UMXXX UMxxxx User manual STEVAL-BCN002V1 User Manual 1. Introduction The STEVAL-BNC002V1 is an BLE-enabled sensor node. The STEVAL-BCN002V1 platform includes the following components: inertial and environmental digital MEMS sensors, a digital MEMS microphone, a time-of-flight proximity sensor, and a BLE wireless system-on-chip with a Cortex-M0 core that can run the user application and the radio stack (BLE or proprietary), to enable communication with any device equipped with BLE.
UMXXX Figure 2. STEVAL-BCN002V1 battery holder and SWD connector 2. Features The STEVAL-BCN002V1 includes the following components and features: • BLUENRG-2 Bluetooth low-energy wireless system-on-chip: the device includes an ultra low-power ARM Cortex-M0 MCU with 256KB Flash and 24KB RAM with retention, plus an extensive range of enhanced I/O and peripherals (10bit ADC, 2 general purpose 16bit timers, watchdog and RTC, DMA controller, PDM stream processor, 2 I2C, 1 SPI, 1 UART, up to 26 GPIOs).
UMXXX 96dB link budget. • BALF-NRG-02D3 50ohm nominal input / conjugate match to BlueNRG transceiver with integrated harmonic filter. • LSM6DSO inertial digital module with 3-axis accelerometer and 3-axis gyroscope. Ultra-low power (0.55mA in combo high-performance mode at the highest datarate, 6.6kS/s).
UMXXX (repeatability improves at lower data rate, 2.5mm standard deviation with 200msec measurement); Ranging distance from 4cm to 400cm (under 4cm the device will detect a target but measurement will not be accurate). Ranging error within 20mm. Figure 3. STEVAL-BCN002V1 block diagram 3. System architecture The BLE sensor node is powered by a coin-cell battery (CR2032). The voltage is NOT regulated because all sensors and the BlueNRG-2, they can all operate at the voltage range of the battery.
UMXXX to enable the lowest power consumption in sleep mode: • Sleep mode, 32kHz RO (Ring oscillator), 24kB RAM retention: 2.1uA at 3V • Sleep mode, 32kHz XO (Crystal oscillator), 24kB RAM retention: 0.9uA at 3V RADIO FREQUENCY SECTION The Radio Frequency section of the BLE sensor node includes three elements: • The first element is BALF-NRG-02D3, an ultra-miniature balun which integrates matching network and harmonics filter.
UMXXX detection; pedometer, step detector and step counter; up to 16 finite state machines to process • The LPS22HH barometer interrupt pin is the same as for LSM6DSO: it is an input pin at boot and must be low so that I2C interface is activated. It can be configured as push-pull or open-drain after boot. The interrupt pin of this sensor is not connected to BlueNRG-2. • The HTS221 relative humidity and temperature interrupt pin is push-pull at boot and can be reconfigured as open-drain after boot.
UMXXX does exploit the embedded digital filter of the ADC peripheral for PDM to PCM conversion when reading the PDM output of the MEMS microphone MP34DT05-A. The low-speed clock is used in low-power mode and can be supplied by the internal RC oscillator or by an external crystal (32kHz +/-50ppm). The high-speed clock is supplied by a fast-starting internal RC oscillator (16MHz) while the external crystal is starting up.
UMXXX • The SRAM is divided in two banks o 12KB from 0x2000_0000 to 0x2000_2FFF, retention always-on o 12KB from 0x2000_3000 to 0x2000_5FFF, retention optional o The FULL BLE stack needs 9.6KB of SRAM; see below for FULL BLE stack features. o The BASIC BLE stack needs 0.0KB of SRAM; see below for BASIC BLE stack features.
UMXXX successful update, the new application can be copied over the old application or the role of the first two sections can be exchanged. 5. Inertial MEMS sensors features Each sensor is made of two parts: the first is the Micro Electro Mechanical system (MEMS) which includes the sensing element; the second is the dedicated ASIC with the analog acquisition chain, the analog-to-digital converter (ADC), and the dedicated digital signal processing (DSP) and control logic.
UMXXX mentioned above); the double tap event is detected when a first tap is detected, and a second tap is detected after the programmed “quiet” time window but before the maximum “duration” time window; for a reliable detection of short duration shock events, it is suggested to configure the device to use a high sampling rate (e.g. 400Hz). If more than one axis is enabled, and they are over their respective threshold, the highest priority axis is used; the priority can be configured.
