BMA255 SHUTL

Data sheet BMA255 Data sheet BMA255 Digital, triaxial acceleration sensor Page 1 Bosch Sensortec BMA255: Data sheet Document revision 1.2 Document release date 01 August 2014 Document number BST-BMA255-DS004-05 Technical reference code(s) 0 273 141 171 Notes Data 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’s appearance. Not intended for publishing BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 2 BMA255 12 BIT, DIGITAL, TRIAXIAL ACCELERATION SENSOR WITH INTELLIGENT ON-CHIP MOTION-TRIGGERED INTERRUPT CONTROLLER Key features  Ultra-Small package  Digital interface  Programmable functionality   On-chip FIFO On-chip interrupt controller  Ultra-low power   Temperature sensor RoHS compliant, halogen-free LGA package (12 pins), footprint 2mm x 2mm, height 0.95mm SPI (4-wire, 3-wire), I²C, 2 interrupt pins VDDIO voltage range: 1.2V to 3.6V Acceleration ranges ±2g/±4g/±8g/±16g Low-pass filter bandwidths 1kHz - 0V) or vice versa. When the VDDIO supply is switched off, all interface pins (CSB, SDI, SCK, PS) must be kept close to GNDIO potential. The device contains a power-on reset (POR) generator. It resets the logic part and the register values after powering-on VDD and VDDIO. Please note, that all application specific settings which are not equal to the default settings (refer to 6.2 register map), must be re-set to its designated values after POR. There are no constraints on the switching sequence of both supply voltages. In case the I²C interface shall be used, a direct electrical connection between VDDIO supply and the PS pin is needed in order to ensure reliable protocol selection. For SPI interface mode the PS pin must be directly connected to GNDIO. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 14 4.2 Power modes The BMA255 has six different power modes. Besides normal mode, which represents the fully operational state of the device, there are five energy saving modes: deep-suspend mode, suspend mode, standby mode, low-power mode 1 and low-power mode 2. The possible transitions between the power modes are illustrated in figure 2: DEEPSUSPEND Mode NORMAL Mode SUSPEND Mode Low Power Mode 1 STANDBY Mode Low Power Mode 2 Figure 2: Power mode transition diagram After power-up BMA255 is in normal mode so that all parts of the device are held powered-up and data acquisition is performed continuously. In deep-suspend mode the device reaches the lowest possible power consumption. Only the interface section is kept alive. No data acquisition is performed and the content of the configuration registers is lost. Deep suspend mode is entered (left) by writing ‘1’ (‘0’) to the (0x11) deep_suspend bit while (0x11) suspend bit is set to ‘0’. The I2C watchdog timer remains functional. The (0x11) deep_ suspend bit, the (0x34) spi3 bit, (0x34) i2c_wdt_en bit and the (0x34) i2c_wdt_sel bit are functional in deep-suspend mode. Equally the interrupt level and driver configuration registers (0x20) int1_lvl, (0x20) int1_od, (0x20) int2_lvl, and (0x20) int2_od are accessible. Still it is possible to enter normal mode by performing a softreset as described in chapter 4.8. Please note, that all application specific settings which are not equal to the default settings (refer to 6.2 register map), must be re-set to its designated values after leaving deepsuspend mode. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 15 In suspend mode the whole analog part is powered down. No data acquisition is performed. While in suspend mode the latest acceleration data and the content of all configuration registers are kept. Writing to and reading from registers is supported except from the (0x3E) fifo_config_1, (0x30) fifo_config_0 and (0x3F) fifo_data register. It is possible to enter normal mode by performing a softreset as described in chapter 4.8. Suspend mode is entered (left) by writing ´1´ (´0´) to the (0x11) suspend bit after bit (0x12) lowpower_mode has been set to ‘0’. Although write access to registers is supported at the full interface clock speed (SCL or SCK), a waiting period must be inserted between two consecutive write cycles (please refer also to section 7.2.1). In standby mode the analog part is powered down, while the digital part remains largely operational. No data acquisition is performed. Reading and writing registers is supported without any restrictions. The latest acceleration data and the content of all configuration registers are kept. Standby mode is entered (left) by writing ´1´ (´0´) to the (0x11) suspend bit after bit (0x12) lowpower_mode has been set to ‘1’. It is also possible to enter normal mode by performing a softreset as described in chapter 4.8. In low-power mode 1, the device is periodically switching between a sleep phase and a wakeup phase. The wake-up phase essentially corresponds to operation in normal mode with complete power-up of the circuitry. The sleep phase essentially corresponds to operation in suspend mode. Low-power mode is entered (left) by writing ´1´ (´0´) to the (0x11) lowpower_en bit with bit (0x12) lowpower_mode set to ‘0’. Read access to registers is possible except from the (0x3F) fifo_data register. However, unless the register access is synchronised with the wake-up phase, the restrictions of the suspend mode apply. Low-power mode 2 is very similar to low-power mode 1, but register access is possible at any time without restrictions. It consumes more power than low-power mode 1. In low-power mode 2 the device is periodically switching between a sleep phase and a wake-up phase. The wakeup phase essentially corresponds to operation in normal mode with complete power-up of the circuitry. The sleep phase essentially corresponds to operation in standby mode. Low-power mode is entered (left) by writing ´1´ (´0´) to the (0x11) lowpower_en bit with bit (0x12) lowpower_mode set to ‘1’. The timing behaviour of the low-power modes 1 and 2 depends on the setting of the (0x12) sleeptimer_mode bit. When (0x12) sleeptimer_mode is set to ‘0’, the event-driven time-base mode (EDT) is selected. In EDT the duration of the wake-up phase depends on the number of samples required by the enabled interrupt engines. If an interrupt is detected, the device stays in the wake-up phase as long as the interrupt condition endures (non-latched interrupt), or until the latch time expires (temporary interrupt), or until the interrupt is reset (latched interrupt). If no interrupt is detected, the device enters the sleep phase immediately after the required number of acceleration samples have been taken and an active interface access cycle has ended. The EDT mode is recommended for power-critical applications which do not use the FIFO. Also, EDT mode is compatible with legacy BST sensors. Figure 3 shows the timing diagram for lowpower modes 1 and 2 when EDT is selected. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Settle Sample Sample Sample Settle Sample Settle Sample Sample Active phase Sample tACTIVE State Sleep phase Page 16 tSLEEP tSLEEP t Figure 3: Timing Diagram for low-power mode 1/2, EDT When (0x12) sleeptimer_mode is set to ‘1’, the equidistant-sampling mode (EST) is selected. The use of the EST mode is recommended when the FIFO is used since it ensures that equidistant samples are sampled into the FIFO regardless of whether the active phase is extended by active interrupt engines or interface activity. In EST mode the sleep time tSLEEP is defined as shown in Figure 4. The FIFO sampling time tSAMPLE is the sum of the sleep time tSLEEP and the sensor data sampling time tSSMP. Since interrupt engines can extend the active phase to exceed the sleep time tSLEEP, equidistant sampling is only guaranteed if the bandwidth has been chosen such that 1/(2 * bw) = n * tSLEEP where n is an integer. If this condition is infringed, equidistant sampling is not possible. Once the sleep time has elapsed the device will store the next available sample in the FIFO. This set-up condition is not recommended as it may result in timing jitter. Sampled into FIFO tSLEEP tSSMP tSAMPLE tSLEEP Settle Sample Settle Sample Sample Sample Settle Sample Sleep phase Settle Sample Sample Active phase Sample State tSLEEP tSAMPLE tSAMPLE t Figure 4: Timing Diagram for low-power mode 1/2, EST BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 17 The sleep time for lower-power mode 1 and 2 is set by the (0x11) sleep_dur bits as shown in the following table: Table 3: Sleep phase duration settings (0x11) sleep_dur 0000b 0001b 0010b 0011b 0100b 0101b 0110b 0111b 1000b 1001b 1010b 1011b 1100b 1101b 1110b 1111b Sleep Phase Duration tsleep 0.5ms 0.5ms 0.5ms 0.5ms 0.5ms 0.5ms 1ms 2ms 4ms 6ms 10ms 25ms 50ms 100ms 500ms 1s The current consumption of the BMA255 in low-power mode 1 (IDDlp1) and low-power mode 2 (IDDlp2) can be estimated with the following formulae: I DDlp1  I DDlp 2  t sleep  I DDsum  t active  I DD t sleep  t active . t sleep  I DDsbm  t active  I DD t sleep  t active When estimating the length of the wake-up phase tactive, the corresponding typical wake-up time, tw,up1 or tw,up2 and tut (given in Table 4) have to be considered: If bandwidth is >=31.25 Hz: tactive = tut + tw,up1 - 0.9 ms (or tactive = tut + tw,up2 - 0.9 ms) else: tactive = 4 tut + tw,up1 - 0.9 ms (or tactive = 4 tut + tw,up2 - 0.9 ms) During the wake-up phase all analog modules are held powered-up, while during the sleep phase most analog modules are powered down. Consequently, a wake-up time of at least tw,up1 (tw,up2) is needed to settle the analog modules so that reliable acceleration data are generated. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 18 4.3 Sensor data 4.3.1 Acceleration data The width of acceleration data is 12 bits given in two´s complement representation. The 12 bits for each axis are split into an MSB upper part (one byte containing bits 11 to 4) and an LSB lower part (one byte containing bits 3 to 0 of acceleration and a (0x02, 0x04, 0x06) new_data flag). Reading the acceleration data registers shall always start with the LSB part. In order to ensure the integrity of the acceleration data, the content of an MSB register is locked by reading the corresponding LSB register (shadowing procedure). When shadowing is enabled, the MSB must always be read in order to remove the data lock. The shadowing procedure can be disabled (enabled) by writing ´1´ (´0´) to the bit shadow_dis. With shadowing disabled, the content of both MSB and LSB registers is updated by a new value immediately. Unused bits of the LSB registers may have any value and should be ignored. The (0x02, 0x04, 0x06) new_data flag of each LSB register is set if the data registers have been updated. The flag is reset if either the corresponding MSB or LSB part is read. Two different streams of acceleration data are available, unfiltered and filtered. The unfiltered data is sampled with 2kHz. The sampling rate of the filtered data depends on the selected filter bandwidth and is always twice the selected bandwidth (BW = ODR/2). Which kind of data is stored in the acceleration data registers depends on bit (0x13) data_high_bw. If (0x13) data_high_bw is ´0´ (´1´), then filtered (unfiltered) data is stored in the registers. Both data streams are offset-compensated. The bandwidth of filtered acceleration data is determined by setting the (0x10) bw bit as followed: Table 4: Bandwidth configuration bw Bandwidth 00xxx 01000 01001 01010 01011 01100 01101 01110 01111 1xxxx *) 7.81Hz 15.63Hz 31.25Hz 62.5Hz 125Hz 250Hz 500Hz 1000Hz *) Update Time tut 64ms 32ms 16ms 8ms 4ms 2ms 1ms 0.5ms - *) Note: Settings 00xxx result in a bandwidth of 7.81 Hz; settings 1xxxx result in a bandwidth of 1000 Hz. It is recommended to actively set an application specific and an appropriate bandwidth and to use the range from ´01000b´ to ´01111b´ only in order to be compatible with future products. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 19 The BMA255 supports four different acceleration measurement ranges. A measurement range is selected by setting the (0x0F) range bits as follows: Table 5: Range selection Range 0011 0101 1000 1100 others Acceleration measurement range ±2g ±4g ±8g ±16g reserved Resolution 0.98mg/LSB 1.95mg/LSB 3.91mg/LSB 7.81mg/LSB - 4.3.2 Temperature sensor The width of temperature data is 8 bits given in two´s complement representation. Temperature values are available in the (0x08) temp register. The slope of the temperature sensor is 0.5K/LSB, its center temperature is 23°C [(0x08) temp = 0x00]. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 20 4.4 Self-test This feature permits to check the sensor functionality 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 4 g. The self-test is activated individually for each axis by writing the proper value to the (0x32) self_test_axis bits (´01b´ for xaxis, ´10b´ for y-axis, ´11b´ for z-axis, ´00b´ to deactivate self-test). It is possible to control the direction of the deflection through bit (0x32) self_test_sign. The excitation occurs in negative (positive) direction if (0x32) self_test_sign = ´0b´ (´1b´). After the self-test is enabled, the user should wait 50ms before interpreting the acceleration data. In order to ensure a proper interpretation of the self-test signal it is recommended to perform the self-test for both (positive and negative) directions and then to calculate the difference of the resulting acceleration values. Table 6 shows the minimum differences for each axis. The actually measured signal differences can be significantly larger. Table 6: Self-test difference values resulting minimum difference signal x-axis signal y-axis signal z-axis signal 800 mg 800 mg 400 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, enable desired interrupts. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 21 4.5 Offset compensation Offsets in measured signals can have several causes but they are always unwanted and disturbing in many cases. Therefore, the BMA255 offers an advanced set of four digital offset compensation methods which are closely matched to each other. These are slow, fast, and manual compensation as well as inline calibration. The compensation is performed with unfiltered data, and is then applied to both, unfiltered and filtered data. If necessary the result of this computation is saturated to prevent any overflow errors (the smallest or biggest possible value is set, depending on the sign). However, the registers used to read and write compensation values have a width of 8 bits. An overview of the offset compensation principle is given in figure 5: I2C/SPI/NVM mapping 12 bit acceleration data range +-16g +-8g +-4g 8g Sign 4g 4g Sign 2g 2g 2g Sign 1g 1g 1g 1g 500mg 500mg 500mg 500mg 500mg 250mg 250mg 250mg 250mg 250mg 125mg 125mg 125mg 125mg 62.5mg 62.5mg 62.5mg 62.5mg 31.2mg 31.2mg 31.2mg 31.2mg 31.2mg 15.6mg 15.6mg 15.6mg 15.6mg 15.6mg 7.8mg 7.8mg 7.8mg 7.8mg 3.9mg 3.9mg MSB 125mg Read/ Write 62.5mg LSB Sign Sign +-2g MSB MSB - 1.9mg LSB MSB LSB MSB LSB LSB 7.8mg 3.9mg 1.9mg 0.97mg Figure 5: Principle of offset compensation BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 22 The public offset compensation registers (0x38) offset_x, (0x39) offset_y, (0x3A) offset_z are images of the corresponding registers in the NVM. With each image update (see section 4.6 Non-volatile memory for details) the contents of the NVM registers are written to the public registers. The public registers can be over-written by the user at any time. After changing the contents of the public registers by either an image update or manually, all 8bit values are extended to 12bit values for internal computation. In the opposite direction, if an internally computed value changes it is converted to an 8bit value and stored in the public register. Depending on the selected g-range the conversion from 12bit to 8bit values can result in a loss of accuracy of one to several LSB. This is shown in figure 5. In case an internally computed compensation value is too small or too large to fit into the corresponding register, it is saturated in order to prevent an overflow error. By writing ´1´ to the (0x36) offset_reset bit, all offset compensation registers are reset to zero. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 23 4.5.1 Slow compensation st Slow compensation is based on a 1 order high-pass filter, which continuously drives the average value of the output data stream of each axis to zero. The bandwidth of the high-pass filter is configured with bit (0x37) cut_off according to Table 7. Table 7: Compensation period settings (0x37) cut_off high-pass filter bandwidth Example bw = 500 Hz 0b 1b *bw: please insert selected decimal data bandwidth value [Hz] from table 4 The slow compensation can be enabled (disabled) for each axis independently by setting the bits (0x36) hp_x_en, hp_y_en, hp_z_en to ´1´ (´0´), respectively. Slow compensation should not be used in combination with low-power mode. In low-power mode the conditions (availability of necessary data) for proper function of slow compensation are not fulfilled. 4.5.2 Fast compensation Fast compensation is a one-shot process by which the compensation value is set in such a way that when added to the raw acceleration, the resulting acceleration value of each axis approaches the target value. This is best suited for “end-of-line trimming” with the customer’s device positioned in a well-defined orientation. For fast compensation the g-range has to be switched to 2g. The algorithm in detail: An average of 16 consecutive acceleration values is computed and the difference between target value and computed value is written to (0x38, 0x39, 0x3A) offset_filt_x/y/z. The public registers (0x38, 0x39, 0x3A) offset_filt_x/y/z are updated with the contents of the internal registers (using saturation if necessary) and can be read by the user. Fast compensation is triggered for each axis individually by setting the (0x36) cal_trigger bits as shown in Table 8: Table 8: Fast compensation axis selection (0x36) cal_trigger 00b 01b 10b 11b BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Selected Axis none x y z Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 24 Register (0x36) cal_trigger is a write-only register. Once triggered, the status of the fast correction process is reflected in the status bit (0x36) cal_rdy. Bit (0x36) cal_rdy is ‘0’ while the correction is in progress. Otherwise it is ‘1’. Bit (0x36) cal_rdy is ´0´ when (0x36) cal_trigger is not ´00´. For the fast offset compensation, the compensation target can be chosen by setting the bits (0x37) offset_target_x, (0x37) offset_target_y, and (0x37) offset_target_z according to Table 9: Table 9: Offset target settings (0x37) offset_target_x/y/z 00b 01b 10b 11b Target value 0g +1g -1g 0g Fast compensation should not be used in combination with any of the low-power modes. In lowpower mode the conditions (availability of necessary data) for proper function of fast compensation are not fulfilled. 4.5.3 Manual compensation The contents of the public compensation registers (0x38, 0x39, 0x3A) offset_filt_x/y/z can be set manually via the digital interface. It is recommended to write into these registers directly after a new data interrupt has occurred in order not to disturb running offset computations. Writing to the offset compensation registers is not allowed while the fast compensation procedure is running. 4.5.4 Inline calibration For certain applications, it is often desirable to calibrate the offset once and to store the compensation values permanently. This can be achieved by using one of the aforementioned offset compensation methods to determine the proper compensation values and then storing these values permanently in the NVM. See section 4.6 Non-volatile memory for details of the storing procedure. Each time the device is reset, the compensation values are loaded from the non-volatile memory into the image registers and used for offset compensation until they are possibly overwritten using one of the other compensation methods. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 25 4.6 Non-volatile memory The entire memory of the BMA255 consists of three different kinds of registers: hard-wired, volatile, and non-volatile. Part of it can be both read and written by the user. Access to nonvolatile memory is only possible through (volatile) image registers. Altogether, there are eight registers (octets) with NVM backup which are accessible by the user. The addresses of the image registers range from 0x38 to 0x3C. While the addresses up to 0x3A are used for offset compensation (see 4.4 Offset Compensation), addresses 0x3B and 0x3C are general purpose registers not linked to any sensor-specific functionality. The content of the NVM is loaded to the image registers after a reset (either POR or softreset) or after a user request which is performed by writing ´1´ to the write-only bit (0x33) nvm_load. As long as the image update is in progress, bit (0x33) nvm_rdy is ´0´, otherwise it is ´1´. The image registers can be read and written like any other register. Writing to the NVM is a three-step procedure: 1. Write the new contents to the image registers. 2. Write ´1´ to bit (0x33) nvm_prog_mode in order to unlock the NVM. 3. Write ´1´ to bit (0x33) nvm_prog_trig and keep ´1´ in bit (0x33) nvm_prog_mode in order to trigger the write process. Writing to the NVM always renews the entire NVM contents. It is possible to check the write status by reading bit (0x33) nvm_rdy. While (0x33) nvm_rdy = ´0´, the write process is still in progress; if (0x33) nvm_rdy = ´1´, then writing is completed. As long as the write process is ongoing, no change of power mode and image registers is allowed. Also, the NVM write cycle must not be initiated while image registers are updated, in low-power mode, and in suspend mode. Please note that the number of permitted NVM write-cycles is limited as specified in Table 1. The number of remaining write-cycles can be obtained by reading bits (0x33) nvm_remain. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 26 4.7 Interrupt controller The BMA255 is equipped with eight programmable interrupt engines. Each interrupt can be independently enabled and configured. If the trigger condition of an enabled interrupt is fulfilled, the corresponding status bit is set to ´1´ and the selected interrupt pin is activated. The BMA255 provides two interrupt pins, INT1 and INT2; interrupts can be freely mapped to any of these pins. The state of a specific interrupt pin is derived from a logic ´or´ combination of all interrupts mapped to it. The interrupt status registers are updated when a new data word is written into the acceleration data registers. If an interrupt is disabled, all active status bits associated with it are immediately reset. 4.7.1 General features An interrupt is cleared depending on the selected interrupt mode, which is common to all interrupts. There are three different interrupt modes: non-latched, latched, and temporary. The mode is selected by the (0x21) latch_int bits according to Table 10. Table 10: Interrupt mode selection (0x21) latch_int 0000b 0001b 0010b 0011b 0100b 0101b 0110b 0111b 1000b 1001b 1010b 1011b 1100b 1101b 1110b 1111b Interrupt mode non-latched temporary, 250ms temporary, 500ms temporary, 1s temporary, 2s temporary, 4s temporary, 8s latched non-latched temporary, 250µs temporary, 500µs temporary, 1ms temporary, 12.5ms temporary, 25ms temporary, 50ms latched An interrupt is generated if its activation condition is met. It can not be cleared as long as the activation condition is fulfilled. In the non-latched mode the interrupt status bit and the selected pin (the contribution to the ´or´ condition for INT1 and/or INT2) are cleared as soon as the activation condition is no more valid. Exceptions to this behavior are the new data, orientation, and flat interrupts, which are automatically reset after a fixed time. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 27 In latched mode an asserted interrupt status and the selected pin are cleared by writing ´1´ to bit (0x21) reset_int. If the activation condition still holds when it is cleared, the interrupt status is asserted again with the next change of the acceleration registers. In the temporary mode an asserted interrupt and selected pin are cleared after a defined period of time. The behaviour of the different interrupt modes is shown graphically in figure 6. The timings in this mode are subject to the same tolerances as the bandwidths (see Table 1). internal signal from interrupt engine interrupt output non-latched latch period temporary latched Figure 6: Interrupt modes Several interrupt engines can use either unfiltered or filtered acceleration data as their input. For these interrupts, the source can be selected with the bits in register (0x1E). These are (0x1E) int_src_data, (0x1E) int_src_tap, (0x1E) int_src_slo_no_mot, (0x1E) int_src_slope, (0x1E) int_src_high, and (0x1E) int_src_low. Setting the respective bits to ´0´ (´1´) selects filtered (unfiltered) data as input. The orientation recognition and flat detection interrupt always use filtered input data. It is strongly recommended to set interrupt parameters prior to enabling the interrupt. Changing parameters of an already enabled interrupt may cause unwanted interrupt generation and generation of a false interrupt history. A safe way to change parameters of an enabled interrupt is to keep the following sequence: disable the desired interrupt, change parameters, wait for at least 10ms, and then re-enable the desired interrupt. 4.7.2 Mapping to physical interrupt pins (inttype to INT Pin#) Registers (0x19) to (0x1B) are dedicated to mapping of interrupts to the interrupt pins “INT1” or “INT2”. Setting (0x19) int1_”inttype” to ´1´ (´0´) maps (unmaps) “inttype” to pin “INT1”. Correspondingly setting (0x1B) int2_”inttype” to ´1´ (´0´) maps (unmaps) “inttype” to pin “INT2”. Note: “inttype” to be replaced with the precise notation, given in the memory map in chapter 6. Example: For flat interrupt (int1_flat): Setting (0x19) int1_flat to ´1´ maps int1_flat to pin “INT1”. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 28 4.7.3 Electrical behaviour (INT pin# to open-drive or push-pull) Both interrupt pins can be configured to show the desired electrical behaviour. The ´active´ level of each interrupt pin is determined by the (0x20) int1_lvl and (0x20) int2_lvl bits. If (0x20) int1_lvl = ´1´ (´0´) / (0x20) int2_lvl = ´1´ (´0´), then pin “INT1” / pin “INT2” is active ´1´ (´0´). The characteristic of the output driver of the interrupt pins may be configured with bits (0x20) int1_od and (0x20) int2_od. By setting bits (0x20) int1_od / (0x20) int2_od to ´1´, the output driver shows open-drive characteristic, by setting the configuration bits to ´0´, the output driver shows push-pull characteristic. When open-drive characteristic is selected in the design, external pull-up or pull-down resistor should be applied according the int_lvl configuration. 4.7.4 New data interrupt This interrupt serves for synchronous reading of acceleration data. It is generated after storing a new value of z-axis acceleration data in the data register. The interrupt is cleared automatically when the next data acquisition cycle starts. The interrupt status is ´0´ for at least 50µs. The interrupt mode of the new data interrupt is fixed to non-latched. It is enabled (disabled) by writing ´1´ (´0´) to bit (0x17) data_en. The interrupt status is stored in bit (0x0A) data_int. Due to the settling time of the filter, the first interrupt after wake-up from suspend or standby mode will take longer than the update time. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 29 4.7.5 Slope / any-motion detection Slope / any-motion detection uses the slope between successive acceleration signals to detect changes in motion. An interrupt is generated when the slope (absolute value of acceleration difference) exceeds a preset threshold. It is cleared as soon as the slope falls below the threshold. The principle is made clear in figure 7. acceleration acc(t0) acc(t0−1/(2*bw)) time slope(t0)=acc(t0)−acc(t0−1/(2*bw)) slope slope_th time slope_dur slope_dur INT time Figure 7: Principle of any-motion detection The threshold is defined through register (0x28) slope_th. In terms of scaling 1 LSB of (0x28) slope_th corresponds to 3.91 mg in 2g-range (7.81 mg in 4g-range, 15.6 mg in 8g-range and 31.3 mg in 16g-range). Therefore the maximum value is 996 mg in 2g-range (1.99g in 4grange, 3.98g in 8g-range and 7.97g in 16g-range). The time difference between the successive acceleration signals depends on the selected bandwidth and equates to 1/(2*bandwidth) (t=1/(2*bw)). In order to suppress false triggers, the interrupt is only generated (cleared) if a certain number N of consecutive slope data points is larger (smaller) than the slope threshold given by (0x28) slope_th. This number is set by the (0x27) slope_dur bits. It is N = (0x27) slope_dur + 1 for (0x27). Example: (0x27) slope_dur = 00b, …, 11b = 1decimal, …, 4decimal. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 30 4.7.5.1 Enabling (disabling) for each axis Any-motion detection can be enabled (disabled) for each axis separately by writing ´1´ (´0´) to bits (0x16) slope_en_x, (0x16) slope_en_y, (0x16) slope_en_z. The criteria for any-motion detection are fulfilled and the slope interrupt is generated if the slope of any of the enabled axes exceeds the threshold (0x28) slope_th for [(0x27) slope_dur +1] consecutive times. As soon as the slopes of all enabled axes fall or stay below this threshold for [(0x27) slope_dur +1] consecutive times the interrupt is cleared unless interrupt signal is latched. 4.7.5.2 Axis and sign information of slope / any motion interrupt The interrupt status is stored in bit (0x09) slope_int. The any-motion interrupt supplies additional information about the detected slope. The axis which triggered the interrupt is given by that one of bits (0x0B) slope_first_x, (0x0B) slope_first_y, (0x0B) slope_first_z that contains a value of ´1´. The sign of the triggering slope is held in bit (0x0B) slope_sign until the interrupt is retriggered. If (0x0B) slope_sign = ´0´ (´1´), the sign is positive (negative). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 31 4.7.6 Tap sensing Tap sensing has a functional similarity with a common laptop touch-pad or clicking keys of a computer mouse. A tap event is detected if a pre-defined slope of the acceleration of at least one axis is exceeded. Two different tap events are distinguished: A ‘single tap’ is a single event within a certain time, followed by a certain quiet time. A ‘double tap’ consists of a first such event followed by a second event within a defined time frame. Single tap interrupt is enabled (disabled) by writing ´1´ (´0´) to bit (0x16) s_tap_en. Double tap interrupt is enabled (disabled) by writing ´1´ (´0´) to bit (0x16) d_tap_en. While temporary latching is used do not simultaneously enable single tap interrupt and double tap interrupt. The status of the single tap interrupt is stored in bit (0x09) s_tap_int, the status of the double tap interrupt is stored in bit (0x09) d_tap_int. The slope threshold for detecting a tap event is set by bits (0x2B) tap_th. The meaning of (0x2B) tap_th depends on the range setting. 