SENtral MandM Technical Datasheet_rG
Contents
1. 4 3 RUNNING IN NORMAL OPERATION Em 4 32 Read Results 4 4 STANDBY 5 tr ict eerte 4 5 PASS THROUGH 4 6 TROUBLESHOOTING 4 6 1 Hardware Related Error Conditions 4 6 2 Software Related Error Conditions 5 PACKAGE INFORMATION 6 ASSEMBLY 7 SENTRAL M amp MS WITH PRESSURE SENSORS OVERVIEW 7 1 SYSTEM SCHEMATICS 7 2 SPECIFIGATIONS amp 7 3 INTERFACE ccccccccccccsesseseceeceeceesseaeeeseeececeesseaeeeeeeseeenes APPENDIX I CONVERTING QUATERNIONS APPENDIX Il PARAMETER APPENDIX Ill MEASURING CURRENT CONSUMPTION PNI Sensor Corporation SENtral M amp M Technical Datasheet Doc 1020129 revG Page 1 List of Figures Figure 1 1 SENtral M amp M Module Reference Schematic 4 Figure 3 1 c i2. SENSOR CORPORATION SENtral M amp M Motion amp Measurement Modules General Description PNIs SENtral M amp M motion measurement modules provide accurate heading and orientation data in a small low power consumption and easy to integrate package A module incorporates the SENtral motion coprocessor a magnetometer accelerometer gyroscope and an optional barometric pressure sensor with different SENtral M amp M versions comprising different sensor models Unlike other inertial measurement units IMUs requiring extensive sensor fusion algorithm development and sensor calibration work the Sentral M amp M modules are pre engineered to provide high accuracy motion tracking heading environmental data And this is obtained at a fraction of the power used by any other solution on the market The SENtral M amp M comes ready to integrate into a user s systemThe on board EEPROM contains SENtral s configuration file and this automatically uploads into SENtral RAM when powered up With the SENtral M amp M modules you can quickly and easily incorporate industry leading motion tracking and orientation measurement in your mobile device We re sure you ll be impressed Features e All in one motion amp orientation tracking module incorporates the SENtral motion coprocessor 3 axis gyroscope 3 axis accelerometer 3 axis magnetometer and barometric pressure sensor Low power c
3. d Interpret and act on the EventStatus register in the priority shown in Figure 4 3 If bit 1 the Error bit is 1 see Section 4 3 1 If bits 2 3 4 or 5 the Results bits are 1 see Section 4 3 2 Bit 0 the CPUReset bit should never be 1 since this bit only can be 1 after a Reset or powering up and prior to loading the Configuration File and on the SENtral M amp M module loading of the Configuration File is automatically performed after powering up e Repeat steps c and d until new orientation data is not needed and or the host decides to enter a different state Reading the EventStatus register clears it It is possible for more than one bit position to be 1 in the EventStatus register especially if the host does not always read the EventStatus register after receiving an interrupt Similarly if multiple bits are set to 1 in the EventStatus register once the register is read all the bits will be set to 0 For this reason the EventStatus register should be processed in the priority shown in Figure 4 3 as information will be cleared for events that are not handled PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 17 Host Receives Interrupt from Sentral or decides to Poll Sentral Host Reads EventStatus Register EventStatus Error ventStatus Quaternion Read Results Exit Routine Figure 4 3 SENtral Norm
4. 36 Figure A3 0 1 SENtral Blue M amp M Zero Ohm Resistor Location 40 List of Tables Table 2 1 Performance Characteristics enne 6 Table 2 2 Absolute Maximum 6 Table 2 3 Operating 7 Table 3 1 SENtral M amp M Module Pin Assignments 8 Table 3 2 Miming Parameters sciet 10 Table 4 1 Configuration File Upload from EEPROM Registers 14 Table 4 2 Registers for Initial 1 nennen 15 Table 4 3 Normal Operation Registers essent 17 Table 4 4 Results Hegisters nete nea een 19 Table 4 5 Standby Registers erste titer ait e Cri Cel e edad 20 Table 4 6 Pass Through 5 21 Table 4 7 Hardware Related Error 22 Table 4 8 Software Related Error 23 Table 4 9 ErrorRegister eene nnne nnne 23 Table 4 10 RAMVersion Register 24 Table 7 1 Pressure Senor Data Accesss 31 Table A2 0 1 Registers Used for Para
5. 4 7 1 3 0 5 us HIGH period of SCL 4 0 e 0 6 0 26 us i eal e 2 0 6 0 26 us tup pat Data hold time 0 0 0 us tsu DAT Data set up time 250 100 50 ns Set Up ti f tsu sta 52 2 4 7 0 6 0 26 Us tsu sto Stop set up time 4 0 0 6 0 26 us Bus free time between STOP amp START 4 7 1 3 0 5 HS 2 3 2 Host Interface Host Bus PNI Sensor Corporation SENtral M amp M Technical Datasheet The host will control the SENtral M amp M on the host bus via SENtral s C host interface The host interface consists of 2 wires the serial clock SCLS and the serial data line SDAS Both lines are bi directional SENtral is connected to the host bus via the SDAS and SCLS Note the SENtral M amp M module incorporates 4 7 k 2 pull up resistors on the host bus clock and data lines so if the pins which incorporate open drain drivers within the device host system also incorporates pull up resistors on these line the resistors will act in parallel The SENtral M amp M s 7 bit slave address is 0x28 060101000 The shifted address is 0x50 Data transfer is always initiated by the host Data is transferred between the host and SENtral serially through the data line SDAS in an 8 bit transfer format The transfer is synchronized by the serial clock line SCLS Supported transfer formats are single byte read multiple byte read single byte write and multiple byte write The data line can
6. M amp M Module Reference Schematic PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 4 A few points on diagram The layout shows a discrete magnetometer accelerometer and gyroscope SENtral M amp M modules generally incorporate a combo sensor that combines the gyroscope and accelerometer into a single device or all three sensors into a single device SENtral acts as a slave on a host system bus This does not need to be a dedicated bus although it is shown this way in the schematic SCLM and SDAM lines can be used to monitor SENtral s PC sensor bus but this is not necessary These lines are optional and may be left unconnected If the host will poll SENtral rather than running in an interrupt driven manner it is not necessary to connect GPIO 6 the host interrupt line to the host system GPIO 4 is intended for future use and currently serves no purpose This can be left unconnected PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 5 2 SENtral Specifications 2 1 Performance Characteristics Table 2 1 Performance Characteristics Parameter Minimum Typical Maximum Units Heading Accuracy 2 rms Output Data Rate 200 400 Hz 2 2 Electrical Characteristics Table 2 2 Absolute Maximum Ratings Parameter Symbol Minimum Maximum Units Supply Voltage Vpp 0 3 3 6 VDC Input Pin Voltage Vin GND 0 3 Vpp 0 3 VDC Sto
7. Product in effect at time of order PNI will make no changes to the specifications or manufacturing processes that affect form fit or function of the Product without written notice to the Customer however PNI may at any time without such notice make minor changes to specifications or manufacturing processes that do not affect the form fit or function of the Product This warranty will be void if the Products serial number or other identification marks have been defaced damaged or removed This warranty does not cover wear and tear due to normal use or damage to the Product as the result of improper usage neglect of care alteration accident or unauthorized repair THE ABOVE WARRANTY IS IN LIEU OF ANY OTHER WARRANTY WHETHER EXPRESS IMPLIED OR STATUTORY INCLUDING BUT NOT LIMITED TO ANY WARRANTY OF MERCHANTABILITY FITNESS FOR ANY PARTICULAR PURPOSE OR ANY WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL SPECIFICATION OR SAMPLE PNI NEITHER ASSUMES NOR AUTHORIZES ANY PERSON TO ASSUME FOR IT ANY OTHER LIABILITY If any Product furnished hereunder fails to conform to the above warranty Customer s sole and exclusive remedy and PNI s sole and exclusive liability will be at PNI s option to repair replace or credit Customer s account with an amount equal to the price paid for any such Product which fails during the applicable warranty period provided that 1 Customer promptly notifies PNI in writing that such Product is defective and f
