Home

SENtral

1. Standard Fast Fast Plus Units Parameter Min Max Min Max Min Max fsct SCL Clock 0 100 0 400 0 1000 kHz t SDA Ce 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 tiow Clock 4 7 1 3 0 5 US HIGH period of SCL ties pies 4 0 e 0 6 0 26 us i eal MESI ED E 0 6 0 26 us tHD DAT Data hold time 0 0 0 us tsu DAT Data set up time 250 100 50 ns Set Up time for tsu sTa ere Start 4 7 0 6 z 0 26 US tsu sto Stop set up time 4 0 0 6 0 26 us Bus free time between Jour STOP amp START 4 7 1 3 0 5 US PNI Sensor Corporation SENtral Technical Data Sheet 4 2 IC Host Interface Host Bus The host will control SENtral on the host bus via SENtral s PC 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 pins which incorporate open drain drivers within the device The host bus lines must be externally connected to a positive supply voltage DVIO via a pull up resistor See Section 4 4 for more on the pull up resistor SENtral s 7 bit PC slave address is 0b010100x where the most significant 6 bits of the slave The least significant bit is user configurable using the SAO pin to set the bit to 0 or l For example grounding the SAO pin
2. 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 Qgenu 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 Qenu values can be substituted to give the rotation matrix with an ENU convention Qw Qx ay aZ 2 Qx Qy Qw Qz 2 Qx Qz Qw Qy R 2 Qx Qy Qw Qz Qw Qx Qy az 2 Qy Qz Qw Qy 2 Qx Qz Qw Qy 2 Qy Qz Qw Qy Owi ax Qy az PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 41 Appendix Ill Sample Schematic Set The schematics provided are for a complete Bluetooth enabled device incorporating SENtral and either an ST LSM9DSO 9 axis sensor or an ST LSM330 gyro accel combo sensor with an AKM AK8963C magnetometer Except for the last schematic the schematics are common regardless of sensors CHARGER DATA IO PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 42 VDD VDD a ci2 C6 cs C4 IND CHIP 0201 BOOT1 PBO PB1 PB2 PB3 PB4 PBS PB6 PB7 PBS PBS EEFT HHE BATMEAS 8 E a PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 43 B
3. the GPIO pins are interchangeable and can be configured as is most convenient for the user 6 2 3 Slave Address This establishes the slave address for the respective sensor and the user needs to input the sensor s slave address here The 7 bit slave address will be provided in the sensor s PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 30 technical data sheet and normally will be a function of 5 or 6 fixed bits and 1 or 2 bits that are configurable by 1 or 2 of the sensor s pins 6 2 4 Orientation Matrix This matrix defines how the sensors are physically laid out in the host system The values are normally Is 1s or Os The matrix is used to convert the physical layout into a north east down NED convention where north is defined as the line of sight or direction of travel The matrix is defined as shown in the equation below omz I OUO I m DI C F N lt X where A through I are the matrix values that need to be populated 1s or 0s X Y and Z represent the orientation of the x axis y axis and z axis sensors where north is defined as the line of sight and NED is the north east down convention that the orientation matrix converts X Y Z into For the accelerometer matrix it is necessary to multiply the matrix by 1 Examples Below are three examples The first is if the sensor is laid out in an NED convention such that the x axis points north the y axis points eas
4. 0 value results in the 7 bit address of 0b0101000 This should be set so the SENtral slave address is unique to any other devices on the host bus address are pre defined in hardware and are the same for all SENtral devices Note that setting SAO to 1 requires utilizing microvia technology as discussed in Section 8 Doc 1018049 R02 Page 13 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 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 4 2 1 C Slave Transfer formats Figure 4 2 illustrates writing data to registers in single byte or multiple byte mode START SLAVE ADDRESS RW ACK REGISTER ADDRESS N ACK DATA TO REGISTER N ACK DATA TO REGISTER N 1 ACK STOP S A6 A5 A4A3 A2 A1 AO0 O 0 R7R6 R5 RARSR2 R1 RO 0 D7P6 D5 D4 D31D2 D1 DO 0 D7D6 D5 D4D3 D2 D1 DO 0 B From Host to SENtral From SENtral to Host Figure 4 2 FC Slave Wr
5. Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 6 Table 2 3 Operating Conditions 1 PNI Sensor Corporation SENtral s current consumption in normal operation is dependent on a number of variables including the sensor update rates and the I C sensor bus rate The range given will be typical for most customers There is a trade off between sensor update rates and current consumption as more frequent sensor update rates result in improved motion tracking performance while less frequent sensor update rates result in reduced current consumption Faster UC sensor bus rates result in lower current consumption Pass Through current consumption assumes SENtral previously was in Standby State which is recommended and a sensor bus rate of 400 kbits s Fast mode SENtral s C 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 SENtral Technical Data Sheet Parameter Symbol Min Typical Max Supply Voltage Von 1 6 3 3 VDG Power On Reset Threshold VnEG VpPon Vpor VREG 0 125 VDC High Level Input Voltage Vin 0 7 Vpp Vpp VDC Low Level Input Voltage Vit 0 0 3 Vpp VDC Hig
6. in Figure 8 2 and the associated processing parameters are given in Table 8 1 both on the following page Oven type and tolerances thermocouple tolerance solder type and the temperature difference across the board will affect the actual implemented profile PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 36 EK Ramp Down L Preheat J Temperature C Time Figure 8 2 Typical Solder Reflow Profile Table 8 1 Typical Solder Processing Parameters Parameter Value Ramp Up Rate 3 C second Preheat Temperature Range 150 C to 180 C Preheat Time 60 180 seconds Liquidus Temperature 220 C Time above Liquidus 30 90 seconds Peak Temperature 255 C 5 C Time within 5 C of Peak Temperature 10 20 seconds Ramp Down Rate 6 C second maximum PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 37 Appendix I Configuration File Image Format Table Al 1 provides the format for the Configuration File image While understanding the Configuration File image format is not mandatory for operation it can be useful when debugging errors Table A1 1 Configuration File Image Format Byte Index Content Note 0x00 Magic Number Lower Byte Ox2A is expected value 0x01 Magic Number Upper Byte 0x65 is expected value 0x02 amp 0x03 Flags Bit 0 EEPROMExec 0 Execute after EEPROM upload default 1 Do not execute afte
7. this list is not exhaustive e Microchip 24LC256T I 5N e ST M24MOI DRCS e Renesas RIEX24512ASASOA PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 11 4 C Interface Communication with the host processor and sensors is via an DC interface and interrupt lines The SENtral Motion Coprocessor acts as the DC master with the sensors and as a slave with the host processor The sensor interrupt lines let SENtral know when new data is available while the host interrupt line lets the host system know when SENtral has updated the quaternions The sensor and host output data rates are set by the MagRate AccelRate GyroRate and QRateDivisor registers SENtral s IC interface complies with NXP s UM10204 specification and user manual rev 04 Standard Fast Fast Plus and High Speed modes of the C protocol are supported by SENtral s DC host interface Below is a link to this document http www nxp com documents user_manual UM10204 pdf 4 1 IC Timing SENtral s C timing requirements are set forth below in Figure 4 1 and Table 4 1 For the timing requirements shown in Figure 4 1 transitions are 30 and 70 of Vpp REPEATED START START SDA t tsu pAT lt t HD DAT SCL i i tow tHicH E tup srA gt Te i iet Figure 4 1 FC Timing Diagram PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 12 Table 4 1 C Timing Parameters
8. 0 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 Each line should be attached to a pull up resistor which is further discussed in Section 4 4 4 4 C Pull Up Resistance The pull up resistor value for both the host and sensor bus will depend on the IC data rate and the number of devices on the bus Table 4 2 provides the maximum acceptable bus capacitance as a function of bus rate which can be accommodated with a 4 7 kQ or 2 4 kQ pull up resistor As a general rule each device connected to the bus represents 10 pF of capacitance on the bus so a bus with 4 devices would require a Max Cb value of gt 40 pF Table 4 2 I C Pull Up Resistance Table Rate Rise Time Max Cb pF 12C Mode kbit kbit s ns 4 7 KQ pull up 2 4 KQ pull up Standard 100 1000 251 1 491 8 Fast 400 300 75 3 147 5 Fast Plus 1000 120 30 1 59 0 Clock 1700 80 20 1 39 3 High Speed 1 7 MHz Data 1700 160 40 2 78 7 Clock 3400 40 10 0 19 7 High Speed 3 4 MHz Data 3400 80 20 1 39 3 As the table implies for most Standard and Fast Mode implementations a 4 7 kQ pull up should work well while a 2 4 kQ pull up normally should be used for Fast Plus See Section 7 1 of NXP s UM10204 specification for additio