1 LSB of (0x2B) tap_th corresponds to a slope of 62.5mg in 2g-range, 125mg in 4g-range, 250mg in 8g-range, and 500mg in 16g-range. In figure 8 the meaning of the different timing parameters is visualized: slope 1st tap 2nd tap tap_th time tap_shock tap_quiet tap_dur tap_shock tap_quiet single tap detection 12.5 ms time double tap detection 12.5 ms time Figure 8: Timing of tap detection BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 32 The parameters (0x2A) tap_shock and (0x2A) tap_quiet apply to both single tap and double tap detection, while (0x2A) tap_dur applies to double tap detection only. Within the duration of (0x2A) tap_shock any slope exceeding (0x2B) tap_th after the first event is ignored. Contrary to this, within the duration of (0x2A) tap_quiet no slope exceeding (0x2B) tap_th must occur, otherwise the first event will be cancelled. 4.7.6.1 Single tap detection A single tap is detected and the single tap interrupt is generated after the combined durations of (0x2A) tap_shock and (0x2A) tap_quiet, if the corresponding slope conditions are fulfilled. The interrupt is cleared after a delay of 12.5 ms. Do not map single-tap to any INT pin if you do not want to use it. 4.7.6.2 Double tap detection A double tap interrupt is generated if an event fulfilling the conditions for a single tap occurs within the set duration in (0x2A) tap_dur after the completion of the first tap event. The interrupt is automatically cleared after a delay of 12.5 ms. 4.7.6.3 Selecting the timing of tap detection For each of parameters (0x2A) tap_shock and (0x2A) tap_quiet two values are selectable. By writing ´0´ (´1´) to bit (0x2A) tap_shock the duration of (0x2A) tap_shock is set to 50 ms (75 ms). By writing ´0´ (´1´) to bit (0x2A) tap_quiet the duration of (0x2A) tap_quiet is set to 30 ms (20 ms). The length of (0x2A) tap_dur can be selected by setting the (0x2A) tap_dur bits according to Table 11: Table 11: Selection of tap_dur (0x2A) tap_dur 000b 001b 010b 011b 100b 101b 110b 111b BST-BMA255-DS004-05 | Revision 1.2 | August 2014 length of tap_dur 50 ms 100 ms 150 ms 200 ms 250 ms 375 ms 500 ms 700 ms Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 33 4.7.6.4 Axis and sign information of tap sensing The sign of the slope of the first tap which triggered the interrupt is stored in bit (0x0B) tap_sign (´0´ means positive sign, ´1´ means negative sign). The value of this bit persists after clearing the interrupt. The axis which triggered the interrupt is indicated by bits (0x0B) tap_first_x, (0x0B) tap_first_y, and (0x0B) tap_first_z. The bit corresponding to the triggering axis contains a ´1´ while the other bits hold a ´0´. These bits are cleared together with clearing the interrupt status. 4.7.6.5 Tap sensing in low power mode In low-power mode, a limited number of samples is processed after wake-up to decide whether an interrupt condition is fulfilled. The number of samples is selected by bits (0x2B) tap_samp according to Table 12. Table 12: Meaning of (0x2B) tap_samp (0x2B) tap_samp 00b 01b 10b 11b BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Number of Samples 2 4 8 16 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 34 4.7.7 Orientation recognition The orientation recognition feature informs on an orientation change of the sensor with respect to the gravitational field vector ‘g’. The measured acceleration vector components with respect to the gravitational field are defined as shown in figure 9. Figure 9: Definition of vector components Therefore, the magnitudes of the acceleration vectors are calculated as follows: acc_x = 1g x sin x cos acc_y = −1g x sin x sin acc_z = 1g x cos acc_y/acc_x = −tan Depending on the magnitudes of the acceleration vectors the orientation of the device in the space is determined and stored in the three (0x0C) orient bits. These bits may not be reset in the sleep phase of low-power mode. There are three orientation calculation modes with different thresholds for switching between different orientations: symmetrical, high-asymmetrical, and low-asymmetrical. The mode is selected by setting the (0x2C) orient_mode bits as given in Table 13. Table 13: Orientation mode settings (0x2C) orient_mode 00b 01b 10b 11b BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Orientation Mode symmetrical high-asymmetrical low-asymmetrical symmetrical Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 35 For each orientation mode the (0x0C) orient bits have a different meaning as shown in Table 14 to Table 16: Table 14: Meaning of the (0x0C) orient bits in symmetrical mode (0x0C) orient Name Angle x00 portrait upright 315° <  < 45° x01 portrait upside down 135° <  < 225° x10 landscape left 45° <  < 135° x11 landscape right 225° <  < 315° Condition |acc_y| < |acc_x| - ‘hyst’ and acc_x - ‘hyst’’ ≥ 0 |acc_y| < |acc_x| - ‘hyst’ and acc_x + ‘hyst’ < 0 |acc_y| ≥ |acc_x| + ‘hyst’ and acc_y < 0 |acc_y| ≥ |acc_x| + ‘hyst’ and acc_y ≥ 0 Table 15: Meaning of the (0x0C) orient bits in high-asymmetrical mode (0x0C) orient Name Angle x00 portrait upright 297° <  < 63° x01 portrait upside down 117° <  < 243° x10 landscape left 63° <  < 117° x11 landscape right 243° <  < 297° Condition |acc_y| < 2∙|acc_x| - ‘hyst’ and acc_x - ‘hyst’ ≥ 0 |acc_y| < 2∙|acc_x| - ‘hyst’ and acc_x + ‘hyst’ < 0 |acc_y| ≥ 2∙|acc_x| + ‘hyst’ and acc_y < 0 |acc_y| ≥ 2∙|acc_x| + ‘hyst’ and acc_y ≥ 0 Table 16: Meaning of the (0x0C) orient bits in low-asymmetrical mode (0x0C) orient Name Angle x00 portrait upright 333° <  < 27° x01 portrait upside down 153° <  < 207° x10 landscape left 27° <  < 153° x11 landscape right 207° <  < 333° Condition |acc_y| < 0.5∙|acc_x| - ‘hyst’ and acc_x - ‘hyst’ ≥ 0 |acc_y| < 0.5∙|acc_x| - ‘hyst’ and acc_x + ‘hyst’ < 0 |acc_y| ≥ 0.5∙|acc_x| + ‘hyst’ and acc_y < 0 |acc_y| ≥ 0.5∙|acc_x| + ‘hyst’ and acc_y ≥ 0 In the preceding tables, the parameter ‘hyst’ stands for a hysteresis, which can be selected by setting the (0x2C) orient_hyst bits. 1 LSB of (0x2C) orient_hyst always corresponds to 62.5 mg, in any g-range (i.e. increment is independent from g-range setting). It is important to note that by using a hysteresis ≠ 0 the actual switching angles become different from the angles given in the tables since there is an overlap between the different orientations. The most significant bit of the (0x0C) orient bits (which is displayed as an ´x´ in the above given tables) contains information about the direction of the z-axis. It is set to ´0´ (´1´) if acc_z ≥ 0 (acc_z < 0). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 36 Figure 10 shows the typical switching conditions between the four different orientations for the symmetrical mode i.e. without hysteresis: portrait portraitupright upright landscape left portrait portraitupside upside down landscape landscaperight right portrait upright 2 1.5 1 0.5 0 0 45 90 135 180 225 270 315 360 -0.5 acc_y/acc_x -1 acc_x/sin(theta) -1.5 acc_y/sin(theta) -2 phi  Figure 10: Typical orientation switching conditions w/o hysteresis The orientation interrupt is enabled (disabled) by writing ´1´ (´0´) to bit (0x16) orient_en. The interrupt is generated if the value of (0x0C) orient has changed. It is automatically cleared after one stable period of the (0x0C) orient value. The interrupt status is stored in the (0x09) orient_int bit. The register (0x0C) orient always reflects the current orientation of the device, irrespective of which interrupt mode has been selected. Bit (0x0C) orient reflects the device orientation with respect to the z-axis. The bits (0x0C) orient reflect the device orientation in the x-y-plane. The conventions associated with register (0x0C) orient are detailed in chapter 6. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 37 4.7.7.1 Orientation blocking The change of the (0x0C) orient value and – as a consequence – the generation of the interrupt can be blocked according to conditions selected by setting the value of the (0x2C) orient_blocking bits as described by Table 17. Table 17: Blocking conditions for orientation recognition (0x2C) orient_blocking 00b 01b 10b 11b Conditions no blocking theta blocking or acceleration in any axis > 1.5g theta blocking or acceleration slope in any axis > 0.2 g or acceleration in any axis > 1.5g theta blocking or acceleration slope in any axis > 0.4 g or acceleration in any axis > 1.5g and value of orient is not stable for at least 100 ms The theta blocking is defined by the following inequality: tan   blocking _ theta . 8 The parameter blocking_theta of the above given equation stands for the contents of the (0x2D) orient_theta bits. It is possible to define a blocking angle between 0° and 44.8°. The internal blocking algorithm saturates the acceleration values before further processing. As a consequence, the blocking angles are strictly valid only for a device at rest; they can be different if the device is moved. Example: To get a maximum blocking angle of 19° the parameter blocking_theta is determined in the following way: (8 * tan(19°) )² = 7.588, therefore, blocking_value = 8dec = 001000b has to be chosen. In order to avoid unwanted generation of the orientation interrupt in a nearly flat position (z ~ 0, sign change due to small movements or noise), a hysteresis of 0.2 g is implemented for the zaxis, i. e. a after a sign change the interrupt is only generated after |z| > 0.2 g. 4.7.7.2 Up-Down Interrupt Suppression Flag Per default an orientation interrupt is triggered when any of the bits in register (0x0C) orient BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 38 changes state. The BMA255 can be configured to trigger orientation interrupts only when the device position changes in the x-y-plane while orientation changes with respect to the z-axis are ignored. A change of the orientation of the z-axis, and hence a state change of bit (0x0C) orient is ignored (considered) when bit (0x2D) orient_ud_en is set to ‘0’ (‘1’). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 39 4.7.8 Flat detection The flat detection feature gives information about the orientation of the devices´ z-axis relative to the g-vector, i. e. it recognizes whether the device is in a flat position or not. The flat angle  is adjustable by (0x2E) flat_theta from 0° to 44.8°. The flat angle can be set according to following formula: 1    atan flat_theta  8  A hysteresis of the flat detection can be enabled by (0x2F) flat_hy bits. In this case the flat position is set if the angle drops below following threshold: 1 flat _ hy  flat _ hy    hyst,ll  atan flat_theta  1   8  1024 16     The flat position is reset if the angle exceeds the following threshold: 1 flat _ hy  flat _ hy    hyst,ul  atan flat_theta  1   8  1024 16     The flat interrupt is enabled (disabled) by writing ´1´ (´0´) to bit (0x16) flat_en. The flat value is stored in the (0x0C) flat bit if the interrupt is enabled. This value is ´1´ if the device is in the flat position, it is ´0´ otherwise. The flat interrupt is generated if the flat value has changed and the new value is stable for at least the time given by the (0x2F) flat_hold_time bits. A flat interrupt may be also generated if the flat interrupt is enabled. The actual status of the interrupt is stored in the (0x09) flat_int bit. The flat orientation of the sensor can always be determined from reading the (0x0C) flat bit after interrupt generation. If unlatched interrupt mode is used, the (0x09) flat_int value and hence the interrupt is automatically cleared after one sample period. If temporary or latched interrupt mode is used, the (0x09) flat_int value is kept fixed until the latch time expires or the interrupt is reset. The meaning of the (0x2F) flat_hold_time bits can be seen from Table 18. Table 18: Meaning of flat_hold_time (0x2F) flat_hold_time 00b 01b 10b 11b BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Time 0 512 ms 1024 ms 2048 ms Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 40 4.7.9 Low-g interrupt This interrupt is based on the comparison of acceleration data against a low-g threshold, which is most useful for free-fall detection. The interrupt is enabled (disabled) by writing ´1´ (´0´) to the (0x17) low_en bit. There are two modes available, ‘single’ mode and ‘sum’ mode. In ‘single’ mode, the acceleration of each axis is compared with the threshold; in ‘sum’ mode, the sum of absolute values of all accelerations |acc_x| + |acc_y| + |acc_z| is compared with the threshold. The mode is selected by the contents of the (0x24) low_mode bit: ´0´ means ‘single’ mode, ´1´ means ‘sum’ mode. The low-g threshold is set through the (0x23) low_th register. 1 LSB of (0x23) low_th always corresponds to an acceleration of 7.81 mg (i.e. increment is independent from g-range setting). A hysteresis can be selected by setting the (0x24) low_hy bits. 1 LSB of (0x24) low_hy always corresponds to an acceleration difference of 125 mg in any g-range (as well, increment is independent from g-range setting). The low-g interrupt is generated if the absolute values of the acceleration of all axes (´and´ relation, in case of single mode) or their sum (in case of sum mode) are lower than the threshold for at least the time defined by the (0x22) low_dur register. The interrupt is reset if the absolute value of the acceleration of at least one axis (´or´ relation, in case of single mode) or the sum of absolute values (in case of sum mode) is higher than the threshold plus the hysteresis for at least one data acquisition. In bit (0x09) low_int the interrupt status is stored. The relation between the content of (0x22) low_dur and the actual delay of the interrupt generation is: delay [ms] = [(0x22) low_dur + 1] • 2 ms. Therefore, possible delay times range from 2 ms to 512 ms. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 41 4.7.10 High-g interrupt This interrupt is based on the comparison of acceleration data against a high-g threshold for the detection of shock or other high-acceleration events. The high-g interrupt is enabled (disabled) per axis by writing ´1´ (´0´) to bits (0x17) high_en_x, (0x17) high_en_y, and (0x17) high_en_z, respectively. The high-g threshold is set through the (0x26) high_th register. The meaning of an LSB of (0x26) high_th depends on the selected grange: it corresponds to 7.81 mg in 2g-range, 15.63 mg in 4g-range, 31.25 mg in 8g-range, and 62.5 mg in 16g-range (i.e. increment depends from g-range setting). A hysteresis can be selected by setting the (0x24) high_hy bits. Analogously to (0x26) high_th, the meaning of an LSB of (0x24) high_hy is g-range dependent: It corresponds to an acceleration difference of 125 mg in 2g-range, 250 mg in 4g-range, 500 mg in 8g-range, and 1000mg in 16g-range (as well, increment depends from g-range setting). The high-g interrupt is generated if the absolute value of the acceleration of at least one of the enabled axes (´or´ relation) is higher than the threshold for at least the time defined by the (0x25) high_dur register. The interrupt is reset if the absolute value of the acceleration of all enabled axes (´and´ relation) is lower than the threshold minus the hysteresis for at least the time defined by the (0x25) high_dur register. In bit (0x09) high_int the interrupt status is stored. The relation between the content of (0x25) high_dur and the actual delay of the interrupt generation is delay [ms] = [(0x22) low_dur + 1] • 2 ms. Therefore, possible delay times range from 2 ms to 512 ms. The interrupt will be cleared immediately once acceleration is lower than threshold. 