8. Red Green amp Yellow M amp M Solder Pad Layout Dimensions in inches mm _ 88 88 28 SOLDER PAD TN ao Se DN 1 27 X 1 15 5 050 X 045 16 PLCS 1 Fp mE d 038 Fm d 0 95 axl H 2x 286 190 4 83 nn 9 67 Figure 6 2 SENtral White M amp M Solder Pad Layout PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 27 Dimensions in 234 3 234 SA Hug 1 E4 140 SOLDER PAD 1 40 X 1 15 055 X 045 12 PLCS SOLDER PAD 1 40 X 1 15 055 X 045 1 PLC A 667 16 95 Figure 6 3 SENtral Blue M amp M Solder Pad Layout PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 28 7 SENtral M amp Ms with Pressure Sensors Overview SENtral M amp M Pink and M amp M Purple include barometric pressure sensors In addition to expanding the range of applications and features that the M amp M s support pressure sensors are an important component in accurate dead reckoning and indoor navigation The pressure sensors used also provide temperature Application Functionality e Barometric pressure for weather forecasting e Floor and elevator detection for indoor navigation e Slope detection and altimeter for outdoor navigation e Climbing speed Ambient temperature This data is available in addition to the SENtral quaternion and algorithm ou
9. Reset or I2C ResetReq Automatic Register Initialization Automatic EEPROM Upload of Configuration File Initialized tate Set Sensor ODR amp EnableEvent Registers Run Request Normal Operation Figure 4 1 SENtral Initialization Sequence Once the initialization sequence is complete there are three states in which SENtral may reside Normal Operation Standby and Pass Through Figure 4 2 indicates the recommended way to get from one state to another and these states are discussed in detail in Sections 4 2 and 0 Normal Operation 4 4 Standby and 4 5 Pass Through Standby Request Pass Through Request Normal Standby Operation Pass Through State State Standby Done Pass Through Done Figure 4 2 SENtral Operational States PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 13 4 1 Power Up After powering up or issuing a ResetReq command SENtral automatically initializes the registers and loads the SENtral Configuration File from the onboard EEPROM as indicated in Figure 4 1 The Configuration File contains information specific to the particular SENtral M amp M flavor and is discussed more thoroughly in the SENtral Motion Coprocessor Technical Datasheet Once the upload is complete SENtral enters Initialized State and waits for instructions from the host Table 4 1 Configuration File Upload from EEPROM Regi
10. and returns SENtral to Standby State e Write 0x00 to the AlgorithmControl register This takes SENtral out of Standby State and normally will place it back into Normal Operation PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 21 4 6 Troubleshooting This section provides guidance in troubleshooting SENtral and is divided into hardware related and software related errors 4 6 1 Hardware Related Error Conditions Possible indications of a hardware related problem are given below in Table 4 7 Table 4 7 Hardware Related Error Indications Register Name Address Error Indication 0 1 CPURest SENtral Configuration File needs uploading See Section 4 1 2 1 EEUploadError Issue with SentralStatus 0x37 uploading from the dedicated EEPROM See Section 4 1 MagRate 0x55 0x00 Value lost AccelRate 0x56 0x00 Value lost GyroRate 0x57 0x00 Value lost In the event of such errors SENtral will enter Standby State shut down the sensors and generate an interrupt to the host Possible reasons for hardware related errors include problems with the EEPROM upload power transients detected by power management and errors in software detected by Watchdog Often the error can be cleared by sending the ResetReq command PNI Sensor Corporation SENtral M amp M Technical Datasheet Doc 1020129 revG Page 22 4 6 2 Software Related Error Conditions Possible
11. indications of software related errors are given below in Table 4 8 Register Name Table 4 8 Software Related Error Indications Address Error Indication EventStatus 0x35 1 1 Error SensorStatus 0x36 0 MagNACK 1 NACK from magnetometer 1 AccelNACK 1 from accelerometer 2 GyroNACK 1 NACK from gyroscope 4 MagDevicelDErr 1 Unexpected DevicelD from magnetometer 5 AccelDevicelDErr 1 Unexpected DevicelD from accelerometer 6 GyroDevicelDErr 1 Unexpected DevicelD from gyroscope SentralStatus 0x37 3 1 Idle SENtral in Initialized State ErrorRegister 0x50 Non zero value indicated an error See Table 4 9 RAMVersion 0x72 0x73 Unexpected Configuration File revision level If the ErrorRegister indicates a non zero value then the value provides additional information on the sensor that is causing a problem as given in Table 4 9 Table 4 9 ErrorRegister Indications Value Error Condition Response 0x00 No error 0x80 Invalid sample rate selected Check sensor rate settings 0x30 Mathematical Error Check for software updates 0x21 Magnetometer initialization failed This error can be caused by a wrong CENA SN driver physically bad sensor 0x22 Accelerometer initialization failed connection or incorrect Pe eevee 0x24 Gyroscope initialization failed address in the driver PNIS magnetometer rate failure This erro
12. it should not affect performance PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 40 To measure average current consumption simply touch either side of the 100 Q resistor with the voltmeter s probe tips and measure the voltage drop Convert to current consumption using pA 10 mV assuming 100 resistor It is possible to observe the current consumption waveform using an oscilloscope In this case place a 100 uF capacitor in parallel with the 100 resistor This reduces the measurement bandwidth so the waveform can be better observed Note that SENtral s bypass capacitors are electrically connected nearest the device after the sense resistor or the voltage meter s resistor This will bandlimit the measurement to 1 5 kHz for a 100 resistor The onboard bypass capacitance totals 1 1 uF Method 2 Remove zero ohm resistor and place ammeter in series This method is relatively straight forward to implement as the probes are physically soldered to the PCB To help prevent damage to the PCB surface pads PNI strongly recommends implementing a strain relief for the wires Note that the burden voltage of a typical digital multimeter ammeter is 100uV uA or 100 PNI has tested such an ammeter in the Method 2 scenario and seen that it does not affect operation Also note that negative voltages produced by transient currents are smoothed by the local bypass capacitors Also it may be diff
13. the CalStatus MagTransient and AlgorithmSlow bits become undefined 4 3 Running in Normal Operation After performing the steps listed above SENtral is ready to start generating orientation data The registers used to run in Normal Operation are given in Table 4 2 the steps to follow comes after this and a flow diagram is given in Figure 4 3 PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 16 Table 4 3 Normal Operation Registers Register Name Address Register Value 0 1 RunEnable 0 Enable Initialized State Standby State generally Sperone E is preferred since enabling Initialized State resets the SENtral algorithm including calibration data indicates a new event has been generated 0 CPUReset 1 Error EventStatus 0x35 2 QuaternionResult 3 MagResult 4 AccelResult 5 GyroResult Below are the steps to follow when operating in Normal Operation state a Write 0 01 to the HostControl register This sets the RunEnable bit to 1 and enables the sensors and the SENtral algorithm b If operating in an interrupt driven mode then the host waits until it receives an interrupt signal from SENtral Alternatively the host may operate on a polling basis rather than an interrupt driven basis in which case the interrupt line may not be used c Once an interrupt is received by the host or the host otherwise decides to read new data read the EventStatus register