9. Ceni SENSOR CORPORATION SENtral Motion Coprocessor General Description The SENtral Motion Coprocessor is a custom integrated circuit that makes it easy to quickly incorporate optimize and operate multiple motion sensors on mobile consumer electronics devices SENtral employs and manages a user specified 3 axis magnetometer 3 axis accelerometer and 3 axis gyroscope to provide reliable motion tracking and accurate heading and orientation data SENtral gathers data from the individual sensors then integrates and fuses this data using PNI s proprietary Kalman filtering and heuristic algorithms By offloading the sensor fusion and interface from a dedicated sensor hub MCU or the host CPU to SENtral overall power requirements are dramatically lowered and processing power is opened up for other uses These advantages make SENtral the ideal choice for mobile and consumer electronics devices desiring ultra lower power consumption and best in class sensor fusion Features e Heading Accuracy of 2 rms Ultra Low Power Consumption Continuous Soft and Hard Iron Magnetic Auto Calibration e Magnetic Anomaly Compensation e FC Interface 100 to 3400 kHz e Small Form Factor e Sensor Flexibility Applications Cell Phones Tablets Ultrabooks TV Remote Controls Video Game Controllers Ordering Information Item Part Quantity Package SENtral 13658P lt 4000 SENtral 13658 4000 Cut Tape Tape amp Re
10. Gyroscope 1 0 1 radian second PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 32 7 Package Information Dimensions in mm 1 6 Figure 7 1 Mechanical Drawing PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 33 Dimensions in mm 4 00 0 10 4 00 0 10 8 00 30 10 J Direction of Unwinding 0 50 0 10 25 0 02 LR 5 MAX 5 MAX E 1 71 0 05 0 81 0 05 1 71 0 05 Figure 7 2 Tape Dimensions PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 34 8 Assembly Guidelines SENtral is provided in a lead free wafer level chip scale package WL CSP General design guidelines can be found in Amkor s Application Note for Surface Mount Assembly of Amkor s Eutectice and Lead Free CSP TM Wafer Level Chip Scale Packages which is available from Amkor s website Specific assembly guidelines are discussed below Comments specific to SENtral include Microvia technology is NOT required if GPIO 3 and GPIO 5 are not used and the slave address pin SAO is set LOW In this case the slave address pin C3 should be connected to C2 unused and C2 should be connected to D2 which is GND Pins B2 GPIO 5 and B3 GPIO 3 should be left unconnected If either GPIO 3 and GPIO 5 are to be used or the slave address pin SAO is to be set HI then microvia technology is required Due to
11. H GTATE nnn n nnn 25 5 6 TROUBLESHOOTING serven e e ener erba Deua CY e a dee 27 5 6 1 Hardware Related Error Conditions 27 5 6 2 Software Related Error Conditions annae nennen eenen 27 6 SENTRAL CONFIGURATION TOOL nononono nn nnn nnn nnns 29 6 1 CONFIGURATION TOOL GENERAL SETTINGS esee 30 6 1 1 SDK ReviSIOn vicaria id saga ode aid od nd gv na nd dava v saa va vd Fara va od oa dava d 30 6 1 2 Host Interrupt Pin eenen a 30 6 1 3 EEPROM Max Upload Speed sss 30 6 2 CONFIGURATION TOOL SENSOR CONFIGURATION ee 30 6 21 TEE 30 6 2 2 Interrupt TI 30 6 2 3 Slave Address ii emde echa a vu da Ta va md larva vd od dava vd 30 6 2 4 Orientation Matrix 31 6 2 5 e e CC 32 7 PACKAGE INFORMATION en enennnnnannannnnnanansaansnannsnsnansnansnsnsnennensn 33 8 ASSEMBLY GUIDELINES aaan enenen en enen en enenenenenenenenenenenenenenenen 35 APPENDIX I CONFIGURATION FILE IMAGE FORMAT eenen 38 APPENDIX II CONVERTING QUATERNIONS sanannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnne 40 APPENDIX III SAMPLE SCHEMATIC SET asannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnne 42 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 1 List of Figures Figure 1 1 SENtral Block Diagram sssssssseseseneenenneeeene nnne nennen nennen nnne 4 Figure 3 1 SENtral System Reference Schematic sssssss
12. IO2 pull selection Bit 6 amp 7 GPIO3 pull selection Bit 8 amp 9 GPIO4 pull selection Bit 10 amp 11 GPIO5 pull selection Bit 12 amp 13 GPIO6 pull selection Others reserved 0x1C to 0x2B Device Name 16 character string When uploading the Configuration File from a dedicated EEPROM SENtral first checks the Magic Number upper and lower bytes to ensure they match the expected values If they do then the upload will commence and during the upload SENtral calculates the CRC32 value over the incoming data At the end of the upload process the calculated CRC32 value is compared with the valued stored in the header If they match the Configuration File has been successfully uploaded If the the EEPROMExec bit is set to 0 then the SENtral algorithm automatically will execute and move SENtral in Initialized state as shown in Figure 5 1 PNI Sensor Corporation SENtral Technical Data Sheet Doc 1018049 R02 Page 39 Appendix Il 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 orientat
