User Guide
Contents
1. From Host to SENtral eurer Data Transferred n bytes acknowledge From SENtral to Host Figure 3 4 Slave read register from current address 3 3 Sensor Interface Sensor Bus The SENtral motion coprocessor on the SENtral M amp M module communicates with the module s accelerometer gyroscope and magnetometer over the module s sensor bus where SENtral acts as the PC master and the sensors act as slave devices Understanding how the sensor bus operates is not necessary when using the SENtral M amp M module but it may be useful if operating in Pass Through state to communicate directly with a sensor or the EEPROM PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 11 On the sensor bus SENtral initiates data transfer and generates the serial clock 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 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 to a 4 7 KQ pull up resistor 3 4 Host Interrupt GPIO Lines GPIO 6 provides an interrupt to the host whenever a defined event occurs2. 13 Figure 4 3 SENtral Normal Operation Flow 18 Figure 5 1 SENtral Orange Red Green amp Yellow M amp M Mechanical Drawing 24 Figure 5 2 SENtral White M amp M Mechanical Drawing sss 24 Figure 5 3 SENtral Blue M amp M Mechanical Drawing eee 25 Figure 6 1 SENtral Orange Red Green amp Yellow M amp M Solder Pad Layout 26 Figure 6 2 SENtral White M amp M Solder Pad 26 Figure 6 3 SENtral Blue M amp M Solder Pad Layout sse 27 Figure A 1 SENtral Blue M amp M Zero Ohm Resistor Location 30 List of Tables Table 2 1 Performance Characteristics eee enne 6 Table 2 2 Absolute Maximum 6 Table 2 3 Operating Conditions eene 7 Table 3 1 SENtral M amp M Module Pin 8 Table 3 2 Timing Parameters icc tede ih iced er adie ee 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 17 Table 4 4 Results Registers tee cedere pda ene edie 19 Table 4 5 Standby Registers seen entente ennt nint enne 20 Table 4 6 Pass
3. 4 1 22 02 0000 0 4 2 INITIAL REGISTER 4 3 RUNNING IN NORMAL OPERATION 4 3 2 Read 800 4 4 STANDBY STATE tetti he teet ede e 4 5 PASS THROUGH 4 6 TROUBLESHOOTING essere enne 4 6 1 Hardware Related Error Conditions 4 6 2 Software Related Error Conditions 5 PACKAGE 2 2 4 nnne 0100 6 ASSEMBLY 2 224 4 4222 2 APPENDIX I CONVERTING QUATERNIONS APPENDIX Il MEASURING CURRENT CONSUMPTION PNI Sensor Corporation SENtral M amp M Technical Datasheet Doc 1020129 rD Page 1 List of Figures Figure 1 1 SENtral M amp M Module Reference 4 Figure 3 1 c NEBST E 9 Figure 3 2 l G Slave Write scd e dicii Fuer sedia 11 Figure 3 3 Slave Read Example with Repeated 11 Figure 3 4 Slave read register from current 11 Figure 4 1 SENtral Initialization Sequence sse enne 13 Figure 4 2 SENtral Operational
4. SENSOR CORPORATION SENtral M amp M Motion amp Measurement Modules General Description PNIs SENtral M amp M motion measurement modules provide highly accurate heading and orientation data in a small low power consumption and easy to integrate package module incorporates the SENtral motion coprocessor Features magnetometer an accelerometer and a e All in one motion amp orientation tracking gyroscope with different SENtral M amp M module incorporates the SENtral motion versions comprising different sensor models coprocessor 3 axis gyroscope 3 axis Unlike other inertial measurement units accelerometer and 3 axis magnetometer IMUs requiring unexpected and extensive e Low power consumption sensor fusion algorithm development and e 11x11 mm footprint and SMT design for sensor calibration work the Sentral M amp M ease of integration into a user s system modules are pre engineered to provide the e Multiple test points for debugging and highest accuracy motion tracking and evaluating performance heading measurement And this is obtained e Multiple versions with different sensors at a fraction of the power consumption of any other solution on the market Applications The SENtral M amp M comes ready to integrate e Personal Navigation amp LBS into a user s system Designed with SMT e Gaming amp Augmented Reality bonding in mind the pins are on an e Movement Science amp Fitnes
5. PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 29 Appendix 11 Measuring Current Consumption SENtral M amp M modules except 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 100 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 A 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 alth
6. 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 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 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 a