14. Motion Coprocessor datasheet PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 20 Since operating in Pass Through State requires stopping the SENtral algorithm Pass Through State is not recommended for accessing sensor data unless reliable heading data is not required If sensor data and reliable heading data are both desired they can both be accessed during Normal Operation from the Results Registers as given in Table 4 4 Table 4 6 provides the registers associated with Pass Through State Table 4 6 Pass Through Registers Register Name Register Value 0 1 StandbyEnable AlgorithmControl 0x54 0 Disable Standby State 0 1 SENtral in Standby State Agonhmetatus 9x38 0 SENtral not in Standby State 0 1 Enable Pass Through State Oxo 0 Disable Pass Through State 0 1 SENtral in Pass Through State PEGS 055 0 SENtral Pass Through State The steps to go in and out of Pass Through State are given below e Write 0x01 to the AlgorithmControl register This places SENtral in Standby State e Write 0x01 to the PassThroughControl register This places SENtral in Pass Through State e Read the PassThroughStatus register If bit 0 is 1 then SENtral is in Pass Through State This step is optional e When you are done in Pass Through State write 0x00 to the PassThroughControl register This terminates Pass Through mode
15. OF to the MagRate register Since SENtral automatically increments to the next register this also populates the AccelRate and GyroRate registers This sets MagRate to 100 Hz AccelRate to 100 Hz and GyroRate to 150 Hz e Write 0x02 to the QRateDivisor Register This sets the quaternion output data rate to be half the GyroRate This step is optional as the default register value of 0 00 sets the quaternion output data rate equal to GyroRate e Write 0x06 to the AlgorithmControl register This enables heading pitch and roll orientation outputs and raw sensor data outputs This step is optional as the default register value of 0x00 results in outputs of quaternions and scaled sensor data e Write 0x07 to the EnableEvents register This sets the host to receive interrupts from SENtral whenever the quaternion results registers QX QY QZ and QW are updated an error has been detected or SENtral has been Reset but the Configuration File has not been uploaded If the host regularly will poll SENtral rather than run in an interrupt driven manner it is not necessary to set the EnableEvents register Note It is necessary to set the MagRate AccelRate AND GyroRate registers to non zero values for the SENtral algorithm to function properly and to obtain reliable orientation and scaled sensor data If Sensor Rate register is left as 0x00 after power up or is changed to 0x00 this effectively disables that sensor within the SENtral algorithm Also
16. ag accel loads or retrieves the magnetometer range data in ParamByteO and ParamBytel while the accelerometer range data is in ParamByte2 and ParamByte3 For example a likely readout for SensorRange mag accel in the 4x RetrieveParamByte registers is 0xE8030200 corresponding to a magnetometer dynamic range of 0 03 8 1000 and an accelerometer dynamic range of 0x0002 2 SensorRange gyro loads or retrieves the gyroscope range in ParamByteO and ParamBytel while ParamByte2 and ParamByte3 are reserved and should be 0x00 DriverlD and AlgorithmID Sensor driver and algorithm revision information can be retrieved using the Parameter Transfer process Table A2 0 3 indicates how these parameters are defined ParameterBytes 2 and 3 for Parameter Numbers 78 and 80 are 0x00 and reserved for future use PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 38 Table A2 0 3 DriverlD amp AlgorithmID Definition Parameter Parameter Parameter Number Name Byte Mag Driver Revision Mag Driver ID DriverlD mag accel Accel Driver Revision Accel Driver ID Gyro Driver Revision DriverlD gyro Gyro Driver ID Algorithm Revision Minor 80 AlgorithmID Algorithm Revision Major PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 39 Appendix 11 Measuring Current Consumption All SENtral M amp M modules exce
17. al Operation Flow A discussion of how to handle the events follows 4 3 1 Error In the event of an error SENtral will trigger an error interrupt and SENtral will enter Standby State See the Section 4 6 for recommendations on Troubleshooting and or reset SENtral by sending 0x01 to the ResetReq register at address Ox9B 4 3 2 Read Results The Results Registers addresses formats and full scale ranges are given below in Table 4 4 For an explanation of how to convert quaternions to the rotation vector the rotation PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 18 matrix or Euler angles heading pitch and roll see Appendix I The resolution is 32 kHz for all timestamps least significant byte is stored at the lowest address and transmitted first over the bus Table 4 4 Results Registers Description Format Full Scale Range QX 00 03 Normalized Quaternion X or Heading Float32 0 0 1 0 QY 04 07 Normalized Quaternion Y or Pitch Float32 0 0 1 0 or 7 2 QZ 08 Normalized Quaternion Z or Roll Float32 0 0 1 0 or x QW 0 0 Normalized Quaternion W or 0 0 Float32 0 0 1 0 QTime 10 11 Quaternion Data Timestamp UlInt16 0 2048 msec MX 12 13 Magnetic Field X Axis or Raw Mag Data Int16 1000 uT when scaled MY 14 15 Magnetic Field Y Axis or Raw Mag Data Int16 1000 uT wh
18. arameterTransfer bit set to 1 Read ParamAcknowledge Read ParamAcknowledge No No Optional but Recommended Acknowledge Check Mandatory Acknowledge Check ParamAcknowledge ParamAcknowledge ParamRequest ParamRequest Read RetrieveParamByte0 Read RetrieveParamByte1 Read RetrieveParamByte2 Read RetrieveParamByte3 Read RetrieveParamByteO Read RetrieveParamByte1 Read RetrieveParamByte2 Read RetrieveParamByte3 Figure A2 0 2 Parameter Retrieve Process The process is initiated by the host writing to the ParamRequest register the desired non zero parameter number The MSB of ParamRequest register should be 0 to indicate a Retrieve procedure After writing to the ParamRequest register the ParamTransfer bit in the AlgorithmControl register must be set to Next the host should perform repetitive reads of the ParamAcknowledge register until it contains the requested parameter number PNI Sensor Corporation Doc 1020129 revG SENiral M amp M Technical Datasheet Page 36 Now the host can read the RetrieveParamByte registers to obtain the parameter value Note the host can read the ParamAcknowledge and RetrieveParamByte registers using a single five byte read transaction Also the RetrieveParamByte values are given in little Endian format such that RetrieveParamByte3 contains the least significant byte of the parameter s 4 byte float value The host can continu
19. ation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 37 parameters associated with SENtral s continuous background calibration function and gyro bias correction When SENtral is powered down or otherwise re initialized these parameters also are re initialized and the parameter refinement process must start over The parameter transfer process provides the ability to save these parameters to the host as they are refined and to reload them if the parameters within SENtral are re initialized Thus if the WarmStart parameters periodically are retrieved from SENtral and saved by the host it is possible to effectively warm start SENtral after it is re initialized by reloading the WarmStart parameters into SENtral that previously were saved to the host To effectively enable a warm start process it is necessary to periodically save all 35 WarmsStart parameters and to reload all of them after SENtral is re initialized SensorRange The dynamic ranges of the sensors used in conjunction with SENtral normally are set as part of the Configuration File Typically the gyroscope will be set to 2000 dps the accelerometer to 2 g or 4 g and the magnetometer to 1 However there may be instances when it is desirable to change the dynamic range For instance if SENtral will be used in an application with frequent shock such as jogging it may be necessary to increase the accelerometer range to something greater than 4 g SensorRange m
