BMA400

BMA400 3-axes ultra-low power accelerometer BMA400 – Data sheet Document revision 1.2 Document release date July 2019 Document number BST-BMA400-DS000-03 Technical reference code 0 273 141 275 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 2 | 126 Bosch Sensortec | BMA400 Data sheet BMA400 – Basic Description 12 bit, digital, triaxial acceleration sensor with smart on-chip motion and position-triggered interrupt features. Key features  Small package size LGA package (12 pins), footprint 2mm x 2mm, height 0.95 mm  Ultra-low power Low current consumption of data acquisition without compromising on performance (< 14.5 µA with highest performance)  Programmable functionality Acceleration ranges ±2g/±4g/±8g/±16g Low-pass filter bandwidths = 0.48*ODR up to a max. output data read out of 800Hz  On-chip FIFO Integrated FIFO on sensor with 1 KB  On-chip interrupt features Auto-low power/Auto wakeup Activity/In-activity Step Counter (overall device current consumption 4µA) Activity Recognition (Walking, Running, Standing still) Orientation detection Tap/double tap  Digital interface SPI (4-wire, 3-wire), I²C, 2 interrupt pins VDDIO voltage range: 1.2V to 3.6V  RoHS compliant, halogen-free Typical applications        Step Counting with ultra-low current consumption for extensive battery lifetime Advanced system power management for mobile applications and (smart) watches Fitness applications / Activity Tracking Tap / double tap sensing Drop detection for warranty logging Window/door measurements for climate control and alarm systems IoT applications powered by coin cell driven batteries, requiring 1) & 0x03 power_mode = 0x00 ? power_mode = 0x01 ? normal mode End STATUS.power_mode sleep mode, no accel data available YES YES low power mode NO acc_data = read_reg_burst(0x08,6) X = acc_data(0) + 256*acc_data(1) if ( X>2047 ) X=X-4096 Modifications reserved | Data subject to change without notice 6 byte Burst read X,Y,Z data registers in normal or low power mode, calculate X data Document number: BST-BMA400-DS000-03 Revision_1.2_072019 15 | 126 Bosch Sensortec | BMA400 Data sheet 1. Example 3: Testing interrupt engine of BMA400 (example: inactivity interrupt) a. -performing reconfiguration sequence (interrupt feature: significant motion) Normal mode write_reg(addr=0x21,0x04) write_reg(addr=0x20,0x00) write_reg(addr=0x24,0x02) all interrupts only available in normal mode except wake-up, data ready map gen1 interrupt to int1 pin interrupts are non-latched: if interrupt reason vanishes, int1 is deasserted Int1 pin interrupt = HIGH active write_reg(addr=0x3F,0xFA) Enable X,Y,Z axis, data source = acc_filt2 (fixed 100Hz), update reference every time, hysteresis= 48mg write_reg(addr=0x40,0x01) Configure gen1 interrupt to inactivity (criterion=0), AND combination of all axes write_reg(addr=0x41,0x10) set threshold: 8mg/LSB write_reg(addr=0x42,0x00) write_reg(addr=0x43,0x0f) write_reg(addr=0x1F,0x04) set min. duration LSBs to 15 ODR ticks Enable gen1 interrupt in normal mode, mapped to int1 pin and configured as inactivity interrupt with 15ODR ticks minimum duration Shake sensor, int1 should remain LOW. Put sensor on table and wait for the interrupt pin int1 to get HIGH Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 16 | 126 Further steps: The BMA400 has many more capabilities that are described in this document and include FIFO, power saving modes, synchronization capabilities with host processor, data synchronization, many interrupts generation and more features like step counter, etc. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 17 | 126 Bosch Sensortec | BMA400 Data sheet 4. Functional Description Block Diagram acc_osr acc_odr acc_filt1 MEMS C2V, ADC SENSOR DATA AND SENSORTIME REGISTER DIGITAL SIGNAL FILTERING DIGITAL INTERFACE SPI / I2C acc_filt2 FIFO ENGINE Interrupt engine INT1, INT2 acc_filt1: 12.5Hz to 800 Hz acc_filt2: fixed to 100Hz Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 18 | 126 Supply Voltage and Power Management BMA400 has two distinct power supply pins:   VDD is the main power supply. VDDIO is a separate power supply pin used for supplying power for the digital communication interface. There are no limitations with respect to the voltage level applied to the VDD and VDDIO pins, as long as it lies within the respective operating range. Furthermore, the device can be completely switched off (VDD=0V) while keeping the VDDIO supply within operating range or vice versa. However if the VDDIO supply is switched off, all interface pins (CSB, SDX, SCX) must be kept close to GNDIO potential. No constraints exist for the minimum slew-rate of the voltage applied to the VDD and VDDIO pins. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 19 | 126 Bosch Sensortec | BMA400 Data sheet Power Modes – performance modes The power mode and all major settings affecting performance, current consumption, noise and output data rate are controlled in registers ACC_CONFIG0, ACC_CONFIG1 and ACC_CONFIG2. The BMA400 knows three power modes: sleep mode, low-power mode and normal mode. In sleep mode, current consumption is 200nA, and data conversions are stopped as well as sensortime functionality. In low power mode, data conversion runs with a fixed rate of 25Hz, and performance can be controlled via ACC_CONFIG0.osr_lp setting. Current consumption ranges between 800 nA and 1200 nA depending on performance setting. The low power mode should be mainly used in combination with activity detection as self wake-up mode. In this use case, 800 nA are sufficient. In normal mode, output data rates between 800Hz and 12.5Hz can be configured using the registers ACC_CONFIG1.acc_odr and ACC_CONFIG1.osr. The noise density performance of the BMA400 is mainly determined by ACC_CONFIG1.osr. The RMS noise and the resulting current consumption of the device is influenced by ACC_CONFIG1.acc_odr and ACC_CONFIG1.osr. In all three power modes both register contents and FIFO contents are retained. FIFO readout and flushing can be done in normal and low power mode. The FIFO is written only in normal mode. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 20 | 126 Bosch Sensortec | BMA400 Data sheet ACC_CONFIG0. power_mode Description Details b00 b11 Sleep mode (default state after power-up and after reset) No sensortime. No FIFO read, no data conversions. Register and FIFO content retained, registers readable and writeable. Low-power mode Data conversion at 25Hz fixed. Noise performance and current consumption tunable by ACC_CONFIG0.osr_lp setting. Auto wake-up function using wake-up interrupt or timer to switch automatically into normal mode. FIFO read is supported. No FIFO write. Normal mode Data conversion configurable between 800Hz and 12.5Hz. Noise performance and current consumption tunable by ACC_CONFIG1.osr. FIFO read and write All interrupts available Auto-low-power function using generic interrupt 1 or timer to switch automatically into low-power mode. b01 b10 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 21 | 126 Bosch Sensortec | BMA400 Data sheet Current consumption (uA) in normal mode and low-power mode ACC_CONFIG1.osr / ACC_CONFIG0.osr_lp Normal mode ACC_CONFIG0. power_mode = b10 Low-power mode ACC_CONFIG0. power_mode = b01 11 10 01 00 14.5 9.5 5.8 3.5 1.35 1.1 0.93 0.85 Noise performace (rms in mg) in normal mode and low-power mode in 4g range (x and y axes are shown, Z-axis is 1.45 x higher ) ACC_CONFIG1.osr / ACC_CONFIG0.osr_lp ODR [Hz] 11 10 01 00 800 4.23 5.49 7.39 10.24 400 2.98 3.89 5.23 7.24 200 2.11 2.74 3.70 5.13 100 1.50 1.93 2.61 3.63 50 1.05 1.38 1.84 2.55 25 0.74 0.97 1.31 1.81 12.5 0.54 0.68 0.92 1.29 3.92 5.53 7.75 10.96 Normal mode ACC_CONFIG0. power_mode = b10 Low-power mode ACC_CONFIG0. power_mode = b01 Modifications reserved | Data subject to change without notice 25 Document number: BST-BMA400-DS000-03 Revision_1.2_072019 22 | 126 Bosch Sensortec | BMA400 Data sheet Auto wake-up The auto-wakeup function is part of the power management concept of the BMA400. If the wakeup function (only available in low-power mode) changes the power mode to “normal”, the host processor can be notified by an interrupt. This is called “wakeup interrupt”, thus, the two topics “auto wakeup” and “wakeup interrupt” are handled together in this chapter. The transition from Low-power to Normal mode is named “wake-up”. Switching into Normal mode from Low-power mode can be explicitly triggered by a serial interface command. This can also be done automatically by using the auto wakeup function. Auto wakeup can be either timer triggered or activity triggered. Each selected condition is independent and can be used as wake-up condition. In case more than one condition is selected, the first occurred condition sets the BMA400 into normal mode. The three possible triggers for wake-up from low-power mode are: - by serial command - by timeout - by wake-up interrupt on activity Wakeup by timeout The source condition wkup_timeout (enabling bit) and the timeout counter threshold value AUTOWAKEUP(0/1).wakeup_timeout_thres is configured in register AUTOWAKEUP_(0/1). The wakeup_timeout_thres has 12bits for configuration of counter duration, with a resolution of 2.5ms/LSB. The maximum timeout for wake-up is 10.24s (4096*2.5ms). Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 23 | 126 Bosch Sensortec | BMA400 Data sheet Wake-up interrupt on activity In low-power mode BMA400 wake-up interrupt is triggered, if the conditions as defined by the configuration registers are fulfilled. This function is always on in low power mode, and can be mapped to interrupt pin. The wake-up can be used for auto wake-up of BMA400 to normal mode and/or the wake-up of the external MCU by mapping the interrupt to the interrupt pin. The wake-up interrupt function evaluates acceleration data and is set as soon as the value of the sampled data exceeds the preconfigured acceleration threshold. The comparison of the current acceleration value with a reference is configurable between relative reference (last sampled value stored in the register) and absolute reference (the reference values are set once and not changing after each acceleration conversion). The delay between two data conversions is 40ms (25Hz conversion ODR in Low-power). The auto wake-up by wakeup interrupt on activity is activated by setting AUTOWAKEUP_1.wkup_int bit. The wakeup status is available in INT_STAT0.wkup_int. When woken up, an interrupt can be generated and mapped to the interrupt pins. The wake-up interrupt function supports following configurations:  Selectable axis for wake-up: the wake-up interrupt function supports independent activation/deactivation of each acceleration axis for function evaluation. This is performed by setting the bits WKUP_INT_CONGIF0.wkup_X/Y/Z_en accordingly.  Reference update mode (configured by setting WKUP_INT_CONFIG0.wkup_refu) wkup_refu description of wake-up interrupt references update mode b00 manual update The references (int_wkup_refX/Y/Z) are not updated automatically, they shall be set manually by user in low-power mode. b01 one time The references is updated every time at entering low power mode. The first measured acceleration in Low-power mode is used as reference. b10 or b11 every time The reference is updated every time after the acceleration conversion in low-power mode The reference values are 8-bit signed values. The activity measurement takes the upper 8 bits of the acceleration value and compares against the reference WKUP_INT_CONFIG[2-4].int_wkup_ref[x,y,z].  Threshold for activity detection: the threshold for activity detection (comparison of the difference between the measured acceleration data and reference acceleration data) has 8-bit resolution, corresponding to the upper 8 bits of the absolute value of the 12bit acceleration, WKUP_INT_CONFIG1.int_wkup_thres.  Number of samples for decision: the number of samples for wake-up decision is configured between 1 and 8 by the register WKUP_INT_CONFIG0. num_of_samples (number of samples is the register value + 1). Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 24 | 126 Bosch Sensortec | BMA400 Data sheet The condition for activity-driven automatic wake-up from low-power is (assuming all 3 axes are enabled): ( abs(a_x-ref_x) > thresh_x ) OR ( abs(a_y-ref_y) > thresh_y ) OR( abs(a_z-ref_z) > thresh_z ) This condition must persist for WKUP_INT_CONFIG0. num_of_samples data samples. The wake-up on activty is illustrated in the following picture Wake-up interrupts can be used latched and non-latched (see chapter 0). Latched and non-latched behavior is shown below. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 25 | 126 Bosch Sensortec | BMA400 Data sheet Auto low-power mode Power mode can be changed from Normal to Low-power mode through a serial interface command. It is also possible to change automatically (without a serial command) from normal mode to low-power mode, which is called auto low-power. The following timed and non-timed triggers are supported for automatic switching from Normal mode to Low-power mode: • First data ready: (AUTOLOWPOW_1.auto_lp_timeout =b00) If AUTOLOWPOW_1.drdy = ‘1’, BMA400 is set into low-power mode when new data calculation is finished. • Generic interrupt 1: (AUTOLOWPOW_1.auto_lp_timeout =b00) If AUTOLOWPOW_1.gen1_int = ‘1’, BMA400 is set into Low-power mode as soon as the Generic interrupt 1 is detected. (see chapter 4.7) • low_power_timeout (AUTOLOWPOW_1.auto_lp_timeout =b01): the sensor is set into low-power mode as soon the timeout counter reaches AUTOLOWPOW_1.auto_lp_timeout_thres. The auto-low-power timeout counter is 12 bits wide and is incremented every 2.5ms. • low_power_timeout with counter reset on activity detected (AUTOLOWPOW_1.auto_lp_timeout =b10,b11): the timeout counter is restarted in case generic interrupt 2 (see chapter 4.7) is asserted. The sensor is set into low-power mode when finally the timeout counter reaches AUTOLOWPOW_1.auto_lp_timeout_thres. The auto-low-power timeout counter is 12 bits wide and is incremented every 2.5ms. The timed timeout trigger can be configured by setting AUTOLOWPOW_1.auto_lp_timeout bits in register according to the table below. AUTOLOWPOW_1.auto_lp_ti meout Description b00 timeout disabled, use either AUTOLOWPOW_1.drdy or AUTOLOWPOW_1.gen1_int to switch automatically into low-power mode b01 timeout active, BMA400 switching into low-power mode as soon as timeout counter reaches AUTOLOWPOW_1.auto_lp_timeout_thres b10 or b11 Low-power timeout active, timeout counter resets on activity detection Multiple selections of auto-low-power conditions are supported. Any selected condition switches the device into low-power mode (OR condition). The logical connection of the auto-low-power conditions is shown in the picture below. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet Modifications reserved | Data subject to change without notice 26 | 126 Document number: BST-BMA400-DS000-03 Revision_1.2_072019 27 | 126 Bosch Sensortec | BMA400 Data sheet Sensor Data Acceleration Data The width of acceleration data is 12 bits given in two´s complement representation in the registers 0x04 to 0x09 (ACC_X_LSB, ACC_X_MSB, ACC_Y_LSB, ACC_Y_MSB, ACC_Z_LSB, ACC_Z_MSB ). The 12 bits for each axis are split into an MSB upper part (4 bit) and an LSB lower part (8 bit). In order to ensure the integrity of the acceleration data read, the content of all data registers must be read in a single burst read, since these registers are write-protected during a read access. As soon as the burst read is finished the register content will be updated if new data are available. Filter Configuration Two major filter paths are implemented, see block diagram. Filter output can either be fed into the data registers, into the FIFO, or used to process interrupts in the interrupt engine. This is selectable by customer. Filter1 (acc_filt1) has a data rate between 800Hz and 12.5Hz, controlled by ACC_CONFIG0.acc_odr. Its bandwidth can be configured additionally by ACC_CONFIG0.filt1_bw:  ACC_CONFIG0.filt1_bw = 0x0 0.48 x ODR  ACC_CONFIG0.filt1_bw = 0x1 0.24 x ODR ACC_CONFIG0.acc_odr Output Data Rate [Hz] 0xB .. 0xF 800 0xA 400 0x9 200 0x8 100 0x7 50 0x6 25 0x0 .. 0x5 12.5 Filter2 (acc_filt2) has a fixed data rate of 100 Hz. In addition, these 100 Hz data of filter2 can be used by a low pass filter (acc_filt_lp) with a bandwidth of 1 Hz. The output data rate will stay at 100 Hz. This data can be used as input for the data registers and also in the interrupt engine. Access via FIFO is not possible. ACC_CONFIG2.data_src_reg Filter output going into data registers (not FIFO!) 0x0,0x3 acc_filt1(selectable ODR) 0x01 acc_filt2 (100Hz ODR) 0x02 acc_filt_lp (1 Hz BW, 100 Hz ODR) FIFO_CONFIG0.fifo_data_src Filter output going into FIFO 0x0 acc_filt1(selectable ODR) 0x1 acc_filt2 (100Hz ODR) In low-power mode, only data at 25Hz ODR is available. Depending on the setting of ACC_CONFIG0.osr_lp, noise and current consumption is controllable. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 28 | 126 Bosch Sensortec | BMA400 Data sheet G-range selection The measurement g-range can be selected between 2g and 16g. It can be configured ACC_CONFIG1.acc_range. ACC_CONFIG1.acc_range 11 10 01 00 Selected g-range 16g 8g 4g 2g Data Ready Interrupt This interrupt fires whenever a new data sample set is complete. This allows a low latency data readout. In non-latched mode, the interrupt and the flag in Register INT_STAT0 are cleared automatically after 1/(1600Hz). If this automatic clearance is unwanted, latched-mode can be used. In order to enable/use the data ready interrupt map it on the desired interrupt pin via INT1_MAP or INT2_MAP. Temperature Sensor The temperature sensor has 8 bits resolution. The temperature value is defined in Register TEMP_DATA and updated every 160ms. It is always on when the sensor is active (in normal and in low-power mode, not in sleep mode). Value Temperature 0x7F 87.5 °C … … 0x02 25 °C … … 0x80 -40.0 °C The temperature sensor is calibrated with a precision of +/-5°C. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 29 | 126 Bosch Sensortec | BMA400 Data sheet Sensor Time The BMA400 has an integrated sensor timer. The sensor time can be used for synchronization purposes between the external MCU and the sensor. The sensor timer counts the clock cycles generated by the system clock which is always running in low-power and normal modes. Sensor timer is inactive in sleep mode and reset when entering the sleep mode. Counter values are stored in registers SENSOR_TIME(0/1/2). The sensor timer has a resolution of 21 bits stored in 3 bytes. For compatibility with other sensors that use faster counters with 25.6 kHz, the lower three bits of the counter (sensor_time) are always 0. Thus, the lowest significant bit of the counter is sensor_time. After the timer has reached the maximum value, the counter resets to zero. Bit m in 23 22 21 … 8 7 81.92 s … 10 ms 5 ms 6 5 4 3 sensor_time Resolution 327.68 s 163.84 s 2.5 ms 1.250 ms 0.625 ms 0.3125 ms Update rate 0.0031 0.0061 0.012 … 100 200 400 800 1600 [Hz] The sensortime is synchronized with the data capturing in the data register and the FIFO. The sensortime supports multiple seconds of sample counting and a sub-millisecond resolution. Burst reads on the registers SENSORTIME_0 to SENSORTIME_2 deliver always consistent values, i.e. the value of the register does not change during the burst read. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 3200 30 | 126 Bosch Sensortec | BMA400 Data sheet FIFO FIFO description Acceleration data are stored in a 1024Bytes FIFO. The FIFO is written only in normal mode. When FIFO_CONFIG0.fifo_stop_on_full = ‘0’, the device is in stream mode. When FIFO_CONFIG0.fifo_stop_on_full = ‘1’, the device is in FIFO mode.  Stream mode: overwrites oldest data on FIFO full condition  FIFO full mode: discards newest data on FIFO full condition The FIFO depth is 1024 byte and supports the following interrupts:  FIFO full interrupt  FIFO watermark interrupt The data to be collected is defined through fifo_data_src, fifo_x_en, fifo_y_en and fifo_z_en bits. FIFO is disabled when no writing is defined; FIFO is therefore disabled when fifo_x_en=’0’, fifo_y_en=’0’ and fifo_z_en=’0’. If the FIFO is disabled when FIFO byte count is greater than 0, no new frame is written to the FIFO, but FIFO is operational:  Frames already written in the FIFO remain stored and can be read out  FIFO interrupts and their corresponding statuses are still evaluated  after all bytes are read out, sensortime (if enabled) and empty frames are generated  FIFO can be flushed FIFO input data Storing of acceleration measurement results is enabled by setting respectively fifo_x_en = ’1’ and/or fifo_y_en = ’1’ and/or fifo_z_en = ’1’. Storing of data can be enabled or disabled on a per-axis basis in any combination. acc_filt1 or acc_flit2 data are stored in the FIFO depending on fifo_data_src bit. Thus, the data rate with which data is stored in the FIFO equals the data rate with which the filter serving as data source is configured. The number of bytes available in the FIFO is readable through fifo_bytes_cnt. The FIFO byte count registers FIFO_LENGTH0 and FIFO_LENGTH1 are updated only when a full frame has been written to the FIFO and is available for read-out. FIFO byte count registers are also updated after each full frame read from the FIFO. FIFO byte count registers increment or decrement is equal to the frame length; intermediate increments (corresponding to a partial frame) are not readable. The FIFO shall support two modes for acceleration data storage in FIFO: 12 bits stored as two bytes into FIFO and 8-bit mode (upper 8 bits of 12 bits) stored as single byte into FIFO per acceleration axis. The 8-bit mode activation shall be performed by setting FIFO_CONFIG0.fifo_8bit_en = ‘1’. FIFO read out The FIFO can be read out via FIFO_DATA register in a single burst read, this allows a complete reading of the FIFO content within one burst read transaction. FIFO read out is not supported in Sleep mode. FIFO read out is supported in normal and Low-power mode if FIFO_PWR_CONFIG.fifo_read_dis = ‘0’. The minimum delay Tfifo_read = 50µs has to be applied between enabling FIFO read and the start of FIFO read. Don’t read the FIFO when FIFO_PWR_CONFIG.fifo_read_dis =‘1’. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 31 | 126 Bosch Sensortec | BMA400 Data sheet FIFO overflow behavior A FIFO overflow occurs if the FIFO is full and a new data is to be written to the FIFO. FIFO full means free space is less than maximum frame length of 9 bytes. The largest frame is 7 bytes long, however each time FIFO is written (at the end of the measurement), 9 bytes can be written to the FIFO in total, consisting of 2 frames: one with the measurement results (maximum of 7 bytes), and configuration change frame consisting of 2 bytes. The definition of the full interrupt uses 9 bytes limit to give the host system time to react to it before the FIFO overflows. In case of overflow the FIFO can either stop recording data or overwrite the oldest data. The behavior is controlled by register fifo_stop_on_full. Streaming mode, fifo_stop_on_full = ’0’: if the new frame does not fit inside the remaining free space in the FIFO RAM, FIFO will repeatedly delete the oldest frame until it creates enough space for the new one. FIFO stop-on-full mode, fifo_stop_on_full = ’1’: The newest frame is discarded. Normal operation resumes if the FIFO full condition no longer persists. Frames The FIFO captures data in frames, which consist of a header and a payload.  Each data frame consists of a one byte header describing properties of the frame, (which data are included in this frame) and the data itself. Beside the data frames, there are control frames, sensortime frames and empty frames. The header has a length of 8 bit and the following format: Bit Header 7 6 fh_mode 5 4 3 fh_param 2 1 0 0 fh_mode and fh_param indicate whether the frame is a data frame (accel data), a sensortime frame ( sensortime data), a control frame or an empty frame (all data 0). A data frame is composed of the said header and a set of acceleration data organized as described in table below. Bit Header Data 1..7 7 6 5 4 3 2 1 0 fh_mode fh_param 0 1 .. 7 Data bytes, number depending of 12 or 8bit storage mode and number of axes enabled. These fh_mode and fh_parm fields are defined below fh_mode Definition fh_param fh_param fh_param 0b10 Sensor data frame b0: Sensor data frame b0: 8bit mode b1: 12bit mode Enabled axes 0b10 sensortime frame b1: sensortime frame no meaning No meaning 0b01 Control frame Modifications reserved | Data subject to change without notice b00100 Document number: BST-BMA400-DS000-03 Revision_1.2_072019 32 | 126 Bosch Sensortec | BMA400 Data sheet Name fh_parm Bit Content 2 1 0 z-enabled y-enabled x-enabled f_param=0b0000 is invalid for regular mode, a header of 0x80 indicates an uninitialized frame. In a data frame, fh_param defines which sensors axes are included in the data part of the frame. fh_param defines in which resolution – 8 or 12bit – the data are stored. fh_param indicate whether Z, y or x axis data are stored. Thus, fh_param allows to calculate the amount of data payload following the header. The maximal payload is 6 bytes if all axes are enabled and 12bits are stored. 3bytes payload are needed if all axes are enabled and 8bits are stored. A lesser amount of data is required if one or two axes are disabled. As an example, data frames with 12bit and 8bit resolution are shown below, all axes enabled Bit Header 7 1 6 0 5 0 4 1: 12bit 3 1: Z unused 2 1 1: Y 1: X acc_x 0 0 acc_x data unused acc_y acc_y unused acc_z acc_z Bit Header 7 1 6 0 5 0 4 3 0: 8bit 1: Z acc_x 2 1: Y 1 1: X 0 0 acc_y data acc_z A FIFO empty frame is a sensor data frame, this is what the header indicates (fh_mode=b10). fh_param=b000 shows that the frame delivered is an empty frame and contains 1 data byte of value 0x00 after the header. This kind of frame is delivered if the last frame in the FIFO was already read out or if the FIFO is empty. The format is shown below. Bit Header Data 7 1 0 6 0 0 Modifications reserved | Data subject to change without notice 5 0 0 4 0 0 3 0 0 2 0 0 1 0 0 0 0 0 Document number: BST-BMA400-DS000-03 Revision_1.2_072019 33 | 126 Bosch Sensortec | BMA400 Data sheet If fh_param= b10000, the header indicates a sensor-time frame to come, its format shown below. Bit Header 7 1 6 0 time 5 1 4 3 0 0 sensor_time sensor_time sensor_time 2 0 1 0 0 0 The data for the sensor-time frame consists of registers sensor_time2/1/0 at the moment the sensor-time frame transmission has started. A sensor-time frame is not stored in the FIFO, it is created on-the-fly and delivered with a FIFO burst read operation when all acceleration data frames have been transmitted and the burst read carries on requesting data. The sensortime frame will only be delivered if fifo_time_en = ‘1’. The already mentioned control frame looks as follows Bit 7 6 5 4 3 2 1 Header 0 1 0 0 1 0 0 Opcode 0 1 1 0 0 acc_config1_chg acc_config0_chg - 0 0 fifo_config0_chg fifo_config0_chg = b1: The control frame will be inserted when FIFO_CONFIG0.fifo_data_src change becomes active in FIFO. acc_config0_chg = b1: The control frame will be inserted when ACC_CONFIG0.filt1_bw change is valid for data stored in FIFO. acc_config1_chg: The control frame will be inserted when ACC_CONFIG1.acc_odr or ACC_CONFIG1.osr or ACC_CONFIG1.acc_range change is valid for data stored in FIFO. If more changes become active at one acceleration sample just one control frame will be inserted, with more than one of the three CONF_chg bits set. The data format for data frames is identical to the format defined for the data registers: signed integer. If no axis is selected for FIFO storage no frames are written into the FIFO. Under-read In case the FIFO is under-read (not all frames were taken from the FIFO, but the last frame read was read entirely), the next readout will continue at the frame that was just about to be sent. Partial frame read In case the FIFO is under-read and a partial data frame read occurred (not all frames were taken from the FIFO, and the last frame read was not read entirely), the entire last data frame is repeated upon the next read access. When fifo_stop_on_full=‘0’ oldest frames are overwritten when new frames are available and the FIFO is full. When this happens, the partially read data frame is not repeated but the oldest frame available in the memory is sent instead. Sensortime frame is not repeated when it is read only partially. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 34 | 126 If the read of a frame is interrupted during the frame's last byte read, this partial read is not recognized and the frame is discarded like a fully read frame. Over-read If the burst read continues after all frames have been read out, a sensortime frame is sent after the FIFO becomes empty during a burst read operation if fifo_time_en=’1’. After that or when FIFO was completely read, the empty frame is returned as long as the burst read is active. Reading nearly-empty FIFO FIFO contains a reading cache buffer for a complete frame. When there is only one unread byte left in the reading buffer, the FIFO starts prefetching the next frame from the memory to be ready for burst reading if there is any further frame, or it evaluates itself as empty. If new data frames/config frames are written to the FIFO before this reading event, the FIFO will behave as containing one further frame and the new frame will be made available for reading as the next frame. If new data/config frames are written to the FIFO after the moment when "only one unread byte is left in the buffer", then user will see the FIFO as empty after the current frame will be finished. FIFO flushing A FIFO flush operation is executed when a flush command is written to the CMD register, when a softreset command is issued or when the device changes power mode and FIFO auto flush is enabled through FIFO_CONFIG0.auto_flush bit. For system simplicity, a flush is executed as soon as possible. FIFO can be written or flushed at any time when FIFO is not read. Flush operation does not depend on serial interface activity to finish. Power mode transition (or write) does not have to wait for the Flush to finish. Serial interface always reads what is in the FIFO at the moment the next frame is prepared for the output buffer. Empty frames are read if the FIFO was flushed during the transaction. FIFO watermark interrupt Watermark interrupt status is asserted when the watermark interrupt condition is satisfied i.e. when the filling level of the FIFO (number of unread bytes in the FIFO) is greater or equal to the watermark level (fifo_bytes_cnt ≥ fifo_watermark). FIFO watermark interrupt is enabled by setting INT_CONFIG0.fwm_int = ‘1’. It can be mapped to INT1/2 pad. When the FIFO watermark level is set to zero, the interrupt condition is never satisfied. The status of the watermark interrupt can be read back through the INT_STAT0.fwm_int bit. Interrupt status is cleared by reading the INT_STAT0.fwm_int bit when the FIFO filling level is lower than the watermark level. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 35 | 126 Bosch Sensortec | BMA400 Data sheet The interrupt is only evaluated after entire frames have been read out or written (as the counter is only in-/decreased on a frame basis). Watermark interrupt condition is also updated after the end of the serial interface (burst write) transaction which wrote into the registers fifo_watermark or fifo_watermark. The behavior of the FIFO watermark is shown in the figures below. FIFO watermark interrupt, non-latched, with reads from FIFO FIFO watermark interrupt, latched, with reads from FIFO FIFO full interrupt The full interrupt can be enabled by setting bit INT_CONFIG0.ffull_en = ‘1’. It can be mapped to INT1/2 pad. Full interrupt status is asserted when the full interrupt condition is satisfied, when the filling level of the FIFO (number of unread bytes in the FIFO = fifo_bytes_cnt) is equal or higher than 1016. The status of the full interrupt can be read back through the INT_STAT0.ffull_int bit. Interrupt status is cleared by reading the INT_STAT0.ffull_int bit high '1' when the FIFO filling level is lower than 1016. The behavior of the FIFO full interrupt is shown in the figures below. INT_STATUS.ffull_int FIFO full interrupt, non-latched, with reads from FIFO Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 36 | 126 Bosch Sensortec | BMA400 Data sheet INT_STATUS.ffull_int FIFO full interrupt, latched, with reads from FIFO Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 37 | 126 General Interrupt Pin configuration Interrupt Pin Mapping The content of the interrupt status registers can be mapped to pins INT1 or INT2, by setting the corresponding bits from the registers INT1_MAP, respectively INT2_MAP or INT12_MAP. To disconnect the features outputs to the external pins, the same corresponding bits must be reset, from the registers, INT1_MAP, respectively INT2_MAP or INT12_MAP. Once a feature triggered the output pin, the Host can read out the corresponding bit from the register, INT_STAT0, INT_STAT1 or INT_STAT2 . Interrupt latching Interrupts can be configured as non-latched or latched. The mode is selected by INT_CONFIG1.latch_int. Latching determines when an interrupt is released. The behavior of the different interrupt modes is shown graphically in the figure below Non-latched mode In the non-latched mode (INT_CONFIG1.latch_int = 0), both the INT pins (the contribution to the ´or´ condition for the INT pin) and the interrupt status bit in INT_STAT are reset when the interrupt activation condition is released. Latched mode In latched mode (INT_CONFIG1.latch_int = 1) an asserted interrupt status in INT_STAT(0/1/2) and the INT pin (the contribution to the ´or´ condition for the INT pin) is cleared by reading the corresponding status register. If the FIFO filling activation condition still holds true then the interrupt status is not cleared. Data ready and advanced interrupts' statuses are cleared upon reading INT_STAT register. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 38 | 126 Interrupt behavior during power mode switching When the device leaves normal mode, all internal interrupt status registers are cleared. There are two exceptions: - The step counter keeps its state (i.e. the step count) on mode switching. If the mode is switched to normal with enabled step counter, it continues counting on the previous value. The internal interrupt status is cleared. - FIFO interrupts are not cleared by mode switching Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 39 | 126 Bosch Sensortec | BMA400 Data sheet Electrical Interrupt Pin Behavior Both interrupt pins INT1 and INT2 can be configured to show the desired electrical behavior. The ‘active’ level of each interrupt pin is determined by the int1_lvl and int2_lvl bits. If int1_lvl = 1 / int2_lvl = 1, then pin “INT1” / pin “INT2” are active HIGH. The characteristic of the output driver of the interrupt pins is configured with bits int1_od and int2_od. By setting bits int1_od / int2_od to ‘1’, the output drivers show open-drive characteristic, by setting the configuration bits to 0, the output drivers show CMOS push-pull characteristic. When open-drive characteristic is selected in the design, an external pull-up or pull-down resistor should be applied according the int(1/2)_lvl configuration. For all interrupts, the user is responsible of the settings, no hardware checks of the settings are implemented before processing interrupts. int(1/2)_od int(1/2)_lvl “INT1” / “INT2” output driver 0 0 active ‘0’ push-pull characteristic 0 1 active ‘1’ push-pull characteristic 1 0 active ‘0’ open-drive characteristic sink (NMOS) 1 1 active ‘1’ open-drive characteristic source (PMOS) Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 40 | 126 Bosch Sensortec | BMA400 Data sheet Interrupt Features The following interrupts exist in the BMA400: Basic interrupts - Data ready interrupt - FIFO watermark - FIFO full - Interrupt engine overrun - Wake-up interrupt Advanced Interrupts - Generic interrupt 1 - Generic interrupt 2 - Step detector interrupt/step counter - Activity changed interrupt - Single tap / Double tap sensing - Orientation changed interrupt Basic interrupts can all be enabled independently from each other. Advanced interrupts are only available in normal mode, the interrupt engine is disabled in low power mode and sleep mode. Advanced interrupts are served by the interrupt engine. They share the same resources, thus, enabling too many interrupts of this type in parallel may lead to a so-called Interrupt engine overrun. This interrupt indicating that the interrupt engine could not finish calculating all selected interrupt conditions. If this occurs, advanced interrupts of lesser importance must be disabled until the Interrupt engine overrun condition/interrupt vanishes. Any change of an interrupt configuration must be executed when the corresponding interrupt is disabled. For most interrupts a data rate of 100Hz is recommended, only tap sensing requires 200Hz. It is then necessary to configure the data source of the tap sensing interrupt, filter acc_filt1, to 200Hz, which implies that the other interrupts requiring 100Hz data rate use another filter. Interrupt pin mapping, interrupt status The BMA400 supports flexible INT1 and INT2 pin mapping configurations via interrupt mapping registers INT1_MAP, INT2_MAP and INT12_MAP. Depending on these registers settings, all interrupt sources are mapped to the INT1 and INT2 pins. The status of the interrupts can be read out at the status registers INT_STAT0, INT_STAT1 and INT_STAT2. Additionally, the step counter value is stored in the registers STEP_CNT0…STEP_CNT2 . These registers need to be read out using a burst read to avoid one register being updated while another step count register is read. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 41 | 126 Bosch Sensortec | BMA400 Data sheet Generic Interrupt 1 and 2 The generic interrupts 1 and 2 have the exact same implementation. They are designed to detect activity or inactivity. The generic interrupt monitors acceleration change with respect to a reference, or in other words, the difference between actual acceleration and reference is calculated and compared against a threshold. The comparison is de-noised using a hysteresis. The generic interrupt is triggered when the above mentioned difference lasts for a minimum time. Reference, threshold, hysteresis and duration are configurable. Both generic interrupts work the same way, but have separate sets of registers to be processed independently of each other.  Generic interrupt 1 is enabled by ‘INT_CONFIG0.gen1_int_en = 1’  Generic interrupt 2 is enabled by ‘INT_CONFIG0.gen2_int_en = 1’ The generic interrupt supports selectable acceleration axes for evaluation: GEN(1/2)INT_CONFIG0.act_(x/y/z)_en. GEN(1/2)INT_CONFIG1.comb_sel selects if the interrupt shall be based on an AND (comb_sel = 1) or an OR (comb_sel = 0) combination of all enabled axes. The acceleration data source is selectable between acceleration from acc_filt1 or acc_filt2 by setting GEN1/2INT_CONFIG0.data_src (0: acc_filt1, 1:acc_filt2). The data rate for the filter output must be 100Hz. Using acc_filt2 is recommended. In this case acc_filt1 can be used independently from the interrupt engine for the data output registers and the FIFO. GEN(1/2)INT_CONFIG0.data_src Source for generic interrupt data 0 acc_filt1 1 Figure 1:Signal flow for generic interrupt acc_filt2 The mentioned reference can be static (user defined) or it can be updated dynamically. The reference acceleration registers support reference update modes after comparison evaluation has been done. The mode is set in GEN(1/2)INT_CONFIG0.act_refu Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 42 | 126 Bosch Sensortec | BMA400 Data sheet GEN(1/2)INT_CONFIG0.act_refu Description of reference update mode b00 manual update – reference is statically set by user using GEN(1/2)INT_CONFIG4/5/6/7/8/9 (read back after interrupt is activated) b01 one time – the reference is updated once by acceleration data taken from the data source (acc_filt1 or acc_filt2) after triggering the interrupt Reference will also be updated after entering normal mode. b10 every time – the reference is updated at the end of the interrupt evaluation, it is taken from the data source (acc_filt1 or acc_filt2). This mode especially makes sense for activity detection where a “constantly” increasing acceleration shall be detected. b11 every time - the reference is updated at the end of the interrupt evaluation, it is taken from the data source acc_filt_lp. Remember the large group delay (1Hz bandwidth) of acc_filter_lp As already mentioned, both interrupts can be configured to detect activity or inactivity. This is done using GEN(1/2)INT_CONFIG1.criterion_sel. GEN(1/2)INT_CONFIG1.criterion_sel = 0: inactivity detection, referenced acceleration below threshold GEN(1/2)INT_CONFIG1.criterion_sel = 1: activity detection, referenced acceleration above threshold The reference values for each axis are stored in registers GEN(1/2)INT_CONFIGX.int_th_ref(x/y/z), they are 12-bit signed values. The values are range sensitive, and the physical value of LSB corresponds to 2^(2+acc_range)/4096, here acc_range = 0, 1, 2, 3 corresponds to +/-2g, +/-4g, +/-8g, +/-16g. The threshold value are stored in register GEN(1/2)INT_CONFIGX.gen_int_thres, it is 8-bit unsigned value, fixed resolution of 8mg for all measurement ranges. The interrupt supports a configurable duration condition: GEN(1/2)INT_CONFIGX.gen1_int_dur indicates the resolution in data ready ticks. So, the duration depends on the data rate the selected filter delivers. A hysteresis helps to suppress noise in the decision-making. The effective threshold value is set to (gen_int_thres – act_hyst) after the first true evaluation of the threshold condition and changed back to (gen_int_thres) as soon as the condition is false. GEN(1/2)INT_CONFIG0.act_hyst. Following hysteresis configurations for the activity comparison are available: GEN(1/2)INT_CONFIG0.act_hyst Description of hysteresis amplitude (mg) b00 0 b01 24 b10 48 b11 96 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 43 | 126 Bosch Sensortec | BMA400 Data sheet Step Detector / Step Counter The Step Counter algorithm is optimized to high accuracy, while Step Detector is optimized to low latency. Both are running in parallel, once enabled. The step counter computation is enabled if INT_CONFIG1.step_int = ‘1’. Step Counter: The step counter accumulates the steps detected by the step detector interrupt, and makes available the 24 bit current step counter value in the 3 registers STEP_CNT0... STEP_CNT2 , each holding 8bit. Step Detector: Once a step is detected the INT_STAT1.step_int interrupt signal is set to 1 (one step detected) or 2 (step detected and very likely to have missed a step before; "double step"). There are situations when the step counting value is different than the sum of steps detected by the step detector. Step Counter/Detector sensitivity: The step counter uses 24 configuration registers STEP_COUNTER_CONFIG0 to STEP_COUNTER_CONFIG23. The step counter and detector use case (device position) can be modified by setting these parameters to the corresponding values in the table below. By default and after reset, the wrist use case is configured. Register name Address STEP_COUNTER_CONFIG0 0x59 1 1 STEP_COUNTER_CONFIG1 0x5A 45 50 STEP_COUNTER_CONFIG2 0x5B 123 120 STEP_COUNTER_CONFIG3 0x5C 212 230 STEP_COUNTER_CONFIG4 0x5D 68 135 STEP_COUNTER_CONFIG5 0x5E 1 0 STEP_COUNTER_CONFIG6 0x5F 59 132 STEP_COUNTER_CONFIG7 0x60 122 108 STEP_COUNTER_CONFIG8 0x61 219 156 STEP_COUNTER_CONFIG9 0x62 123 117 STEP_COUNTER_CONFIG10 0x63 63 100 STEP_COUNTER_CONFIG11 0x64 108 126 STEP_COUNTER_CONFIG12 0x65 205 170 STEP_COUNTER_CONFIG13 0x66 39 12 STEP_COUNTER_CONFIG14 0x67 25 12 STEP_COUNTER_CONFIG15 0x68 150 74 STEP_COUNTER_CONFIG16 0x69 160 160 STEP_COUNTER_CONFIG17 0x6A 195 0 STEP_COUNTER_CONFIG18 0x6B 14 0 STEP_COUNTER_CONFIG19 0x6C 12 12 STEP_COUNTER_CONFIG20 0x6D 60 60 STEP_COUNTER_CONFIG21 0x6E 240 240 STEP_COUNTER_CONFIG22 0x6F 0 1 STEP_COUNTER_CONFIG23 0x70 247 0 Modifications reserved | Data subject to change without notice wrist (default) non-wrist Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 44 | 126 The parameters for wrist use case and non-wrist use case have been obtained using hundreds of experiments used to tweak these parameters for optimal performance. Changing these parameters should only be done by experts. The reset parameters can be overwritten before enabling the step counter/interrupt. The step count value is reset during power-on-reset, soft-reset, or step counter reset command transmitted to the device via the command Register CMD. The step count value is not reset when the step counter is enabled or disabled. Activity recognition The step counter state is indicated in the register STEP_STAT.step_stat_field, it contains the status STILL(0x00), WALK(0x01) or RUN(0x02). Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 45 | 126 Bosch Sensortec | BMA400 Data sheet Activity changed interrupt The device provides an “activity changed” interrupt. The activity changed interrupt evaluates acceleration data for a certain activity over a predefined observation period and sets an interrupt after activity change is detected compared to previously evaluated activity. The enable signal for this interrupt is INT_CONFIG1.actch_int. The activity changed interrupt supports data source selection by setting ACTCH_CONFIG1.actch_data_src bit. The acceleration data source shall be selectable between acceleration from acc_filt1 and acceleration acc_filt2. data_src Description 0 acc_filt1 1 acc_filt2 Following steps are performed for activity changed interrupt evaluation:  Evaluation of the current activity parameter: average (| acc - acc_lp |) of the dynamic acceleration with respect to the quasi-static acceleration (low-pass filtered value acc_filt_lp) over a certain observation period.  Comparison of the currently evaluated activity parameter with last stored activity parameters (activity parameters for previous observation period): abs(curr_value – last_value) > threshold.  Update / store the activity parameters: curr_value => last_value.  Activity changed status bits (actch_z_int, actch_y_int, actch_x_int): signalize activity changed for corresponding axes, “1” for activity changed. Following configurations are supported for activity changed interrupt:  Selectable acceleration axis for evaluation (actch_x_en, actch_y_en, actch_z_en)  Threshold for activity change. The configuration of the activity threshold is defined by ACTCH_CONFIG0.actch_thres  Number of samples of the observation duration. The observation period is defined by the number of data samples used for the evaluation of the activity parameters. The observation period is defined by the setting ACTCH_CONFIG1.actch_npts. ACTH_CONFIG1.actch_npts 0000 0001 0010 0011 0100 .. 1111 Modifications reserved | Data subject to change without notice Number of samples for observation 32 64 128 256 512 Document number: BST-BMA400-DS000-03 Revision_1.2_072019 46 | 126 Bosch Sensortec | BMA400 Data sheet Tap Sensing Interrupt The tap interrupt is operating on an input data rate of 200Hz. It can detect single and double taps. For configuration, there are the registers TAP_CONFIG and TAP_CONFIG_1. (TAP_CONFIG. tap_sensitivity) allows to modify the threshold for the minimum tap amplitude (TAP_CONFIG_1. quiet) and (TAP_CONFIG_1. quiet_dt) allow to define the duration of quiet times between double taps and between taps. acc_filt1 is the data source for the tap interrupt, so, this filter must be configured to 200Hz ODR if this interrupt shall be enabled. There are two different interrupts that can be enabled separately: single tap (INT_CONFIG1.s_tap_int) and double tap detection (INT_CONFIG1.d_tap_int). The status of the interrupts is available in INT_STAT1.s_tap_int and INT_STAT1.d_tap_int. With INT12_MAP.tap_int1 the logical OR of both interrupt statuses can be mapped to the INT1 pin. INT12_MAP.tap_int2 does the same for the INT2 pin. Config Register Comment TAP_CONFIG. tap_sensitivity[2:0] modifies the threshold for the minimum tap amplitude The three bits form an unsigned integer (‘d0.. ‘d7) reset default: “000” TAP_CONFIG. sel_axis[1:0] reset default: “00” TAP_CONFIG_1. quiet[3:2] reset default: “01” TAP_CONFIG_1. quiet_dt[5:4] reset default: “00” TAP_CONFIG_1. tics_th[1:0] reset default: “10” Modifies the selection of the data provided to the algorithm If TAP_CONFIG.sel_axis ==”00” use Z axis data If TAP_CONFIG.sel_axis ==”01” use Y axis data If TAP_CONFIG.sel_axis ==”1X” use X axis data QUIET_TIME = ‘d60 if TAP_CONFIG_1.quiet==”00” QUIET_TIME = ‘d 80 if TAP_CONFIG_1.quiet==”01” QUIET_TIME = ‘d 100 if TAP_CONFIG_1.quiet==”10” QUIET_TIME = ‘d 120 if TAP_CONFIG_1.quiet==”11” QUIET_TIME_DT = ‘d4 if TAP_CONFIG_1.quiet_dt==”00” QUIET_TIME_DT = ‘d 8 if TAP_CONFIG_1.quiet_dt==”01” QUIET_TIME_DT = ‘d 12 if TAP_CONFIG_1.quiet_dt==”10” QUIET_TIME_DT = ‘d 16 if TAP_CONFIG_1.quiet_dt==”11” TICS_TH= ‘d6 if TAP_CONFIG_1.tics_th=="00" TICS_TH= ‘d9 if TAP_CONFIG_1.tics_th=="01" TICS_TH= ‘d12 if TAP_CONFIG_1.tics_th=="10" TICS_TH= ‘d18 if TAP_CONFIG_1.tics_th=="11" Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 47 | 126 Interrupt engine overrun The interrupt overrun is asserted if filter and interrupt computations cannot be finished in a sample acquisition time. The interrupt status is mapped (mirrored) to all interrupt registers INT_STAT0, INT_STAT1 and INT_STAT2, bit ieng_overrun_stat. The interrupt is cleared by reading of any of these registers. The interrupt is mapped to pads INT1 and INT2 by the registers INT1_MAP. ieng_overrun_int1 and INT2_MAP. ieng_overrun_int2. The interrupt behavior is not dependent on non-latch, latch mode setting. If this occurs, advanced interrupts of less importance must be disabled until the Interrupt engine overrun vanishes. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 48 | 126 Bosch Sensortec | BMA400 Data sheet Orientation change interrupt The orientation-change interrupt is enabled by (INT_CONFIG0.orientch_int) = 1. The interrupt is optimized to detect a (screen) orientation change when the product is used in a wearable device or similar application. The orientation change is evaluated by monitoring the acceleration change in X/Y/Z direction (each individually selectable) and by measuring the “stability” of the new orientation. The stability of the orientation is evaluated by monitoring the difference between the last acceleration value and current acceleration values. The orientation change is evaluated as difference to the last stable orientation stored in the reference registers. The orientation changed interrupt is generated as soon as the orientation change condition is fulfilled on one of the enabled axes selected by (ORIENTCH_CONFIG0.orient_X/Y/Z_en). Signal flow for orientation change interrupt The orientation change interrupt supports two input acceleration data streams for evaluation: acc_filt2; and the low-pass filtered data source with 1Hz cut-off frequency acc_filt_lp ORIENTCH_CONFIG0.data_src Data source for Interupt 0 acc_filt2 1 acc_filt_lp The threshold for the orientation change interrupt can be configured in the register ORIENTCH_CONFIG1.orient_thres. The threshold configuration has 8 bits and a resolution of 8mg/LSB. In case the acceleration is above the reference acceleration stored for last position for defined period of time ORIENTCH_CONFIG3.orient_dur; the BMA400 orientation change condition is true. In case the stability check is selected the orientation must be stable within the stability threshold ORIENTCH_CONFIG2.stability_thres. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 49 | 126 Bosch Sensortec | BMA400 Data sheet The minimum duration of a new orientation (which shall trigger an interrupt) can be configured in the register ORIENTCH_CONFIG3.orient_dur. The duration register has 8 bits and a resolution of 10ms/LSB. The stability evaluation mode can be configured in the Register ORIENTCH_CONFIG0.stability_mode. Following configurations are supported for stability evaluation mode:  stability check disable  Difference to last value from filter acc_filt2  Difference to last value from filter acc_filt_lp ORIENTCH_CONFIG0.stability_mode Description b00 Stability disabled: the stability check is disabled. The orientation change is based only on the difference and duration condition to reference values b01 Last ordinary acceleration: stability condition evaluated by using the acc_filt2 acceleration b10 or b11 Last low-pass filtered acceleration: stability condition evaluated by using the low-pass filtered acceleration data acc_filt_lp When the duration condition is fulfilled, the reference orientation is updated according to the configuration stored in the Register (ORIENTCH_CONFIG0.orient_refu). The reference update mode supports following modes:  no automatic update at all, the reference orientation will be updated by the user when needed  update with output from filter acc_filt2  update with output from filter acc_filt_lp Summarized, the orientation changed interrupt supports following configuration:  Axis selection for orientation evaluation  Data source for data evaluation o acc_filt2 o acc_filt_lp  Stability mode configuration o Stability check disabled o Last acceleration from acc_filt2 for stability check o Last acceleration from acc_filt_lp for stability check  Thresholds o Threshold for orientation change: 8 bits, 8 mg/lsb resolution o Stability threshold for stable position: 8bits 8 mg/lsb resolution o Duration for stable orientation: 8bits, 10ms/lsb resolution  Reference update mode: o manual update, it is set by user. The values are range sensitive, and the physical value of lsb corresponds to 2^(2+acc_range)/4096, here acc_range = 0, 1, 2, 3 corresponds to +/-2g, +/-4g, +/-8g, +/-16g. o update with acc_filt2 value, the reference orientation is updated with current acceleration value as soon as stable orientation is detected o update with acc_filt_lp value, the reference orientation is updated with current acceleration value as soon as stable orientation is detected Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 50 | 126 Bosch Sensortec | BMA400 Data sheet Sensor Self-Test The BMA400 has a comprehensive self test function for the MEMS element by applying electrostatic forces to the sensor core instead of external accelerations. By actually deflecting the seismic mass, the entire signal path of the sensor can be tested. Activating the self-test results in a static offset of the acceleration data; any external acceleration or gravitational force applied to the sensor during active self-test will be observed in the output as a superposition of both acceleration and self-test signal. Before the self-test is enabled the g-range should be set to 4g. In order to ensure a proper interpretation of the self-test signal it is recommended to perform the selftest for both (positive and negative) excitations: SELF_TEST.self_test_sign= b0, b1 and then to calculate the difference of the resulting acceleration values. The table below shows the minimum differences for each axis in order for the self test to pass. The actually measured signal differences can be significantly larger. Self-test: Resulting minimum difference signal for BMA400. BMA400 x-axis signal y-axis signal z-axis signal 1500 mg 1200 mg 250 mg It is recommended to perform a reset of the device after a self-test has been performed. If the reset cannot be performed, the following sequence must be kept to prevent unwanted interrupt generation: disable interrupts, change parameters of interrupts, wait for at least 50ms, and enable desired interrupts. The recommended self test procedure is as follows: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Disable all interrupts which could be triggered by self-test activity, this is no hard requirement Enable accelerometer with OSR=3, normal mode. Set ±4g range Set ODR=100Hz, use acc_filt1 output Wait for > 2 ms Enable self-test for all axes and set positive self-test excitation (SELF_TEST.self_test_sign= 1b0, SELF_TEST.self_test_en_x/y/z = b1) Wait for > 50ms Read and store acceleration + positive excitation values of each axis of interest Change to negative excitation by setting negative self-test exciation SELF_TEST.self_test_sign= b1 Wait for > 50ms Read and store acceleration + negative excitation value of each axis of interest Calculate difference of measured acceleration values from steps 8 and 11 Disable self-test for all axes: SELF_TEST.self_test_en_x/y/z = b0, SELF_TEST.self_test_sign= 1b0 Wait 50ms before re-enabling interrupts By subtracting values with both contain the acceleration part (gravity), what remains is the pseudoacceleration value caused by the self-test excitations. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 51 | 126 Soft-Reset A softreset can be initiated at any time by writing the command softreset (0xB6) to register CMD. The softreset performs a fundamental reset to the device which is largely equivalent to a power cycle. Following a delay, all user configuration settings are overwritten with their default state (setting stored in the NVM) wherever applicable. This command is functional in all operation modes but must not be performed while NVM writing operation is in progress. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 52 | 126 Bosch Sensortec | BMA400 Data sheet 5. Register description Register map Addr (hex) RegName 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E CHIPID reserved ERR_REG STATUS ACC_X_LSB ACC_X_MSB ACC_Y_LSB ACC_Y_MSB ACC_Z_LSB ACC_Z_MSB SENSOR_TIME0 SENSOR_TIME1 SENSOR_TIME2 EVENT INT_STAT0 0x0F INT_STAT1 0x10 INT_STAT2 0x11 0x12 0x13 0x14 0x15 0x16 0x17 0x18 0x19 0x1A 0x1B 0x1F 0x20 TEMP_DATA FIFO_LENGTH0 FIFO_LENGTH1 FIFO_DATA STEP_CNT0 STEP_CNT1 STEP_CNT2 STEP_STAT ACC_CONFIG0 ACC_CONFIG1 ACC_CONFIG2 INT_CONFIG0 INT_CONFIG1 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 chipid reserved drdy cmd_err power_mode cmd_rdy int_active acc_x 0 0 0 0 acc_x acc_y 0 0 0 0 acc_y acc_z 0 0 0 0 acc_z sensor_time sensor_time sensor_time drdy_int fwm_int ffull_int ieng_ gen2_int overrun ieng_ d_tap_int overrun ieng_ overrun temp_data fifo_bytes_cnt gen1_int orientch_int s_tap_int por_detected wkup_int step_int actch_z_int actch_y_int actch_x_int fifo_bytes_cnt fifo_data step_cnt step_cnt step_cnt osr_lp filt1_bw acc_range drdy_int latch_int fwm_int osr ffull_int Modifications reserved | Data subject to change without notice actch_int step_stat power_mode acc_odr data_src_reg gen2_int gen1_int d_tap_int s_tap_int orientch_int step_int Rst val Access mode 0x90 0x88 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 R R R R R R R R R R R R R R R 0x00 R 0x00 R 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x49 0xE0 0x00 0x00 R R R R R R R R RW RW RW RW RW Document number: BST-BMA400-DS000-03 Revision_1.2_072019 53 | 126 Bosch Sensortec | BMA400 Data sheet Addr (hex) RegName bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 Rst val Access mode 0x21 INT1_MAP drdy_int1 fwm_int1 ffull_int1 gen2_int1 gen1_int1 orientch_int1 wkup_int1 0x00 RW 0x22 INT2_MAP drdy_int2 fwm_int2 ffull_int2 gen2_int2 gen1_int2 orientch_int2 wkup_int2 0x00 RW 0x23 0x24 0x25 0x26 INT12_MAP INT12_IO_CTRL actch_int2 tap_int2 int2_od ieng_overr un_int1 ieng_overr un_int2 step_int2 actch_int1 tap_int1 int1_od step_int1 int2_lvl int1_lvl RW RW FIFO_CONFIG0 fifo_z_en fifo_y_en fifo_x_en 0x00 0x00 0x00 0x00 0x27 0x28 0x29 0x2A 0x2B 0x2C 0x2D FIFO_CONFIG1 FIFO_CONFIG2 FIFO_PWR_CONFIG AUTOLOWPOW_0 AUTOLOWPOW_1 AUTOWAKEUP_0 AUTOWAKEUP_1 0x00 0x00 0x00 0x00 0x00 0x00 0x00 RW RW RW RW RW RW RW 0x2F WKUP_INT_CONFIG 0 WKUP_INT_CONFIG 1 WKUP_INT_CONFIG 2 WKUP_INT_CONFIG 3 WKUP_INT_CONFIG 4 ORIENTCH_CONFI G0 ORIENTCH_CONFI G1 ORIENTCH_CONFI G2 ORIENTCH_CONFI G3 ORIENTCH_CONFI G4 ORIENTCH_CONFI G5 ORIENTCH_CONFI G6 ORIENTCH_CONFI G7 ORIENTCH_CONFI G8 ORIENTCH_CONFI G9 0x00 RW int_wkup_thres 0x00 RW int_wkup_refx 0x00 RW int_wkup_refy 0x00 RW int_wkup_refz 0x00 RW 0x00 RW orient_thres 0x00 RW stability_thres 0x00 RW orient_dur 0x00 RW int_orient_refx 0x00 RW 0x00 RW 0x00 RW 0x00 RW 0x00 RW 0x00 RW 0x30 0x31 0x32 0x33 0x35 0x36 0x37 0x38 0x39 0x3A 0x3B 0x3C 0x3D 0x3E fifo_8bit_e fifo_data_sr n c fifo_watermark fifo_time_en fifo_stop_on _full auto_flush fifo_watermark fifo_read_dis auto_lp_timeout_thres auto_lp_timeout wakeup_timeout_thres wakeup_timeout_thres wkup_timeo ut wkup_z_en wkup_y_en wkup_x_en num_of_samples auto_lp_timeout_thres orient_z_en orient_y_en Modifications reserved | Data subject to change without notice orient_x_en data_src orient_refu gen1_int drdy wkup_int wkup_refu stability_mode int_orient_refx int_orient_refy int_orient_refy int_orient_refz int_orient_refz Document number: BST-BMA400-DS000-03 Revision_1.2_072019 RW 54 | 126 Bosch Sensortec | BMA400 Data sheet Addr (hex) RegName bit7 bit6 bit5 bit4 0x3F act_z_en act_y_en act_x_en data_src 0x57 GEN1INT_CO NFIG0 GEN1INT_CO NFIG1 GEN1INT_CO NFIG2 GEN1INT_CO NFIG3 GEN1INT_CO NFIG31 GEN1INT_CO NFIG4 GEN1INT_CO NFIG5 GEN1INT_CO NFIG6 GEN1INT_CO NFIG7 GEN1INT_CO NFIG8 GEN1INT_CO NFIG9 GEN2INT_CO NFIG0 GEN2INT_CO NFIG1 GEN2INT_CO NFIG2 GEN2INT_CO NFIG3 GEN2INT_CO NFIG31 GEN2INT_CO NFIG4 GEN2INT_CO NFIG5 GEN2INT_CO NFIG6 GEN2INT_CO NFIG7 GEN2INT_CO NFIG8 GEN2INT_CO NFIG9 ACTH_CONFI G0 ACTH_CONFI G1 TAP_CONFIG 0x58 TAP_CONFIG1 0x7C IF_CONF 0x7D SELF_TEST 0x7E CMD 0x40 0x41 0x42 0x43 0x44 0x45 0x46 0x47 0x48 0x49 0x4A 0x4B 0x4C 0x4D 0x4E 0x4F 0x50 0x51 0x52 0x53 0x54 0x55 0x56 bit3 bit2 bit1 act_refu bit0 act_hyst criterion_sel comb_sel gen_int_thres gen_int_dur gen_int_dur int_th_refx int_th_refx int_th_refy int_th_refy int_th_refz int_th_refz act_z_en act_y_en act_x_en data_src act_refu act_hyst criterion_sel comb_sel gen_int_thres gen_int_dur gen_int_dur int_th_refx int_th_refx int_th_refy int_th_refy int_th_refz int_th_refz acth_thres actch_z_en actch_y_en Modifications reserved | Data subject to change without notice actch_x_ en actch_data _src sel_axis quiet_dt actch_npts tap_sensitivity quiet tics_th spi3 acc_self_te st_sign cmd acc_self_test_ en_z acc_self_test_ en_y acc_self_te st_en_x Rst val 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 0 0x0 6 0x0 0 0x0 0 0x0 0 Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Acces s mode RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW 55 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x00) CHIPID DESCRIPTION: the register contains the chip identification code read 0x90 to identify product RESET: 0x90 DEFINITION (Go to register map): Name Register (0x00) CHIPID Bit 7 6 5 4 Read/Write R R R R Reset Value 1 0 0 1 Content chipid_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content chipid_7_0 Register (0x01) (reserved) Register (0x02) ERR_REG DESCRIPTION: reserved RESET: 0x00 DEFINITION (Go to register map): Name Register (0x02) ERR_REG Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a n/a R n/a Reset Value 0 0 0 0 Content reserved cmd_err reserved cmd_err: command (written to command register(0x7E)) execution failed. This is a clear-onread bit. cmd_err== 0x1: Command execution failed. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 56 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x03) STATUS DESCRIPTION: the register contains the sensor status bits RESET: 0x00 DEFINITION (Go to register map): Name Register (0x03) STATUS Bit 7 6 5 4 Read/Write R n/a n/a R Reset Value 0 0 0 0 Content drdy_stat reserved Bit 3 2 1 0 Read/Write n/a R R R Reset Value 0 0 0 0 Content reserved power_mode_stat int_active: cmd_rdy int_active the int_active bit is set if one of the interrupts is triggered int_active 0x00 not-triggered one of the interrupts is triggered 0x01 triggered one of the interrupts is triggered power_mode_stat: current power mode of the sensor power_mode_stat 0x00 sleep_mode device in sleep mode 0x01 low_power_mode device in low power mode 0x02 normal_mode device in normal mode cmd_rdy: CMD (command register (0x7E)) decoder status. cmd_rdy 0x00 in_progress command in progress 0x01 new_command ready for new command drdy_stat: data ready status is set as soon the accelerometer data conversion is ready drdy_stat 0x00 not-ready data conversion not ready 0x01 ready data conversion ready, new data available, clear on data read Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 57 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x04) ACC_X_LSB DESCRIPTION: Register for accelerometer data. The ACC_X_LSB-ACC_Z_MSB registers contain the latest data for x, y and z axis of accelerometer. A read operation on the register ACC_X_LSBACC_Z_MSB resets the INT_STAT0.drdy_int (data ready bit). RESET: 0x00 DEFINITION (Go to register map): Name Register (0x04) ACC_X_LSB Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content acc_x_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content acc_x_7_0 acc_x_7_0: lsb of accelerometer x-axis data acceleration is obtained by the following operations: acc_x/y/z = acc_x/y/z_7_0 + 256*acc_x/y/z_11_8 if(acc_x/y/z> 2047) acc_x/y/z=acc_x/y/z-4096 Register (0x05) ACC_X_MSB DESCRIPTION: Register for accelerometer data. The ACC_X_LSB-ACC_Z_MSB registers contain the latest data for x, y and z axis of accelerometer. A read operation on the register ACC_X_LSBACC_Z_MSB resets the INT_STAT0.drdy_int (data ready bit). RESET: 0x00 DEFINITION (Go to register map): Name Register (0x05) ACC_X_MSB Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content acc_x_11_8 acc_x_11_8: msb of accelerometer x-axis data acceleration is obtained by the following operations: acc_x/y/z = acc_x/y/z_7_0 + 256*acc_x/y/z_11_8 if(acc_x/y/z> 2047) acc_x/y/z=acc_x/y/z-4096 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 58 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x06) ACC_Y_LSB DESCRIPTION: Register for accelerometer data. The ACC_X_LSB-ACC_Z_MSB registers contain the latest data for x, y and z axis of accelerometer. A read operation on the register ACC_X_LSBACC_Z_MSB resets the INT_STAT0.drdy_int (data ready bit). RESET: 0x00 DEFINITION (Go to register map): Name Register (0x06) ACC_Y_LSB Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content acc_y_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content acc_y_7_0 acc_y_7_0: lsb of accelerometer y-axis data acceleration is obtained by the following operations: acc_x/y/z = acc_x/y/z_7_0 + 256*acc_x/y/z_11_8 if(acc_x/y/z> 2047) acc_x/y/z=acc_x/y/z-4096 Register (0x07) ACC_Y_MSB DESCRIPTION: Register for accelerometer data. The ACC_X_LSB-ACC_Z_MSB registers contain the latest data for x, y and z axis of accelerometer. A read operation on the register ACC_X_LSBACC_Z_MSB resets the INT_STAT0.drdy_int (data ready bit). RESET: 0x00 DEFINITION (Go to register map): Name Register (0x07) ACC_Y_MSB Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content acc_y_11_8 acc_y_11_8: msb of accelerometer y-axis data acceleration is obtained by the following operations: acc_x/y/z = acc_x/y/z_7_0 + 256*acc_x/y/z_11_8 if(acc_x/y/z> 2047) acc_x/y/z=acc_x/y/z-4096 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 59 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x08) ACC_Z_LSB DESCRIPTION: Register for accelerometer data. The ACC_X_LSB-ACC_Z_MSB registers contain the latest data for x, y and z axis of accelerometer. A read operation on the register ACC_X_LSBACC_Z_MSB resets the INT_STAT0.drdy_int (data ready bit). RESET: 0x00 DEFINITION (Go to register map): Name Register (0x08) ACC_Z_LSB Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content acc_z_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content acc_z_7_0 acc_z_7_0: lsb of accelerometer z-axis data acceleration is obtained by the following operations: acc_x/y/z = acc_x/y/z_7_0 + 256*acc_x/y/z_11_8 if(acc_x/y/z> 2047) acc_x/y/z=acc_x/y/z-4096 Register (0x09) ACC_Z_MSB DESCRIPTION: Register for accelerometer data. The ACC_X_LSB-ACC_Z_MSB registers contain the latest data for x, y and z axis of accelerometer. A read operation on the register ACC_X_LSBACC_Z_MSB resets the INT_STAT0.drdy_int (data ready bit). RESET: 0x00 DEFINITION (Go to register map): Name Register (0x09) ACC_Z_MSB Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content acc_z_11_8 acc_z_11_8: msb of accelerometer z-axis data acceleration is obtained by the following operations: acc_x/y/z = acc_x/y/z_7_0 + 256*acc_x/y/z_11_8 if(acc_x/y/z> 2047) acc_x/y/z=acc_x/y/z-4096 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 60 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x0A) SENSOR_TIME0 DESCRIPTION: the register contains the sensor time RESET: 0x00 DEFINITION (Go to register map): Name Register (0x0A) SENSOR_TIME0 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content sensor_time_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content sensor_time_7_0 sensor_time_7_0: The internal sensor time is calculated using the formula ttemp=sensor_time_7_0+256*sensor_time_15_8+65536*sensor_time_23_16 sensor_time=ttemp*312.5us Register (0x0B) SENSOR_TIME1 DESCRIPTION: the register contains the sensor time RESET: 0x00 DEFINITION (Go to register map): Name Register (0x0B) SENSOR_TIME1 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content sensor_time_15_8 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content sensor_time_15_8 sensor_time_15_8: The internal sensor time is calculated using the formula ttemp=sensor_time_7_0+256*sensor_time_15_8+65536*sensor_time_23_16 sensor_time=ttemp*312.5us Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 61 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x0C) SENSOR_TIME2 DESCRIPTION: the register contains the sensor time RESET: 0x00 DEFINITION (Go to register map): Name Register (0x0C) SENSOR_TIME2 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content sensor_time_23_16 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content sensor_time_23_16 sensor_time_23_16: The internal sensor time is calculated using the formula ttemp=sensor_time_7_0+256*sensor_time_15_8+65536*sensor_time_23_16 sensor_time=ttemp*312.5us Register (0x0D) EVENT DESCRIPTION: the register contains event bits. RESET: 0x00 DEFINITION (Go to register map): Name Register (0x0D) EVENT Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a n/a n/a R Reset Value 0 0 0 0 Content reserved por_detected por_detected: power on reset bit , clear on read por_detected 0x00 no-por no power up or softreset detected 0x01 por-detected power up or softreset detected Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 62 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x0E) INT_STAT0 DESCRIPTION: the registers contain the interrupt status bits RESET: 0x00 DEFINITION (Go to register map): Name Register (0x0E) INT_STAT0 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content drdy_int_stat fwm_int_stat ffull_int_stat ieng_overrun_stat Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content gen2_int_stat gen1_int_stat orientch_int_stat