the XLSB part [3:0] of the raw temperature measurement output data. Contents depend on temperature resolution controlled by oversampling setting. Content<bit position> Description 5.3.4.3 Humidity data Register Name Address hum_msb 0x25 hum_msb<7:0> Contains the MSB part [15:8] of the raw humidity measurement output data. hum_lsb 0x26 hum_lsb<7:0> Contains the LSB part [7:0] of the raw humidity measurement output data. 5.3.4.4 Gas resistance data Register Name Address Content<bit position> Description gas_r_msb 0x2A gas_r<7:0> Contains the MSB part gas resistance [9:2] of the raw gas resistance. gas_r_lsb 0x2B gas_r<7:6> Contains the LSB part gas resistance [1:0] of the raw gas resistance. 5.3.4.5 Gas resistance range Register Name gas_r_lsb Address 0x2B Content<bit position> gas_range_r<3:0> Modifications reserved |Data subject not change without notice | Printed in Germany Description Contains ADC range of measured gas resistance. Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 36 | 53 Status registers 5.3.5.1 New data status The measured data are stored into the output data registers at the end of each TPHG conversion phase along with status flags and index of measurement. Register Name Address Content<bit position> Description meas_status_0 0x1D new_data_0<7> New data flag 5.3.5.2 Gas measuring status Measuring bit is set to "1 only during gas measurements, goes to "0 as soon as measurement is completed and data transferred to data registers. The registers storing the configuration values for the measurement (gas_wait_shared, gas_wait_x, res_heat_x, idac_heat_x, image registers) should not be changed when the device is measuring. Register Name meas_status_0 Address 0x1D Content<bit position> gas_measuring<6> Description Gas measuring status flag 5.3.5.3 Measuring status Measuring status will be set to `1' whenever a conversion (temperature, pressure, humidity and gas) is running and back to `0' when the results have been transferred to the data registers. Register Name meas_status_0 Address 0x1D Content<bit position> measuring<5> Description Measuring status flag 5.3.5.4 Gas Measurement Index User can program a sequence of up to 10 conversions by setting nb_conv<3:0>. Each conversion has its own heater resistance target but 3 field registers to store conversion results. The actual gas conversion number in the measurement sequence (up to 10 conversions numbered from 0 to 9) is stored in gas_meas_index register. Register Name meas_status_0 Address 0x1D Content<bit position> gas_meas_index_0<3:0> Modifications reserved |Data subject not change without notice | Printed in Germany Description Gas measurement index Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 37 | 53 5.3.5.5 Gas valid status In each TPHG sequence contains a gas measurement slot, either a real one which result is used or a dummy one to keep a constant sampling rate and predictable device timing. A real gas conversion (i.e., not a dummy one) is indicated by the gas_valid_r status register. Register Name gas_r_lsb Address 0x2B Content<bit position> gas_valid_r<5> Description Gas valid bit 5.3.5.6 Heater Stability Status Heater temperature stability for target heater resistance is indicated heat_stab_x status bits. Register Name gas_r_lsb Address 0x2B Content<bit position> heat_stab_r<4> Modifications reserved |Data subject not change without notice | Printed in Germany Description Heater stability bit Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 38 | 53 6. Digital interfaces The sensor supports the IC and SPI digital interfaces, where it acts as a slave for both protocols. The IC interface supports the Standard, Fast and High Speed modes. The SPI interface supports both SPI mode `00' (CPOL = CPHA = `0') and mode `11' (CPOL = CPHA = `1') in 4-wire and 3-wire configuration. The following transactions are supported: * * * * Single byte write multiple byte write (using pairs of register addresses and register data) single byte read multiple byte read (using a single register address which is auto-incremented) 6.1 Interface selection Interface selection is done automatically based on CSB (chip select) status. If CSB is connected to VDDIO, the IC interface is active. If CSB is pulled down, the SPI interface is activated. After CSB has been pulled down once (regardless of whether any clock cycle occurred), the IC interface is disabled until the next power-on-reset. This is done in order to avoid inadvertently decoding SPI traffic to another slave as IC data. Since the device startup is deferred until both VDD and VDDIO are established, there is no risk of incorrect protocol detection because of the power-up sequence used. However, if IC is to be used and CSB is not directly connected to VDDIO but is instead connected to a programmable pin, it must be ensured that this pin already outputs the VDDIO level during power-on-reset of the device. If this is not the case, the device will be locked in SPI mode and not respond to IC commands. 