7. 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 available for reading Alternately the host may poll SENtral s EventStatus register discussed in Section 4 3 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 quickly identified 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 rD SENtral M amp M Technical Datasheet Page 12 4 Figure 4 1 provides a flow chart of the SENtral M amp M module s initialization process and discussion of this process follows in Section 4 1 Power Up Watchdog Reset or I2C ResetReq Automatic Register Initialization Automatic EEPROM Upload of Configuration File Initialized State 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
8. SENtral M amp M Technical Datasheet Page 19 Table 4 5 Standby Registers Register Name Address Register Value 0 1 StandbyEnable 0 Disable Standby State 0 1 SENtral in Standby State 0 SENtral not in Standby State AlgorithmControl 0x54 AlgorithmStatus 0x38 The steps to enter and exit Standby State are given below Write 0x01 to the AlgorithmControl register This places SENtral in Standby State Read the AlgorithmStatus register If bit 0 is 1 then SENtral 15 in Standby State This step is optional e 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 e 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 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
9. A 1 667 16 95 Figure 6 3 SENtral Blue M amp M Solder Pad Layout PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 27 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 pitch 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 E Qz Qx Qy 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
10. Through 0 21 Table 4 7 Hardware Related Error 22 Table 4 8 Software Related Error 23 Table 4 9 ErrorRegister 23 PNI Sensor Corporation Doc 1020129 rD 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 and evaluate a complete motion sensor fusion system into a mobile device module incorporates the SENtral Motion Coprocessor a magnetometer an accelerometer and a gyroscope with different SENtral M amp M versions integrating different sensor models SENtral motion coprocessor manages and uses data from the three sensors to provide reliable motion tracking and an accurate compass heading while consuming about 1 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 i e 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 Benefi
11. acceptance be free from defects in material and workmanship and will operate in accordance with PNI s published specifications and documentation for the 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 15 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 Pr
12. arguments may be reversed Heading atan2 Qx Qz Qw 2 QxQy QzQw Pitch asin 2 QxQz QyQw Roll atan2 Qx Qz 2 QxQw QyQz Where Results are in radians e The quaternions are the outputs from SENtral in NED convention 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 Roll increases when rolling clockwise and the range is 90 PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 28 Rotation Vector The rotation vector is the first three elements of the quaternion output Qx Qy and Qz The fourth element is not included in the rotation vector 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 Qx 022 2 Qx Qy Qw Qz 2 Qx Qz Qw Qy R 2 Qx Qy Qw Qz az 2 Qy Qz Qw Qy 2 Qx Qz Qw Qy 2 Qy Qz Qx az
13. 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 Write 0 07 to the EnableEvents register This sets the host to receive interrupts from SENtral whenever the quaternion results registers 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 will regularly poll SENtral rather than run in an interrupt driven manner it is not necessary to set the EnableEvents register 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 rD SENtral M amp M Technical Datasheet Page 16 Table 4 3 Normal Operation Registers Register Name Address Register Value 0 1 2 RunEnable H 4 Delonte is 0 Enable Initialized State 1 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
14. pat Data hold time 0 0 0 us tsu DAT Data set up time 250 100 50 ns Set Up time for tsu sta 2 Start 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 PNI Sensor Corporation SENtral M amp M Technical Datasheet 3 2 Host Interface Host Bus 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 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 050101000 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 be driven Doc 1020129 rD Page 10 either by the host or SENtral Normally the serial clock line will be driven b