20. be driven Doc 1020129 revG Page 10 either by the host or SENtral Normally the serial clock line will be driven by the host although exceptions can exist when clock stretching is implemented in Pass Through State 3 2 1 Transfer formats Figure 3 2 illustrates writing data to registers in single byte or multiple byte mode START SLAVE ADDRESS RW ACK REGISTER ADDRESS S 6 A5 A4 A3 A2A1 AO DATA TO REGISTER N ACK 0 R7R6 R5 RARSR2 R1 DATA TO REGISTER N 1 D1 DO D7D6 D5 ACK STOP D2 D1 DO RO 0 D7p6 D5 D4D3 D2 From Host to SENtral From SENtral to Host Figure 3 2 Slave Write Example The host interface supports both a read sequence using repeated START conditions shown in Figure 3 3 and a sequence in which the register address is sent in a separate sequence than the data shown in Figure 3 4 and Figure 3 5 START SLAVE ADDRESS REGISTER ADDRESS START SLAVE ADDRESS RW DATA FROM REGISTER NACK STOP 11 ve op o Data Transferred n bytes acknowledge Figure 3 3 Slave Read Example with Repeated START START SLAVE ADDRESS RW ACK REGISTER ADDRESS STOP Ls eee ee Figure 3 4 Slave Writ
21. cations Sensor data available through SENtral is output at scale factors detailed in the following table Product Scale Factor 3Pa LSB 300 1100 hPa M amp M Purple Pressure M amp M Purple Temperature 0 01 C LSB 40 85 C M amp M Pink Pressure 3Pa LSB 260 1260 hPa M amp M Pink Temperature 0 01 C LSB 40 85 C 1 Least Significant Bit PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 30 7 3 Interface Pressure sensor data is available separate from the quaternion outputs and can be accessed without the need to wakeup the inertial sensors on the board The data can be accessed at the following registers Table 7 1 Pressure Senor Data Accesss Register Name Register Address Register Value FeatureO 0x2A 0x2B Barometer Data Feature 0x2C 0x2D Barometer Timestamp Feature2 Ox2E 0x2F Temperature Data Feature3 0x30 0x31 Temperature Timestamp PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 31 Appendix Converting Quaternions SENtral outputs orientation data in quaternions using a North East Down NED convention This is done to avoid the singularities inherent in using Euler angles heading pitch and roll and because the fusion algorithms are easier to implement with quaternions However normally quaternions are not the desired final output format Most end users will want heading pi
22. e Register Address Only START SLAVE ADDRESS RW ACK DATA FROM REG N DATA FROM REG N 1 NACK STOP S 6 5 2 1 0 1 D7D6 D5 D4D3 D2 D1 DO D7D6 D5 D4D3D2 D1 DO 1 P From Host to SENtral Data Transferred bytes acknowledge From SENtral to Host Figure 3 5 Slave read register from current address PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 11 3 3 Sensor Interface Sensor Bus Understanding how the sensor interface operates is not necessary when using the SENtral M amp M module However understanding the sensor interface is useful if there is a need to communicate directly with a sensor or the EEPROM in Pass Through state The SENtral Motion Coprocessor on the SENtral M amp M module communicates with the module s accelerometer gyroscope magnetometer and pressure sensor over the module s sensor bus where SENtral is the master and the sensors are slave devices On the sensor bus SENtral initiates data transfer and generates the serial clock The two wires comprising the sensor bus are SDAM the serial data line and SCLM the serial clock Both are bidirectional and driven by open drain transistors within SENtral These can be monitored by the host but should not be written to by the host Each line is attached
23. e reading other parameters by varying normally incrementing the parameter number contained in the ParamRequest registers Reading the ParamAcknowledge register is optional for subsequent parameters The procedure is terminated by the host writing 0x00 to the ParamRequest and AlgorithmControl registers Interleaving Parameter Load and Retrieve The host can interleave the Parameter Load and Parameter Retrieve processes during a single process invocation This can be done for each parameter by setting the MSB bit of the ParamRequest register appropriately Note that SENtral can be copying a new value into a RetrieveParamByte register while a Parameter Load operation is requested Interleaving can be utilized by the host as an additional check that the parameter value was updated correctly Parameters The parameter numbers and associated names are given below in Table A2 0 2 A discussion on the WarmStart SensorRange and DriverID parameters follows Table A2 0 2 Parameter Numbers ParamRequest Parameter Bram Parameter Name Value Number Load Retrieve WarmStart 1 to 0x81 to WarmStart 35 SensorRange mag accel OxCA SensorRange gyro OxCB DriverlD mag accel DriverlD gyro AlgorithmID WarmStart A significant number of parameters are used in the SENtral algorithm as it executes and these parameters are refined as the SENtral device is used These include PNI Sensor Corpor
24. eie E rab errs rere errr 9 Figure 3 2 l G Slave Write 11 Figure 3 3 Slave Read Example with Repeated 11 Figure 3 4 Slave Write Register Address 11 Figure 3 5 Slave read register from current 11 Figure 4 1 SENtral Initialization Sequence sse 13 Figure 4 2 SENtral Operational 1 13 Figure 4 3 SENtral Normal Operation 18 Figure 5 1 SENtral Orange Red Green amp Yellow M amp M Mechanical Drawing 25 Figure 5 2 SENtral White M amp M Mechanical 25 Figure 5 3 SENtral Blue M amp M Mechanical Drawing see 26 Figure 6 1 SENtral Orange Red Green amp Yellow M amp M Solder Pad Layout 27 Figure 6 2 SENtral White M amp M Solder Pad 27 Figure 6 3 SENtral Blue M amp M Solder Pad Layout sse 28 Figure 7 1 SENtral M amp M Purple 29 Figure 7 2 SENtral M amp M Pink 30 Figure A2 0 1 Parameter Load 35 Figure A2 0 2 Parameter Retrieve
25. en scaled MZ 16 17 Magnetic Field Z Axis or Raw Mag Data Int16 1000 uT when scaled MTime 18 19 Magnetometer Interrupt Timestamp Ulnti6 0 2048 msec AX 1A 1B Linear Acceleration X Axis or Raw Accel Data Int16 16 g when scaled AY 1C 1D Linear Acceleration Y Axis or Raw Accel Data Int16 16 g when scaled AZ 1E 1F Linear Acceleration Z Axis or Raw Accel Data Int16 16 g when scaled ATime 20 21 Accelerometer Interrupt Timestamp Ulnti6 0 2048 msec GX 22 23 Rotational Velocity Axis or Raw Gyro Data Int16 5000 s when scaled GY 24 25 Rotational Velocity Y Axis or Raw Gyro Data Int16 5000 s when scaled GZ 26 27 Rotational Velocity Z Axis or Raw Gyro Data Int16 5000 s when scaled GTime 28 29 Gyroscope Interrupt Timestamp Ulnt16 0 0 2 048 sec 4 4 Standby State In Standby State overall system power consumption is dramatically reduced because both the SENtral algorithm and the sensors are shut down Table 4 5 provides the registers associated with Standby State PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 19 Table 4 5 Standby Registers Register Name Address Register Value 0 1 StandbyEnable AlgorithmControl 0x54 0 Disable Standby State 0 1 SENtral in Standby State exes 0 SENtral not in Standby State The steps to enter and exit Standby State are given below Write 0x01 to the AlgorithmControl reg