6.2 IC Interface For detailed timings, please review Table 22 . All modes (standard, fast, high speed) are supported. SDA and SCL are not pure open-drain. Both pads contain ESD protection diodes to VDDIO and GND. As the devices does not perform clock stretching, the SCL structure is a high-Z input without drain capability. Picture 3: SDI/SCK ESD schematic The 7-bit device address is 111011x. The 6 MSB bits are fixed. The last bit is changeable by SDO value and can be changed during operation. Connecting SDO to GND results in slave address 1110110 (0x76); connection it to VDDIO results in slave address 1110111 (0x77), which is the same as BMP280's IC address. The SDO pin cannot be left floating; if left floating, the IC address will be undefined. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 39 | 53 The IC interface uses the following pins: * * * SCK: SDI: SDO: serial clock (SCL) data (SDA) Slave address LSB (GND = `0', VDDIO = `1') CSB must be connected to VDDIO to select IC interface. SDI is bi-directional with open drain to GND: it must be externally connected to VDDIO via a pull up resistor. Refer to Chapter 7 for connection instructions. The following abbreviations will be used in the IC protocol figures: * * * * * S P ACKS ACKM NACKM Start Stop Acknowledge by slave Acknowledge by master Not acknowledge by master IC write Writing is done by sending the slave address in write mode (RW = `0'), resulting in slave address 111011X0 (`X' is determined by state of SDO pin. Then the master sends pairs of register addresses and register data. The transaction is ended by a stop condition. This is depicted in Picture 4. Control byte Slave Address Start S 1 1 1 0 1 Register address (A0h) RW ACKS 1 X 0 Data byte 1 0 1 0 0 0 0 Register data - address A0h ACKS 0 bit7 bit6 bit5 Control byte 1 0 1 0 0 bit3 bit2 ... bit1 bit0 Data byte Register address (A1h) ... bit4 ACKS 0 0 Register data - address A1h ACKS 1 bit7 bit6 bit5 bit4 bit3 bit2 ACKS Stop bit1 bit0 P Picture 4: IC multiple byte write (not auto-incremented) IC read To be able to read registers, first the register address must be sent in write mode (slave address 111011X0). Then either a stop or a repeated start condition must be generated. After this the slave is addressed in read mode (RW = `1') at address 111011X1, after which the slave sends out data from auto-incremented register addresses until a NOACKM and stop condition occurs. This is depicted in Picture 5, where register 0xF6 and 0xF7 are read. Control byte Slave Address Start S 1 1 1 0 1 Register address (F6h) RW ACKS 1 X 0 1 1 1 1 0 1 ACKS 1 0 Data byte Slave Address Start S 1 1 1 0 1 Register data - address F6h RW ACKS 1 X 1 Data byte bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 Register data - address F7h ACKM bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 NOACKM Stop P Picture 5: IC multiple byte read Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 40 | 53 6.3 SPI interface The SPI interface is compatible with SPI mode `00' (CPOL = CPHA = `0') and mode `11' (CPOL = CPHA = `1'). The automatic selection between mode `00' and `11' is determined by the value of SCK after the CSB falling edge. The SPI interface has two modes, namely 4-wire and 3-wire mode. However, the protocol is the same for both. The 3-wire mode is selected by setting `1' to the register spi3w_en. The pad SDI is used as a data pad in 3-wire mode. The SPI interface uses the following pins: * * * * CSB: SCK: SDI: SDO: chip select, active low serial clock serial data input; data input/output in 3-wire mode serial data output; hi-Z in 3-wire mode For more connection instructions, please refer to Chapter 7. CSB is active low and has an integrated pull-up resistor. Data on SDI is latched by the device at SCK rising edge and SDO is changed at SCK falling edge. Communication starts when CSB goes to low and stops when CSB goes to high; during these transitions on CSB, SCK must be stable. The SPI protocol is shown in It is important to note that Picture 6. For timing details, please review Table 23. CSB SCK SDI RW AD6 AD5 AD4 AD3 AD2 AD1 AD0 DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0 tri-state SDO Picture 6: SPI protocol (shown for mode `11' in 4-wire configuration) It is important to note that in the SPI mode, only 7 bits of the register addresses are used; the MSB of register