15. M Mechanical Drawing PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 24 Dimensions inches mm Top View Side View Unpopulated Populated No 0 5 mm o PIN 8 6 9 5 10 866 22 00 G 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 rD SENtral M amp M Technical Datasheet Page 25 6 Assembly Guidelines Dimensions in inches 33 Sus X e 3 00 254 SOLDER PAD T 1 40 X 1 15 LJ L 055 X 045 T 10 PLCS A30 L sg T 234 C 5 94 Figure 6 1 SENtral Orange Red Green amp Yellow M amp M Solder Pad Layout Dimensions in inches mm _ 88 88 28 SOLDER PAD 22 ao Se DN 1 27 X 1 15 5 050 X 045 16 PLCS 1 E xdg T am 0 95 i er 095 1131 H 2 5 190 4 83 nn 9 67 Figure 6 2 SENtral White M amp M Solder Pad Layout PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 26 Dimensions 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
16. by SENtral and when exiting Pass Through State any register changes will be retained Uses for the Pass Through State include e Direct control of sensors if desired Debugging e 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 Motion Coprocessor datasheet PNI Sensor Corporation Doc 1020129 rD 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 Address Register Value 0 1 StandbyEnable AlgorithmControl 0x54 0 Disable Standby State 0 1 SENtral in Standby State 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 in Pass Through State The steps to go in and out of Pass Through State are given below e Write 0x01 to the AlgorithmControl regi
17. d sensor data 2 HPRoutput 1 Heading pitch and roll output in QX QY amp QZ QW 0 0 0 Quaternion outputs indicates an interrupt to the host will be generated for the event 0 CPUReset Non maskable 1 Error 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 rate 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 should be 1 304 OxOA 104 and 0x14 204 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 0x14 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 D
18. e 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 Pin Name _ Description IHE Pin Pin Pin DVDD d 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 Al 5 SDAM sensor bus SDA data line 9 A4 9 SCLM C 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 2 GPIO 6 Host Event Interrupt 4 C1 4 5 0 Slave Address Pin 0 zs C3 ES VCAP Regulator Capacitor Reserved Reserved not connected C2 1 12 13 Communication with the host processor is via SENtral s host interface The SENtral acts as a slave device while the host processor acts as the master The host interrupt line lets the host system know 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 acts as the PC master and the sens
19. een 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 difficult 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 rD SENtral M amp M Technical Datasheet Page 31 2013 Sensor Corporation All Rights Reserved Reproduction adaptation or translation without prior written permission is prohibited except as allowed under copyright laws Revised January 2014 for the most recent version 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 i 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
20. h Float32 0 0 1 0 or 7 2 QZ 08 0B 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 when 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 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 when scaled ATime 20 21 Accelerometer Interrupt Timestamp Ulnti6 0 2048 msec GX 22 23 Rotational Velocity X Axis or Raw 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 rD
21. hese 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 rD 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 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 supports Standard and Fast Modes PNI Sensor Corporation Doc 1020129 rD Page 7 3 Interface The SENtral M amp M pin out is given in Table 3 1 The same pin outs also ar
22. in detail in Sections 4 2 and 4 3 Normal Operation 4 4 Standby and 4 5 Pass Through Pass Through Standby Request Request Normal 3 Standby Pass Through Operation Standby State Pass Thu State Done Done Figure 4 2 SENtral Operational States PNI Sensor Corporation Doc 1020129 rD 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 Registers Register Name Address Register Value 0 EEPROM 1 EEPROM detected 1 EEUploadDone 1 EEPROM upload completed 2 EEUploadError 1 Calculated CRC of EEPROM is correct 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 SentralS