wkup_int_stat wkup_int_stat: orientch_int_stat: gen1_int_stat: gen2_int_stat: ieng_overrun_stat: ffull_int_stat: fwm_int_stat: drdy_int_stat: wake-up interrupt status: '0'= not set; '1'= set (wake-up condition is valid) orientation changed interrupt status: '0'= not set; '1'= set (orientation is changed) generic interrupt 1 status: '0'= not set; '1'= set generic interrupt 2 status: '0'= not set; '1'= set issued when interrupt calculation could not be finished FIFO full interrupt status: '0'= not set; '1'= set (FIFO full) FIFO watermark interrupt status: '0'= not set; '1'= set data ready interrupt is status: '0'= not set; '1'= set Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 63 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x0F) INT_STAT1 DESCRIPTION: the registers contain the interrupt status bits RESET: 0x00 DEFINITION (Go to register map): Name Register (0x0F) INT_STAT1 Bit 7 6 5 4 Read/Write n/a n/a n/a R Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content d_tap_int_stat s_tap_int_stat step_int_stat step_int_stat: ieng_overrun_stat step detector interrupt status: '0'= not set; '1'= set (step detected); '2'= set (step detected and very likely to have missed a step before; "double step"); '3'= not used single tap interrupt status: '0'= not set; '1'= set (single tap detected) double tap interrupt status: '0'= not set; '1'= set (double tap detected) issued when interrupt calculation could not be finished s_tap_int_stat: d_tap_int_stat: ieng_overrun_stat: Register (0x10) INT_STAT2 DESCRIPTION: the registers contain the interrupt status bits RESET: 0x00 DEFINITION (Go to register map): Name Register (0x10) INT_STAT2 Bit 7 6 5 4 Read/Write n/a n/a n/a R Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a R R R Reset Value 0 0 0 0 Content reserved actch_z_int_stat actch_y_int_stat actch_x_int_stat actch_x_int_stat: actch_y_int_stat: actch_z_int_stat: ieng_overrun_stat: ieng_overrun_stat x-axis activity change detected: '0'= no change; '1'= changed y-axis activity change detected: '0'= no change; '1'= changed z-axis activity change detected: '0'= no change; '1'= changed issued when interrupt calculation could not be finished Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 64 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x11) TEMP_DATA DESCRIPTION: The register contains the temperature of the sensor. The output word of the 8-bit temperature sensor is Two‘s complement. RESET: 0x00 DEFINITION (Go to register map): Name Register (0x11) TEMP_DATA Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content temp_data_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content temp_data_7_0 temp_data_7_0: Conversion to real temperature is done using the formula temp=((real)((signed)temp_data))*0.5+23.0 Register (0x12) FIFO_LENGTH0 DESCRIPTION: the register contains the number of bytes stored in FIFO RESET: 0x00 DEFINITION (Go to register map): Name Register (0x12) FIFO_LENGTH0 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content fifo_bytes_cnt_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content fifo_bytes_cnt_7_0 fifo_bytes_cnt_7_0: This is the LSBs data of the FIFO size count fifo_size_bytes = fifo_bytes_cnt_7_0 + 256*fifo_bytes_cnt_10_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 65 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x13) FIFO_LENGTH1 DESCRIPTION: the register contains the number of bytes stored in FIFO RESET: 0x00 DEFINITION (Go to register map): Name Register (0x13) FIFO_LENGTH1 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a R R R Reset Value 0 0 0 0 Content reserved fifo_bytes_cnt_10_8 fifo_bytes_cnt_10_8: This is the MSBs data of the FIFO size count fifo_size_bytes = fifo_bytes_cnt_7_0 + 256*fifo_bytes_cnt_10_8 Register (0x14) FIFO_DATA DESCRIPTION: the register contains the FIFO data. The FIFO data can be read out as burst read. The number of bytes written in the FIFO to be read is stored in the registers FIFO_LENGTH(0/1). RESET: 0x00 DEFINITION (Go to register map): Name Register (0x14) FIFO_DATA Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content fifo_data_field Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content fifo_data_field Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 66 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x15) STEP_CNT_0 DESCRIPTION: the register contains the number of steps detected by step counter. RESET: 0x00 DEFINITION (Go to register map): Name Register (0x15) STEP_CNT_0 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content step_cnt_7_0 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content step_cnt_7_0 step_cnt_7_0: step_count=step_cnt_7_0+256*step_cnt_15_8+65536*step_cnt_23_16 Register (0x16) STEP_CNT_1 DESCRIPTION: the register contains the number of steps detected by step counter. RESET: 0x00 DEFINITION (Go to register map): Name Register (0x16) STEP_CNT_1 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content step_cnt_15_8 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content step_cnt_15_8 step_cnt_15_8: step_count=step_cnt_7_0+256*step_cnt_15_8+65536*step_cnt_23_16 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 67 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x17) STEP_CNT_2 DESCRIPTION: the register contains the number of steps detected by step counter. RESET: 0x00 DEFINITION (Go to register map): Name Register (0x17) STEP_CNT_2 Bit 7 6 5 4 Read/Write R R R R Reset Value 0 0 0 0 Content step_cnt_23_16 Bit 3 2 1 0 Read/Write R R R R Reset Value 0 0 0 0 Content step_cnt_23_16 step_cnt_23_16: step_count=step_cnt_7_0+256*step_cnt_15_8+65536*step_cnt_23_16 Register (0x18) STEP_STAT DESCRIPTION: the register filed contains the status STILL(00), WALK(01) or RUN(01) RESET: 0x00 DEFINITION (Go to register map): Name Register (0x18) STEP_STAT Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a n/a R R Reset Value 0 0 0 0 Content reserved step_stat_field step_stat_field 0x00 still no walking, no running 0x01 walking step counter detects walking activity 0x02 running step counter detects running activity Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 68 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x19) ACC_CONFIG0 DESCRIPTION: the registers contain the accelerometer configuration. RESET: 0x00 DEFINITION (Go to register map): Name Register (0x19) ACC_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW n/a Reset Value 0 0 0 0 Content filt1_bw osr_lp Bit 3 2 1 0 Read/Write n/a n/a RW RW Reset Value 0 0 0 0 Content reserved power_mode_conf: reserved power_mode_conf '000'= sleep; '001'= low power mode; '010'= normal mode power_mode_conf 0x00 sleep_mode sleep mode 0x01 low_power_mode low power mode 0x02 normal_mode normal mode 0x03 reserved switches to sleep mode (0x0) osr_lp: filt1_bw: oversampling ratio for low power mode bandwidth selector for filt1 output, valid only for ODRs smaller than 100Hz filt1_bw 0x00 high 0.4x ODR 0x01 low 0.2x ODR Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 69 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x1A) ACC_CONFIG1 DESCRIPTION: the registers contain the accelerometer configuration RESET: 0x49 DEFINITION (Go to register map): Name Register (0x1A) ACC_CONFIG1 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 1 0 0 Content acc_range Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 1 0 0 1 Content acc_odr acc_odr: output data rate of accelerometer for acc_filt1 acc_odr ODR [Hz] 0x00 reserved 0x01 reserved 0x02 reserved 0x03 reserved 0x04 reserved 0x05 12.5 0x06 25 0x07 50 0x08 100 0x09 200 0x0a 400 0x0b 800 0x0c reserved 0x0d reserved 0x0e reserved 0x0f reserved osr: osr oversampling rate 0/1/2/3 for normal mode osr=0: lowest power, lowest oversampling rate, lowest accuracy osr=3: highest accuracy, higest oversampling rate, highest power settings 0, 1, 2 and 3 allow linearly trading power versus accuracy(noise) acc_range: accelerometer measurement range acc_range 0x00 2g +/-2g measurement range 0x01 4g +/-4g measurement range 0x02 8g +/-8g measurement range 0x03 16g +/-16g measurement range Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 70 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x1B) ACC_CONFIG2 DESCRIPTION: the registers contain the accelerometer configuration RESET: 0x00 DEFINITION (Go to register map): Name Register (0x1B) ACC_CONFIG2 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW n/a n/a Reset Value 0 0 0 0 Content data_src_reg reserved data_src_reg: Select source for data registers data_src_reg 0x00 acc_filt1 variable ODR filter 0x01 acc_filt2 fixed 100Hz output data rate filter 0x02 acc_filt_lp fixed 100Hz output data rate filter, 1Hz bandwidth 0x03 acc_filt1 variable ODR filter Register (0x1F) INT_CONFIG0 DESCRIPTION: The register contains interrupt control bits, 0 = not enabled, 1 = enabled RESET: 0x00 DEFINITION (Go to register map): Name Register (0x1F) INT_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW n/a Reset Value 0 0 0 0 Content drdy_int_en fwm_int_en ffull_int_en reserved Bit 3 2 1 0 Read/Write RW RW RW n/a Reset Value 0 0 0 0 Content gen2_int_en gen1_int_en orientch_int_en reserved orientch_int_en: gen1_int_en: gen2_int_en: ffull_int_en: fwm_int_en: drdy_int_en: orientation changed interrupt generic interrupt 1 generic interrupt 2 FIFO full interrupt FIFO watermark interrupt data ready interrupt Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 71 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x20) INT_CONFIG1 DESCRIPTION: The register contains interrupt control bits, 0 = not enabled, 1 = enabled RESET: 0x00 DEFINITION (Go to register map): Name Register (0x20) INT_CONFIG1 Bit 7 6 5 4 Read/Write RW n/a n/a RW Reset Value 0 0 0 0 Content latch_int reserved Bit 3 2 1 0 Read/Write RW RW n/a RW Reset Value 0 0 0 0 Content d_tap_int_en s_tap_int_en reserved step_int_en step_int_en: s_tap_int_en: d_tap_int_en: actch_int_en: latch_int: actch_int_en step detected interrupt (step counter) single tap interrupt double tap interrupt activity changed interrupt latched interrupt mode configuration latch_int 0x00 nolatch non-latched mode 0x01 latching latching mode Register (0x21) INT1_MAP DESCRIPTION: The register contains the interrupt to physical INT1 pin mapping 0: interrupt is not mapped to INT1 1: interrupt is mapped to pin INT1 RESET: 0x00 DEFINITION (Go to register map): Name Register (0x21) INT1_MAP Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content drdy_int1 fwm_int1 ffull_int1 ieng_overrun_int1 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int1 gen1_int1 orientch_int1 wkup_int1 wkup_int1: orientch_int1: gen1_int1: gen2_int1: wake-up interrupt is mapped to int1 orientation changed interrupt is mapped to int1 generic interrupt 1 is mapped to int1 generic interrupt 2 is mapped to int1 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 72 | 126 Bosch Sensortec | BMA400 Data sheet ieng_overrun_int1: interrupt overrun mapped to int1 ffull_int1: fifo full interrupt is mapped to int1 fwm_int1: fifo watermark interrupt is mapped to int1 drdy_int1: data ready interrupt is mapped to int1 Register (0x22) INT2_MAP DESCRIPTION: The register contains the interrupt to physical INT2 pin mapping 0: interrupt is not mapped to INT2 1: interrupt is mapped to pin INT2 RESET: 0x00 DEFINITION (Go to register map): Name Register (0x22) INT2_MAP Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content drdy_int2 fwm_int2 ffull_int2 ieng_overrun_int2 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int2 gen1_int2 orientch_int2 wkup_int2 wkup_int2: wake-up interrupt is mapped to INT2 orientch_int2: orientation changed interrupt is mapped to INT2 gen1_int2: generic interrupt 1 is mapped to INT2 gen2_int2: generic interrupt 2 is mapped to INT2 ieng_overrun_int2: interrupt overrun mapped to int2 ffull_int2: fifo full interrupt is mapped to INT2 fwm_int2: fifo watermark interrupt is mapped to INT2 drdy_int2: data ready interrupt is mapped to INT2 Register (0x23) INT12_MAP DESCRIPTION: the registers contain the interrupts mapping to physical pins RESET: 0x00 DEFINITION (Go to register map): Name Register (0x23) INT12_MAP Bit 7 6 5 4 Read/Write RW RW n/a RW Reset Value 0 0 0 0 Content actch_int2 tap_int2 reserved step_int2 Bit 3 2 1 0 Read/Write RW RW n/a RW Reset Value 0 0 0 0 Content actch_int1 tap_int1 reserved step_int1 step_int1: step detector interrupt is mapped to INT1 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 73 | 126 Bosch Sensortec | BMA400 Data sheet tap_int1: actch_int1: step_int2: tap_int2: actch_int2: tap sensing interrupt is mapped to INT1 activity changed interrupt is mapped to INT1 step detector interrupt is mapped to INT2 tap sensing interrupt is mapped to INT2 activity changed interrupt is mapped to INT2 Register (0x24) INT12_IO_CTRL DESCRIPTION: the register contains physical behaviour of interrupt pins configurations RESET: 0x22 DEFINITION (Go to register map): Name Register (0x24) INT12_IO_CTRL Bit 7 6 5 4 Read/Write n/a RW RW n/a Reset Value 0 0 1 0 Content reserved int2_od int2_lvl reserved Bit 3 2 1 0 Read/Write n/a RW RW n/a Reset Value 0 0 1 0 Content reserved int1_od int1_lvl reserved int1_lvl: INT1 pin output level int1_lvl 0x00 interrupt pin INT1 low-active 0x01 interrupt pin INT1 high-active int1_od: INT1 pin output driver mode: CMOS or open drain int1_od 0x00 Push-pull 0x01 open drain int2_lvl: CMOS push-pull drive characteristic INT2 pin output level int2_lvl 0x00 interrupt pin INT2 low-active 0x01 interrupt pin INT2 high-active int2_od: INT2 pin output driver mode: see interrupt physical behaviour int2_od 0x00 Push-pull 0x01 open drain CMOS push-pull drive characteristic Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 74 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x26) FIFO_CONFIG0 DESCRIPTION: the registers contain the FIFO control and FIFO configuration settings RESET: 0x00 DEFINITION (Go to register map): Name Register (0x26) FIFO_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content fifo_z_en fifo_y_en fifo_x_en fifo_8bit_en Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content fifo_data_src fifo_time_en fifo_stop_on_full auto_flush auto_flush: auto flush FIFO when changing power-mode auto_flush 0x00 noaction no FIFO flush on changing power mode 0x01 fifo-flush FIFO flush on changing power mode fifo_stop_on_full: FIFO writing - stream mode / FIFO full mode fifo_stop_on_full 0x00 streaming overwrite oldest FIFO data when FIFO full 0x01 fifo-stop-on-full stop writing into FIFO when full fifo_time_en: Enable sending of sensortime frame when reading burst from FIFO and the FIFO runs empty fifo_time_en 0x00 Disable sensortime in FIFO 0x01 Enable sensortime in FIFO fifo_data_src: acceleration data source for storing into FIFO fifo_data_src 0x00 acc_filt1 store data from acc_filt1 (variable data rate) in FIFO 0x01 acc_filt2 store data from acc_filt2 (100Hz data rate) in FIFO fifo_8bit_en: enables 8 bit FIFO mode fifo_8bit_en 0x00 12bit store data in 12bit format (default), two bytes occupied 0x01 8bit store data in 8bit format fifo_x_en: x-channel data storage control fifo_x_en 0x00 nostore do not store x axis data 0x01 store store x axis data Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 75 | 126 Bosch Sensortec | BMA400 Data sheet fifo_y_en: y-channel data storage control fifo_y_en 0x00 nostore do not store y axis data 0x01 store store y axis data fifo_z_en: z-channel data storage control fifo_z_en 0x00 nostore do not store z axis data 0x01 store store z axis data Register (0x27) FIFO_CONFIG1 DESCRIPTION: the registers contain the FIFO control and FIFO configuration settings RESET: 0x00 DEFINITION (Go to register map): Name Register (0x27) FIFO_CONFIG1 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content fifo_watermark_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content fifo_watermark_7_0 fifo_watermark_7_0: LSB of FIFO watermark threshold configuration: watermark[byte]= fifo_watermark_7_0 + 256*fifo_watermark_10_8 Register (0x28) FIFO_CONFIG2 DESCRIPTION: the registers contain the FIFO control and FIFO configuration settings RESET: 0x00 DEFINITION (Go to register map): Name Register (0x28) FIFO_CONFIG2 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a RW RW RW Reset Value 0 0 0 0 Content reserved fifo_watermark_10_8 fifo_watermark_10_8: MSB of FIFO watermark threshold configuration watermark[byte]= fifo_watermark_7_0 + 256*fifo_watermark_10_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 76 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x29) FIFO_PWR_CONFIG DESCRIPTION: the registers contain the FIFO read power circuit settings, saves 100nA when set RESET: 0x00 DEFINITION (Go to register map): Name Register (0x29) FIFO_PWR_CONFIG Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a n/a n/a RW Reset Value 0 0 0 0 Content reserved fifo_read_disable: fifo_read_disable manual disable for the FIFO read power circuit when set HIGH Register (0x2A) AUTOLOWPOW_0 DESCRIPTION: the registers contain configurations for auto-low-power condition RESET: 0x00 DEFINITION (Go to register map): Name Register (0x2A) AUTOLOWPOW_0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content auto_lp_timeout_thres_11_4 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content auto_lp_timeout_thres_11_4 auto_lp_timeout_thres_11_4: MSB of auto-low-power timeout threshold temp = auto_lp_timeout_thres_3_0 +16*auto_lp_timeout_thres_11_4 timeout= temp*2.5ms Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 77 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x2B) AUTOLOWPOW_1 DESCRIPTION: the registers contain configurations for auto-low-power condition RESET: 0x00 DEFINITION (Go to register map): Name Register (0x2B) AUTOLOWPOW_1 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content auto_lp_timeout_thres_3_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content