13. M is used the EEPROM needs to be connected to SENtral as a slave device on the sensor bus 5 1 1 Configuration File Upload from EEPROM If a dedicated EEPROM is used to store the Configuration File then this EEPROM initially would be loaded with the Configuration File either using an EEPROM programmer or by writing the file into the EEPROM from the host while SENtral is in Pass Through State This later method also can be used if a new revision of the SENtral algorithm is available or if the user is testing a variety of sensors and consequently needs PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 17 to change the Configuration File depending on the sensors As previously mentioned the EEPROM should be connected to SENtral via SENtral s sensor bus Table 5 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 SES SES one 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 SENtral automatically checks the sensor bus after powering up or reseting to see if an EEPROM is connected on the sensor bus If an EEPROM is detected SENtral checks the first 2 bytes of the EEPROM file whic
14. SENtral s ball grid array 0 4 mm pitch and 0 26 mm ball diameter connections to these inner pins should be made with a via in pad design using microvias General CSP assembly guidelines for SENtral include A non solder mask defined NSMD land pattern is recommended Solder mask registration is critical and the correct solder mask opening dimension should be 50um either side of the copper pad The actual size of the copper pad should be between 80 and 100 of the diameter of the solder ball The copper layer thickness should 30 um or less The copper pads should be finished with Organic Solderability Preservative OSP coating such as ENTEK PLUS Cu 106A Standard epoxy glass PCB substrates are compatible High temperature FR4 is preferred over standard FR4 for improved package reliability PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 35 Figure 8 1 provides design parameters for a typical SENtral solder mask and pad pattern Copper Trace Width Pitch 0 4 mm Bump Height um 210 k y PCB Design Parameters y Solder Pad Width um Solder Mask Opening um Solder Pad Width Solder Mask Thickness um Solder Mask Opening Copper Trace Thickness um Solder Mask S C Copper Trace Copper Trace Width um Thickness Thickness T i Solder Mask PCB Substrate Copper Pad Figure 8 1 Typical Solder Mask and Land Pad Parameters A typical recommended solder reflow profile is given
15. T_RSTN Ep PNI Sensor Corporation SENtral Technical Data Sheet C30 C31 100nF 100nF BALUN amp AND ANTENNA MATCHING NETWORK C44 56pF 4 E Kl 5 pr da C46 1 5pF 15 1 2nH C32 100PF 100nF Doc 1018049 R02 Page 44 There are 2 sensor layouts shown on this page Only one should be used or the OEM may select a different sensor set and generate their own layout ST LSM9DS0 c10 10uF AKM AK8963C amp ST LSM330 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 45 2013 PNI Sensor Corporation All Rights Reserved Reproduction adaptation or translation without prior written permission is prohibited except as allowed under copyright laws Revised February 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 acceptance be free from defects in material and workmanshi
16. ace it back into Normal Operation PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 26 5 6 Troubleshooting This section provides guidance in troubleshooting SENtral and is divided into hardware related and software related errors 5 6 1 Hardware Related Error Conditions Possible indications of a hardware related problem are given below in Table 5 9 Table 5 9 Hardware Related Error Indications Register Name Address Error Indication 0 1 CPURest SENtral Configuration EES Ee File needs uploading See Section 5 1 2 1 EEUploadError Issue with SentralStatus 0x37 uploading from the dedicated EEPROM See Section 5 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 an external 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 and reloading the Configuration File 5 6 2 Software Related Error Conditions Possible indications of software related errors are given below in Table 5 10 Table 5 10 Software Related Error Indications Register Name Address Error Indication EventStatus 0x35 1 1 Error Non zero value indi