23. nsumer electronics motion sensors so designers can choose the sensors most appropriate for their systems PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 3 1 2 Small form factor 1 6x1 6x0 5 mm chip scale package 0 4 mm pitch Uses little PCB real estate allowing for painless integration interface Uses industry standard 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 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 so the SENtral M amp M the White and Blue M amp M modules are significantly different Specific schematics for each module are available from PNI How to interface with the SENtral M amp M is covered in more detail in Section 3 Host System Magnetometer DVIO GND AGND SCLS _ NM Figure 1 1 SENtral M amp M Module Reference Schematic A few points on diagram The layout shows a discrete magnetometer accelerometer and gyroscope SENtral M amp M modules generally incorpora
24. oc 1020129 rD 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 Establish how SENtral s orientation and sensor data 15 to be output 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 Establish which events will trigger an interrupt to the host by configuring the EnableEvent register 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 e Write 0x640A0F 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 0x01 to the QRateDivisor Register This sets the quaternion output data rate to equal the GyroRate This step is optional since the default register value of 0x00 also sets the quaternion output data rate equal to GyroRate e Write 0x06 to the AlgorithmControl register This enables heading pitch and roll orientation
25. oduct which fails during the applicable warranty period provided that i Customer promptly notifies PNI in writing that such Product is defective and furnishes an explanation of the deficiency ii such Product is returned to PNI s service facility at Customer s risk and expense and iii 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
26. 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 all 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 rD SENtral M amp M Technical Datasheet Page 32
27. or can be caused by a wrong e driver physically bad sensor 0x22 Accelerometer initialization failed connection or incorrect lC device 0x24 Gyroscope initialization failed address in the driver wae Magneloniater tate This error indicates the given sensor 0x12 Accelerometer rate failure is unreliable and has stopped 0x14 Gyroscope rate failure producing dale PNI Sensor Corporation SENtral M amp M Technical Datasheet Doc 1020129 rD Page 23 5 Package Information Dimensions in inches mm Top View Side View Unpopulated Populated 056 1 43 PIN FUNC r DVDD E DVDD2 XI SCLS 8 GPIO6 m SDAS GPIO4 433 AVDD i M Pin 00 GND SDAM SCLM 10x solder pads backside 76 0301 ID x 1 27 0501 x 635 025 See next section for 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 i A2 4 GP102 A4 SDAM B1 SCLS B2 GPIO5 B3 GPIO3 B4 SCLM C1 GPIO6 C2 RES 5 0 1 D1 DVDD D2 GND D3 VCAP 016 D4 GPIOO 0 41 16x solder pads on backside aa 340 76 0301 ID 1 27 T 0501 x 635 025 8 64 See next section for location Figure 5 2 SENtral White M amp
28. ors act as slave devices PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 8 Understanding how the sensor bus operates is not necessary when using SENtral amp module but it may be useful if operating in Pass Through state 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 UM 10204 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 te i 4 i tsu sro STOP SCL EL d lt P tow tup sta gt iet Figure 3 1 Timing Diagram PNI Sensor Corporation Doc 1020129 rD 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 epe tU EC 1000 20 300 120 ns _ 20 Vpp 20 Vpp ti SDA amp SCL Fall Time 300 5 5V 300 5 5V 120 ns EOW iia pos 47 1 3 0 5 us HIGH paternal SCL 4 0 0 6 0 26 is MESI e 0 6 0 26 us tup
29. ough 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 it should not affect performance PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 30 To measure average current consumption simply touch either side of the 100 resistor with the voltmeter s probe tips and measure the voltage drop Convert to current consumption using pA 10 mV assuming a 100 Q 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 Q 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 15 100uV uA or 100 has tested such an ammeter in the Method 2 scenario and s