auto_lp_timeout gen1_int drdy_lowpow_trig drdy_lowpow_trig: data ready as source for auto-low-power condition drdy_lowpow_trig 0x00 notrig no triggering of low-power 0x01 trig-newdata new data ready triggers going into low-power gen1_int: generic interrupt 1 as source for auto-low-power condition gen1_int 0x00 nodtrig no triggering of low-power 0x01 trig-gen1 generic interrupt 1 triggers going into low-power auto_lp_timeout: auto-low-power timeout as source for auto-low-power condition auto_lp_timeout 0x00 auto_lp_timeout_0 Low-power timeout disabled 0x01 auto_lp_timeout_1 Low-power timeout active, device shall switch into low power mode as soon timeout counter is expired 0x02 auto_lp_timeout_2 Low-power timeout active, as 0x01, but timeout counter resets if gen2_int is asserted 0x03 auto_lp_timeout_3 same as 0x01 auto_lp_timeout_thres_3_0: LSB of auto-low-power timeout threshold temp = auto_lp_timeout_thres_3_0 +16*auto_lp_timeout_thres_11_4 timeout= temp*2.5ms Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 78 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x2C) AUTOWAKEUP_0 DESCRIPTION: the register contains configurations for auto-wake-up condition. The auto-wake-up condition is evaluated as soon as the sensor changes into low power mode RESET: 0x00 DEFINITION (Go to register map): Name Register (0x2C) AUTOWAKEUP_0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content wakeup_timeout_thres_11_4 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content wakeup_timeout_thres_11_4 wakeup_timeout_thres_11_4: MSB of wake-up timeout threshold temp= wakeup_timeout_thres_3_0 + 16*wakeup_timeout_thres_11_4 timeout=temp=2.5ms Register (0x2D) AUTOWAKEUP_1 DESCRIPTION: the register contains configurations for auto-wake-up condition. The auto-wake-up condition is evaluated as soon as the sensor changes into low power mode RESET: 0x00 DEFINITION (Go to register map): Name Register (0x2D) AUTOWAKEUP_1 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content wakeup_timeout_thres_3_0 Bit 3 2 1 0 Read/Write n/a RW RW n/a Reset Value 0 0 0 0 Content reserved wkup_timeout wkup_int reserved wkup_int: wake-up interrupt as source for auto-wake-up condition wkup_int 0x00 nowakeup not use wake-up interrupt for auto-wake-up 0x01 en-wakeup use wake-up interrupt for auto-wake-up wkup_timeout: wake-up timeout as source for auto-wake-up condition wkup_timeout 0x00 no-timeout timer not used for auto-wake-up 0x01 enab-timeout timer triggers auto-wake-up Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 79 | 126 Bosch Sensortec | BMA400 Data sheet wakeup_timeout_thres_3_0: LSB of wake-up timeout threshold temp= wakeup_timeout_thres_3_0 + 16*wakeup_timeout_thres_11_4 timeout=temp*2.5ms Register (0x2F) WKUP_INT_CONFIG0 DESCRIPTION: the registers contain configurations for wake-up interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x2F) WKUP_INT_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content wkup_z_en wkup_y_en wkup_x_en num_of_samples Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content num_of_samples wkup_refu: wkup_refu wake-up interrupt reference update mode wkup_refu 0x00 manual manual update (reference registers are updated by external MCU) 0x01 onetime one time automated update before going into low power mode 0x02 everytime every time after data conversion num_of_samples: number of data samples used for interrupt condition evaluation, allowed range 0...7 (number of samples(real) = num_of_samples(set) + 1) wkup_x_en: enable wake-up interrupt for x channel wkup_x_en 0x00 disabled no x axis evaluation 0x01 enabled wakeup function evaluates x axis wkup_y_en: enable wake-up interrupt for y channel wkup_y_en 0x00 disabled no y axis evaluation 0x01 enabled wakeup function evaluates y axis wkup_z_en: enable wake-up interrupt for z channel wkup_z_en 0x00 disabled no z axis evaluation 0x01 enabled wakeup function evaluates z axis Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 80 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x30) WKUP_INT_CONFIG1 DESCRIPTION: the register contains configurations for wake-up interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x30) WKUP_INT_CONFIG1 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_thres Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_thres int_wkup_thres: interrupt threshold The value is range sensitive, unsigned and defines the threshold for activity which must be present to cause a wake-up. The physical value of LSB corresponds to 2^(2+acc_range)/256, here acc_range = 0, 1, 2, 3 corresponds to +/-2g, +/-4g, +/-8g, +/-16g. Register (0x31) WKUP_INT_CONFIG2 DESCRIPTION: the register contains configurations for wake-up interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x31) WKUP_INT_CONFIG2 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_refx Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_refx int_wkup_refx: reference acceleration x-axis for the wake-up interrupt. The value is range sensitive and a signed integer, either provided by the host (wkup_refu=0) or automatically the wake-up interrupt calculates abs(acc_x/y/z-int_wkup_refx/y/z*16)>int_wkup_thres*16 to determine whether activity is sufficiently high on the x/y/z-axis to cause wake-up Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 81 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x32) WKUP_INT_CONFIG3 DESCRIPTION: the register contains configurations for wake-up interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x32) WKUP_INT_CONFIG3 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_refy Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_refy int_wkup_refy: reference acceleration y-axis for the wake-up interrupt. The value is range sensitive and a signed integer, either provided by the host (wkup_refu=0) or automatically the wake-up interrupt calculates abs(acc_x/y/z-int_wkup_refx/y/z*16)>int_wkup_thres*16 to determine whether activity is sufficiently high on the x/y/z-axis to cause wake-up Register (0x33) WKUP_INT_CONFIG4 DESCRIPTION: the register contains configurations for wake-up interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x33) WKUP_INT_CONFIG4 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_refz Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_wkup_refz int_wkup_refz: reference acceleration z-axis for the wake-up interrupt. The value is range sensitive and a signed integer, either provided by the host (wkup_refu=0) or automatically the wake-up interrupt calculates abs(acc_x/y/z-int_wkup_refx/y/z*16)>int_wkup_thres*16 to determine whether activity is sufficiently high on the x/y/z-axis to cause wake-up Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 82 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x35) ORIENTCH_CONFIG0 DESCRIPTION: the registers contain configurations for orientation changed interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x35) ORIENTCH_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content orient_z_en orient_y_en orient_x_en orient_data_src Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content orient_refu stability_mode stability_mode: stability mode for new orientation stability_mode 0x00 inactive not active 0x01 enabled1 acc_filter2 data used for stability check 0x02 enabled2 low pass filtered acceleration used for stability check orient_refu: reference update mode for orientation changed interrupt orient_refu 0x00 manual manual update (reference registers are updated by serial interface command) 0x01 onetime_2 one time automated update using acc_filt2 data 0x02 onetime_lp one time automated update using acc_filt_lp data orient_data_src: data source selection for orientation changed interrupt evaluation orient_data_src 0x00 filt2 data source is acc_filt2 0x01 filt_lp data source is acc_filt_lp orient_x_en: orient_y_en: orient_z_en: enable orientation changed interrupt for x-axis: 0-not active;1-active enable orientation changed interrupt for y-axis: 0-not active;1-active enable orientation changed interrupt for z-axis: 0-not active;1-active Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 83 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x36) ORIENTCH_CONFIG1 DESCRIPTION: the registers contain configurations for orientation change interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x36) ORIENTCH_CONFIG1 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content orient_thres Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content orient_thres orient_thres: threshold configuration for orientation changed interrupt 8mg/lsb resolution Register (0x37) ORIENTCH_CONFIG2 DESCRIPTION: the registers contain configurations for orientation changed interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x37) ORIENTCH_CONFIG2 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content stability_thres Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content stability_thres stability_thres: stability threshold used for the stability evaluation of the new orientation 8mg/lsb resolution Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 84 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x38) ORIENTCH_CONFIG3 DESCRIPTION: the registers contain configurations for orientation changed interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x38) ORIENTCH_CONFIG3 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content orient_dur Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content orient_dur orient_dur: duration for (stable) new orientation before interrupt is triggered duration is a multiple of the number of data samples processed (ODR=100HZ) from the selected filter Register (0x39) ORIENTCH_CONFIG4 DESCRIPTION: the register contains configurations for orientation change interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x39) ORIENTCH_CONFIG4 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refx_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refx_7_0 int_orient_refx_7_0: LSB of x-axis reference for orientation change evaluation the value is a signed integer, either provided by the host (orient_refu=0) or automatically the interrupt calculates abs(acc_x/y/z-int_orientch_refx/y/z)>orient_thres to determine whether activity is sufficiently high on the x/y/z-axis to cause an interrupt trigger int_orientch_refx = int_orient_refx_7_0 + 256*int_orient_refx_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 85 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x3A) ORIENTCH_CONFIG5 DESCRIPTION: the register contains configurations for orientation changed interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x3A) ORIENTCH_CONFIG5 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refx_11_8 int_orient_refx_11_8: sensitive MSB of x-axis reference for orientation change evaluation. The value is range Register (0x3B) ORIENTCH_CONFIG6 DESCRIPTION: the register contains configurations for orientation change interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x3B) ORIENTCH_CONFIG6 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refy_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refy_7_0 int_orient_refy_7_0: LSB of y-axis reference for orientation change evaluation The value is range sensitive and a signed integer, either provided by the host (orient_refu=0) or automatically the interrupt calculates abs(acc_x/y/z-int_orientch_refx/y/z)>orient_thres to determine whether activity is sufficiently high on the x/y/z-axis to cause an interrupt trigger int_orientch_refy = int_orient_refy_7_0 + 256*int_orient_refy_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 86 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x3C) ORIENTCH_CONFIG7 DESCRIPTION: the register contains configurations for orientation changed interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x3C) ORIENTCH_CONFIG7 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refy_11_8 int_orient_refy_11_8: MSB of y-axis reference for orientation change evaluation Register (0x3D) ORIENTCH_CONFIG8 DESCRIPTION: the registers contain configurations for orientation changed interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x3D) ORIENTCH_CONFIG8 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refz_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refz_7_0 int_orient_refz_7_0: LSB of z-axis reference for orientation change evaluation The value is range sensitive and a signed integer, either provided by the host (orient_refu=0) or automatically the interrupt calculates abs(acc_x/y/z-int_orientch_refx/y/z)>orient_thres to determine whether activity is sufficiently high on the x/y/z-axis to cause an interrupt trigger int_orientch_refz = int_orient_refz_7_0 + 256*int_orient_refz_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 87 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x3E) ORIENTCH_CONFIG9 DESCRIPTION: the registers contain configurations for orientation changed interrupt RESET: 0x00 DEFINITION (Go to register map): Name Register (0x3E) ORIENTCH_CONFIG9 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content int_orient_refz_11_8 int_orient_refz_11_8: MSB of z-axis reference for orientation change evaluation Register (0x3F) GEN1INT_CONFIG0 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x3F) GEN1INT_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_act_z_en gen1_act_y_en gen1_act_x_en gen1_data_src Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_act_refu gen1_act_hyst gen1_act_hyst: hysteresis configuration for interrupt evaluation gen1_act_hyst 0x00 not-active no hysteresis 0x01 24mg 24mg hysteresis 0x02 48mg 48mg hysteresis 0x03 96mg 96mg hysteresis gen1_act_refu: reference update mode for evaluation gen1_act_refu 0x00 manual manual update (reference registers are updated by a serial interface command) 0x01 onetime one time automated update by the selected data source 0x02 everytime every time automated update by the selected data source 0x03 everytime_lp every time automated update by acc_filt_lp Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 88 | 126 Bosch Sensortec | BMA400 Data sheet gen1_data_src: data source selection for interrupts evaluation gen1_data_src 0x00 filt1 data source is acc_filt1 0x01 filt2 data source is acc_filt2 gen1_act_x_en: gen1_act_y_en: gen1_act_z_en: x-axis channel control for interrupt evaluation: '0'- not active; '1'- active y-axis channel control for interrupt evaluation: '0'- not active; '1'- active z-axis channel control for interrupt evaluation: '0'- not active; '1'- active Register (0x40) GEN1INT_CONFIG1 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x40) GEN1INT_CONFIG1 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a n/a RW RW Reset Value 0 0 0 0 Content reserved gen1_criterion_sel gen1_comb_sel gen1_comb_sel: Select logical combination for creating the interrupt signal from the individual axes that have been enabled gen1_comb_sel 0x00 OR OR combination of x/y/z axis evaluation results 0x01 AND AND combination of x/y/z axis evaluation results gen1_criterion_sel: Select criterion for threshold comparison gen1_criterion_sel 0x00 inactivity acceleration below threshold: inactivity detection 0x01 activity acceleration above threshold: activity detection Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 89 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x41) GEN1INT_CONFIG2 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x41) GEN1INT_CONFIG2 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_thres Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_thres gen1_int_thres: threshold configuration for detection: 8 mg/lsb unsigned integer Register (0x42) GEN1INT_CONFIG3 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x42) GEN1INT_CONFIG3 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_dur_15_8 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_dur_15_8 gen1_int_dur_15_8: duration for which the condition has to persist until interrupt can be triggered duration is measured in data samples of selected data source gen1_int_dur= 256*gen1_int_dur_15_8 + gen1_int_dur_7_0 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 90 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x43) GEN1INT_CONFIG31 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x43) GEN1INT_CONFIG31 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_dur_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_dur_7_0 gen1_int_dur_7_0: duration for which the condition has to persist until interrupt can be triggered duration is measured in data samples of selected data source gen1_int_dur= 256*gen1_int_dur_15_8 + gen1_int_dur_7_0 Register (0x44) GEN1INT_CONFIG4 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x44) GEN1INT_CONFIG4 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refx_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refx_7_0 gen1_int_th_refx_7_0: LSB of reference x-axis value for evaluation. The value is range sensitive. gen1_int_refx = gen1_int_th_refx_7_0 + 256*gen1_int_th_refx_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 91 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x45) GEN1INT_CONFIG5 DESCRIPTION: the register contains configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x45) GEN1INT_CONFIG5 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refx_11_8 gen1_int_th_refx_11_8: MSB of reference x-axis value for evaluation. The value is range sensitive. gen1_int_refx = gen1_int_th_refx_7_0 + 256*gen1_int_th_refx_11_8 Register (0x46) GEN1INT_CONFIG6 DESCRIPTION: the register contains configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x46) GEN1INT_CONFIG6 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refy_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refy_7_0 gen1_int_th_refy_7_0: LSB of reference y-axis value for evaluation. The value is range sensitive. gen1_int_refy = gen1_int_th_refy_7_0 + 