26. eter Load Process Initially the parameter values must be written into the LoadParamByte registers followed by sending a non zero parameter number into the ParamRequest register The parameter numbers are given in Table A2 0 2 The MSB of the ParamRequest register should be set to 1 to indicate a Load procedure five bytes can be written using a single PNI Sensor Corporation Doc 1020129 revG SENiral M amp M Technical Datasheet Page 35 transaction AFTER the first parameter is written the ParamTransfer bit in the AlgorithmControl register must be set to 1 Sentral acknowledges receipt of a parameter value by setting ParamAcknowledge equal to ParamRequest and the host should check the ParamAcknowledge register after writing the first parameter Once SENtral acknowledges successfully uploading the first parameter the host can begin writing the remaining parameters in a loop Reading the ParamAcknowledge register is optional for subsequent parameters The host terminates the load procedure by setting the ParamRequest register to 0x00 and the AlgorithmControl register s ParamTransfer bit to 0 Parameter Retrieve The Parameter Retrieve flowchart is given in Figure A2 0 2 Yes Last Parameter ParamRequest 0x00 AlgorithmControl 0x00 ParamRequest ParamNumber with MSB set to 0 Select next ParamNumber ParamRequest ParamNumber with MSB set to 0 AlgorithmControl 128 P
27. icult to measure DC current using ammeters with very fast measurement times due to the periodic wake sleep cycles of SENtral Consequently handheld DMMs with relatively long measurement integration times work well for making average current measurement Precision benchtop meters with an averaging or smoothing filter also can work well PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 41 2013 PNI Sensor Corporation All Rights Reserved Reproduction adaptation or translation without prior written permission is prohibited except as allowed under copyright laws Revised April 2014 for the most recent version of this document visit our website at www pnicorp com PNI Sensor Corporation 2331 Circadian Way Santa Rosa CA 95407 USA Tel 707 566 2260 Fax 707 566 2261 Warranty and Limitation of Liability PNI Sensor Corporation PNI manufactures its Products from parts and components that are new or equivalent to new in performance PNI warrants that each Product to be delivered hereunder if properly used will for ninety 90 days following the date of shipment unless a different warranty time period for such Product is specified 1 in PNI s Price List in effect at time of order acceptance or ii on PNI s web site www pnicorp com at time of order acceptance be free from defects in material and workmanship and will operate in accordance with PNI s published specifications and documentation for the
28. ister This places SENtral in Standby State Read the AlgorithmStatus register If bit 0 is 1 then SENtral is in Standby State This step is optional When you are ready to exit Standby State write 0x00 to the AlgorithmControl register This takes SENtral out of Standby State and normally will place it back into Normal Operation Read the AlgorithmStatus register If bit 0 is 0 then SENtral is not in Standby State This step is optional 4 5 Pass Through State In Pass Through State SENtral s sensor and host interfaces are connected by internal switches so the host system can communicate directly with the sensors or EEPROM To enter Pass Through State SENtral first either should be in Standby or Initialized State Consequently in Pass Through State the SENtral algorithm host interrupt line and sensors are disabled unless a sensor is directly turned on by the host When exiting Pass Through State SENtral will return to its prior state Note When entering Pass Through State the sensor s registers retain the values established by SENtral and when exiting Pass Through State any register changes will be retained Uses for the Pass Through State include Direct control of sensors if desired Debugging Communication with the dedicated EEPROM if implemented Specifically if a new Configuration File is generated the host can write this into the EEPROM when in Pass Through State as discussed in the SENtral
29. l claims regarding a Product exceed the price paid for the Product PNI neither assumes nor authorizes any person to assume for it any other liabilities Some states and provinces do not allow limitations on how long an implied warranty lasts or the exclusion or limitation of incidental or consequential damages so the above limitations or exclusions may not apply to you This warranty gives you specific legal rights and you may have other rights that vary by state or province PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 42 Revision Control Block Revision Description of Change A Initial Preliminary Release B Renamed product to SENtral M amp M Rewrote front page Removed Performance Characteristics table Updated and moved pin out table Added White amp Green mechanical drawings and pad layouts Updated Blue Red amp Yellow LSM330 mechanical drawing and pad layout Added Red electrical schematic Added TOC List of Figures and List of Tables Changed picture on front page Added M amp M Orange module Added Blue electrical schematic Removed castellated board from Red amp Green schematics D Renamed product description to be Motion amp Measurement Module s Renamed module types by putting color prior to M amp M Added Sections 1 3 and 4 and Appendix Il Added Table 2 1 Performance Characteristics Corrected Operating Conditions and Pin Assignment tables regarding DVDD am
30. location Figure 5 1 SENtral Orange Red Green amp Yellow M amp M Mechanical Drawing Dimensions in inches Top View Side View PIN FUNC 1452 1 SDAS 2 GPIO4 A3 GP102 A4 SDAM B1 SCLS B2 GPIO5 B3 GPIO3 B4 SCLM C1 GPIO6 C2 RES SAO 1 D1 DVDD D2 GND D3 VCAP 016 l D4 GPIOO 0 41 16x solder pads on backside b 340 76 0301 ID x 1 27 T 0501 x 635 025 8 64 See next section for location Figure 5 2 SENtral White M amp M Mechanical Drawing PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 25 Dimensions in inches mm Top View Side View Unpopulated Populated No 0 5 mm o PIN 8 L G PIN 9 5 10 866 22 00 PIN 12 650 ZN PIN 13 16 50 T 2 n 433 11 00 13x solder pads on backside 76 030 ID x 1 27 050 x 635 025 See next section for location Figure 5 3 SENtral Blue M amp M Mechanical Drawing PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 26 6 Assembly Guidelines Dimensions in inches 33 Sus e 5 94 234 254 SOLDER PAD n s 1 40 X 1 15 3 118 E 2x 318 EJ 234 C 5 94 Figure 6 1 SENtral Orange
31. meter 34 Table A2 0 2 Parameter 37 Table A2 0 3 DriverID amp AlgorithmID Definition 39 PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 2 1 Product Overview The SENtral M amp M Motion and Measurement Module is a castellated printed circuit assembly that makes it easy to quickly integrate a complete motion sensor fusion system into a wearable or mobile device A module incorporates the SENtral Motion Coprocessor a magnetometer an accelerometer a gyroscope and an optional barometric pressure sensor with different SENtral M amp M versions integrating different sensor models The SENtral Motion Coprocessor manages and uses data from the sensors to provide reliable motion tracking and an accurate compass heading while consuming about 196 of the power of a comparable ARM based sensor fusion microprocessor SENtral outputs Euler angles aka heading pitch and roll quaternions and sensor data Quaternions uniquely define orientation and unlike Euler angles do not experience a singularity gimbal lock when pointing straight up They easily can be converted to Euler angles the rotation vector and the rotation matrix aka DCM as discussed in Appendix I 1 1 SENtral Features and Benefits At the heart of the SENtral M amp M module is PNI s revolutionary SENtral Moti