17. ating 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 scaled sensor data can be accessed during Normal Operation from the Results Registers as given in Table 5 6 Table 5 8 provides the registers associated with Pass Through State Table 5 8 Pass Through Registers Register Name Address Register Value 0 1 StandbyEnable AlgorithmControl 0x54 0 Disable Standby State 0 1 SENtral in Standby State AgonthnSigtus 0 88 0 SENtral not in Standby State 0 1 Enable Pass Through State A oe 0 Disable Pass Through State 0 1 SENtral in Pass Through State PESOS Ne DSE 0 SENtral not in 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 and returns SENtral to Standby State e Write 0x00 to the AlgorithmControl register This takes SENtral out of Standby State and normally will pl
18. cates sensor related error Check SensorStatus 0x36 sensors by communicating in Pass Through State See Table 5 11 3 1 Idle SENtral in Initialized or Unprogrammed SentralStatus 0x37 State ErrorRegister 0x50 Non zero value indicated an error See Table 5 12 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 27 If the SensorStatus register indicates a non zero value then the value provides additional information on the sensor that is causing a problem as given in Table 5 11 SensorStatus Table 5 11 SensorStatus Register Indications Register Name Address Error Indication r m m m 0 MagNACK 1 NACK from magnetometer 1 AccelNACK 1 NACK from accelerometer 2 GyroNACK 1 NACK from gyroscope 4 MagDevicelDErr 1 Unexpected DevicelD 0x36 from magnetometer 5 AccelDevicelDErr 1 Unexpected DevicelD from accelerometer 6 GyroDevicelDErr 1 Unexpected DevicelD from gyroscope 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 5 12 Table 5 12 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 EE driver physically bad sen
19. ction 5 3 1 If bit 0 the CPUReset bit is 1 see Section 5 3 2 If bits 2 3 4 or 5 the Results bits are 1 see Section 5 3 1 e Repeat steps c and d until new orientation data is not needed and or the host decides to enter a different state Note that 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 5 3 as information will be cleared for events that are not handled 5 3 1 Error In the event of an error SENtral will trigger an error interrupt and SENtral will enter Standby State See the Section 5 6 for recommendations on Troubleshooting and or reset SENtral by sending 0x01 to the ResetReq register at address Ox9B PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 23 5 3 2 CPUReset SENtral will report a CPUReset event after the ResetReq command has been issued and prior to uploading the Configuration File In this case SENtral is in Unprogrammed State and needs the Configuration File to be uploaded If a dedicated EEPROM is used to store the Configuration File then CPUReset shou
20. d 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 e Establish the quaternion or Euler angle output data rate where the output data rate equals GyroRate divided by QRateDivisor The default for QRateDivisor is 0x00 which is interpreted as 1 and results in the 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 default is 0x00 corresponding to quaternion 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 e Write Ox640A0F 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 G
21. dedicated EEPROM connected to SENtral s sensor bus Once the Configuration File is uploaded SENtral will move into Initialized state Once the initialization sequence is complete there are three states in which SENtral may reside Normal Operation Standby and Pass Through Figure 5 2 indicates the recommended way to get from one state to another and these states are discussed in detail in Sections 225 3 Normal Operation 5 4 Standby and 5 5 Pass Through Standby Pass Through Request Request Normal Standby Pass Through Operation Standby State Pascmeugh State Done Done Figure 5 2 SENtral Operational States 5 1 Power Up and Configuration File Upload After powering up or issuing a ResetReq command SENtral automatically initializes the registers and then looks for an EEPROM on the sensor bus as indicated in Figure 5 1 The Configuration File must now be uploaded This file contains information on how the sensor system is configured in the user s system and is generated with the SENtral Configuration Tool as discussed in Section 6 It can be stored in non volatile memory in the host CPU or in a dedicated EEPROM The primary advantages of using a dedicated EEPROM are freeing up host processor memory and minimizing the time from powering up until the upload is complete The advantages of using the host CPU s memory are no additional cost and no additional system footprint requirement If a dedicated EEPRO