256*gen1_int_th_refy_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 92 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x47) GEN1INT_CONFIG7 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x47) GEN1INT_CONFIG7 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refy_11_8 gen1_int_th_refy_11_8: MSB of reference y-axis value for evaluation. The value is range sensitive. gen1_int_refy = gen1_int_th_refy_7_0 + 256*gen1_int_th_refx_11_8 Register (0x48) GEN1INT_CONFIG8 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x48) GEN1INT_CONFIG8 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refz_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refz_7_0 gen1_int_th_refz_7_0: LSB of reference z-axis value for evaluation. The value is range sensitive. gen1_int_refz = gen1_int_th_refz_7_0 + 256*gen1_int_th_refz_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 93 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x49) GEN1INT_CONFIG9 DESCRIPTION: the registers contain configurations for generic interrupt 1 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x49) GEN1INT_CONFIG9 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen1_int_th_refz_11_8 gen1_int_th_refz_11_8: MSB of reference z-axis value for evaluation. The value is range sensitive. gen1_int_refz = gen1_int_th_refz_7_0 + 256*gen1_int_th_refz_11_8 Register (0x4A) GEN2INT_CONFIG0 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x4A) GEN2INT_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_act_z_en gen2_act_y_en gen2_act_x_en gen2_data_src Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_act_refu gen2_act_hyst gen2_act_hyst: hysteresis configuration for interrupt evaluation gen2_act_hyst 0x00 not-active no hysteresis 0x01 24mg 24mg hysteresis 0x02 48mg 48mg hysteresis 0x03 96mg 96mg hysteresis gen2_act_refu: reference update mode for evaluation gen2_act_refu 0x00 manual manual update (reference registers are updated by serial interface command) 0x01 onetime one time automated update by the selected data source 0x02 everytime every time automated update by the selected data source 0x03 everytime_lp every time automated update by acc_filt_lp Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 94 | 126 Bosch Sensortec | BMA400 Data sheet gen2_data_src: data source selection for interrupts evaluation gen2_data_src 0x00 filt1 data source is acc_filt1 0x01 filt2 data source is acc_filt2 gen2_act_x_en: gen2_act_y_en: gen2_act_z_en: x-axis channel control for interrupt evaluation: 0 - not active; 1 - active y-axis channel control for interrupt evaluation: 0 - not active; 1 - active z-axis channel control for interrupt evaluation: 0 - not active; 1 - active Register (0x4B) GEN2INT_CONFIG1 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x4B) GEN2INT_CONFIG1 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a n/a RW RW Reset Value 0 0 0 0 Content reserved gen2_criterion_sel gen2_comb_sel gen2_comb_sel: Select logical combination for creating the interrupt signal from the individual ^ axes that have been enabled gen2_comb_sel 0x00 OR OR combination of x/y/z axis evaluation results 0x01 AND AND combination of x/y/z axis evaluation results gen2_criterion_sel: Select criterion for threshold comparison gen2_criterion_sel 0x00 inactivity acceleration below threshold: inactivity detection 0x01 activity acceleration above threshold: activity detection Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 95 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x4C) GEN2INT_CONFIG2 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x4C) GEN2INT_CONFIG2 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_thres Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_thres gen2_int_thres: threshold configuration for interrupt detection: 8 mg/LSB unsigned integer Register (0x4D) GEN2INT_CONFIG3 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x4D) GEN2INT_CONFIG3 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_dur_15_8 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_dur_15_8 gen2_int_dur_15_8: duration for which the condition has to persist until interrupt can be triggered duration is measured in data samples of selected data source gen2_int_dur= 256*gen2_int_dur_15_8 + gen2_int_dur_7_0 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 96 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x4E) GEN2INT_CONFIG31 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x4E) GEN2INT_CONFIG31 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_dur_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_dur_7_0 gen2_int_dur_7_0: duration for which the condition has to persist until interrupt can be triggered duration is measured in data samples of selected data source gen2_int_dur= 256*gen2_int_dur_15_8 + gen2_int_dur_7_0 Register (0x4F) GEN2INT_CONFIG4 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x4F) GEN2INT_CONFIG4 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refx_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refx_7_0 gen2_int_th_refx_7_0: LSB of reference x-axis value for evaluation. The value is range sensitive. gen2_int_refx = gen2_int_th_refx_7_0 + 256*gen2_int_th_refx_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 97 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x50) GEN2INT_CONFIG5 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x50) GEN2INT_CONFIG5 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refx_11_8 gen2_int_th_refx_11_8: MSB of reference x-axis value for evaluation. The value is range sensitive. gen2_int_refx = gen2_int_th_refx_7_0 + 256*gen2_int_th_refx_11_8 Register (0x51) GEN2INT_CONFIG6 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x51) GEN2INT_CONFIG6 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refy_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refy_7_0 gen2_int_th_refy_7_0: LSB of reference y-axis value for evaluation. The value is range sensitive. gen2_int_refy = gen2_int_th_refy_7_0 + 256*gen2_int_th_refy_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 98 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x52) GEN2INT_CONFIG7 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x52) GEN2INT_CONFIG7 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refy_11_8 gen2_int_th_refy_11_8: MSB of reference y-axis value for evaluation. The value is range sensitive. gen2_int_refy = gen2_int_th_refy_7_0 + 256*gen2_int_th_refy_11_8 Register (0x53) GEN2INT_CONFIG8 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x53) GEN2INT_CONFIG8 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refz_7_0 Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refz_7_0 gen2_int_th_refz_7_0: LSB of reference z-axis value for evaluation. The value is range sensitive. gen2_int_refz = gen2_int_th_refz_7_0 + 256*gen2_int_th_refz_11_8 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 99 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x54) GEN2INT_CONFIG9 DESCRIPTION: the registers contain configurations for generic interrupt 2 evaluation RESET: 0x00 DEFINITION (Go to register map): Name Register (0x54) GEN2INT_CONFIG9 Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content gen2_int_th_refz_11_8 gen2_int_th_refz_11_8: MSB of reference z-axis value for evaluation. The value is range sensitive. gen2_int_refz = gen2_int_th_refz_7_0 + 256*gen2_int_th_refz_11_8 Register (0x55) ACTCH_CONFIG0 DESCRIPTION: Activity changed interrupt configuration registers RESET: 0x00 DEFINITION (Go to register map): Name Register (0x55) ACTCH_CONFIG0 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content actch_thres Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content actch_thres actch_thres: threshold configuration for activity changed interrupt: 8mg/g resolution Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 100 | 126 Bosch Sensortec | BMA400 Data sheet Register (0x56) ACTCH_CONFIG1 DESCRIPTION: Activity changed interrupt configuration registers RESET: 0x00 DEFINITION (Go to register map): Name Register (0x56) ACTCH_CONFIG1 Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content actch_z_en actch_y_en actch_x_en actch_data_src Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content actch_npts actch_npts: number of points for evaluation of the activity: 32, 64, 128, 256, 512 actch_npts 0x00 32 32 points 0x01 64 64 points 0x02 128 128 points 0x03 256 256 points 0x04 512 512 points 0x05-0x0F reserved actch_data_src: data source actch_data_src 0x00 actch_use_acc_filt1 0x01 actch_use_acc_filt2 actch_x_en: actch_y_en: actch_z_en: activity changed evaluation for x-axis enabled: '0'- not active; '1'- active activity changed evaluation for y-axis enabled: '0'- not active; '1'- active activity changed evaluation for z-axis enabled: '0'- not active; '1'- active Register (0x57) TAP_CONFIG DESCRIPTION: tap interrupt configuration registers RESET: 0x00 DEFINITION (Go to register map): Name Register (0x57) TAP_CONFIG Bit 7 6 5 4 Read/Write n/a n/a n/a RW Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content sel_axis tap_sensitivity Modifications reserved | Data subject to change without notice sel_axis Document number: BST-BMA400-DS000-03 Revision_1.2_072019 101 | 126 Bosch Sensortec | BMA400 Data sheet tap_sensitivity: sensitivity of the tap algorithm 0: highest sensitivity 7: lowest sensitivity possible values range from 0 to 7 for a monotonic decrease of sensitivity with every setting sel_axis: Modifies the selection of the data provided to the algorithm sel_axis 0x00 Z use Z axis data 0x01 Y use Y axis data 0x02 X use X axis data Register (0x58) TAP_CONFIG1 DESCRIPTION: tap interrupt configuration registers RESET: 0x06 DEFINITION (Go to register map): Name Register (0x58) TAP_CONFIG1 Bit 7 6 5 4 Read/Write n/a n/a RW RW Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 1 1 0 Content quiet tics_th: quiet_dt tics_th Maximum time between upper and lower peak of a tap, in data samples this time depends on the mechanics of the device tapped onto default = 12 samples tics_th 0x00 6 6 data samples for high-low tap signal change time 0x01 9 9 data samples for high-low tap signal change time 0x02 12 12 data samples for high-low tap signal change time 0x03 18 18 data samples for high-low tap signal change time quiet: Minimum quiet time before and after double tap, in data samples This time also defines the longest time interval between two taps so that they are considered as double tap quiet 0x00 60 60 data samples quiet tie between single or doube taps 0x01 80 80 data samples quiet tie between single or doube taps 0x02 100 100 data samples quiet tie between single or doube taps 0x03 120 120 data samples quiet tie between single or doube taps Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 102 | 126 Bosch Sensortec | BMA400 Data sheet quiet_dt: Minimum time between the two taps of a double tap, in data samples quiet_dt 0x00 4 4 data samples minimum time between double taps 0x01 8 8 data samples minimum time between double taps 0x02 12 12 data samples minimum time between double taps 0x03 16 16 data samples minimum time between double taps Register (0x7C) IF_CONF DESCRIPTION: Serial interface settings RESET: 0x00 DEFINITION (Go to register map): Name Register (0x7C) IF_CONF Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write n/a n/a n/a RW Reset Value 0 0 0 0 Content reserved spi3: spi3 Configure SPI Interface Mode for primary interface spi3 0x00 spi4 SPI 4-wire mode 0x01 spi3 SPI 3-wire mode Register (0x7D) SELF_TEST DESCRIPTION: Settings for the sensor self-test configuration and trigger RESET: 0x00 DEFINITION (Go to register map): Name Register (0x7D) SELF_TEST Bit 7 6 5 4 Read/Write n/a n/a n/a n/a Reset Value 0 0 0 0 Content reserved Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content acc_self_test_sign acc_self_test_en_ z acc_self_test_en_ y acc_self_test_en_ x Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 103 | 126 Bosch Sensortec | BMA400 Data sheet acc_self_test_en_x: trigger self test for X axis acc_self_test_en_x 0x00 disabled disabled 0x01 enabled enabled acc_self_test_en_y: trigger self test for Y axis acc_self_test_en_y 0x00 disabled disabled 0x01 enabled enabled acc_self_test_en_z: trigger self test for Z axis acc_self_test_en_z 0x00 disabled disabled 0x01 enabled enabled acc_self_test_sign: select sign of self-test excitation acc_self_test_sign 0x00 negative negative 0x01 positive positive Register (0x7E) CMD DESCRIPTION: Command Register RESET: 0x00 DEFINITION (Go to register map): Name Register (0x7E) CMD Bit 7 6 5 4 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content cmd Bit 3 2 1 0 Read/Write RW RW RW RW Reset Value 0 0 0 0 Content cmd cmd: Available commands (Note: Register will always read as 0x00): cmd 0x00 nop reserved. No command. 0xb0 fifo_flush Clears all data in the FIFO, does not change FIFO_CONFIG and FIFO_DOWNS registers 0xb1 step_cnt_clear Clears the value of the step counter to 0 0xb6 softreset Triggers a reset, all user configuration settings are overwritten with their default state Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 104 | 126 Bosch Sensortec | BMA400 Data sheet The device supports a command set to trigger certain activities and state transitions of the device. The command interpreter is connected to register cmd. A command is invoked if the corresponding Opcode is written to the cmd register. Writing an undefined command to register cmd has no effect and ERR_REG.cmd_err=’0’ in this case. The device implements a simple handshaking mechanism to signal its readiness for accepting a new command. Prior to writing a new command to the cmd register the user must read the status bit STATUS.cmd_rdy: cmd_rdy = ’1’: device is ready to accept a command cmd_rdy = ’0’: a command is being executed, any new command is ignored cmd_err is set to ‘1’ when command execution failed. cmd_err is reset to ‘0’ if the last command execution was successful. This is a clear-on-read bit. After the softreset command has been invoked, status and error register are updated after Tst_up. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 105 | 126 Bosch Sensortec | BMA400 Data sheet 6. Digital Interfaces Interface By default, the BMA400 operates in I2C mode. The BMA400 interface can also be configured to operate in a SPI 4-wire configuration. It can also be re-configured by software to work in 3-wire mode instead of 4-wire mode. All three possible digital interfaces share partly the same pins. The mapping for the primary interface of the BMA400 is given in the following table: Pin# Name I/O Type Description 1 SDO Digital I/O 2 SDX Digital I/O 5 6 10 12 INT1 INT2 CSB SCX Digital I/O Digital I/O Digital in Digital in Serial data output in SPI Address select in I²C mode see chapter 7.2 SDA serial data I/O in I²C SDI serial data input in SPI 4W SDA serial data I/O in SPI 3W Interrupt output 1 (default) Interrupt output 2 (default) Chip select for SPI mode SCK for SPI serial clock SCL for I²C serial clock Connect to (Primary IF) in SPI4W in SPI3W in I2C SDO DNC (float) GND for default I2C addr. SDI SDA SDA INT1 INT2 CSB SCK INT1 INT2 CSB SCK INT1 INT2 VDDIO SCL * If INT1 and/or INT2 are not used, please do not connect them (DNC). The following table shows the electrical specifications of the interface pins: Parameter Symbol Condition Pull-up Resistance, CSB pin I²C Bus Load Capacitance (max. drive capability) Rup Internal Pull-up Resistance to VDDIO CI2C_Load Modifications reserved | Data subject to change without notice Min Typ Max 120 Units k 400 pF Document number: BST-BMA400-DS000-03 Revision_1.2_072019 106 | 126 Bosch Sensortec | BMA400 Data sheet Interface I2C/SPI Protocol Selection The protocol is automatically selected based on the chip select CSB pin behavior after power-up. At reset / power-up, BMA400 is in I2C mode. If CSB is connected to VDDIO during power-up and not changed the sensor interface works in I2C mode. For using I2C, it is recommended to hard-wire the CSB line to VDDIO. Since power-on-reset is only executed when both VDD and VDDIO are established, there is no risk of incorrect protocol detection due to power-up sequence. If CSB sees a rising edge after power-up, the BMA400 interface switches to SPI until a reset or the next power-up occurs. Therefore, a CSB rising edge is needed before starting the SPI communication. Hence, it is mandatory to perform a SPI single read of e.g. register CHIP_ID (the obtained value will be invalid) before the actual communication start, in order to use the SPI interface. SPI interface and protocol The timing specification for SPI of the BMA400 is given in the following table: Following SPI timing table, valid at VDDIO ≥ 1.71V Parameter Symbol Condition Clock Frequency fSPI Max. Load on SDI or SDO = 25pF, VDDIO ≥ 1.71 V VDDIO < 1.71V SCK Low Pulse SCK High Pulse SDI Setup Time SDI Hold Time tSDI_setup tSDI_hold SDO Output Delay tSDO_OD CSB Setup Time tCSB_setup CSB Hold Time tSCKL tSCKH tCSB_hold Modifications reserved | Data subject to change without notice Min Max Units 17 MHz 7 MHz 20 20 20 20 Load = 25pF, VDDIO ≥ 1.71V For first SPI transaction after reset (due to interface changed from I2C to SPI mode) 20 ns ns ns ns 30 ns 20 ns 50 ns Document number: BST-BMA400-DS000-03 Revision_1.2_072019 107 | 126 Bosch Sensortec | BMA400 Data sheet The following figure shows the definition of the SPI timings: tCSB_setup tCSB_hold CSB SCK tSCKL tSCKH SDI tSDI_setup SDO tSDI_hold tSDO_OD SPI timing diagram The SPI interface of the BMA400 is compatible with two modes, ´00´ [CPOL = ´0´ and CPHA = ´0´] and ´11´ [CPOL = ´1´ and CPHA = ´1´]. The automatic selection between ´00´ and ´11´ is controlled based on the value of SCK after a falling edge of CSB. Two configurations of the SPI interface are supported by the BMA400: 4-wire and 3-wire. The same protocol is used by both configurations. The