4.7.10.1 Axis and sign information of high-g interrupt The axis which triggered the interrupt is indicated by bits (0x0C) high_first_x, (0x0C) high_first_y, and (0x0C) high_first_z. The bit corresponding to the triggering axis contains a ´1´ while the other bits hold a ´0´. These bits are cleared together with clearing the interrupt status. The sign of the triggering acceleration is stored in bit (0x0C) high_sign. If (0x0C) high_sign = ´0´ (´1´), the sign is positive (negative). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 42 4.7.11 No-motion / slow motion detection The slow-motion/no-motion interrupt engine can be configured in two modes. In slow-motion mode an interrupt is triggered when the measured slope of at least one enabled axis exceeds the programmable slope threshold for a programmable number of samples. Hence the engine behaves similar to the any-motion interrupt, but with a different set of parameters. In order to suppress false triggers, the interrupt is only generated (cleared) if a certain number N of consecutive slope data points is larger (smaller) than the slope threshold given by (0x27) slo_no_mot_dur. The number is N = (0x27) slo_no_mot_dur + 1. In no-motion mode an interrupt is generated if the slope on all selected axes remains smaller than a programmable threshold for a programmable delay time. Figure 11 shows the timing diagram for the no-motion interrupt. The scaling of the threshold value is identical to that of the slow-motion interrupt. However, in no-motion mode register (0x27) slo_no_mot_dur defines the delay time before the no-motion interrupt is triggered. Table 19 lists the delay times adjustable with register (0x27) slo_no_mot_dur. The timer tick period is 1 second. Hence using short delay times can result in considerable timing uncertainty. If bit (0x18) slo_no_mot_sel is set to ‘1’ (‘0’) the no-motion/slow-motion interrupt engine is configured in the no-motion (slow-motion) mode. Common to both modes, the engine monitors the slopes of the axes that have been enabled with bits (0x18) slo_no_mot_en_x, (0x18) slo_no_mot_en_y, and (0x18) slo_no_mot_en_z for the x-axis, y-axis and z-axis, respectively. The measured slope values are continuously compared against the threshold value defined in register (0x29) slo_no_mot_th. The scaling is such that 1 LSB of (0x29) slo_no_mot_th corresponds to 3.91 mg in 2g-range (7.81 mg in 4g-range, 15.6 mg in 8g-range and 31.3 mg in 16g-range). Therefore the maximum value is 996 mg in 2g-range (1.99g in 4g-range, 3.98g in 8g-range and 7.97g in 16g-range). The time difference between the successive acceleration samples depends on the selected bandwidth and equates to 1/(2 * bw). Table 19: No-motion time-out periods (0x27) slo_no_mot_dur 0 1 2 ... 14 15 Delay time 1s 2s 3s ... 15 s 16 s (0x27) slo_no_mot_dur 16 17 18 19 20 21 Delay time 40 s 48 s 56 s 64 s. 72 s 80 s (0x27) slo_no_mot_dur 32 33 34 ... 62 63 Delay Time 88 s 96 s 104 s ... 328 s 336 s Note: slo_no_mot_dur values 22 to 31 are not specified BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet acceleration Page 43 acc(t0+Δt) acc(t0) slope axis x, y, or z slope(t0+Δt)= acc(t0+Δt) - acc(t0) axis x, y, or z slo_no_mot_th -slo_no_mot_th slo_no_mot_dur timer INT time Figure 11: Timing of No-motion interrupt BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 44 4.8 Softreset A softreset causes all user configuration settings to be overwritten with their default value and the sensor to enter normal mode. A softreset is initiated by means of writing value 0xB6 to register (0x14) softreset. Subsequently a waiting time of tw,up1 (max.) is required prior to accessing any configuration registers. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 45 5. FIFO Operation 5.1 FIFO Operating Modes The BMA255 features an integrated FIFO memory capable of storing up to 32 frames. Conceptually each frame consists of three 16 bit words corresponding to the x, y and z- axis, which are sampled at the same point in time. At the core of the FIFO is a buffer memory, which can be configured to operate in the following modes:  FIFO Mode: In FIFO mode the acceleration data of the selected axes are stored in the buffer memory. If enabled, a watermark interrupt is triggered when the buffer has filled up to a configurable level. The buffer will be continuously filled until the fill level reaches 32 frames. When it is full the data collection is stopped, and all additional samples are ignored. Once the buffer is full, a FIFO-full interrupt is generated if it has been enabled.  STREAM Mode: In STREAM mode the acceleration data of the selected axes are stored in the buffer until it is full. The buffer has a depth of 31 frames. When the buffer is full the data collection continues and oldest entry is discarded. If enabled, a watermark interrupt is triggered when the buffer is filled to a configurable level. Once the buffer is full, a FIFO-full interrupt is generated if it has been enabled.  BYPASS Mode: In bypass mode, only the current sensor data can be read out from the FIFO address. Essentially, the FIFO behaves like the STREAM mode with a depth of 1. Compared to reading the data from the normal data registers, the advantage to the user is that the packages X, Y, Z are from the same timestamp, while the data registers are updated sequentially and hence mixing of data from different axes can occur. The primary FIFO operating mode is selected with register (0x3E) fifo_mode according to ‘00b’ for BYPASS mode, ‘01b’ for FIFO mode, and ‘10b’ for STREAM mode. Writing to register (0x3E) clears the buffer content and resets the FIFO-full and watermark interrupts. When reading register (0x3E) fifo_mode always contains the current operating mode. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 46 5.2 FIFO Data Readout The FIFO stores the data that are also available at the acceleration read-out registers (0x02) to (0x07). Thus, all configuration settings apply to the FIFO data as well as the acceleration data readout registers. The FIFO read out is possible through register (0x3F). The readout can be performed using burst mode since the read address counter is no longer incremented, when it has reached address (0x3F). This implies that the trapping also occurs when the burst read access starts below address (0x3F). A single burst can read out one or more frames at a time. Register (0x3E) fifo_data_select controls the acceleration data of which axes are stored in the FIFO. Possible settings for register (0x3E) fifo_data_select are ‘00b’ for x, y- and z-axis, ‘01b’ for x-axis only, ‘10b’ for y-axis, ‘11b’ for z-axis only. The depth of the FIFO is independent of whether all or a single axis have been selected. Writing to register (0x3E) clears the buffer content and resets the FIFO-full and watermark interrupts. If all axes are enabled, the format of the data read-out from register (0x3F) is as follows: … X LSB X MSB Y LSB Y MSB Z LSB Z MSB … Frame 1 If only one axis is enabled, the format of the data read-out from register (0x3F) is as follows (example shown: y-axis only, other axes are equivalent). Y LSB Y MSB Frame 1 Y LSB Y MSB … Frame 2 If a frame is not completely read due to an incomplete read operation, the remaining part of the frame is discarded. In this case the FIFO aligns to the next frame during the next read operation. In order for the discarding mechanism to operate correctly, there must be a delay of at least 1.5 us between the last data bit of the partially read frame and the first address bit of the next FIFO read access. Otherwise frames must not be read out partially. If the FIFO is read beyond the FIFO fill level zeroes (0) will be read. If the FIFO is read beyond the FIFO fill level the read or burst read access time must not exceed the sampling time tSAMPLE. Otherwise frames may be lost. 5.3 FIFO Frame Counter and Overrun Flag Register (0x0E) fifo_frame_counter reflects the current fill level of the buffer. If additional frames are written to the buffer although the FIFO is full, the (0x0E) fifo_overrun bit is set to ‘1’. The FIFO buffer is cleared, the FIFO fill level indicated in register (0x0E) fifo_frame_counter and the (0x0E) fifo_overrun bit are both set to ‘0’ each time one a write access to one of the FIFO configuration registers (0x3E) or (0x30) occurs. The (0x0E) fifo_overrun bit is not reset when the FIFO fill level (0x0E) fifo_frame_counter has decremented to ‘0’ due to reading from register (0x3F). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 47 5.4 FIFO Interrupts The FIFO controller can generate two different interrupt events, a FIFO-full and a watermark event. The FIFO-full and watermark interrupts are functional in all FIFO operating modes. The watermark interrupt is asserted when the fill level in the buffer has reached the frame count defined by register (0x30) fifo_water_mark_trigger_retain. In order to enable (disable) the watermark interrupt, the (0x17) int_fwm_en bit must be set to ‘1’ (‘0’). To map the watermark interrupt signal to INT1 pin (INT2 pin), (0x1A) int1_fwm ((0x1A) int2_fwm) bit must be set to ‘1’. The status of the watermark interrupt may be read back through the (0x0A) fifo_wm_int bit. Writing to register (0x30) fifo_water_mark_trigger_retain clears the FIFO buffer. The FIFO-full interrupt is triggered when the buffer has been completely filled. In FIFO mode this occurs 32, in STREAM mode 31 samples, and in BYPASS mode 1 sample after the buffer has been cleared. In order to enable the FIFO-full interrupt, bit (0x17) int_ffull_en as well as one or both of bits (0x1A) int1_fful or (0x1A) int2_fful must also be set to ‘1’. The status of the FIFOfull interrupt may be read back through bit (0x0A) fifo_full_int. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 48 6. Register description 6.1 General remarks The entire communication with the device is performed by reading from and writing to registers. Registers have a width of 8 bits; they are mapped to a common space of 64 addresses from (0x00) up to (0x3F). Within the used range there are several registers which are either completely or partially marked as ‘reserved’. Any reserved bit is ignored when it is written and no specific value is guaranteed when read. It is recommended not to use registers at all which are completely marked as ‘reserved’. Furthermore it is recommended to mask out (logical and with zero) reserved bits of registers which are partially marked as reserved. Registers with addresses from (0x00) up to (0x0E) are read-only. Any attempt to write to these registers is ignored. There are bits within some registers that trigger internal sequences. These bits are configured for write-only access, e. g. (0x21) reset_int or the entire (0x14) softreset register, and read as value ´0´. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 49 6.2 Register map Register Address 0x3F 0x3E 0x3D 0x3C 0x3B 0x3A 0x39 0x38 0x37 0x36 0x35 0x34 0x33 0x32 0x31 0x30 0x2F 0x2E 0x2D 0x2C 0x2B 0x2A 0x29 0x28 0x27 0x26 0x25 0x24 0x23 0x22 0x21 0x20 0x1F 0x1E 0x1D 0x1C 0x1B 0x1A 0x19 0x18 0x17 0x16 0x15 0x14 0x13 0x12 0x11 0x10 0x0F 0x0E 0x0D 0x0C 0x0B 0x0A 0x09 0x08 0x07 0x06 0x05 0x04 0x03 0x02 0x01 0x00 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 Access Default fifo_data_output_register fifo_mode fifo_data_select GP1 GP0 offset_z offset_y offset_x offset_target_y cal_rdy offset_target_z cal_trigger offset_reset nvm_remain offset_target_x hp_z_en hp_y_en nvm_load i2c_wdt_en nvm_rdy self_test_sign cut_off hp_x_en i2c_wdt_sel spi3 nvm_prog_trig nvm_prog_mode self_test_axis fifo_water_mark_level_trigger_retain flat_hold_time flat_hy flat_theta orient_theta orient_blocking tap_th orient_ud_en orient_hyst tap_samp tap_quiet tap_shock orient_mode tap_dur slo_no_mot_th slope_th slo_no_mot_dur high_th high_dur slope_dur high_hy low_mode low_hy low_th low_dur reset_int latch_int int2_lvl int1_od int2_od int1_lvl int_src_data int_src_tap int_src_slo_no_mot int_src_slope int_src_high int_src_low int2_slope int1_ffull int1_slope slo_no_mot_en_z high_en_z slope_en_z int2_high int1_fwm int1_high slo_no_mot_en_y high_en_y slope_en_y int2_low int1_data int1_low slo_no_mot_en_x high_en_x slope_en_x int2_flat int2_data int1_flat int2_orient int2_fwm int1_orient int2_s_tap int2_ffull int1_s_tap int2_d_tap int2_slo_no_mot int1_d_tap int_ffull_en s_tap_en data_en d_tap_en int1_slo_no_mot slo_no_mot_sel low_en flat_en int_fwm_en orient_en softreset data_high_bw suspend shadow_dis lowpower_mode lowpower_en sleeptimer_mode low_power_mode (reserved) deep_suspend sleep_dur bw range fifo_overrun flat tap_sign data_int flat_int fifo_frame_counter tap_first_z fifo_wm_int orient_int orient tap_first_y fifo_full_int s_tap_int tap_first_x high_sign slope_sign high_first_z slope_first_z high_first_y slope_first_y high_first_x slope_first_x slope_int high_int low_int d_tap_int slo_no_mot_int temp acc_z_msb acc_z_lsb new_data_z acc_y_msb acc_y_lsb new_data_y acc_x_msb acc_x_lsb new_data_x chip_id ro w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r w/r wo w/r w/r w/r w/r w/r ro w/r ro ro ro ro ro ro ro ro ro ro ro ro ro 0x00 0x00 0xFF 0x00 0x00 0x00 0x00 0x00 0x00 0x10 0x00 0x00 0xF0 0x00 0xFF 0x00 0x11 0x08 0x48 0x18 0x0A 0x04 0x14 0x14 0x00 0xC0 0x0F 0x81 0x30 0x09 0x00 0x05 0xFF 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 0x00 0x00 0xFF 0x00 0x00 0x00 0x00 0x0F 0x03 0x00 0xFF 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 -0xFA common w/r registers: Application specific settings which are not equal to the default settings, must be re-set to its designated values after POR, soft-reset and wake up from deep suspend. user w/r registers: Initial default content = 0x00. Freely programmable by the user. Remains unchanged after POR, soft-reset and wake up from deep suspend. Figure 12: Register map BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 50 Register 0x00 (BGW_CHIPID) The register contains the chip identification code. Name Bit Read/Write Reset Value Content 0x00 7 R n/a Bit Read/Write Reset Value Content 3 R n/a chip_id: BGW_CHIPID 6 R n/a 5 R n/a 4 R n/a 2 R n/a 1 R n/a 0 R n/a chip_id chip_id Fixed value b’1111’1010 Register 0x02 (ACCD_X_LSB) The register contains the least-significant bits of the X-channel acceleration readout value. When reading out X-channel acceleration values, data consistency is guaranteed if the ACCD_X_LSB is read out before the ACCD_X_MSB and shadow_dis=’0’. In this case, after the ACCD_X_LSB has been read, the value in the ACCD_X_MSB register is locked until the ACCD_X_MSB has been read. This condition is inherently fulfilled if a burst-mode read access is performed. Acceleration data may be read from register ACCD_X_LSB at any time except during power-up and in DEEP_SUSPEND mode. Name Bit Read/Write Reset Value Content 0x02 7 R n/a Bit Read/Write Reset Value Content acc_x_lsb: undefined: new_data_x: ACCD_X_LSB 6 R n/a 5 R n/a 4 R n/a 3 R n/a 2 R n/a 1 R n/a 0 R n/a undefined undefined