address is not used and replaced by a read/write bit (RW = `0' for write and RW = `1' for read). For example, address 0xF7 is accessed by using SPI register address 0x77. On the one hand, the byte 0x77 is transferred for write access, and on the other hand, the byte 0xF7 is transferred for read access. SPI write Writing is done by lowering CSB and sending pairs control bytes and register data. The control bytes consist of the SPI register address (= full register address without bit 7) and the write command (bit7 = RW = `0'). Several pairs can be written without raising CSB. The transaction is ended by a raising CSB. The SPI write protocol is depicted in Picture 7. Control byte Start CSB = 0 0 Data byte Register address (F4h) RW 1 1 1 0 1 0 0 bit7 bit6 bit5 bit4 bit3 Data byte Control byte Data register - address F4h bit2 Register address (F5h) RW bit1 bit0 0 1 1 1 0 1 0 Data register - adress F5h 1 bit7 bit6 bit5 bit4 bit3 bit2 Stop bit1 bit0 CSB = 1 Picture 7: SPI multiple byte write (not auto-incremented) Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 41 | 53 SPI read Reading is done by lowering CSB and first sending one control byte. The control bytes consist of the SPI register address (= full register address without bit 7) and the read command (bit 7 = RW = `1'). After writing the control byte, data is sent out of the SDO pin (SDI in 3-wire mode); the register address is automatically incremented. The SPI read protocol is depicted in Picture 8. Control byte Register address (F6h) Start RW CSB = 0 1 1 1 1 0 1 1 0 Data byte Data byte Data register - address F6h Data register - address F7h bit15 bit14 bit13 bit12 bit11 bit10 bit9 bit8 bit7 bit6 bit5 bit4 bit3 Stop bit2 bit1 bit0 CSB = 1 Picture 8: SPI multiple byte read 6.4 Interface parameter specification General interface parameters Table 21: Interface parameters Parameter Symbol Condition Input low level Vil_si VDDIO=1.2 V to 3. 6V Input high level Vih_si VDDIO=1.2 V to 3.6 V Output low level I2C Vol_SDI VDDIO=1.62 V, Iol=3 mA 20 %VDDIO Output low level I2C Vol_SDI_1.2 VDDIO=1.20 V, Iol=3 mA 23 %VDDIO Output low level SPI Vol_SDO VDDIO=1.62 V, Iol=1 mA 20 %VDDIO Output low level SPI Vol_SDO_1.2 VDDIO=1.20 V, Iol=1 mA 23 %VDDIO Output high level Voh VDDIO=1.62 V, Ioh=1 mA (SDO, SDI) 80 %VDDIO Output high level Voh_1.2 VDDIO=1.20 V, Ioh=1 mA (SDO, SDI) 60 %VDDIO Pull-up resistor Rpull Internal CSB pull-up resistor to VDDIO 70 I2C bus load capacitor Cb On SDI and SCK Modifications reserved |Data subject not change without notice | Printed in Germany Min Typ Max Unit 20 80 %VDDIO %VDDIO 120 190 k 400 pF Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 42 | 53 IC timings For IC timings, the following abbreviations are used: * * * "S&F mode" = standard and fast mode "HS mode" = high speed mode Cb = bus capacitance on SDA line All other naming refers to IC specification 2.1 (January 2000). The IC timing diagram is in Picture 9. The corresponding values are given in Table 22 SDI tBUF tf tLOW SCK tHIGH tHDSTA tr tHDDAT tSUDAT SDI tSUSTA tSUSTO Picture 9: I2C timing diagram Table 22: I2C timings Parameter Symbol SDI setup time tSU;DAT SDI hold time tHD;DAT SCK low pulse tLOW SCK low pulse tLOW Condition Min S&F Mode 160 ns HS mode 30 ns S&F Mode, Cb100 pF S&F Mode, Cb400 pF HS mode, Cb100 pF HS mode, Cb400 pF 80 90 18 24 ns ns ns ns HS mode, Cb100 pF VDDIO = 1.62 V HS mode, Cb100 pF VDDIO = 1.2 V Typ Max 115 150 Unit 160 ns 210 ns The above-mentioned I2C specific timings correspond to the following internal added delays: * * Input delay between SDI and SCK inputs: SDI is more delayed than SCK by typically 100 ns in Standard and Fast Modes and by typically 20 ns in High Speed Mode. Output delay from SCK falling edge to SDI output propagation is typically 140 ns in Standard and Fast Modes and typically 70 ns in High Speed Mode. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 43 | 53 SPI timings The SPI timing diagram is in Picture 10, while the corresponding values are given in Table 23. All timings apply both to 4and 3-wire SPI. T_hold_csb T_setup_csb CSB T_low_sck T_high_sck SCK SDI T_setup_sdi T_hold_sdi SDO T_delay_sdo Picture 10: SPI timing diagram Table 23: SPI timings Parameter Symbol SPI clock i/p frequency F_spi 0 SCK low pulse T_low_sck 20 ns SCK high pulse T_high_sck 20 ns SDI setup time T_setup_sdi 20 ns SDI hold time T_hold_sdi 20 ns SDO output delay T_delay_sdo 25 pF load, VDDIO=1.6 V min 30 ns SDO output delay T_delay_sdo 25 pF load, VDDIO=1.2 V min 40 ns CSB setup time T_setup_csb 20 ns CSB hold time T_hold_csb 20 ns SPI clock input frequency F_spi 0 Condition Modifications reserved |Data subject not change without notice | Printed in Germany Min Typ Max Unit 10 MHz 10 MHz Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 44 | 53 7. Pin-out and connection diagram 7.1 Pin-out The pin numbering of BME680 is performed in the untypical clockwise direction when seen in top view and counter-clockwise when seen in bottom view. Picture 11 and Table 24 give a detailed description and illustration of the input/output pins. Picture 11: Top (left) and bottom (right) views of the chip with input/output pins Table 24: Pin description Connection Pin Name I/O type Description 1 GND Supply Ground GND 2 CSB In Chip select 3 SDI In/Out 4 SCK In SPI 4W SPI 3W I2C CSB CSB VDDIO Serial data input SDI SDI/SDO SDA Serial clock input SCK SCK SCL DNC GND for default address 5 SDO In/Out Serial data output SDO 6 VDDIO Supply Digital / Interface supply VDDIO 7 GND Supply Ground GND 8 VDD Supply Analog supply VDD Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 45 | 53 7.2 Connection diagrams For the I2C connection, it is recommended to use 100 nF for C1 and C2. Moreover, the value for the pull-up resistors R1 and R2 should be based on the interface timing and the bus load; a normal value is 4.7 k. Finally, a direct connection between CSB and VDDIO is required. Similarly for the 4- and 3-wire SPI connections, it is suggested to use 100 nF for C1 and C2. (a) (b) (c) Picture 12: Connection diagrams for (a) I2C, (b) 4-wire SPI, and (c) 3-wire SPI Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 46 | 53 7.3 Package dimensions Picture 13: Package dimensions for top, bottom and side view Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 47 | 53 7.4 Landing pattern recommendation For the design of the landing pattern, the dimensions shown in Picture 14: Recommended landing pattern (top view; dimensions are in milli-meters) are recommended. It is important to note that areas marked in red are exposed PCB metal pads. * In case of a solder mask defined (SMD) PCB process, the land dimensions should be defined by solder mask openings. The underlying metal pads are larger than these openings. * In case of a non-solder mask defined (NSMD) PCB process, the land dimensions should be defined in the metal layer. The mask openings are larger than these metal pads. 0.60 0.40 1 0.10 8 2 6 3 0.60 5 0.40 0.20 1.50 3.00 7 4 Soldier stop Landing pattern 1.50 3.00 Picture 14: Recommended landing pattern (top view; dimensions are in milli-meters) Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 48 | 53 7.5 Marking Mass production devices Table 25: Marking of mass production parts Marking Symbol Description CCC Lot counter: 3 alphanumeric digits, variable to generate mass production trace-code T Product number: 1 alphanumeric digit, fixed to identify product type, T = "S" or "E" "S" is associated with the product BME680 (part number 0 273 141 229) "E" is associated with the product BME680 (part number 0 273 141 312) L Sub-contractor ID: 1 alphanumeric digit, variable to identify sub-contractor (L = "P") Engineering samples Table 26: Marking of engineering samples Marking Symbol Description XX Sample ID: 2 alphanumeric digits, variable to generate trace-code N Eng. Sample ID: 1 alphanumeric digit, fixed to identify engineering sample, N = " * " or "e" or "E" CC Counter ID: 2 alphanumeric digits, variable to generate trace-code Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 49 | 53 7.6 Soldering guidelines and reconditioning recommendations The moisture sensitivity level of the BME680 sensors corresponds to JEDEC Level 1, see also: * IPC/JEDEC J-STD-020C "Joint Industry Standard: Moisture/Reflow Sensitivity Classification for non-hermetic Solid State Surface Mount Devices" * IPC/JEDEC J-STD-033A "Joint Industry Standard: Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices" The sensor fulfils the lead-free soldering requirements of the above-mentioned IPC/JEDEC standard, i.e. reflow soldering with a peak temperature up to 260C. The minimum height of the solder after reflow shall be at least 50 m. This is required for good mechanical decoupling between the sensor device and the printed circuit board (PCB). Picture 15: Soldering profile 7.7 Mounting and assembly recommendations This HSMI-document provides all the necessary instructions to handle, solder and mount the environmental sensor BME680. Following the reported guidelines is very important to prevent the damage of the sensor and the resultant loss of warranty. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 50 | 53 7.8 Environmental safety RoHS The BME680 sensor meets the requirements of the EC restriction of hazardous substances (RoHS) directive, see also: Directive 2011/65/EU of the European Parliament and of the Council of 8 June 2011 on the restriction of the use of certain hazardous substances in electrical and electronic equipment. Halogen content The BME680 is halogen-free. For more details on the analysis results please contact your Bosch Sensortec representative. Internal package structure Within the scope of Bosch Sensortec's ambition to improve its products and secure the mass product supply, Bosch Sensortec qualifies additional sources (e.g. 2nd source) for the packaging and processing of the BME680. While Bosch Sensortec took care that all of the technical packages parameters are described above are 100% identical for all sources, there can be differences in the chemical content and the internal structural between the different package sources. However, as secured by the extensive product qualification process of Bosch Sensortec, this has no impact to the usage or to the quality of the BME680 product. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 51 | 53 8. Legal disclaimer 8.1 Engineering samples Engineering Samples are marked with an asterisk (*) or (e). Samples may vary from the valid technical specifications of the product series contained in this data sheet. They are therefore not intended or fit for resale to third parties or for use in end products. Their sole purpose is internal client testing. The testing of an engineering sample may in no way replace the testing of a product series. Bosch Sensortec assumes no liability for the use of engineering samples. The Purchaser shall indemnify Bosch Sensortec from all claims arising from the use of engineering samples. 8.2 Product use Bosch Sensortec products are developed for the consumer goods industry. They may only be used within the parameters of this product data sheet. They are not fit for use in life-sustaining or safety-critical systems. Safetycritical systems are those for which a malfunction is expected to lead to bodily harm, death or severe property damage. In addition, they shall not be used directly or indirectly for military purposes (including but not limited to nuclear, chemical or biological proliferation of weapons or development of missile technology), nuclear power, deep sea or space applications (including but not limited to satellite technology). The resale and/or use of Bosch Sensortec products are at the purchaser's own risk and his own responsibility. The examination of fitness for the intended use is the sole responsibility of the purchaser. The purchaser shall indemnify Bosch Sensortec from all third party claims arising from any product use not covered by the parameters of this product data sheet or not approved by Bosch Sensortec and reimburse Bosch Sensortec for all costs in connection with such claims. The purchaser accepts the resonsibility to monitor the market for the purchased products, particularly with regard to product safety, and to inform Bosch Sensortec without delay of all safety-critical incidents. 8.3 Application examples and hints With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Bosch Sensortec hereby disclaims any and all warranties and liabilities of any kind, including without limitation warranties of non-infringement of intellectual property rights or copyrights of any third party. The information given in this document shall in no event be regarded as a guarantee of conditions or characteristics. They are provided for illustrative purposes only and no evaluation regarding infringement of intellectual property rights or copyrights or regarding functionality, performance or error has been made. Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 52 | 53 9. Document history and modifications Rev. Chapter 1.0 1.1 1.2 5.2 7.5.1 1.2 3.3 4.1 5.3.1.4 5.2 8. Description of modifications Date Initial release July 2017 Fixed typo Added new technical reference code April 2019 Added Hyperlinks to Table of contents Table 4 updated Added code examples & Tables 11-16 Added q-ULP to Table 17 Added new BSEC outputs to Table 18 Removed Ambient temperature, Ambient relative humidity Changed ranges of memory pages Changed status register from 01h to 00h New disclaimer May 2019 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019 Bosch Sensortec | BME680 Datasheet 53 | 53 Bosch Sensortec GmbH Gerhard-Kindler-Strae 9 72770 Reutlingen / Germany www.bosch-sensortec.com Modifications reserved | Printed in Germany Preliminary - specifications subject to change without notice Document number: BST-BME680-DS001-02 Revision_1.2_052019 Modifications reserved |Data subject not change without notice | Printed in Germany Document number: BST-BME680-DS001-02 Revision_1.2_052019