device operates in 4-wire configuration by default. It can be switched to 3-wire configuration by writing IF_CONF.spi3 = 0b1. Pin SDI is used as the common data pin in 3-wire configuration. For single byte read as well as write operations, 8-bit protocols are used. The BMA400 also supports multiple-byte read and write operations. In SPI 4-wire configuration CSB (chip select low active), SCK (serial clock), SDI (serial data input), and SDO (serial data output) pins are used. The communication starts when the CSB is pulled low by the SPI master and stops when CSB is pulled high. SCK is also controlled by SPI master. SDI and SDO are driven at the falling edge of SCK and should be captured at the rising edge of SCK. The basic write operation waveform for 4-wire configuration is depicted in the following figure. During the entire write cycle SDO remains in high-impedance state. CSB SCX X SDX SDO logical R/W A D6 A D5 A D4 A D3 A D2 A D1 A D0 X DI7 DI6 DI5 DI4 DI3 Z R/W + register address DI2 DI1 DI0 X X Data 4-wire basic SPI write sequence (mode ´00´) Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 108 | 126 Bosch Sensortec | BMA400 Data sheet Multiple write operations are possible by keeping CSB low and continuing the data transfer. Every data must be preceded by R/W flag and address, there is no address auto-increment like in burst read mode. The principle of multiple write is shown in figure below: CSB SCX X SDX SDO R/W A D6 A D5 A D4 A D3 A D2 A D1 A D0 X logical DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 R/W A D6 A D5 A D4 A D3 A D2 A D1 A D0 DI7 DI6 DI5 DI4 DI3 DI2 DI1 X DI0 Z R/W + register address k X Data (address k) Data (address l) R/W + register address l address data SPI multiple write The basic read operation waveform for 4-wire configuration is depicted in the figure below. Please note that the first byte received from the BMA400 via the SDO line correspond to a dummy byte and the 2nd byte correspond to the value read out of the specified register address. That means, for a basic read operation two bytes have to be read and the first has to be dropped and the second byte must be interpreted. CSB SCX 7 X SDX SDO logical R/W A D6 A D5 A D4 A D3 A D2 A D1 A D0 X 6 5 3 2 1 X Z R/W + register address 0 DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0 Dummy Dummy Read Data 4-wire basic SPI read sequence (mode ´00´) The data bits are used as follows: R/W: Read/Write bit. When 0, the data SDI is written into the chip. When 1, the data SDO from the chip is read. AD6-AD0: Register Address DI7-DI0: When in write mode, these are the data SDI, which will be written into the address. DO7-DO0: When in read mode, these are the data SDO, which are read from the address. Multiple read operations are possible by keeping CSB low and continuing the data transfer. Only the first register address has to be written. Addresses are automatically incremented after each read access as long as CSB stays active low. Please note that the first byte received from the BMA400 via the SDO line correspond to a dummy byte and the 2nd byte correspond to the value read out of the specified register address. The successive bytes read out correspond to values of incremented register addresses. That means, for a multiple read operation of n bytes, n+1 bytes have to be read, the first has to be dropped and the successive bytes must be interpreted. When reaching address FIFO_DATA, auto-increment stops, and the FIFO is read bytewise. In SPI 3-wire configuration CSB (chip select low active), SCK (serial clock), and SDA (serial data input and output) pins are used. While SCK is high, the communication starts when the CSB is pulled Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 X 109 | 126 Bosch Sensortec | BMA400 Data sheet low by the SPI master and stops when CSB is pulled high. SCK is also controlled by SPI master. SDA is driven (when used as input of the device) at the falling edge of SCK and should be captured (when used as the output of the device) at the rising edge of SCK. The protocol as such is the same in 3-wire configuration as it is in 4-wire configuration. The basic operation wave-form (read or write access) for 3-wire configuration is depicted in the figure below: CSB SCK SDI RW AD6 AD5 AD4 AD3 AD2 AD1 AD0 DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 3-wire basic SPI read or write sequence (mode ´11´) Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 110 | 126 Bosch Sensortec | BMA400 Data sheet Primary I2C Interface The I²C bus uses SCL (= SCx pin, serial clock) and SDA (= SDx pin, serial data input and output) signal lines. Both lines Must be connected to VDDIO externally via pull-up resistors so that they are pulled high when the bus is free. The default I²C address of the device is b001010X . ‘X’ is defined by the SDO pin: if SDO pulled to ´GND´ X equals 0, is SDO is pulled to VDDIO, X equals 1. In I2C, the SDO level must be defined, it cannot be left floating. The I²C interface of the BMA400 is compatible with the I²C Specification UM10204 Rev. 06 (April 2014), available at http://www.nxp.com. The BMA400 supports I²C standard mode and fast mode, only 7-bit address mode is supported. For VDDIO = 1.2V to 1.62 V the guaranteed voltage output levels are slightly relaxed as described in Table 1 of the electrical specification section. BMA400 also supports an extended I²C mode that allows using clock frequencies up to 3.4 MHz. In this mode all timings of the fast mode apply and it additionally supports clock frequencies up to 3.4MHz. The timing specification for I²C of the BMA400 is given in the following table: Parameter Symbol Condition Min Clock Frequency fSCL SCL Low Period tLOW 1.3 SCL High Period tHIGH 0.6 SDA Setup Time tSUDAT 0.1 SDA Hold Time tHDDAT 0.0 Setup Time for a repeated Start Condition tSUSTA 0.6 Hold Time for a Start Condition tHDSTA 0.6 Setup Time for a Stop Condition tSUSTO 0.6 Time before a new Transmission can start tBUF Max Units 3400 kHz µs Modifications reserved | Data subject to change without notice normal mode 1.3 Document number: BST-BMA400-DS000-03 Revision_1.2_072019 111 | 126 Bosch Sensortec | BMA400 Data sheet The figure below shows the definition of the I²C timings SDA tBUF tf tLOW SCL tHIGH tHDSTA tr tHDDAT tSUDAT SDA tSUSTA tSUSTO I²C timing diagram The I²C protocol works as follows: START: Data transmission on the bus begins with a high to low transition on the SDA line while SCL is held high (start condition (S) indicated by I²C bus master). Once the START signal is transferred by the master, the bus is considered busy. STOP: Each data transfer should be terminated by a Stop signal (P) generated by master. The STOP condition is a low to high transition on SDA line while SCL is held high. ACKS: Each byte of data transferred must be acknowledged. It is indicated by an acknowledge bit sent by the receiver. The transmitter must release the SDA line (no pull down) during the acknowledge pulse while the receiver must then pull the SDA line low so that it remains stable low during the high period of the acknowledge clock cycle. In the following diagrams these abbreviations are used: S P ACKS ACKM NACKM RW Start Stop Acknowledge by slave Acknowledge by master Not acknowledge by master Read / Write A START immediately followed by a STOP (without SCL toggling from ´VDDIO´ to ´GND´) is not supported. If such a combination occurs, the STOP is not recognized by the device. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 112 | 126 Bosch Sensortec | BMA400 Data sheet I²C write access: I²C write access can be used to write a data byte in one sequence. The sequence begins with start condition generated by the master, followed by 7 bits slave address and a write bit (RW = 0). The slave sends an acknowledge bit (ACKS = 0) and releases the bus. Then the master sends the one byte register address. The slave again acknowledges the transmission and waits for the 8 bits of data which shall be written to the specified register address. After the slave acknowledges the data byte, the master generates a stop signal and terminates the writing protocol. Example of an I²C write access: Slave Adress Start 0 0 1 0 1 Register address (0x41) R/W ACK 0 Master -> Slave Slave -> Master S 0 L 1 0 0 0 0 0 Register data (0x01) ACK 1 0 0 0 0 0 0 ACK Stop 0 1 S defined by SDO L: tie to LOW, not part of address Multi-byte writes are supported without restriction on normal registers. Slave Adress Start 0 0 1 0 1 Register address (0x41) R/W ACK 0 S 0 L 1 Master->Slave 0 0 0 0 0 1 Register address (0x42) Slave->Master L 1 0 0 0 0 1 Register data (0x01) ACK 0 0 0 0 0 0 1 Register data (0x01) ACK 0 0 ACK 0 0 0 0 0 0 ACK Stop 0 1 I²C read access: I²C read access also can be used to read one or multiple data bytes in one sequence. A read sequence consists of a one-byte I²C write phase followed by the I²C read phase. The two parts of the transmission must be separated by a repeated start condition (S). The I²C write phase addresses the slave and sends the register address to be read. After slave acknowledges the transmission, the master generates again a start condition and sends the slave address together with a read bit (RW = 1). Then the master releases the bus and waits for the data bytes to be read out from slave. After each data byte the master has to generate an acknowledge bit (ACKS = 0) to enable further data transfer. A NACKM (ACKS = 1) from the master stops the data being transferred from the slave. The slave releases the bus so that the master can generate a STOP condition and terminate the transmission. The register address is automatically incremented and, therefore, more than one byte can be sequentially read out. Once a new data read transmission starts, the start address will be set to the register address specified since the latest I²C write command. By default the start address is set at 0x00. In this way repetitive multi-bytes reads from the same starting address are possible. Slave Adress Start 0 0 0 0 1 0 1 S 0 S Slave Adress Start 1 0 1 Register address (0x05) R/W ACK 0 0 L 0 0 0 1 0 ACK 1 Register data - address 0x05 R/W ACK 1 0 d7 d6 d5 d4 d3 d2 d1 Register data - address 0x06 ACK d0 d7 d6 d5 d4 d3 d2 d1 NACK Stop d0 Master->Slave Slave->Master Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 113 | 126 Bosch Sensortec | BMA400 Data sheet 7. Pin-out and Connection Diagrams Pin-out Top View Bottom View Pads not visible! Pads visible! Pin description Pin# Name I/O Type 1 SDO Digital I/O 2 SDX Digital I/O 3 VDDIO Supply 4 5 6 NC INT1 INT2 Digital I/O Digital I/O 7 VDD Supply 8 9 10 11 GNDIO GND CSB NC Ground Ground Digital in 12 SCX Digital in Description Serial data output in SPI Address select in I²C mode see chapter 7.2 SDA serial data I/O in I²C SDI serial data input in SPI 4W SDA serial data I/O in SPI 3W Digital I/O supply voltage (1.2V … 3.6V) Interrupt output 1 (default) Interrupt output 2 (default) Power supply for analog & digital domain (1.62V … 3.6V) Ground for I/O Ground for digital & analog Chip select for SPI mode SCK for SPI serial clock SCL for I²C serial clock Modifications reserved | Data subject to change without notice in SPI 4W Connect to In SPI 3W in I²C SDO DNC (float) GND for default I2C addr. SDI SDA SDA VDDIO VDDIO VDDIO INT1 INT2 INT1 INT2 INT1 INT2 VDD VDD VDD GND GND CSB GND GND CSB GND GND VDDIO SCK SCK SCL Document number: BST-BMA400-DS000-03 Revision_1.2_072019 114 | 126 Bosch Sensortec | BMA400 Data sheet Connection Diagrams SPI 3-wire SCK SCX VDDIO 1 SDX 2 VDDIO 3 12 11 10 CSB BMA400 9 GND Top View 8 (Pads not visible!) 5 INT1 4 100nF 6 7 CS 100nF GNDIO VDD VDD INT2 MOSI/ MISO SDO GND INT1 INT2 It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD). 4-wire SCK SCX MISO SDO 1 MOSI SDX 2 VDDIO 3 10 CSB BMA400 9 GND 5 6 INT2 Top View 8 (Pads not visible!) 4 100nF 11 INT1 VDDIO 12 7 CS 100nF GNDIO VDD VDD GND INT1 INT2 It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD). Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 115 | 126 Bosch Sensortec | BMA400 Data sheet I2C SCL SCX SDA VDDIO SDO 1 SDX 2 VDDIO 3 11 10 CSB BMA400 9 GND Top View 8 (Pads not visible!) 4 100nF 12 5 6 INT2 =1 =0 INT1 I2C_ID.0 7 100nF GNDIO VDD VDD GND INT1 INT2 It is recommended to use 100nF decoupling capacitors at pin 3 (VDDIO) and pin 7 (VDD). Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 116 | 126 8. Package Package outline dimensions Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 117 | 126 Bosch Sensortec | BMA400 Data sheet Sensing axis orientation If the sensor is accelerated in the indicated directions, the corresponding channel will deliver a positive acceleration signal (dynamic acceleration). If the sensor is at rest and the force of gravity is acting along the indicated directions, the output of the corresponding channel will be negative (static acceleration). Example: If the sensor is at rest or at uniform motion in a gravity field according to the figure given below, the output signals are: • • • ± 0g for the X channel ± 0g for the Y channel + 1g for the Z channel The following table lists all corresponding output signals on X, Y, and Z while the sensor is at rest or at uniform motion in a gravity field under assumption of a ±4g range setting, a 16 bit resolution, and a top down gravity vector as shown above. Sensor Orientation (gravity vector ↓) upright Output Signal X 0g / 0 LSB 1g / 1024 LSB 0g / 0 LSB -1g / -1024 LSB 0g / 0 LSB 0g / 0 LSB Output Signal Y -1g / -1024 LSB 0g / 0 LSB 1g / 1024 LSB 0g / 0 LSB 0g / 0 LSB 0g / 0 LSB Output Signal Z 0g / 0 LSB 0g / 0 LSB 0g / 0 LSB 0g / 0 LSB Modifications reserved | Data subject to change without notice 1g / 1024 LSB -1g / -1024 LSB Document number: BST-BMA400-DS000-03 Revision_1.2_072019 118 | 126 Bosch Sensortec | BMA400 Data sheet For reference the figure below shows the device orientation with an integrated BMA400. BMA400 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 119 | 126 Landing pattern recommendation The recommended landing pattern for the BMA400 on customer’s PCB is given in the following figure. It is recommended to avoid any wiring underneath the BMA400 (shaded area). Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 120 | 126 Bosch Sensortec | BMA400 Data sheet Marking Marking of Engineering Samples(A,C) BMA400 Labeling Top view XE NCC Bottom view Name Symbol Remark Sub-con ID X internal use only Eng. sample ID E Identifies Engineering Samples Sample ID NCC ‘N’ to be replaced by ‘A’,’C’, sample status ‘CC’ defines lot number Pin 1 identifier top side • -- Pin 1 identifier bottom side ◤ Triangle points in the direction of pin 1 Name Symbol Remark Supply chain ID ZZ internal use only Counter ID CCC 3 alphanumeric digits, variable to generate trace-code. Pin 1 identifier top side • -- Pin 1 identifier bottom side ◤ Triangle points in the direction of pin 1 Marking of Mass Production Samples BMA400 Labeling Top view Bottom view ZZ CCC Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 121 | 126 Soldering guidelines The moisture sensitivity level of the BMA400 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 260°C. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 122 | 126 Handling instructions Micromechanical sensors are designed to sense acceleration with high accuracy even at low amplitudes and contain highly sensitive structures inside the sensor element. The MEMS sensor can tolerate mechanical shocks up to several thousand g's. However, these limits might be exceeded in conditions with extreme shock loads such as e.g. hammer blow on or next to the sensor, dropping of the sensor onto hard surfaces etc. We recommend to avoid g-forces beyond the specified limits during transport, handling and mounting of the sensors in a defined and qualified installation process. This device has built-in protections against high electrostatic discharges or electric fields (e.g. 2kV HBM); however, anti-static precautions should be taken as for any other CMOS component. Unless otherwise specified, proper operation can only occur when all terminal voltages are kept within the supply voltage range. Unused inputs must always be tied to a defined logic voltage level. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 123 | 126 Environmental safety The BMA400 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 September 2011 on the restriction of the use of certain hazardous substances in electrical and electronic equipment. Halogen content The BMA400 is halogen-free. For more details on the corresponding 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. 2 nd source) for the LGA package of the BMA400. 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 BMA400 product. Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 124 | 126 9. Legal disclaimer 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. 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 safetycritical systems. Safety-critical 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. 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 to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 125 | 126 Bosch Sensortec | BMA400 Data sheet 10. Document history and modification Rev. No Chapter Description of modification/changes Date 1.1 - Public release 31 July 2018 1.2 4.8, 4.7, 8.3, 9.2 Update self test limits Step Counter Configuration Landing Pattern Disclaimer updated July 2019 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Bosch Sensortec | BMA400 Data sheet 126 | 126 Bosch Sensortec GmbH Gerhard-Kindler-Straße 9 72770 Reutlingen / Germany contact@bosch-sensortec.com www.bosch-sensortec.com Modifications reserved Preliminary - specifications subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019 Modifications reserved | Data subject to change without notice Document number: BST-BMA400-DS000-03 Revision_1.2_072019