undefined new_data_x acc_x_lsb Least significant 4 bits of acceleration read-back value; (two’s-complement format) random data; to be ignored. ‚0’: acceleration value has not been updated since it has been read out last ‚1’: acceleration value has been updated since it has been read out last BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 51 Register 0x03 (ACCD_X_MSB) The register contains the most-significant bits of the X-channel acceleration readout value. When reading out X-channel acceleration values, data consistency is guaranteed if the ACCD_X_LSB is read out before the ACCD_X_MSB and shadow_dis=’0’. In this case, after the ACCD_X_LSB has been read, the value in the ACCD_X_MSB register is locked until the ACCD_X_MSB has been read. This condition is inherently fulfilled if a burst-mode read access is performed. Acceleration data may be read from register ACCD_X_MSB at any time except during power-up and in DEEP_SUSPEND mode. Name Bit Read/Write Reset Value Content 0x02 7 R n/a Bit Read/Write Reset Value Content 3 R n/a ACCD_X_MSB 6 R n/a 5 R n/a 4 R n/a 2 R n/a 1 R n/a 0 R n/a acc_x_msb acc_x_msb acc_x_msb: Most significant 8 bits of acceleration read-back value (two’s-complement format) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 52 Register 0x04 (ACCD_Y_LSB) The register contains the least-significant bits of the Y-channel acceleration readout value. When reading out Y-channel acceleration values, data consistency is guaranteed if the ACCD_Y_LSB is read out before the ACCD_Y_MSB and shadow_dis=’0’. In this case, after the ACCD_Y_LSB has been read, the value in the ACCD_Y_MSB register is locked until the ACCD_Y_MSB has been read. This condition is inherently fulfilled if a burst-mode read access is performed. Acceleration data may be read from register ACCD_Y_LSB at any time except during power-up and in DEEP_SUSPEND mode. Name Bit Read/Write Reset Value Content 0x04 7 R n/a Bit Read/Write Reset Value Content acc_y_lsb: undefined: new_data_y: ACCD_Y_LSB 6 R n/a 5 R n/a 4 R n/a 3 R n/a 2 R n/a 1 R n/a 0 R n/a undefined undefined undefined new_data_y acc_y_lsb Least significant 4 bits of acceleration read-back value; (two’s-complement format) random data; to be ignored ‚0’: acceleration value has not been updated since it has been read out last ‚1’: acceleration value has been updated since it has been read out last BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 53 Register 0x05 (ACCD_Y_MSB) The register contains the most-significant bits of the Y-channel acceleration readout value. When reading out Y-channel acceleration values, data consistency is guaranteed if the ACCD_Y_LSB is read out before the ACCD_Y_MSB and shadow_dis=’0’. In this case, after the ACCD_Y_LSB has been read, the value in the ACCD_Y_MSB register is locked until the ACCD_Y_MSB has been read. This condition is inherently fulfilled if a burst-mode read access is performed. Acceleration data may be read from register ACCD_Y_MSB at any time except during power-up and in DEEP_SUSPEND mode. Name Bit Read/Write Reset Value Content 0x05 7 R n/a Bit Read/Write Reset Value Content 3 R n/a ACCD_Y_MSB 6 R n/a 5 R n/a 4 R n/a 2 R n/a 1 R n/a 0 R n/a acc_y_msb acc_y_msb acc_y_msb: Most significant 8 bits of acceleration read-back value (two’s-complement format) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 54 Register 0x06 (ACCD_Z_LSB) The register contains the least-significant bits of the Z-channel acceleration readout value. When reading out Z-channel acceleration values, data consistency is guaranteed if the ACCD_Z_LSB is read out before the ACCD_Z_MSB and shadow_dis=’0’. In this case, after the ACCD_Z_LSB has been read, the value in the ACCD_Z_MSB register is locked until the ACCD_Z_MSB has been read. This condition is inherently fulfilled if a burst-mode read access is performed. Acceleration data may be read from register ACCD_Z_LSB at any time except during power-up and in DEEP_SUSPEND mode. Name Bit Read/Write Reset Value Content 0x06 7 R n/a ACCD_Z_LSB 6 R n/a 5 R n/a 4 R n/a Bit Read/Write Reset Value Content 3 R n/a 2 R n/a 1 R n/a 0 R n/a undefined undefined undefined new_data_z acc_z_lsb Acc_z_lsb: Least significant 4 bits of acceleration read-back value; (two’s-complement format) undefined: random data; to be ignored new_data_z: ‚0’: acceleration value has not been updated since it has been read out last ‚1’: acceleration value has been updated since it has been read out last BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 55 Register 0x07 (ACCD_Z_MSB) The register contains the most-significant bits of the Z-channel acceleration readout value. When reading out Z-channel acceleration values, data consistency is guaranteed if the ACCD_Z_LSB is read out before the ACCD_Z_MSB and shadow_dis=’0’. In this case, after the ACCD_Z_LSB has been read, the value in the ACCD_Z_MSB register is locked until the ACCD_Z_MSB has been read. This condition is inherently fulfilled if a burst-mode read access is performed. Acceleration data may be read from register ACCD_Z_MSB at any time except during power-up and in DEEP_SUSPEND mode. Name Bit Read/Write Reset Value Content 0x07 7 R n/a Bit Read/Write Reset Value Content 3 R n/a ACCD_Z_MSB 6 R n/a 5 R n/a 4 R n/a 2 R n/a 1 R n/a 0 R n/a acc_z_msb acc_z_msb acc_z_msb: Most significant 8 bits of acceleration read-back value (two’s-complement format) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 56 Register 0x08 (ACCD_TEMP) The register contains the current chip temperature represented in two’s complement format. A readout value of temp=0x00 corresponds to a temperature of 23°C. Name Bit Read/Write Reset Value Content 0x08 7 R n/a Bit Read/Write Reset Value Content 3 R n/a temp: ACCD_TEMP 6 R n/a 5 R n/a 4 R n/a 2 R n/a 1 R n/a 0 R n/a temp temp Temperature value (two s-complement format) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 57 Register 0x09 (INT_STATUS_0) The register contains interrupt status flags. Each flag is associated with a specific interrupt function. It is set when the associated interrupt triggers. The setting of latch_int controls if the interrupt signal and hence the respective interrupt flag will be permanently latched, temporarily latched or not latched. The interrupt function associated with a specific status flag must be enabled. Name Bit Read/Write Reset Value Content 0x09 7 R n/a INT_STATUS_0 6 R n/a 5 R n/a 4 R n/a flat_int orient_int s_tap_int d_tap_int Bit Read/Write Reset Value Content 3 R n/a 2 R n/a 1 R n/a 0 R n/a slo_no_mot_int slope_int high_int low_int flat_int: orient_int: s_tap_int: d_tap_int slo_not_mot_int: slope_int: high_int: low_int: flat interrupt status: ‘0’inactive, ‘1’ active orientation interrupt status: ‘0’inactive, ‘1’ active single tap interrupt status: ‘0’inactive, ‘1’ active double tap interrupt status: ‘0’inactive, ‘1’ active slow/no-motion interrupt status: ‘0’inactive, ‘1’ active slope interrupt status: ‘0’inactive, ‘1’ active high-g interrupt status: ‘0’inactive, ‘1’ active low-g interrupt status: ‘0’inactive, ‘1’ active BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 58 Register 0x0A (INT_STATUS_1) The register contains interrupt status flags. Each flag is associated with a specific interrupt function. It is set when the associated interrupt engine triggers. The setting of latch_int controls if the interrupt signal and hence the respective interrupt flag will be permanently latched, temporarily latched or not latched. The interrupt function associated with a specific status flag must be enabled. Name Bit Read/Write Reset Value Content 0x0A 7 R n/a INT_STATUS_1 6 R n/a 5 R n/a 4 R n/a data_int fifo_wm_int fifo_full_int reserved Bit Read/Write Reset Value Content 3 R n/a 2 R n/a 1 R n/a 0 R n/a data_int: fifo_wm_int: fifo_full_int: reserved: reserved data ready interrupt status: ‘0’inactive, ‘1’ active FIFO watermark interrupt status: ‘0’inactive, ‘1’ active FIFO full interrupt status: ‘0’inactive, ‘1’ active reserved, write to ‘0’ BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 59 Register 0x0B (INT_STATUS_2) The register contains interrupt status flags. Each flag is associated with a specific interrupt engine. It is set when the associated interrupt engine triggers. The setting of latch_int controls if the interrupt signal and hence the respective interrupt flag will be permanently latched, temporarily latched or not latched. The interrupt function associated with a specific status flag must be enabled. Name Bit Read/Write Reset Value Content 0x0B 7 R n/a INT_STATUS_2 6 R n/a 5 R n/a 4 R n/a tap_sign tap_first_z tap_first_y tap_first_x Bit Read/Write Reset Value Content 3 R n/a 2 R n/a 1 R n/a 0 R n/a slope_sign slope_first_z slope_first_y slope_first_x tap_sign: tap_first_z: tap_first_y: tap_first_x: slope_sign: slope_first_z: slope_first_y: slope_first_x: sign of single/double tap triggering signal was ‘0’positive, or ‘1’ negative single/double tap interrupt: ‘1’  triggered by, or ‘0’not triggered by z-axis single/double tap interrupt: ‘1’  triggered by, or ‘0’not triggered by y-axis single/double tap interrupt: ‘1’  triggered by, or ‘0’not triggered by x-axis slope sign of slope tap triggering signal was ‘0’positive, or ‘1’ negative slope interrupt: ‘1’  triggered by, or ‘0’not triggered by z-axis slope interrupt: ‘1’  triggered by, or ‘0’not triggered by y-axis slope interrupt: ‘1’  triggered by, or ‘0’not triggered by x-axis BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 60 Register 0x0C (INT_STATUS_3) The register contains interrupt status flags. Each flag is associated with a specific interrupt engine. It is set when the associated interrupt engine triggers. With the exception of orient the setting of latch_int controls if the interrupt signal and hence the respective interrupt flag will be permanently latched, temporarily latched or not latched. The interrupt function associated with a specific status flag must be enabled. Name Bit Read/Write Reset Value Content 0x0C 7 R n/a INT_STATUS_3 6 R n/a flat orient Bit Read/Write Reset Value Content 3 R n/a high_sign flat: orient: orient: high_sign: high_first_z: high_first_y: high_first_x: 5 R n/a 4 R n/a 2 R n/a 1 R n/a 0 R n/a high_first_z high_first_y high_first_x device is in ‘1’  flat, or ‘0’ non flat position; only valid if (0x16) flat_en = ‘1’ Orientation value of z-axis: ´0´  upward looking, or ´1´  downward looking. The flag always reflect the current orientation status, independent of the setting of latch_int. The flag is not updated as long as an orientation blocking condition is active. orientation value of x-y-plane: ‘00’portrait upright; ‘01’portrait upside down; ‘10’landscape left; ‘11’landscape right; The flags always reflect the current orientation status, independent of the setting of latch_int. The flag is not updated as long as an orientation blocking condition is active. sign of acceleration signal that triggered high-g interrupt was ‘0’positive, ‘1’ negative high-g interrupt: ‘1’  triggered by, or ‘0’not triggered by z-axis high-g interrupt: ‘1’  triggered by, or ‘0’not triggered by y-axis high-g interrupt: ‘1’  triggered by, or ‘0’not triggered by x-axis BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 61 Register 0x0E (FIFO_STATUS) The register contains FIFO status flags. Name Bit Read/Write Reset Value Content 0x0E 7 R n/a FIFO_STATUS 6 R n/a fifo_overrun fifo_frame_counter Bit Read/Write Reset Value Content 3 R n/a 2 R n/a 5 R n/a 1 R n/a 4 R n/a 0 R n/a fifo_frame_counter fifo_overrun: FIFO overrun condition has ‘1’  occurred, or ‘0’not occurred; flag can be cleared by writing to the FIFO configuration register FIFO_CONFIG_1 only fifo_frame_counter: Current fill level of FIFO buffer. An empty FIFO corresponds to 0x00. The frame counter can be cleared by reading out all frames from the FIFO buffer or writing to the FIFO configuration register FIFO_CONFIG_1. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 62 Register 0x0F (PMU_RANGE) The register allows the selection of the accelerometer g-range. Name Bit Read/Write Reset Value Content 0x0F 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 PMU_RANGE 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 1 0 R/W 1 reserved 0 range: reserved: range Selection of accelerometer g-range: ´0011b´  ±2g range; ´0101b´  ±4g range; ´1000b´  ±8g range; ´1100b´  ±16g range; all other settings  reserved (do not use) write ‘0’ Register 0x10 (PMU_BW) The register allows the selection of the acceleration data filter bandwidth. Name Bit Read/Write Reset Value Content 0x10 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 1 PMU_BW 6 R/W 0 5 R/W 0 reserved 4 R/W 0 bw 0 bw: reserved: 2 R/W 1 1 R/W 1 0 R/W 1 bw Selection of data filter bandwidth: ´00xxxb´  7.81 Hz, ´01000b´  7.81 Hz, ´01001b´  15.63 Hz, ´01010b´  31.25 Hz, ´01011b´  62.5 Hz, ´01100b´  125 Hz, ´01101b´  250 Hz, ´01110b´  500 Hz, ´01111b´  1000 Hz, ´1xxxxb´  1000 Hz write ‘0’ BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 63 Register 0x11 (PMU_LPW) Selection of the main power modes and the low power sleep period. Name Bit Read/Write Reset Value Content 0x11 7 R/W 0 PMU_LPW 6 R/W 0 5 R/W 0 4 R/W 0 suspend lowpower_en deep_suspend sleep_dur Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 sleep_dur reserved suspend, low_power_en, deep_suspend: Main power mode configuration setting {suspend; lowpower_en; deep_suspend}: {0; 0; 0}  NORMAL mode; {0; 0; 1}  DEEP_SUSPEND mode; {0; 1; 0}  LOW_POWER mode; {1; 0; 0}  SUSPEND mode; {all other}  illegal Please note that only certain power mode transitions are permitted. sleep_dur: Configures the sleep phase duration in LOW_POWER mode: ´0000b´ to ´0101b´  0.5 ms, ´0110b´  1 ms, ´0111b´  2 ms, ´1000b´  4 ms, ´1001b´  6 ms, ´1010b´  10 ms, ´1011b´  25 ms, ´1100b´  50 ms, ´1101b´  100 ms, ´1110b´  500 ms, ´1111b´ 1s Please note, that all application specific settings which are not equal to the default settings (refer to 6.2 register map), must be re-set to its designated values after DEEP_SUSPEND. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 64 Register 0x12 (PMU_LOW_POWER) Configuration settings for low power mode. Name Bit Read/Write Reset Value Content 0x12 7 R/W 0 PMU_LOW_POWER 6 5 R/W R/W 0 0 4 R/W 0 reserved lowpower_mode sleeptimer_mode reserved Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 reserved lowpower_mode: select ‘0’  LPM1, or ‘1´  LPM2 configuration for SUSPEND and LOW_POWER mode. In the LPM1 configuration the power consumption in LOW_POWER mode and SUSPEND mode is significantly reduced when compared to LPM2 configuration, but the FIFO is not accessible and writing to registers must be slowed down. In the LPM2 configuration the power consumption in LOW_POWER mode is reduced compared to NORMAL mode, but the FIFO is fully accessible and registers can be written to at full speed. sleeptimer_mode: when in LOW_POWER mode ‘0’  use event-driven time-base mode (compatible with BMA250), or ‘1´  use equidistant sampling time-base mode. Equidistant sampling of data into the FIFO is maintained in equidistant time-base mode only. reserved: write ‘0’ BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 65 Register 0x13 (ACCD_HBW) Acceleration data acquisition and data output format. Name Bit Read/Write Reset Value Content 0x13 7 R/W 0 data_high_bw ACCD_HBW 6 R/W 0 (1 in 8-bit mode) shadow_dis Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 data_high_bw: shadow_dis: reserved: 5 R/W 0 4 R/W 0 reserved 1 R/W 0 0 R/W 0 reserved select whether ‘1´ unfiltered, or ‘0’ filtered data may be read from the acceleration data registers. ‘1´ disable, or ‘0’ the shadowing mechanism for the acceleration data output registers. When shadowing is enabled, the content of the acceleration data component in the MSB register is locked, when the component in the LSB is read, thereby ensuring the integrity of the acceleration data during read-out. The lock is removed when the MSB is read. write ‘0’ BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 66 Register 0x14 (BGW_SOFTRESET) Controls user triggered reset of the sensor. Name Bit Read/Write Reset Value Content 0x14 7 W 0 Bit Read/Write Reset Value Content 3 W 0 softreset: BGW_SOFTRESET 6 5 W W 0 0 4 W 0 2 W 0 0 W 0 softreset 1 W 0 softreset 0xB6  triggers a reset. Other values are ignored. Following a delay, all user configuration settings are overwritten with their default state or the setting stored in the NVM, wherever applicable. This register is functional in all operation modes. Please note that all application specific settings which are not equal to the default settings (refer to 6.2 register map), must be reconfigured to their designated values. Register 0x16 (INT_EN_0) Controls which interrupt engines in group 0 are enabled. Name Bit Read/Write Reset Value Content 0x16 7 R/W 0 INT_EN_0 6 R/W 0 5 R/W 0 4 R/W 0 flat_en orient_en s_tap_en d_tap_en Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 reserved slope_en_z slope_en_y slope_en_x flat_en: orient_en: s_tap_en: d_tap_en reserved: slope_en_z: slope_en_y: slope_en_x: flat interrupt: ‘0’disabled, or ‘1’ enabled orientation interrupt: ‘0’disabled, or ‘1’ enabled single tap interrupt: ‘0’disabled, or ‘1’ enabled double tap interrupt: ‘0’disabled, or ‘1’ enabled write ‘0’ slope interrupt, z-axis component: ‘0’disabled, or ‘1’ enabled slope interrupt, y-axis component: ‘0’disabled, or ‘1’ enabled slope interrupt, x-axis component: ‘0’disabled, or ‘1’ enabled BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 67 Register 0x17 (INT_EN_1) Controls which interrupt engines in group 1 are enabled. Name Bit Read/Write Reset Value Content 0x17 7 R/W 0 INT_EN_1 6 R/W 0 5 R/W 0 4 R/W 0 reserved int_fwm_en int_ffull_en data_en Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 low_en high_en_z high_en_y high_en_x reserved: int_fwm_en: int_ffull_en: data_en low_en: high_en_z: high_en_y: high_en_x: write ‘0’ FIFO watermark interrupt: ‘0’disabled, or ‘1’ enabled FIFO full interrupt: ‘0’disabled, or ‘1’ enabled data ready interrupt: ‘0’disabled, or ‘1’ enabled low-g interrupt: ‘0’disabled, or ‘1’ enabled high-g interrupt, z-axis component: ‘0’disabled, or ‘1’ enabled high-g interrupt, y-axis component: ‘0’disabled, or ‘1’ enabled high-g interrupt, x-axis component: ‘0’disabled, or ‘1’ enabled BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 68 Register 0x18 (INT_EN_2) Controls which interrupt engines in group 2 are enabled. Name Bit Read/Write Reset Value Content 0x18 7 R/W 0 INT_EN_2 6 R/W 0 5 R/W 0 4 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 slo_no_mot_sel slo_no_mot_en_z slo_no_mot_en_y slo_no_mot_en_x reserved reserved: write ‘0’ slo_no_mot_sel: select ‘0’slow-motion, ‘1’ no-motion interrupt function slo_no_mot_en_z: slow/n-motion interrupt, z-axis component: ‘0’disabled, or ‘1’ enabled slo_no_mot_en_y: slow/n-motion interrupt, y-axis component: ‘0’disabled, or ‘1’ enabled slo_no_mot_en_x: slow/n-motion interrupt, x-axis component: ‘0’disabled, or ‘1’ enabled BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 69 Register 0x19 (INT_MAP_0) Controls which interrupt signals are mapped to the INT1 pin. Name Bit Read/Write Reset Value Content 0x19 7 R/W 0 INT_MAP_0 6 R/W 0 5 R/W 0 4 R/W 0 int1_flat int1_orient int1_s_tap int1_d_tap Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 int1_slo_no_mot int1_slope int1_high int1_low int1_flat: int1_orient: int1_s_tap: int1_d_tap: int1_slo_no_mot: int1_slope: int1_high: int1_low: map flat interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map orientation interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map single tap interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map double tap interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map slow/no-motion interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map slope interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map high-g to INT1 pin: ‘0’disabled, or ‘1’ enabled map low-g to INT1 pin: ‘0’disabled, or ‘1’ enabled BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 70 Register 0x1A (INT_MAP_1) Controls which interrupt signals are mapped to the INT1 and INT2 pins. Name Bit Read/Write Reset Value Content 0x1A 7 R/W 0 INT_MAP_1 6 R/W 0 5 R/W 0 4 R/W 0 int2_data int2_fwm int2_ffull reserved Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 reserved int1_ffull int1_fwm int1_data int2_data: int2_fwm: int2_ffull: reserved: int1_ffull: int1_fwm: int1_data: map data ready interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map FIFO watermark interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map FIFO full interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled write ‘0’ map FIFO full interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map FIFO watermark interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled map data ready interrupt to INT1 pin: ‘0’disabled, or ‘1’ enabled BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 71 Register 0x1B (INT_MAP_2) Controls which interrupt signals are mapped to the INT2 pin. Name Bit Read/Write Reset Value Content 0x1B 7 R/W 0 INT_MAP_2 6 R/W 0 5 R/W 0 4 R/W 0 int2_flat int2_orient int2_s_tap int2_d_tap Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 int2_slo_no_mot int2_slope int2_high int2_low int2_flat: int2_orient: int2_s_tap: int2_d_tap: int2_slo_no_mot: int2_slope: int2_high: int2_low: map flat interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map orientation interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map single tap interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map double tap interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map slow/no-motion interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map slope interrupt to INT2 pin: ‘0’disabled, or ‘1’ enabled map high-g to INT2 pin: ‘0’disabled, or ‘1’ enabled map low-g to INT2 pin: ‘0’disabled, or ‘1’ enabled BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 72 Register 0x1E (INT_SRC) Contains the data source definition for interrupts with selectable data source. Name Bit Read/Write Reset Value Content 0x1E 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 int_src_slo_no_m ot INT_SRC 6 R/W 0 5 R/W 0 4 R/W 0 int_src_data int_src_tap 2 R/W 0 1 R/W 0 0 R/W 0 int_src_slope int_src_high int_src_low reserved reserved: write ‘0’ int_src_data: select ‘0’filtered, or ‘1’ unfiltered data for new data interrupt int_src_tap: select ‘0’filtered, or ‘1’ unfiltered data for single-/double tap interrupt int_src_slo_no_mot: select ‘0’filtered, or ‘1’ unfiltered data for slow/no-motion interrupt int_src_slope: select ‘0’filtered, or ‘1’ unfiltered data for slope interrupt int_src_high: select ‘0’filtered, or ‘1’ unfiltered data for high-g interrupt int_src_low: select ‘0’filtered, or ‘1’ unfiltered data for low-g interrupt BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 73 Register 0x20 (INT_OUT_CTRL) Contains the behavioural configuration (electrical behaviour) of the interrupt pins. Name Bit Read/Write Reset Value Content 0x20 7 R/W 0 Bit Read/Write Reset Value Content reserved: int2_od: int2_lvl: int1_od: int1_lvl: INT_OUT_CTRL 6 R/W 0 5 R/W 0 4 R/W 0 3 R/W 0 2 R/W 1 1 R/W 0 0 R/W 1 int2_od int2_lvl int1_od int1_lvl reserved write ‘0’ select ‘0’push-pull, or ‘1’ open drain behavior for INT2 pin select ‘0’active low, or ‘1’active high level for INT2 pin select ‘0’push-pull, or ‘1’ open drain behavior for INT1 pin select ‘0’active low, or ‘1’active high level for INT1 pin BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 74 Register 0x21 (INT_RST_LATCH) Contains the interrupt reset bit and the interrupt mode selection. Name Bit Read/Write Reset Value Content 0x21 7 W 0 INT_RST_LATCH 6 5 R/W R/W 0 0 reset_int Reserved Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 reset_int: reserved: latch_int: 1 R/W 0 4 R/W 0 0 R/W 0 latch_int write ‘1’  clear any latched interrupts, or ‘0’  keep latched interrupts active write ‘0’ ´0000b´  non-latched, ´0001b´  temporary, 250 ms, ´0010b´  temporary, 500 ms, ´0011b´  temporary, 1 s, ´0100b´  temporary, 2 s, ´0101b´  temporary, 4 s, ´0110b´  temporary, 8 s, ´0111b´  latched, ´1000b´  non-latched, ´1001b´  temporary, 250 s, ´1010b´  temporary, 500 s, ´1011b´  temporary, 1 ms, ´1100b´  temporary, 12.5 ms, ´1101b´  temporary, 25 ms, ´1110b´  temporary, 50 ms, ´1111b´  latched Register 0x22 (INT_0) Contains the delay time definition for the low-g interrupt. Name Bit Read/Write Reset Value Content 0x22 7 W 0 Bit Read/Write Reset Value Content 3 R/W 1 low_dur: INT_0 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 0 0 R/W 1 low_dur low_dur low-g interrupt trigger delay according to [low_dur + 1] • 2 ms in a range from 2 ms to 512 ms; the default corresponds to a delay of 20 ms. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 75 Register 0x23 (INT_1) Contains the threshold definition for the low-g interrupt. Name Bit Read/Write Reset Value Content 0x23 7 W 0 Bit Read/Write Reset Value Content 3 R/W 0 low_th: INT_1 6 R/W 0 5 R/W 1 4 R/W 1 2 R/W 0 1 R/W 0 0 R/W 0 low_th low_th low-g interrupt trigger threshold according to low_th • 7.81 mg in a range from 0 g to 1.992 g; the default value corresponds to an acceleration of 375 mg Register 0x24 (INT_2) Contains the low-g interrupt mode selection, the low-g interrupt hysteresis setting, and the highg interrupt hysteresis setting. Name Bit Read/Write Reset Value Content 0x24 7 R/W 1 Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 reserved low_mode low_hy high_hy: low_mode: low_hy: INT_2 6 R/W 0 high_hy 5 R/W 0 4 R/W 0 reserved 0 R/W 1 hysteresis of high-g interrupt according to high_hy · 125 mg (2-g range), high_hy · 250 mg (4-g range), high_hy · 500 mg (8-g range), or high_hy · 1000 mg (16-g range) select low-g interrupt ‘0’ single-axis mode, or ‘1’ axis-summing mode hysteresis of low-g interrupt according to low_hy · 125 mg independent of the selected accelerometer g-range BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 76 Register 0x25 (INT_3) Contains the delay time definition for the high-g interrupt. Name Bit Read/Write Reset Value Content 0x25 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 1 high_dur: INT_3 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 1 1 R/W 1 0 R/W 1 high_dur high_dur high-g interrupt trigger delay according to [high_dur + 1] • 2 ms in a range from 2 ms to 512 ms; the default corresponds to a delay of 32 ms. Register 0x26 (INT_4) Contains the threshold definition for the high-g interrupt. Name Bit Read/Write Reset Value Content 0x26 7 R/W 1 Bit Read/Write Reset Value Content 3 R/W 0 high_th: INT_4 6 R/W 1 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 high_th high_th threshold of high-g interrupt according to high_th · 7.81 mg (2-g range), high_th · 15.63 mg (4-g range), high_th · 31.25 mg (8-g range), or high_th · 62.5 mg (16-g range) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 77 Register 0x27 (INT_5) Contains the definition of the number of samples to be evaluated for the slope interrupt (anymotion detection) and the slow/no-motion interrupt trigger delay. Name Bit Read/Write Reset Value Content 0x27 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 INT_5 6 R/W 0 5 R/W 0 4 R/W 0 1 R/W 0 0 R/W 0 slo_no_mot_dur 2 R/W 0 slo_no_mot_dur slope_dur slo_no_mot_dur: Function depends on whether the slow-motion or no-motion interrupt function has been selected. If the slow-motion interrupt function has been enabled (slo_no_mot_sel = ‘0’) then [slo_no_mot_dur+1] consecutive slope data points must be above the slow/no-motion threshold (slo_no_mot_th) for the slow-/no-motion interrupt to trigger. If the no-motion interrupt function has been enabled (slo_no_mot_sel = ‘1’) then slo_no_motion_dur defines the time for which no slope data points must exceed the slow/no-motion threshold (slo_no_mot_th) for the slow/nomotion interrupt to trigger. The delay time in seconds may be calculated according with the following equation: slope_dur: slo_no_mot_dur=’b00’  [slo_no_mot_dur + 1] slo_no_mot_dur=’b01’  [slo_no_mot_dur · 4 + 20] slo_no_mot_dur=’1’  [slo_no_mot_dur · 8 + 88] slope interrupt triggers if [slope_dur+1] consecutive slope data points are above the slope interrupt threshold slope_th BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 78 Register 0x28 (INT_6) Contains the threshold definition for the any-motion interrupt. Name Bit Read/Write Reset Value Content 0x28 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 slope_th: INT_6 6 R/W 0 5 R/W 0 4 R/W 1 2 R/W 1 1 R/W 0 0 R/W 0 slope_th slope_th Threshold of the any-motion interrupt. It is range-dependent and defined as a sample-to-sample difference according to slope_th · 3.91 mg (2-g range) / slope_th · 7.81 mg (4-g range) / slope_th · 15.63 mg (8-g range) / slope_th · 31.25 mg (16-g range) Register 0x29 (INT_7) Contains the threshold definition for the slow/no-motion interrupt. Name Bit Read/Write Reset Value Content 0x29 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 INT_7 6 R/W 0 5 R/W 0 4 R/W 1 1 R/W 0 0 R/W 0 slo_no_mot_th 2 R/W 1 slo_no_mot_th slo_no_mot_th: Threshold of slow/no-motion interrupt. It is range-dependent and defined as a sample-to-sample difference according to slo_no_mot_th · 3.91 mg (2-g range), slo_no_mot_th · 7.81 mg (4-g range), slo_no_mot_th · 15.63 mg (8-g range), slo_no_mot_th · 31.25 mg (16-g range) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 79 Register 0x2A (INT_8) Contains the timing definitions for the single tap and double tap interrupts. Name Bit Read/Write Reset Value Content 0x2A 7 R/W 0 INT_8 6 R/W 0 5 R/W 0 4 R/W 0 tap_quiet tap_shock reserved reserved Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 1 1 R/W 0 0 R/W 0 reserved tap_dur tap_quiet: tap_shock: reserved: tap_dur: selects a tap quiet duration of ‘0’ 30 ms, ‘1’ 20 ms selects a tap shock duration of ‘0’ 50 ms, ‘1’75 ms write ‘0’ selects the length of the time window for the second shock event for double tap detection according to ´000b´  50 ms, ´001b´  100 ms, ´010b´  150 ms, ´011b´  200 ms, ´100b´  250 ms, ´101b´  375 ms, ´110b´  500 ms, ´111b´  700 ms. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 80 Register 0x2B (INT_9) Contains the definition of the number of samples processed by the single / double-tap interrupt engine after wake-up in low-power mode. It also defines the threshold definition for the single and double tap interrupts. Name Bit Read/Write Reset Value Content 0x2B 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 1 tap_samp: reserved: tap_th: INT_9 6 R/W 0 tap_samp 2 R/W 0 5 R/W 0 4 R/W 0 reserved tap_th 1 R/W 1 0 R/W 0 tap_th selects the number of samples that are processed after wake-up in the lowpower mode according to ´00b´  2 samples, ´01b´  4 samples, ´10b´  8 samples, and ´11b´  16 samples write ‘0’ threshold of the single/double-tap interrupt corresponding to an acceleration difference of tap_th · 62.5mg (2g-range), tap_th · 125mg (4grange), tap_th · 250mg (8g-range), and tap_th · 500mg (16grange). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 81 Register 0x2C (INT_A) Contains the definition of hysteresis, blocking, and mode for the orientation interrupt Name Bit Read/Write Reset Value Content 0x2C 7 R/W 0 INT_A 6 R/W 0 reserved orient_hyst Bit Read/Write Reset Value Content 3 R/W 1 2 R/W 0 orient_blocking 5 R/W 0 4 R/W 1 1 R/W 0 0 R/W 0 orient_mode reserved: write ‘0’ orient_hyst: sets the hysteresis of the orientation interrupt; 1 LSB corresponds to 62.5 mg irrespective of the selected g-range orient_blocking: selects the blocking mode that is used for the generation of the orientation interrupt. The following blocking modes are available: ´00b´  no blocking, ´01b´  theta blocking or acceleration in any axis > 1.5g, ´10b´  ,theta blocking or acceleration slope in any axis > 0.2 g or acceleration in any axis > 1.5g ´11b´  theta blocking or acceleration slope in any axis > 0.4 g or acceleration in any axis > 1.5g and value of orient is not stable for at least 100ms orient_mode: sets the thresholds for switching between the different orientations. The settings: ´00b´  symmetrical, ´01b´  high-asymmetrical, ´10b´  lowasymmetrical, ´11b´ symmetrical. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 82 Register 0x2D (INT_B) Contains the definition of the axis orientation, up/down masking, and the theta blocking angle for the orientation interrupt. Name Bit Read/Write Reset Value Content 0x2D 7 R/W n/a INT_B 6 R/W 1 5 R/W 0 reserved orient_ud_en orient_theta Bit Read/Write Reset Value Content 3 R/W 1 2 R/W 0 1 R/W 0 4 R/W 0 0 R/W 0 orient_theta orient_ud_en: change of up/down-bit ´1´  generates an orientation interrupt, ´0´  is ignored and will not generate an orientation interrupt orient_theta: defines a blocking angle between 0° and 44.8° Register 0x2E (INT_C) Contains the definition of the flat threshold angle for the flat interrupt. Name Bit Read/Write Reset Value Content 0x2E 7 R/W n/a Bit Read/Write Reset Value Content 3 R/W 1 reserved: flat_theta: INT_C 6 R/W n/a reserved 5 R/W 0 4 R/W 0 flat_theta 2 R/W 0 1 R/W 0 0 R/W 0 flat_theta write ‘0’ defines threshold for detection of flat position in range from 0° to 44.8°. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 83 Register 0x2F (INT_D) Contains the definition of the flat interrupt hold time and flat interrupt hysteresis. Name Bit Read/Write Reset Value Content 0x2F 7 R/W 0 INT_D 6 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 reserved flat_hy reserved 5 R/W 0 4 R/W 1 flat_hold_time 1 R/W 0 0 R/W 1 reserved: write ‘0’ flat_hold_time: delay time for which the flat value must remain stable for the flat interrupt to be generated: ´00b´  0 ms, ´01b´  512 ms, ´10b´  1024 ms, ´11b´  2048 ms flat_hy: defines flat interrupt hysteresis; flat value must change by more than twice the value of flat interrupt hysteresis to detect a state change. For details see chapter 4.7.8. ‘000b’  hysteresis of the flat detection disabled BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 84 Register 0x30 (FIFO_CONFIG_0) Contains the FIFO watermark level. Name Bit Read/Write Reset Value Content 0x30 7 R/W n/a Bit Read/Write Reset Value Content 3 R/W 0 FIFO_CONFIG_0 6 R/W n/a reserved 5 R/W 0 4 R/W 0 fifo_water_mark_level_trigger_retain< 5:4> 2 R/W 0 1 R/W 0 0 R/W 0 fifo_water_mark_level_trigger_retain reserved: write ‘0’ fifo_water_mark_level_trigger_retain: fifo_water_mark_level_trigger_retain defines the FIFO watermark level. An interrupt will be generated, when the number of entries in the FIFO is equal to fifo_water_mark_level_trigger_retain; BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 85 Register 0x32 (PMU_SELF_TEST) Contains the settings for the sensor self-test configuration and trigger. Name Bit Read/Write Reset Value Content 0x32 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 reserved self_test_sign self_test-axis reserved: self_test_sign: self_test_axis: PMU_SELF_TEST 6 5 R/W R/W 0 0 4 R/W 0 reserved 0 R/W 0 write ‘0x0’ select sign of self-test excitation as ´1´  positive, or ´0´  negative select axis to be self-tested: ´00b´  self-test disabled, ´01b´  x-axis, ´10b´  y-axis, or ´11b´  z-axis; when a self-test is performed, only the acceleration data readout value of the selected axis is valid; after the selftest has been enabled a delay of a least 50 ms is necessary for the read-out value to settle BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 86 Register 0x33 (TRIM_NVM_CTRL) Contains the control settings for the few-time programmable non-volatile memory (NVM). Name Bit Read/Write Reset Value Content 0x33 7 R n/a TRIM_NVM_CTRL 6 5 R R n/a n/a 4 R n/a Bit Read/Write Reset Value Content 3 R/W 0 2 R n/a 1 W 0 0 R/W 0 nvm_load nvm_rdy nvm_prog_trig nvm_prog_mode nvm_remain nvm_remain: number of remaining write cycles permitted for NVM; the number is decremented each time a write to the NVM is triggered nvm_load: ´1´  trigger, or ‘0’  do not trigger an update of all configuration registers from NVM; the nvm_rdy flag must be ‘1’ prior to triggering the update nvm_rdy: status of NVM controller: ´0´  NVM write / NVM update operation is in progress, ´1´  NVM is ready to accept a new write or update trigger nvm_prog_trig: ‘1’  trigger, or ‘0’ do not trigger an NVM write operation; the trigger is only accepted if the NVM was unlocked before and nvm_remain is greater than ‘0’; flag nvm_rdy must be ‘1’ prior to triggering the write cycle nvm_prog_mode: ‘1’  unlock, or ‘0’  lock NVM write operation BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 87 Register 0x34 (BGW_SPI3_WDT) Contains settings for the digital interfaces. Name Bit Read/Write Reset Value Content 0x34 7 R/W 0 Bit Read/Write Reset Value Content reserved: i2c_wdt_en: i2c_wdt_sel: spi3: BGW_SPI3_WDT 6 5 R/W R/W 0 0 4 R/W 0 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 reserved i2c_wdt_en i2c_wdt_sel spi3 reserved write ‘0’ if I²C interface mode is selected then ‘1´  enable, or ‘0’  disables the watchdog at the SDI pin (= SDA for I²C) select an I²C watchdog timer period of ‘0’  1 ms, or ‘1’  50 ms select ´0´  4-wire SPI, or ´1´  3-wire SPI mode BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 88 Register 0x36 (OFC_CTRL) Contains control signals and configuration settings for the fast and the slow offset compensation. Name Bit Read/Write Reset Value Content 0x36 7 W 0 OFC_CTRL 6 W 0 offset_reset cal_trigger Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 reserved hp_z_en hp_y_en hp_x_en 5 W 0 4 R 0 cal_rdy offset_reset: ´1´  set all offset compensation registers (0x38 to 0x3A) to zero, or ‘0’  keep their values offset_trigger: trigger fast compensation for ´01b´  x-axis, ´10b´  y-axis, or ´11b´  z-axis; ´00b´  do not trigger offset compensation; offset compensation must not be triggered when cal_rdy is ‘0’ cal_rdy: indicates the state of the fast compensation: ´0´  offset compensation is in progress, or ´1´  offset compensation is ready to be retriggered reserved: write ‘0’ hp_z_en: ‘1´  enable, or ‘0’  disable slow offset compensation for the z-axis hp_y_en: ‘1´  enable, or ‘0’  disable slow offset compensation for the y-axis hp_x_en: ‘1´  enable, or ‘0’  disable slow offset compensation for the x-axis BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 89 Register 0x37 (OFC_SETTING) Contains configuration settings for the fast and the slow offset compensation. Name Bit Read/Write Reset Value Content 0x37 7 R/W 0 OFC_SETTING 6 R/W 0 reserved offset_target_z offset_target_y Bit Read/Write Reset Value Content 3 R/W 0 2 R/W 0 0 R/W 0 offset_target_y offset_target_x 5 R/W 0 1 R/W 0 4 R/W 0 cut_off reserved: write ‘0’ offset_target_z: offset compensation target value for z-axis is ´00b´  0 g, ´01b´  +1 g, ´10b´  -1 g, or ´11b´  0 g offset_target_y: offset compensation target value for y-axis is ´00b´  0 g, ´01b´  +1 g, ´10b´  -1 g, or ´11b´  0 g offset_target_x: offset compensation target value for x-axis is ´00b´  0 g, ´01b´  +1 g, ´10b´  -1 g, or ´11b´  0 g cut_off: (0x37) cut_off high-pass filter bandwidth Example bw = 500 Hz 0b 1b *bw: please insert selected decimal data bandwidth value [Hz] from table 4 BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 90 Register 0x38 (OFC_OFFSET_X) Contains the offset compensation value for x-axis acceleration readout data. Name Bit Read/Write Reset Value Content 0x38 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 offset_ x: OFC_OFFSET_X 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 offset_x offset_x offset value, which is subtracted from the internal filtered and unfiltered xaxis acceleration data; the offset value is represented with two’s complement notation, with a mapping of +127  +0.992g, 0  0 g, and -128  -1 g; the scaling is independent of the selected g-range; the content of the offset_x may be written to the NVM; it is automatically restored from the NVM after each power-on or softreset; offset_x may be written directly by the user; it is generated automatically after triggering the fast offset compensation procedure for the x-axis BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 91 Register 0x39 (OFC_OFFSET_Y) Contains the offset compensation value for y-axis acceleration readout data. Name Bit Read/Write Reset Value Content 0x39 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 offset_ y: OFC_OFFSET_Y 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 offset_y offset_y offset value, which is subtracted from the internal filtered and unfiltered yaxis acceleration data; the offset value is represented with two’s complement notation, with a mapping of +127  +0.992g, 0  0 g, and -128  -1 g; the scaling is independent of the selected g-range; the content of the offset_y may be written to the NVM; it is automatically restored from the NVM after each power-on or softreset; offset_y may be written directly by the user; it is generated automatically after triggering the fast offset compensation procedure for the y-axis BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 92 Register 0x3A (OFC_OFFSET_Z) Contains the offset compensation value for z-axis acceleration readout data. Name Bit Read/Write Reset Value Content 0x3A 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 offset_ z: OFC_OFFSET_Z 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 offset_z offset_z offset value, which is subtracted from the internal filtered and unfiltered zaxis acceleration data; the offset value is represented with two’s complement notation, with a mapping of +127  +0.992g, 0  0 g, and -128  -1 g; the scaling is independent of the selected g-range; the content of the offset_z may be written to the NVM; it is automatically restored from the NVM after each power-on or softreset; offset_z may be written directly by the user; it is generated automatically after triggering the fast offset compensation procedure for the z-axis Register 0x3B (TRIM_GP0) Contains general purpose data register with NVM back-up. Name Bit Read/Write Reset Value Content 0x3B 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 GP0: TRIM_GP0 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 GP0 GP0 general purpose NVM image register not linked to any sensor-specific functionality; register may be written to NVM and is restored after each power-up or softreset BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 93 Register 0x3C (TRIM_GP1) Contains general purpose data register with NVM back-up. Name Bit Read/Write Reset Value Content 0x3C 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 GP1: TRIM_GP1 6 R/W 0 5 R/W 0 4 R/W 0 2 R/W 0 1 R/W 0 0 R/W 0 GP1 GP1 general purpose NVM image register not linked to any sensor-specific functionality; register may be written to NVM and is restored after each power-up or softreset BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 94 Register 0x3E (FIFO_CONFIG_1) Contains FIFO configuration settings. The FIFO buffer memory is cleared and the fifo-full flag is cleared when writing to FIFO_CONFIG_1 register. Name Bit Read/Write Reset Value Content 0x3E 7 R/W 0 Bit Read/Write Reset Value Content 3 R/W 0 FIFO_CONFIG_1 6 R/W 0 fifo_mode Reserved 5 R/W 0 4 R/W 0 Reserved 2 R/W 0 1 R/W 0 0 R/W 0 fifo_data_select fifo_mode: selects the FIFO operating mode: ´00b´  BYPASS (buffer depth of 1 frame; old data is discarded), ´01b´  FIFO (data collection stops when buffer is filled with 32 frames), ´10b´  STREAM (sampling continues when buffer is full; old is discarded), ´11b´  reserved, do not use fifo_data_select: selects whether ´00b´  X+Y+Z, ´01b´  X only, ´10b´  Y only, ´11b´  Z only acceleration data are stored in the FIFO BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 95 Register 0x3F (FIFO_DATA) FIFO data readout register. The format of the LSB and MSB components corresponds to that of the acceleration data readout registers. The new data flag is preserved. Read burst access may be used since the address counter will not increment when the read burst is started at the address of FIFO_DATA. The entire frame is discarded when a fame is only partially read out. Name Bit Read/Write Reset Value Content 0x3F 7 R n/a Bit Read/Write Reset Value Content 3 R n/a FIFO_DATA 6 R n/a 5 R n/a 4 R n/a 1 R n/a 0 R n/a fifo_data_output_register 2 R n/a fifo_data_output_register fifo_data_output_register: FIFO data readout; data format depends on the setting of register fifo_data_select: if X+Y+Z data are selected, the data of frame n is reading out in the order of X-lsb(n), X-msb(n), Y-lsb(n), Y-msb(n), Z-lsb(n), Z-msb(n); if X-only is selected, the data of frame n and n+1 are reading out in the order of X-lsb(n), X-msb(n), X-lsb(n+1), X-msb(n+1); the Y-only and Z-only modes behave analogously BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 96 7. Digital interfaces The BMA255 supports two serial digital interface protocols for communication as a slave with a host device (when operating in general mode): SPI and I²C. The active interface is selected by the state of the Pin#11 (PS) ‘protocol select’ pin: ´0´ (´1´) selects SPI (I²C). For details please refer to section 8). By default, SPI operates in the standard 4-wire configuration. It can be re-configured by software to work in 3-wire mode instead of standard 4-wire mode. Both interfaces share the same pins. The mapping for each interface is given in the following table: Table 20: Mapping of the interface pins Pin# Name use w/ SPI use w/ I²C 1 SDO SDO address 2 SDx SDI SDA 10 CSB CSB unused Chip Select (enable) 12 SCx SCK SCL SPI: Serial Clock I²C: Serial Clock Description SPI: Data Output (4-wire mode) I²C: Used to set LSB of I²C address SPI: Data Input (4-wire mode) Data Input / Output (3-wire mode) I²C: Serial Data The following table shows the electrical specifications of the interface pins: Table 21: Electrical specification of the interface pins Parameter Symbol Condition Min Typ Max Units Pull-up Resistance, CSB pin Rup Internal Pull-up Resistance to VDDIO 75 100 125 k Input Capacitance Cin 5 10 pF I²C Bus Load Capacitance (max. drive capability) CI2C_Load 400 pF BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 97 7.1 Serial peripheral interface (SPI) The timing specification for SPI of the BMA255 is given in the following table: Table 22: SPI timing Parameter Clock Frequency SCK Low Pulse SCK High Pulse SDI Setup Time SDI Hold Time Condition Max Units Max. Load on SDI or SDO = 25pF, VDDIO ≥ 1.62V fSPI 10 MHz VDDIO < 1.62V 7.5 MHz tSCKL tSCKH tSDO_OD Min 20 20 20 20 tSDI_setup tSDI_hold SDO Output Delay CSB Setup Time CSB Hold Time Idle time between write accesses, normal mode, standby mode, low-power mode 2 Idle time between write accesses, suspend mode, lowpower mode 1 Symbol Load = 25pF, VDDIO ≥ 1.62V Load = 25pF, VDDIO < 1.62V Load = 250pF, VDDIO > 2.4V ns ns ns ns 30 ns 50 ns 40 ns tCSB_setup tCSB_hold 20 40 ns ns tIDLE_wacc_nm 2 µs tIDLE_wacc_sum 450 µs BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 98 The following figure shows the definition of the SPI timings given in the following figure: tCSB_setup tCSB_hold CSB SCK tSCKL tSCKH SDI SDO tSDI_setup tSDI_hold tSDO_OD Figure 13: SPI timing diagram The SPI interface of the BMA255 is compatible with two modes, ´00´ and ´11´. The automatic selection between [CPOL = ´0´ and CPHA = ´0´] and [CPOL = ´1´ and CPHA = ´1´] is controlled based on the value of SCK after a falling edge of CSB. Two configurations of the SPI interface are supported by the BMA255: 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 ´1´ to (0x34) spi3. Pin SDI is used as the common data pin in 3-wire configuration. For single byte read as well as write operations, 16-bit protocols are used. The BMA255 also supports multiple-byte read 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. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 99 The basic write operation waveform for 4-wire configuration is depicted in figure 14. During the entire write cycle SDO remains in high- impedance state. CSB SCK SDI R/W AD6 AD5 AD4 AD3 AD2 AD1 SDO AD0 DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 Z tri-state Figure 14: 4-wire basic SPI write sequence (mode ´11´) The basic read operation waveform for 4-wire configuration is depicted in figure 15: CSB SCK SDI R/W AD6 AD5 AD4 AD3 AD2 AD1 AD0 SDO DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0 tri-state Figure 15: 4-wire basic SPI read sequence (mode ´11´) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 100 The data bits are used as follows: Bit0: Read/Write bit. When 0, the data SDI is written into the chip. When 1, the data SDO from the chip is read. Bit1-7: Address AD(6:0). Bit8-15: when in write mode, these are the data SDI, which will be written into the address. 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. The principle of multiple read is shown in figure 16: Control byte Start RW CSB = 0 1 Register adress (02h) 0 0 0 0 0 1 0 X Data byte Data byte Data byte Data register - adress 02h Data register - adress 03h Data register - adress 04h X X X X X X X X X X X X X X X X X X X X X Stop X X CSB = 1 Figure 16: SPI multiple read In SPI 3-wire configuration CSB (chip select low active), SCK (serial clock), and SDI (serial data input and 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 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 waveform (read or write access) for 3-wire configuration is depicted in figure 17: CSB SCK SDI RW AD6 AD5 AD4 AD3 AD2 AD1 AD0 DI7 DI6 DI5 DI4 DI3 DI2 DI1 DI0 Figure 17: 3-wire basic SPI read or write sequence (mode ´11´) BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 101 7.2 Inter-Integrated Circuit (I²C) The I²C bus uses SCL (= SCx pin, serial clock) and SDA (= SDx pin, serial data input and output) signal lines. Both lines are connected to VDDIO externally via pull-up resistors so that they are pulled high when the bus is free. The I²C interface of the BMA255 is compatible with the I²C Specification UM10204 Rev. 03 (19 June 2007), available at http://www.nxp.com. The BMA255 supports I²C standard mode and fast mode, only 7-bit address mode is supported. The default I²C address of the device is 0011000b (0x18). It is used if the SDO pin is pulled to ´GND´. The alternative address 0011001b (0x19) is selected by pulling the SDO pin to ´VDDIO´. The timing specification for I²C of the BMA255 is given in Table 23: Table 23: I²C timings Parameter Symbol Clock Frequency SCL Low Period SCL High Period SDA Setup Time SDA Hold Time Setup Time for a repeated Start Condition Hold Time for a Start Condition Setup Time for a Stop Condition Time before a new Transmission can start Idle time between write accesses, normal mode, standby mode, low-power mode 2 Idle time between write accesses, suspend mode, lowpower mode 1 fSCL tLOW tHIGH Condition Min tSUDAT tHDDAT 1.3 0.6 0.1 0.0 tSUSTA 0.6 Max Units 400 kHz s tHDSTA 0.6 tSUSTO 0.6 tBUF 1.3 tIDLE_wacc_n m tIDLE_wacc_s BST-BMA255-DS004-05 | Revision 1.2 | August 2014 um 2 µs 450 µs Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 102 Figure 18 shows the definition of the I²C timings given in Table 23: SDA tBUF tf tLOW SCL tHIGH tr tHDSTA tHDDAT tSUDAT SDA tSUSTA tSUSTO Figure 18: 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. ACK: 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 SCK toggling from logic “1” to logic “0”) is not supported. If such a combination occurs, the STOP is not recognized by the device. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 103 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 (ACK = 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: Control byte Slave Adress Start S 0 0 1 1 0 Register adress (0x10) RW ACKS 0 0 0 Data byte 0 0 0 1 0 0 Data (0x09) ACKS 0 0 X X X X X ACKS Stop X X X P Figure 19: I²C write 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 (Sr). 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 (ACK = 0) to enable further data transfer. A NACKM (ACK = 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 in 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. In order to prevent the I²C slave of the device to lock-up the I²C bus, a watchdog timer (WDT) is implemented. The WDT observes internal I²C signals and resets the I²C interface if the bus is locked-up by the BMA255. The activity and the timer period of the WDT can be configured through the bits (0x34) i2c_wdt_en and (0x34) i2c_wdt_sel. Writing ´1´ (´0´) to (0x34) i2c_wdt_en activates (de-activates) the WDT. Writing ´0´ (´1´) to (0x34) i2c_wdt_se selects a timer period of 1 ms (50 ms). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 104 Example of an I²C read access: Slave Adress Start S 0 0 1 1 0 RW ACKS 0 0 0 dummy Control byte X Register adress (0x02) 0 0 0 0 0 1 ACKS 0 Data byte Slave Adress Start Sr 0 0 1 1 0 Read Data (0x02) RW ACKS 0 0 1 Data byte X X X X X X Read Data (0x03) ACKM X X X X X Data byte X … X X X X X X X X X X X X X X X X X Data byte Data byte Read Data (0x07) X X … X Read Data (0x05) ACKM Read Data (0x06) X X Data byte Read Data (0x04) … X ACKM X ACKM X X X X X X X X ACKM X … X NACK X X Stop P Figure 20: I²C multiple read 7.2.1 SPI and I²C Access Restrictions In order to allow for the correct internal synchronisation of data written to the BMA255, certain access restrictions apply for consecutive write accesses or a write/read sequence through the SPI as well as I2C interface. The required waiting period depends on whether the device is operating in normal mode (or standby mode, or low-power mode 2) or suspend mode (or lowpower mode 1). As illustrated in figure 21, an interface idle time of at least 2 µs is required following a write operation when the device operates in normal mode (or standby mode, or low-power mode 2). In suspend mode (or low-power mode 1) an interface idle time of least 450 µs is required. X-after-Write Write-Operation X-Operation Register Update Period (> 2us / 450us) Figure 21: Post-Write Access Timing Constraints BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 105 8. Pin-out and connection diagram 8.1 Pin-out Top View Pads not visible! Bottom View Pads visible! Figure 22: Pin-out top view Figure 23: Pin-out bottom view Table 24: Pin description Pin# Name I/O Type 1 SDO Digital out 2 SDx Digital I/O 3 VDDIO Supply 4 5 6 NC INT1 INT2 -Digital out Digital out 7 VDD Supply 8 9 10 GNDIO GND CSB Ground Ground Digital in 11 PS 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 * Interrupt output 2 * Power supply for analog & digital domain (1.62V … 3.6V) Ground for I/O Ground for digital & analog Chip select for SPI mode Protocol select (GND = SPI, VDDIO = I²C) SCK for SPI serial clock SCL for I²C serial clock in SPI 4W Connect to In SPI 3W in I²C SDO DNC (float) GND for default addr. SDI SDA SDA VDDIO VDDIO VDDIO GND INT1 INT2 GND INT1 INT2 GND INT1 INT2 VDD VDD VDD GND GND CSB GND GND CSB GND GND DNC (float) GND GND VDDIO SCK SCK SCL * If INT1 and/or INT2 are not used, please do not connect them (DNC). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 106 8.2 Connection diagram 4-wire SPI Figure 24: 4-wire SPI connection Note: the recommended value for C1, C2 is 100 nF. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 107 8.3 Connection diagram 3-wire SPI Figure 25: 3-wire SPI connection Note: the recommended value for C1, C2 is 100 nF. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 108 8.4 Connection diagram I2C Figure 26: I²C connection Note: the recommended value for C1, C2 is 100 nF. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 109 9. Package 9.1 Outline dimensions The sensor housing is a standard LGA package. Its dimensions are the following. Pin1 marking: Metal pad internally connected to GND (external connection not recommended) Figure 27: Package outline dimensions BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 110 9.2 Sensing axes 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 Figure 28: Orientation of sensing axis 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 ±2g range setting and a top down gravity vector as shown above. Table 25: Output signals depending on sensor orientation Output Signal X 0g / 0LSB 1g / 1024LSB 0g / 0LSB -1g / -1024LSB Output Signal Y -1g / -1024LSB 0g / 0LSB 1g / 1024LSB 0g / 0LSB Output Signal Z 0g / 0LSB 0g / 0LSB BST-BMA255-DS004-05 | Revision 1.2 | August 2014 0g / 0LSB 0g / 0LSB upright upright Sensor Orientation (gravity vector ) 0g / 0LSB 0g / 0LSB 0g / 0LSB 0g / 0LSB 1g / 1024LSB -1g / -1024LSB Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 111 9.3 Landing Pattern Recommendation For the design of the landing patterns, we recommend the following dimensioning: Figure 29: Landing patterns; dimensions are in mm Same tolerances as given for the outline dimensions (Chapter 9.1, Figure 27) should be assumed. A wiring no-go area in the top layer of the PCB below the sensor is strongly recommended (e.g. no vias, wires or other metal structures). BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 112 9.4 Marking 9.4.1 Mass production samples Table 26: Marking of mass production samples Labeling CCC  TL Name Symbol Remark Lot counter CCC 3 alphanumeric digits, variable to generate mass production trace-code Product number T 1 alphanumeric digit, fixed to identify product type, T = “K” Sub-con ID L 1 alphanumeric digit, variable to identify sub-con Pin 1 identifier • -- 9.4.2 Engineering samples Table 27: Marking of engineering samples Labeling XXN  CC Name Symbol Remark Eng. sample ID N 1 alphanumeric digit, fixed to identify engineering sample, N = “ * ” or “e” or “E” Sample ID XX 2 alphanumeric digits, variable to generate trace-code. Counter ID CC 2 alphanumeric digits, variable to generate trace-code Pin 1 identifier • -- BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 113 9.5 Soldering guidelines The moisture sensitivity level of the BMA255 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. Figure 30: Soldering profile BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 114 9.6 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. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 115 9.7 Tape and reel specification The BMA255 is shipped in a standard cardboard box. The box dimension for 1 reel is: L x W x H = 35cm x 35cm x 6cm. BMA255 quantity: 10,000pcs per reel, please handle with care. Figure 31: Tape and reel dimensions in mm BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 116 9.7.1 Orientation within the reel  Processing direction  Figure 32: Orientation of the BMA255 devices relative to the tape BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 117 9.8 Environmental safety The BMA255 sensor meets the requirements of the EC restriction of hazardous substances (RoHS) directive, see also: Directive 2002/95/EC 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. 9.8.1 Halogen content The BMA255 is halogen-free. For more details on the analysis results please contact your Bosch Sensortec representative. 9.8.2 Internal package structure Within the scope of Bosch Sensortec’s ambition to improve its products and secure the mass product supply, Bosch Sensortec qualifies additional sources (e.g. 2nd source) for the LGA package of the BMA255. 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 BMA255 product. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 118 10. Legal disclaimer 10.1 Engineering samples Engineering Samples are marked with an asterisk (*) or (e) 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. 10.2 Product use Bosch Sensortec products are developed for the consumer goods industry. They may only be used within the parameters of this product data sheet. They are not fit for use in life-sustaining or security sensitive systems. Security sensitive systems are those for which a malfunction is expected to lead to bodily harm or significant property damage. In addition, they are not fit for use in products which interact with motor vehicle systems. The resale and/or use of 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 must monitor the market for the purchased products, particularly with regard to product safety, and inform Bosch Sensortec without delay of all security relevant incidents. 10.3 Application examples and hints With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Bosch Sensortec hereby disclaims any and all warranties and liabilities of any kind, including without limitation warranties of noninfringement 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. BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice. BMA255 Data sheet Page 119 11. Document history and modification Rev. No 0.1 0.2 0.3 0.4 0.5 0.6 0.7 1.0 1.1 1.2 Chapter All 1, 4.1, 4.2, 6.2, 7.1, 9.3 4.5.2, 4.7.8, 6.2, 9.1, 9.3 1, 4.2, 4.7.3, 4.7.7, 6.2, 9.3, 9.4.1, 9.8 4.7 6.2 4.2 4.5.1 4.7.6 6.2 7.2 Description of modification/changes Initial internal release Internal revision, not for release Internal revision, not for release Internal revision, not for release Initial external release Date 01 June 2012 Update 24 Sep 2012 Update 22 Oct 2012 Update 21 May 2013 01 August 2012 Update Single tap; update high-g interrupt 12.12.13 Update 0x0F; update 0x2B; update 0x32 sleeptimer_en->sleeptimer_mode, linguistic 01 August 2014 improvement: “… a wake-up time of at least … Slow compensation update (High-pass filter cut off frequency) Tap sensing update (temporary latched interrupt) 0x37 cut_of update I²C description update Bosch Sensortec GmbH Gerhard-Kindler-Strasse 8 72770 Reutlingen / Germany contact@bosch-sensortec.com www.bosch-sensortec.com Modifications reserved | Printed in Germany Specifications subject to change without notice Document number: BST-BMA255-DS004-05 Revision_1.2_August 2014 BST-BMA255-DS004-05 | Revision 1.2 | August 2014 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany. Note: Specifications within this document are subject to change without notice.