32. ne informs the host system when SENtral has updated measurement data The SENtral Motion Coprocessor on the SENtral M amp M module communicates with the module s sensors over the sensor bus where SENtral is the PC master and the sensors are slave devices PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 8 SENtral s interfaces comply with NXP s UM10204 specification and user manual rev 04 Standard Fast Fast Plus and High Speed modes of the protocol are supported by SENtral s host interface Below is a link to this document http www nxp com documents user_manual UM10204 pdf 3 1 Timing SENtral s timing requirements are set forth below in Figure 3 1 and Table 3 2 For the timing requirements shown in Figure 3 1 transitions are 30 and 70 of Vpp REPEATED SDA tp 4 tsupat gt tart i tsu sT0 STOP SCL j i 9 lt t Figure 3 1 PC Timing Diagram PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 9 Table 3 2 Timing Parameters Standard Fast Fast Plus Units Parameter Min Max Min Max Min Max SCL Clock 0 100 0 400 0 1000 kHz t SDA le Rise 1000 20 300 120 ns Ime _ 20 Vpp 20 Vpp ti SDA amp SCL Fall Time 300 5 5V 300 5 5V 120 ns LOW period of SCL Clock
33. oked and terminated by appropriately setting the ParamTransfer bit in the AlgorithmControl register Ten 10 registers are used for the transfer and for handshaking between SENtral and the host One set of four registers is allocated to upload a parameter value to SENtral and another set of four registers is used to retrieve a currently saved parameter from SENtral Values shorter than four bytes can be transferred using only some of the registers Two registers implement the handshake mechanism between SENtral and the host Note that data is stored in little Endian format Parameter Load Figure A2 0 1 shows the Parameter Load process by which the host loads parameter data into SENtral Yes Last Parameter LoadParamByte0 ValueByteO LoadParamByte1 ValueByte1 LoadParamByte2 ValueByte2 LoadParamByte3 ValueByte3 ParamRequest 0x00 AlgorithmControl 0x00 Select next ParamNumber with MSB set to 1 LoadParamByte0 ValueByteO LoadParamByte1 ValueByte1 LoadParamByte2 ValueByte2 LoadParamByte3 ValueByte3 Ee AlgorithmControl 128 ParameterTransfer bit set to 1 Read ParamAcknowledge ParamAcknowledge ParamRequest ParamRequest ParamNumber with MSB set to 1 Read ParamAcknowledge No No Optional but Recommended Acknowledge Check Mandatory Acknowledge Check ParamAcknowledge ParamRequest Figure A2 0 1 Param
34. on Coprocessor Listed below are some of the features and benefits of this device e Low power consumption Offloads sensor processing from the less efficient host CPU consuming lt 1 of the power of a general purpose microprocessor running a comparable sensor fusion algorithm Provides the ability to tailor the tradeoff between power consumption and motion tracking performance e Industry leading heading accuracy Unparalleled heading accuracy for consumer electronics applications e Continuous hard and soft iron auto calibration Unlike other motion tracking products SENtral calibrates for both hard iron and soft iron magnetic distortion Specifically soft iron distortion is quite difficult to correct and can contribute up to 90 of error It can be caused by materials widely used in mobile and consumer electronic devices such as EMI shielding tape and other shielding Additionally since a host system s magnetic signature can change over time and temperature SENtral s continuous auto calibration ensures accuracy over time e Magnetic anomaly compensation With SENtral heading and motion tracking is unaffected by short term magnetic anomalies such as rebar in buildings desks speakers etc that can easily throw off the accuracy SENtral establishes if a transient magnetic anomaly is present and compensates for this e Sensor flexibility SENtral works with most common consumer electronics motion sensors so designers can choose the senso
35. onsumption 11x11 mm footprint and SMT design for ease of integration into a user s system e Multiple versions with different sensors Applications e Personal Navigation amp LBS e Gaming amp Augmented Reality Movement Science amp Fitness Ordering Information Item Sensors Part White none Sentral only 13734 Orange BMI055 AK8963 13771 Red MPU6500 AK8963 13763 Green LSM330 AK8963 13736 Yellow LSM9SDO 13738 Blue LSM330 RM3100 13759 Purple BMI160 BMM150 BMP280 13807 Pink LSM6DS3 AK991 1 LPS25H 13813 Table of Contents 1 PRODUCT OVERVIEW 1 1 SENTRAL FEATURES AND BENEFITS 1 2 SENTRAL M amp M SYSTEM OVERVIEW 2 SENTRAL SPECIFICATIONS 2 1 PERFORMANCE CHARACTERISTICS 2 2 ELECTRICAL CHARACTERISTICS 3 3 1 3 2 IC HOST INTERFACE HOST BUS 3 2 1 Transfer formats 3 3 2 SENSOR INTERFACE SENSOR 3 4 HOST INTERRUPT GPIO LINES 4 eue a aana NEKEA 4 1 POWER UP cc cccccccccecsssseseceeeeeceesesaeeeeeeececsesseaeeeeeeseeenes 4 2 INITIAL REGISTER
36. p DVDD2 Removed Test Point references from Pin Assignment Table and from Mechanical Drawings Corrected solder pad references on Mechanical Drawings Removed the section with specific schematics and added a note that schematics are available from PNI Section 1 2 has a generic schematic E Pertains to both SDK1 1 build 3285 and SDK1 2 build 3639 Corrected Ordering Information Yellow M amp M to read LSM9DSO Added TM to M amp M In Section 3 2 1 changed the notation in the figures so not every bit begins with A Added sentence at beginning of Section 4 regarding Little Endian formatting Added note in Section 5 2 about requirement to set Sensor Rate registers to non zero values Corrected Table 4 1 to indicate bit 2 of SentralStatus is 1 when the CRC is incorrect Section 5 6 2 added discussion of RAMVersion registers and added Table 5 13 Added Appendix on Parameter Transfer F Corretion to DCM conversion table cell 2 3 and 3 2 G Addition of M amp M Pink and Purple required new section 7 to detail functionality of additional pressure sensor PNI Sensor Corporation SENtral M amp M Technical Datasheet Effective Date Approval Dec 4 2013 A Leuzinger Dec 30 2013 A Leuzinger Jan 3 2014 A Leuzinger Jan 30 2014 A Leuzinger Apr 16 2014 A Leuzinger 7 2 14 R Thompson D McKenzie Doc 1020129 revG Page 43
37. pt the White and Blue versions have two distinct electrical supply lines One line is for both the EEPROM and the sensors and one is for just SENtral The pins for these voltages are labeled and DVDD2 respectively To measure the current on these lines PNI recommends placing a 1 resistor in series with the DVDD pin to measure combined current consumption for the EEPROM and sensors and a 100 Q resistor in series with the DVDD2 pin to measure current consumption by SENtral The SENtral Blue M amp M has a single DVDD pin that supplies current for SENtral the EEPROM and the sensors However the current consumption of only the SENtral Motion Coprocessor can be measured by modifying the module as given in the two options listed below 1 Replace a zero ohm resistor with a 1000 resistor and measure voltage across the resistor 2 Remove the zero ohm resistor then solder wires in series with a connected ammeter The location of the zero ohm resistor is given below and a discussion of the two implementation methods follows Resistor Figure A3 0 1 SENtral Blue M amp M Zero Ohm Resistor Location Method 1 Replace zero ohm resistor with 100 resistor This method provides flexibility in terms of measuring with either a voltmeter or an oscilloscope although it may be slightly difficult to implement as holding the probes in the proper position can be tricky As long as the resistor is lt 100 Q there is no need to remove it as
38. r indicates the given sensor 0x12 Accelerometer rate failure is unreliable and has stopped 0x14 Gyroscope rate failure producing data If the RAMVersion register values do not correspond to the expected Configuration File revision level as given in Table 4 10 certain features or functions that are expected to be PNI Sensor Corporation SENtral M amp M Technical Datasheet Doc 1020129 revG Page 23 available may not be available or they may not function as expected This normally can be remedied by generating the latest Configuration File revision level using the SENtral Configuration Tool and then loading this into the onboard EEPROM as discussed in the SENtral Technical Datasheet Table 4 10 RAMVersion Register Values 0x72 Register 0x73 Register Version Config File Value Value Hex Decimal Revision 0x04 0x0C 0 0 04 3076 1 0 0xD5 0x0C 0x0CD5 3285 1 1 0x37 OxOE OxOEO2 3639 1 2 PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 24 5 Package Information Dimensions in inches Top View Side View Unpopulated Populated Q wo 056 1 43 PIN FUNC 1 DVDD 2 DVDD2 XI 3 SCLS 8 4 GPIO6 5 SDAS 6 4 433 i M Pin 00 9 SDAM 10 SCLM Pin 10 10x solder pads on backside 76 0301 ID x 1 27 T 0501 x 635 025 See next section for
