MEMS (sensors)

The LIS3DSH datasheet contains the following text (not very clear):"If a receiver can’t receive another complete byte of data until it has performed some other function, it can hold the clock line, SCL LOW, to force the transmitter into a wait state. Data transfer only continues when the receiver is ready for another byte and releases the data line"I guess it should have been "the clock line" - anyway I have implemented the I2C bus as a single master SCL-push-pull / SDA-bidirectional - and it works flawlessly at 100KHz - but before releasing this for final PCB design I would like a confirmation of my SCL-push-pull approach.- thanks in advance.Best regardsLeif

Hi,I am using LSM6DSO and I am trying to implement the FIFO feature. I am reading from here (https://www.st.com/content/ccc/resource/technical/document/application_note/group0/56/95/d6/a1/34/4c/49/6d/DM00517282/files/DM00517282.pdf/jcr:content/translations/en.DM00517282.pdf) and I cam up to COUNTER_BDR_REG1 register.Can someone clarify me what BDR-counter does? I understand that there is a BDU for non-FIFO approach that makes sure the data that I am reading from data output registers are recorded in the same time.So....what BDR-counter does in relation to FIFO?Regards,Gabriel

Hi, I am using STPM33 for energy monitering. I have 2 STPM33 in my design and hence there are 4 current sense channels where I use shunt resistors for sensing. The problem faced by me is that the fourth channel is showing an offset of 6 mA when zero current is flowing through the shunt. I was able to reduce it by reducing the low pass filter resistor between the stpm33 and shunt resistor from 1K to 220Ohm. Still the 4th channel has got 3mA offset where as all other ports show 1-2mA for zero current through their respective sense resistors. Anyway 3mA is acceptable for me but I want to know why this happens and if there is a better way to solve this problem. aAlso I want to know the significance of 1k resistor as low pass filter. Somebody please help.

Hi, is ST planning to release new version of the X-NUCLEO-IKS01A2 sensor expansion board with the newest recently released sensors? I would like to interface LSM6DSO with NUCLEO-L4. Tks

I have a LSM6DSO and I want to test it with the data ready interrupt, but I don't get any. I am using a logic analyzer to monitor the interrupt.The registers that I set are:0x18 with value 0x010x0B with value 0x010x10 with value 0x400x0D with value 0x01I am also reading the accelerometer registers in while(1) and it is working ok, but I have no interrupt. Should I set anything else?Thanks,Gabriel

I have the FS bits set for +/-100g scale.The accel data is a 12-bit signed value, meaning each bit represents 0.049g.The threshold registers however is only a 7-bit value. From what I understand, this is to be an unsigned magnitude level, representing 0 to full scale. So, each bit represents 0.781g?My issue is that when I get interrupts and read the data, sometimes the levels are below the threshold. For example:Threshold register set to 3 = 3*0.781 = 2.344gAn interrupt occurs and the maximum accel (on any 1 axis) register value is 37. Which is 37*0.049 = 1.813g?Just hoping for some confirmation that I'm understand these values correctly.Thank you for any input.

I am working on a project where I need to calculate the ambient noise in a given environment in decibels, for that purpose I am using st microelectronics's MP34DT01-M microphone which has an digital PDM output. From the stm application notes I got to know that I need to use pdm audio decoding library ,but I don't know from where to download this library , how to use it and how to initialise the stm32cube mx. I'm using nucleo- L476RG. please help.

Where in the 2x2 package is the sensing die for the 3 axis located? Is it dead center? A technical answer as accurate as possible would be best. And if there is some known manufacturing variance ​of this location. ​T​hanks

Hello,I have configured LIS2DH12 to generate interrupt on INT2 pin on activity as well as a strong impact using the register values as follows:CTRL_REG1 - 0x37CTRL_REG2 - 0x00CTRL_REG3 - 0x40CTRL_REG4 - 0x88CTRL_REG5 - 0x0ACTRL_REG6 - 0x28INT1_THS - 0x16INT1_DUR - 0x0CINT1_CFG - 0x95INT2_THS - 0x70INT2_DUR - 0x01INT2_CFG - 0x2AACT_THS - 0x10ACT_DUR - 0x20With this configuration, I would like to know regarding the interrupt generation for activity. 1. Does the interrupt get generated for both sleep to wake transition event as well as wake to sleep transition event? 2. Also, when the sleep to wake transition occurs, does the INT2_SRC register set the one or more of the bits ZH, YH & XH? 3. And when the wake to sleep transition occurs, does the INT2_SRC register set one or more of the bits ZL, YL & XL?4. Does duration s