UMXXX mode, or the step counter is disabled or re-initialized. The step counter can be reset explicitly by the user application. • Significant motion detection: this function generates an interrupt when there is a change in user location, computed by integrating accelerometer data. • Relative tilt detection: this function generates an interrupt when there is a change in the tilt of the device. The interrupt is generated when the change in tilt exceeds 35 degrees.
UMXXX In order to maximize the amount of data stored in the FIFO, the user can enable a lossless DPCM compression algorithm for the accelerometer and/or the gyroscope data.
UMXXX (FIFO threshold level), or when it is full, or when it overflows (overrun). The FIFO can work in the following modes: • Bypass mode: the FIFO buffer is disabled and cleared. • FIFO mode: the FIFO buffer collects data until it is full, then stops. • Continuous mode: the FIFO buffer collects data continuously, when it is full oldest samples are overwritten as in a circular buffer.
UMXXX The LIS2MDL is based on AMR technology (anisotropic magneto-resistive): a set pulse is needed to set an initial operating condition; a reset pulse may be used to enable the compensation of the intrinsic magnetic offset. • If intrinsic offset compensation is disabled, there is no reset pulse. The set pulse can be generated at power-on only (Set_FREQ=1), or every 64 measurements (Set_FREQ=0).
UMXXX 6. Environmental MEMS sensors features LPS22HH ACQUISITION CHAIN The LPS22HH pressure sensor can perform a one-shot measurement and then return to power-down mode, or it can operate in continuous mode with a programmable sampling rate (1, 10, 25, 50, 75, 100 or 200Hz). The measurements can be taken in normal low-noise mode, or in low-power mode to minimize current consumption. When continuous mode is selected, low-noise mode is not available at 100 and 200Hz.
UMXXX AZ-compensated data goes to interrupt logic, while un/filtered OPC-compensated data goes to FIFO and output registers. The FIFO buffer can store up to 128 pressure samples (24 bit each) and 128 temperature samples (16 bit each). FIFO depth can be limited by stopping at the programmable watermark level. The FIFO can work in the following modes: • Bypass mode: the FIFO buffer is disabled and cleared.
UMXXX Celsius degrees), +/-0.5degC (from 15 to 40 Celsius degrees); data rate 1, 7 or 12.5 Hz. Response time 15 s (time to 63%). Long term drift 0.05degC/year. HTS221 ACQUISITION CHAIN All components on the board, the MEMS sensors, the BlueNRG-2 processor, have an embedded temperature sensor. These temperature sensors have been design to enable the measurement of the temperature of the silicon, not the ambient temperature.
UMXXX 5. Second raw T output during calibration: T1_OUT, set T1 = T1_OUT 6. Current raw T output during calibration: T_OUT, set T = T_OUT 7. Current Temperature in Celsius degrees: • T = T0deg + (T1deg-T0deg) * (T-T0)/(T1-T0) HTS221 SYSTEM INTEGRATION To get reliable and consistent measurements, the system design should maximize sensor exposure to the external environment while minimizing error sources. See also application note AN4722.
UMXXX PDM modulated output. The sound inlet (port) can be at the top or at the bottom of the package.
UMXXX 8. Time-of-Flight sensor features The VL53L1X is a state-of-the-art laser-ranging sensor in a miniaturized package. It integrates a 940nm Class 1 vertical-cavity surface-emitting laser (VCSEL), a receiving 16x16 array of single-photon-avalanche-detectors (SPAD), physical infrared filters and optics to achieve the best ranging performance. Unlike conventional ranging sensor, VL53L1X measures the time-of-flight of photons emitted by the laser and reflected back by the target.
UMXXX whenever a new measurement is available. The inter-measurement period must be longer than the selected timing budget plus 4ms.
UMXXX • VL531L1X_CHECKENABLE_SIGMA_FINAL_RANGE: standard deviation in mm, default is 15mm. Decrease to reduce repeatability error, but maximum ranging distance will be reduced. • VL53L1X_CHECKENABLE_SIGNAL_RATE_FINAL_RANGE: rate of photons reflected by target in Mcps, default is 1Mcps. Increase to reduce repeatability error, but maximum ranging distance will be reduced as more photons need to be reflected back and collected by the sensor before a measurement is reported.