39. rage Temperature 50 4150 C CAUTION Stresses beyond those listed above may cause permanent damage to the device These are stress ratings only Operation of the device at these or other conditions beyond those indicated in the operational sections of the specifications is not implied Footnote 1 Specifications subject to change PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 6 Table 2 3 Operating Conditions SENtral M amp M Technical Datasheet Parameter Symbol Min Typ Max Units Digital Supply Voltage Sensors amp EPROM DVDD 1 71 AVDD VDC Supply Voltage SENiral DVDD2 1 6 3 3 VDC Analog Supply Voltage Sensors AVDD 2 4 3 6 VDC Power On Reset Threshold Vpor 1 0 VDC High Level Input Voltage Vin 0 7 Vpp Vop VDC Low Level Input Voltage Vit 0 0 3 Vpp VDC High Level Output Current Vpp 0 3V lou 1 mA Low Level Output Current 0 3V 1 mA Host Bus 3400 kbits sec C Interface Data Rate Sensor Bus 1000 kbits sec Pass Through 400 kbits sec Operating Temperature Top 40 25 85 Footnote 1 SENtral s Host Interface supports Standard Fast Fast Plus and High Speed Modes High Speed Mode 3400 kHz is supported with a reduced range of Vpp and bus capacitance SENtral s IC sensor bus interface supports Standard Fast and Fast Plus Modes Pass Through state which connects the sensor bus and host bus
40. rs most appropriate for their systems PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 3 e Small form factor 1 6x1 6x0 5 mm chip scale package on 0 4 mm pitch Uses little PCB real estate allowing for painless integration e TC interface Uses industry standard PC protocol in a low power implementation to interface to the sensors and the host so system integration is straightforward Standard Fast Fast Plus and High Speed are supported on the host bus Outputs SENtral natively outputs Euler angles heading pitch and roll quaternions rotational velocity linear acceleration and magnetic field Pass Through allows for direct communication with devices on the sensor bus 1 2 SENtral M amp M System Overview Figure 1 1 provides a reference schematic for SENtral M amp M modules While this diagram applies for most versions of the SENtral M amp M the White and Blue M amp M modules differ from what is shown and the Purple and Pink include an additional pressure sensor not shown Section 7 addresses additional functionality provided by the pressure sensor on the Pink amp Purple M amp M modules Specific schematics for each module are available from PNI on request How to interface with the SENtral M amp M is covered in more detail in Section 3 GND AGND DVIO GND AGND D B EEPROM GND Figure 1 1 SENtral
41. should be Ox1E 304 OxOA 104 and 0x14 20 The actual accelerometer and gyro ODRs are limited to the ODRs supported by the specific sensors If the AccelRate or GyroRate register values do not correspond to a supported ODR then the next highest ODR will be used For instance if the GyroRate register is set to 0 14 which corresponds to 200 Hz but the gyro supports 95 Hz 190 Hz and 380 Hz then the actual gyro ODR will be 380 Hz since this is the closest supported rate above that requested by the register PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 15 e Establish the quaternion output data rate where the quaternion output data rate equals GyroRate divided by QRateDivisor The default for QRateDivisor is 0x00 which is interpreted as 1 and results in the quaternion output data rate equaling GyroRate e Establish how SENtral s orientation and sensor data is to be output The AlgorithmControl register allows the user to select either quaternion or Euler angles heading pitch and roll for orientation outputs and either scaled or raw sensor data outputs The defaults are quaternions and scaled sensor data e Establish which events will trigger an interrupt to the host by configuring the EnableEvent register PNI specifically recommends enabling bit 1 the Error interrupt bit in addition to whichever other interrupts the user wants Example steps to do this are below Write OXIEOA
42. sters Register Name Address Register Value 0 EEPROM 1 EEPROM detected 1 EEUploadDone 1 EEPROM upload completed 2 EEUploadError 1 Calculated CRC of EEPROM is incorrect Only valid when EEUploadDone 1 3 Idle 1 Device in Unprogrammed or Initialized state 4 NOEEPROM 1 No EEPROM detected ResetReq Ox9B 0 ResetRequest 1 Emulate a hard power down power up SentralStatus 0x37 The host should confirm a successful EEPROM upload by following the steps below e Read the value from the SentralStatus register e Check bit 0 the EEPROM bit to ensure an EEPROM is detected by SENtral e Check bit 1 the EEUploadDone bit If this is 0 then the Configuration File upload is not complete and reread the SentralStatus register until bit 1 1 Once bit 1 1 check bit 2 the EEUpload Error bit If this is 0 then the upload was successful If the Configuration File upload failed send a Reset command by writing 0 01 to the ResetReq register or power off power on the device If the issue persists refer to the SENtral Motion Coprocessor datasheet for debugging hints 4 2 Initial Register Set Up After the initialization process is complete it is necessary to configure a few of SENtral s registers before running in Normal Operation These registers are given in Table 4 2 PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 14 Table 4 2 Regi
43. sters for Initial Set up Register Name Address Register Value MagRate 0x55 Requested magnetometer output data rate AccelRate 0x56 Requested accelerometer output data rate divided by 10 GyroRate 0x57 Requested gyroscope output data rate divided by 10 QRateDivisor 0x32 Along with GyroRate establishes output data rate for quaternion data 0 1 StandbyEnable 0 Disable Standby State return to Normal Operation 1 RawDataEnable 1 Raw data provided in MX MY MZ AX AY AZ GX GY amp GZ AlgorithmControl 0x54 0 Scaled sensor data 2 HPRoutput 1 Heading pitch and roll output in QX QY amp QZ QW 0 0 0 Quaternion outputs T indicates an interrupt to the host will be generated for the event 0 CPUReset Non maskable 1 Error eem 2 QuaternionResult 3 MagResult 4 AccelResult 5 GyroResult Perform the following operations to run SENtral as desired Set the sensor output data rates ODRs MagRate AccelRate and GyroRate If a sensor rate is set to 0x00 SENtral will shutdown the sensor and disable SENtral background calibration There are two major points regarding setting these registers o The AccelRate and GyroRate register values should be 1 10 the desired ODR while the MagRate value should match the desired ODR For example if the desired ODR is 30 Hz for the magnetometer 100 Hz for the accelerometer and 200 Hz for the gyroscope then the respective register values
44. supports Standard and Fast Modes PNI Sensor Corporation Doc 1020129 revG Page 7 3 Interface The SENtral M amp M pin out is given in Table 3 1 Pin outs also are given alongside the device mechanical drawings in Section 5 See Table 2 3 for the operating ranges of DVDD DVDD2 and AVDD A discussion of the communication interface follows the table Table 3 1 SENtral M amp M Module Pin Assignments M amp M Orange M amp M M amp M Pin Name _ Description Red Green amp White Blue Yellow Pin Pin Pin DVDD c Voltage Sensors amp 1 NA 2 DVDD2 Supply Voltage SENtral 2 D1 2 AVDD Analog Supply Voltage Sensors 7 NA 7 GND Ground 8 D2 8 SCLS host bus SCL clock line 3 B1 3 SDAS host bus SDA data line 5 A1 5 SDAM sensor bus SDA data line 9 A4 9 SCLM sensor bus SCL clock line 10 B4 10 GPIO 0 SENtral Accelerometer Interrupt D4 GPIO 1 SENtral Magnetometer Interrupt 4 GPIO 2 SENtral Gyroscope Interrupt A3 GPIO 3 Reserved B3 GPIO 4 Reserved 6 A2 6 GPIO 5 Reserved B2 GPIO 6 Host Event Interrupt 4 C1 4 SAO Slave Address Pin 0 VCAP Regulator Capacitor D3 Reserved Reserved not connected C2 1 12 13 Communication with the host processor is via SENtral s host interface where SENtral M amp M acts as a slave device and the host s processor acts as the master The host interrupt li