Posted on July 10, 2018 at 16:40The magnetic sensitivity for the LSM9DS1 is 0.14 mguass/LSB on its most sensitive range.  The LIS2MDL is 1.5 mguass/LSB.  Is the LSM9DS1 really 10X more sensitive?  If so, it would seem the best choice for applications like a driveway sensor since it could detect smaller disturbances as vehicles passed by.  On the other hand, it is an older design, so should it be used in new designs?  Is there an alternate part with the same or similar sensitivity?#lsm9ds1-magnetic-sensitivity

This example describes how to set up a finite state machine to enable the built-in detection of a SHAKE action along x-axis. The picture here below shows the steps of the dedicated FSM. SHAKE FSM allows you to check when a double shake event is detected on x-axis, for example for wake up purposes on smartphone devices. In attachment you can find the state machine code to upload on your Unico tool.Input data are the axl output stream (select ODR >= 26Hz)Masks selects as interesting orientation axis the x axis value in both directions (MASK_A=C0) and the overall resultant (MASK_B=0x02)Thresholds are set to -1.6g (T1), -1.6g (T2), 1.2g (T3)Timeout have been selected and tuned as 640ms and 200ms (T3 and T4)Output is an interrupt when a shake on x-axis is detected

Dear ST Members,How can convert the register output X,Y,Z to dps ? I read on datasheet , the range is +/- 245 dps. What's "dps" ?Best regards,Bianchi

Hi ,I am using 3 axis Magnetometer Sensor(LIS3MDL) Sensor for Car detection. but issues is some time it's not working. please suggest me any other low power proximity for detecting car.

Hello I have a MCBSTM32F103 Evaluation Board but I can't connect it with the VL53L1X Satel. I use Keil, first I have include the API to use the functions. Then I use the VL53L1X expansion board Code and modify the platform.c and the main. If I compile the programm I'm in the hardfault handler. Please help me I don't find a way to receive ranging data about weeks. Here I have my project:  https://drive.google.com/open?id=1EY7RbFfVB3nhfKes4ZXp-38BKprBphBq

I have a LSM6DS3 sensor connected to a MCU by SPI. My goal is to fill the FIFO buffer with the following sets of data: Gx, Gy, Gz, XLx, XLy, XLz, Ts, Pd. I am using a watermark to generate an interrupt once a specific FIFO level is reached. Furthermore, I am using ST's LSM6DS3 drivers and I followed the application note AN4650 to enable the step counter and timestamp data in FIFO. I  was able to verify that the accelerometer, the gyroscope, the timestamps and the pedometer are working properly.The issue I am facing is that when I am trying to empty the FIFO and store the data in a buffer, I get incoherent timestamp and pedometer values. Both values read in the FIFO Output register for the timestamp and the pedometer are not coherent with the values stored in their respective registers. Is there a setting that I am missing?

We're evaluating the LSM6DS3. Its appnote (D027415 Rev 5) has table 20 on page 39, "Output data registers content vs. angular rate (FS_G = +/- 250dps)". Zero is zero, no problem there. The other examples are 100 and 200 dps. Let's use the positive values for some sanity checks.For +100 dps when full (positive) scale is 250 dps, you would expect the output value to be (100/250=) 40% of positive full scale. 40% of 32768 = 13107 decimal which is 0x3333. But table 20 indicates the output data will be 0x2CA4 or 11428 decimal, which is just 35% of positive full scale.Looking at +200 dps, table 20 says the output data will be 0x5949 which is 22857 decimal, 70% of positive full scale. But if positive full scale is supposed to be 250 dps, 200 dps should be (200/250=) 80% or roughly 0x6666.We're still doing datasheet evaluation so we don't have physical parts here to test ourselves. Which is correct - the FS_G setting of +/-250 dps, or the appnote dat