UMXXX 9. How to program and debug In order to Flash and debug the BlueNRG-2 sensor node BCN002V1, the corresponding motherboard BCN002V1D is needed. The following software must be installed on the computer: • STSW-STM32102 STM32 Virtual COM port driver (VCOM), not needed for Windows 10. • STSW-BNRGFLASHER utility to Flash using any of the options illustrated below (options A, B, C or D). • STSW-BNRG1STLINK utility to Flash and debug using an ST-Link (see below, options B, C or D).
UMXXX 2. Plug the USB of the motherboard to power the target microcontroller 3. Plug the USB of the external ST-Link to the computer to connect the UART VCOM 4. Run the STSW-BNRG1STLINK utility. The utility will exploit the microcontroller of the external ST-Link. D. Flash and debug using the motherboard (BCN002V1) with ST-Link Stamp V3 assembled (assembled and shown in figure 6). 1. The ST-Link Stamp V3 must be soldered on the motherboard 2.
UMXXX 11. System performance TBD. Figure 10. Average current consumption for the example application 12. Schematic Include schematic already formatted (see companion document). 13. Bill of Materials Include BOM table already formatted (see companion document). 14.
UMXXX • TN1218 Interpreting humidity and temperature readings in the HTS221 digital humidity sensor • TN1198 surface mount guidelines for MEMS sensors in HLGA packages (LPS22HH, HTS221, MP34DT05-A) • AN4428 best practices in the manufacturing process of MEMS microphones • AN4427 gasket design for optimal acoustic performance in MEMS microphones • AN4426 tutorial for MEMS microphones • AN5191 using the programmable region of interest (ROI) with the VL53L1X • UM2356 VL53L1X API user manual Figure
UMXXX exposure. • VL53L1X has an operating range from -20 to +85 degrees. Other components on BlueNRG-2 sensor node have an operating temperature range from -40 to +85 Celsius degrees. The BlueNRG-2 low-energy wireless system-on-chip has a larger operating range from -40 to +105 Celsius degrees. The ambient temperature and relative humidity sensor HTS221 has the largest operating range up to +120 Celsius degrees. • Operating ambient pressure goes from 260 to 1260 hPa.
UMXXX 50 Gauss when magnetic field is aligned with any axis, +/-25 Gauss when it is not aligned. Automatic recovery is activated when larger fields are removed. Recovery is complete if larger field does not exceed 1200 Gauss; if 1200 Gauss limit is exceeded, there will be a residual magnetization of +/-100mGauss for X and Y, +/500mGauss for Z axis. The residual magnetization, if any, can be estimated and compensated as it is done for hard-iron effects (see corresponding paragraph). Max field 10000 Gauss.
UMXXX o Ambient pressure between 260 and 1260 hPa; please note that extreme values or fast variations may cause mechanical stress in the sensor package and affect measurement accuracy. o Relative humidity between 0 and 100%; please note that use of the heating element in HTS221 may be required to restore sensor operation in case of condensation; please note that the board is not protected against condensation of water.
UMXXX 1. This device may not cause interference 2. This device must accept any interference, including interference that may cause undesired operation of the device Déclaration de conformité Cet appareil contient un ou plusieurs émetteurs / récepteurs exemptés de licence conformes à la norme Innovation, Science (s) RSS exemptés de licence par Science et Développement économique Canada.
UMXXX Simplified EU Declaration of Conformity Hereby, STMicroelectronics SRL declares that the radio equipment type STEVALBCN002V1B is in compliance with Directive 2014/53/EU. The full text of the EU declaration of conformity is available at the following internet address: www.st.com/bluetile 18. Radio Features Standard Antenna RF Frequency Max Output Power Bluetooth Low Energy Embedded 2402-2480 8 MHz dBm Table 1: Radio features 19.
UMXXX Given the values shown in tables above, the minimum usage distance is set to: 15 mm.
UMXXX Date Revision Changes 13-Aug-2018 1 A.Vitali: Document draft, some chapter completed. 12-Nov-2018 2 A.Cucchi: Updated chapters for to the radio certifications 21. Contents 1. Introduction ...................................................................................................1 2. Features........................................................................................................2 3. System architecture ...............................................................
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