45. tch and roll while Android looks for a rotation vector and generally uses a rotation matrix for orientation Plus Android and Win8 both expect data to be presented in the East North Up ENU convention This appendix discusses how to convert SENtral s output quaternions into these other output formats Converting from NED to ENU While the North East Down NED convention is common in many industries both Android and Windows 8 use the East North Up convention Below is the equation to convert from NED to ENU Qw Qz Qy Qx 0 0 0 707 0 707 Qz Qw 0 0 0 707 0 707 C 0 707 0 707 0 0 Qy Qw Qz 0 707 0 707 0 0 Qz Qw 0 707 0 707 0 0 NED Heading Pitch and Roll Most end users will want orientation data reported as heading pitch and roll Below are the Excel transformation equations Note that for other programs such as Matlab the ATAN2 arguments may be reversed Heading atan2 Qx Qz 2 QxQy QzQw Pitch asin 2 QxQz QyQw Roll atan2 Qx Qz 2 QxQw QyQz Where e Results are in radians e The quaternions are the outputs from SENtral in NED convention e Heading increases as the device rotates clockwise around a positive Z axis and the range is 0 360 i e it matches what you would expect on a compass e Pitch increases when pitching upward and the range is 180 e Roll increases when rolling clock
46. to a 4 7 kQ pull up resistor SENtral s sensor interface supports Standard mode with a rate up to 100 kbit s Fast mode with a rate up to 400 kbit s and Fast Plus mode with a rate up to 1000 kbit s 3 4 Host Interrupt GPIO Lines GPIO 6 provides an interrupt to the host whenever a defined event occurs Exactly which types of events will trigger an interrupt are set by the EnableEvents register which is discussed in Section 4 2 This interrupt line can be used to signal the host that new results are available for reading Alternately the host may poll SENtral s EventStatus register discussed in Section 0 to determine if any events of interest have been updated If polling will be used PNI recommends polling on a regular interval such that an error event will be identified in a timely manner GPIO 4 is not currently used and generally should be left unconnected This is also true for GPIO 3 and GPIO 5 which are only accessible on the SENtral White M amp M PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 12 4 Operation Figure 4 1 provides a flow chart of the SENtral M amp M module s initialization process and a discussion of this process follows in Section 4 1 For the registers all multi byte elements are stored and transmitted using the Little Endian convention the least significant byte is stored at the lowest address and transmitted first over the bus Power Up Watchdog
47. tputs 7 1 System Schematics Our M amp M modules are an ideal way to test the functionality of a SENtral based system Full size schematics are provided upon request for those wishing to integrate a discrete solution into their system BMI160 BMM150 BMP280 EEPROM Gyro Accel Magnetometer Barometer 8 i woo HH z 2 0207 Ic 9 H 0 5 sa SA 102 GPIQ0 01 6102 GPIO4 Figure 7 1 SENtral M amp M Purple Schematic Key components include PNI SENtral Bosch Sensortech BMI160 Gyro Accel BMM150 Magnetometer and BMP280 Pressure sensor PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 29 LPS25H LSM6DS3 AK9911 Barometer SEN a 4 EEPROM Gyro Accel Magnetometer 2 1 LSM6DS3_ s z wo AKO9911C Inti lt VOD ui INT217 34 2 asm 00 pue ES Glow w amp Figure 7 2 SENtral M amp M Pink Schematic Key components include PNI SENtral ST Micro LSM6DS3 Gyro Accel AKM AK9911 Magnetometer and ST Micro LPS25H Pressure Sensor 7 2 Specifi
48. urnishes an explanation of the deficiency i1 such Product is returned to PNI s service facility at Customer s risk and expense and 11 PNI is satisfied that claimed deficiencies exist and were not caused by accident misuse neglect alteration repair improper installation or improper testing If a Product is defective transportation charges for the return of the Product to Customer within the United States and Canada will be paid by PNI For all other locations the warranty excludes all costs of shipping customs clearance and other related charges PNI will have a reasonable time to make repairs or to replace the Product or to credit Customer s account PNI warrants any such repaired or replacement Product to be free from defects in material and workmanship on the same terms as the Product originally purchased Except for the breach of warranty remedies set forth herein or for personal injury PNI shall have no liability for any indirect or speculative damages including but not limited to consequential incidental punitive and special damages relating to the use of or inability to use this Product whether arising out of contract negligence tort or under any warranty theory or for infringement of any other party s intellectual property rights irrespective of whether PNI had advance notice of the possibility of any such damages including but not limited to loss of use revenue or profit In no event shall PNI s total liability for al
49. used by SENtral Register Usage Table A2 0 1 provides the registers used for the parameter transfer process Table A2 0 1 Registers Used for Parameter Transfer Register Name Address Access Format Description 0 StandbyEnable 1 Enable Standby state 1 RawDataEnable 1 Raw data provided in MX MY MZ AX AY AZ GX GY amp GZ 0 Scaled sensor data Algorithm Control 0x54 R W 7 0 2 HPRoutput 1 Heading pitch and roll output in QX QY amp QZ QW 0 0 0 Quaternion outputs 7 ParamTransfer 1 Enable Parameter Transfer LoadParamByte0 Parameter value to be loaded LSB LoadParamByte1 Parameter value to be loaded LSB 1 LoadParamByte2 Parameter value to be loaded MSB 1 LoadParamByte3 Parameter value to be loaded MSB Bits 0 6 provide the parameter number to ParamRequest 0x64 R W 7 0 be uploaded or retrieved 7 Load Save bit 1 Load 0 Save Bits 0 6 provide the parameter number ParamAcknowledge Ox3A R O 7 0 that was uploaded or retrieved 7 Load Retrieve bit 1 Load 0 Retrieve RetrieveParamByteO Parameter value read from Sentral LSB RetrieveParamByte1 Parameter value read from Sentral LSB 1 RetrieveParamByte2 Parameter value read from Sentral MSB 1 RetrieveParamByte3 Parameter value read from Sentral MSB PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 34 The parameter transfer process is inv
50. wise and the range is 90 PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 32 Rotation Vector The rotation vector is the first three elements of the quaternion output Qx Qy and Qz The fourth element Qw is not included in the rotation vector The rotation vector in ENU convention will be the first three elements of Qguu discussed above Rotation Matrix or Direction Cosine Matrix DCM The rotation matrix also known as the direction cosine matrix DCM can be established from the quaternion output using the following conversion Qzwu values can be substituted to give the rotation matrix with an ENU convention ay 022 2 Qx Qy Qw Qz 2 Qx Qz Qw Qy R 2 Qx Qy Qw Qz az 2 Qy Qz Qw Qx 2 Qx Qz Qw Qy 2 Qy Qz Qw Qx az PNI Sensor Corporation Doc 1020129 revG SENtral M amp M Technical Datasheet Page 33 Appendix Il Parameter Transfer Note Implementing the parameter transfer process is not necessary when using SENtral but can be useful for enabling a warm start for setting the sensor ranges to non default values and or for reading the device driver IDs This appendix provides the protocol for implementing SENtral s parameter transfer process A parameter transfer involves the host either loading parameter values into SENtral or retrieving parameter values currently
Download Pdf Manuals
Related Search