This example describes how to set up a finite state machine to enable the built-in detection of a WRIST TILT action. The picture here below shows the steps of the dedicated FSM. WRIST TILT FSM allows you to check when your wrist tilts, e.g. in case of you want to read a smartphone or a smartwatch.Input data are the axl output stream (select ODR >= 26Hz)Mask selects as interesting orientation axis the x axis value in positive direction x+ (0x80)Thresholds is set to -0.48g (of the 1g gravity)Timeout have been selected as 240ms and 600ms (T3 and T4)Output is an interrupt when an absolute tilt on x-axis is detected

Started working with LIS302DL. Then took the LIS3DSH. The program is the same. After starting LIS3DSH, it gives correct readings along the axes, but after a few seconds of work, the data becomes permanent. The time to failure varies from a few seconds to several tens of seconds. LIS3DSH restores its work only after switching power. I tried to connect to different microcontrollers. Changed the exchange protocol with LIS3DSH. Used different versions of LIS3DSH. After freezing the readings X, Y, Z, read all the registers LIS3DSH. No register is changed anymore. Protocol I2C. If LIS3DSH is read, for example, once per second, then it can run for 20-30 seconds. But as soon as you start to increase the speed of reading, it "freezes" the data on the axes.What is the cause of this behavior of the chip ???

Good morning,I am trying to read the WHO_AM_I register from LSM6DSO, but it doesn't respond as needed. I will attach a picture from signal analyzer (D0 is CS, D1 is CLK, D2 is MISO, D3 is MOSI). It looks like its respond is 0x50 instead of 0x6C. What should I change?I tried with a MAX32630 and it was working (8 bits transfer mode).When I try with RS14100 (16 bits mode) it responds with 0x50 instead of 6C.Gabriel

Hi to all, which is factory calibration value for g for MEMS accelerometers?Is this value the same for all accelerometers (I suppose)?Thanks.

This example describes how to set up a finite state machine to enable the built-in detection of a Motion action. The picture here below shows the steps of the dedicated FSM. Motion FSM allows you to detect the movement of your device from a steady state to a moving state.Input data are the axl output stream (select ODR >= 26Hz)Mask selects as interesting orientation axis the overall resultant in positive direction v+ (0x02)Thresholds is set to 1.1g (of the 1g gravity)Timeout selectable (e.g. 0x7D = 5 s)Output is an interrupt when the device is moving, while it doesn’t generate other interrupt until the device is still for 5 s

Posted on March 20, 2018 at 11:21Hello All,I am having a a bit of an issue working with my SensorTile kit. I am able to get the demo apps working and so on, but I now want to start on my own project.For the moment I have just tried to set the MCU up using CubeMX and I am trying to use the https://github.com/STMicroelectronics/STMems_Standard_C_drivers/tree/master/lsm6dsm_STdC and I am only concentrating on the LSM6DSM. From what I understand all one has to do is write a function for SPI TX and RX and the rest should be taken care of by the driver. I have tried to emulate what the provided example does, but when I try to test communication by reading the WHO_AM_I register, I get no response. Attached is my main.c file and a screen shot of how I set SPI2 up in half duplex

The BMI160 spec sheet says pins 2 and 3 are high impedance when the secondary I2C interface is not being used. The spec sheet also *implies* that the secondary I2C interface defaults to disabled upon a power cycle. The question is, can pins 2 and 3 be safely and permanently connected to Ground if the secondary I2C interface will not be used?The reason this matters is because the BMI160 is pin and package compatible with the ST LSM6DS3, which means they can serve as each other's second source. (The registers are entirely different so firmware must determine the installed device, but that's trivial.) The only question is pins 2 and 3, which the LSM6DS3 wants connected to either VddIO or Ground.Obviously, if the BMI160 has pins 2 and 3 at high impedance, then having them connected to Ground won't matter. The concern is if we can rely on pins 2 and 3 reliably at high impedance after a power cycle. We could get an overcurrent condition on those two pins if the

This example describes how to set up a finite state machine to enable the built-in detection of the Free Fall. The picture here below shows the steps of the dedicated FSM. The algorithm is able to detect the free fall of an object generating an interrupt if e.g. the z-axis acceleration falls below a certain threshold (e.g. 0.4g).Input data are the axl output (select ODR >= 26Hz)Mask selects as interesting orientation axis the overall resultant directions v+, v- (0x03)Thresholds can be set to 0.4gTimeout selectable (e.g. 0x03 = 120 ms, that simulates the time duration of the free fall)Output is an interrupt when a free fall acceleration profile is detected for 120msec