30. s industry standard 3 mm pitch The on board e Ordering Information EEPROM contains SENtral s configuration file and this automatically uploads into Item n SENtral RAM when powered up ls Communication is via protocol White none Sentral only 13734 With the SENtral M amp M modules you can Orange MEM ee quickly and easily incorporate industry Red M amp M MPU6500 AK8963 13763 leading motion tracking and orientation Green LSM330 AK8963 13736 measurement in your mobile device We re Yellow M amp M LSM9SDO 13738 sure you ll be impressed Blue M amp M LSM330 RM3100 13759 Table of Contents 1 PRODUCT OVERVIEW tn mena nana nana nnns nana ns 1 1 SENTRAL FEATURES AND BENEFITS 1 2 SENTRAL M amp M SYSTEM OVERVIEW 2 SENTRAL SPECIFICATIONS eere tntnntnnnnenn 2 1 PERFORMANCE CHARACTERISTICS 2 2 ELECTRICAL 3 hamzlig iecteeE 3 1 3 2 2 HOST INTERFACE HOST BUS 3 2 1 Transfer formats 04 0044 3 3 2 SENSOR INTERFACE SENSOR 3 4 HOST INTERRUPT GPIO LINES 4 iesus
31. s information will be cleared for events that are not handled PNI Sensor Corporation Doc 1020129 rD 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 Normal 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 rD SENtral M amp M Technical Datasheet Page 18 matrix or Euler angles heading pitch and roll see Appendix I 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 aree Description Format Full Scale Range 00 03 Normalized Quaternion X or Heading Float32 0 0 1 0 or T QY 04 07 Normalized Quaternion Y or Pitc
32. ster This places SENtral in Standby State e Write 0x01 to the PassThroughControl register This places SENtral in Pass Through State Read the PassThroughStatus register If bit 0 is 17 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 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 rD 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 Events iallls 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 hos
33. t 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 rD Page 22 4 6 2 Software Related Error Conditions Possible indications of software related errors are given below in Table 4 8 Table 4 8 Software Related Error Indications Register Name Address Error Indication EventStatus 0x35 1 1 Error 0 MagNACK 1 NACK from magnetometer 1 AccelNACK 1 from accelerometer 2 GyroNACK 1 NACK from gyroscope 4 MagDevicelDErr 1 Unexpected DevicelD from 5 AccelDevicelDErr 1 2 Unexpected DevicelD from accelerometer 6 GyroDevicelDErr 1 2 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 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 err
34. tatus 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 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 rD SENtral M amp M Technical Datasheet Page 14 Register Name MagRate Address 0x55 Table 4 2 Registers for Initial Set up Register Value 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 AlgorithmControl 0x54 EnableEvents 0x33 quaternion data 0 1 StandbyEnable 0 Disable Standby State 1 RawDataEnable 1 Raw data provided in MX MY MZ AX AY AZ GX GY amp GZ 0 Scale
35. te a combo sensor that combines the gyroscope and accelerometer into a single device or all three sensors into a single device PNI Sensor Corporation Doc 1020129 rD SENtral M amp M Technical Datasheet Page 4 SENtral acts as a slave a host system bus This does not need to be a dedicated bus although it is shown this way in the schematic The 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 e 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 rD 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 Storage 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 t
36. ts At the heart of the SENtral M amp M module is PNI s revolutionary SENtral Motion Coprocessor Listed below are some of the features and benefits of this device Low power consumption Offloads sensor processing from the less efficient host CPU consuming 146 of the power of a Cortex MO running a comparable sensor fusion algorithm Provides the ability to tailor the tradeoff between power consumption and motion tracking performance Industry leading heading accuracy Unparalleled heading accuracy for consumer electronics applications 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 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 Sensor flexibility SENtral works with most common co
37. y 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 REGISTER ADDRESS N DATA TO REGISTER DATA TO REGISTER N 1 5 S A5 2 1 0 A7A6 5 AA AS A2 A1 AO 0 7 6 AB A4 AS A2 A1 0 7 6 5 A4 AS A2 A1 AO 0 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 START SLAVE ADDRESS RW ACK REGISTER ADDRESS ACK START SLAVE ADDRESS RW DATA FROM REGISTER N STOP 0415 gt ve o Data Transferred n bytes acknowledge Figure 3 3 FC Slave Read Example with Repeated START START SLAVE ADDRESS RW ACK DATA FROM REG N ACK DATA FROM REG N 1 NACK STOP S A6 5 4 2 1 1 7 6 5 2 1 0 7 6 5 2 1 0 1
Download Pdf Manuals
Related Search