22. ed EEPROM Optional A crucial step in using the SENtral coprocessor is uploading the SENtral Configuration File into SENtral s RAM This file contains information on how the sensor system is configured in the user s system and is generated with the SENtral Configuration Tool as discussed in Section 6 The Configuration File can be manually uploaded from non volatile memory in the host CPU or automatically uploaded from a dedicated EEPROM The primary advantages of using a dedicated EEPROM are freeing up host processor memory and minimizing the time from power up until the upload is complete The advantages of using host CPU memory are no additional cost and no additional system footprint requirement If implementing a dedicated EEPROM connect it to SENtral as a slave device on the sensor bus in parallel with the sensors shown in Figure 3 1 The EEPROM upload rate should be set with the SENtral Configuration Tool see Section 6 1 3 Faster is generally better although the sensor bus rate is limited to 1 Mb sec Writing the Configuration File onto the EEPROM can be accomplished either using an EEPROM programmer or by writing to the EEPROM from the host while SENtral is in Pass Through State The primary EEPROM requirements are e 2320 Kbit 40 Kb x 8 bits of memory e Shifted address of OxAO OxA2 OxA4 OxA6 OxA8 or OxAA Unshifted address of 0x50 0x52 0x54 0x56 0x58 or Ox5A The following devices have been used with SENtral but
23. el Table of Contents 1 PRODUCT OVER II 3 1 1 SENTRAL FEATURES AND BENEFITS een 3 1 2 SENTRAL FUNCTIONAL DESCRIPTION en 4 2 SENTRAL SPECIFICATIONS eeeseeeeee enne enenenenenenenenenenenenenenenenenenenenenen 6 2 1 PERFORMANCE CHARACTERISTICS eese 6 2 2 ELECTRICAL CHARACTERISTICS eenen nnne 6 3 W xdollyme sau vaa ade ea rd rd ka 8 3 1 SYSTEM LAYOUT preirata da daa naga rg ua na Fas ru ada ha fate asa ud do daniels 8 3 2 PIN ASSIGNMENCTS ena te ronsreigrersienstonetene aa aa EENEG EENEG 9 3 3 SENSOR LAYOMLJT 5a tard pasan ava sa capa sas dad da daa und haddde daa d add 10 3 4 DEDICATED EEPROM OPTIONAL esee 11 4 IG INTERFACE ee 12 4 1 PO NMNG a EE 12 4 2 DC HOST INTERFACE HOST BUG EE 13 421 PC Slave Transfer formats mett se EVEN 14 4 3 IC SENSOR INTERFACE SENSOR BUS 15 4 4 C PULL UP RESISTANCE EE 15 5 OPERATION exire doccocn ncc nc dd rue 16 5 1 POWER UP AND CONFIGURATION FILE UPLOAD een 17 5 1 1 Configuration File Upload from EEPROM esee 17 5 1 2 Configuration File Upload from Host 19 5 2 INITIAL REGISTER SET UP eenen ennen eneen en enenen nnn 20 5 3 RUNNING IN NORMAL OPERATION eenen en 22 Od EE 23 ise EE HERE Eege eege ees ees 24 5 3 3 Read hesults eic ereetesret rtr ere tau n ei co ava eie agendae eva Aon 24 5 4 STANDBY STATE ipee tacos vate ee tu tati va detur mnu ca va oade laan Rave vd vada aa d a da 25 5 5 PASS THROUG
24. eneen nn eneenenenseerenenneerrnenseeenn ennen 20 Table 5 4 Registers for Initial Set Up nnee ennen enenenenneerenerreneennnenenneenenvenn 20 Table 5 5 Normal Operation Registers essent 23 T bl 5 6 Results Hegisters unne teneerste AE 24 Table 5 7 Standby Registers tette abt Fer d eae ta ent ene eenden 25 Table 5 8 Pass Through Registers eite tenen EE rrt eee Fen tee nea teta 26 Table 5 9 Hardware Related Error Indications nennen ennen vennen ennen nennen 27 Table 5 10 Software Related Error Indications sese 27 Table 5 11 SensorStatus Register Indications sese 28 Table 5 12 ErrorRegister Indications nnnneeneneneenensereenensereenenseeeenenseneenenseneenensene 28 Table 8 1 Typical Solder Processing Parameters sss 37 Table A1 1 Configuration File Image Format 38 Table A1 2 Configuration File Data Structure snoer enneeeenenseerenenneerenenseeern ennen 39 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 2 1 Product Overview The SENtral Motion Coprocessor is an integrated circuit that makes it easy to quickly integrate optimize and operate multiple sensors on mobile consumer electronics devices SENtral manages and uses data from a user specified 3 axis gyroscope 3 axis accelerometer and 3 axis magnetometer to provide reliable motion tracking and an accurate compass heading while consuming ab
25. equested gyroscope output data rate divided by 10 QRateDivisor AlgorithmControl EnableEvents PNI Sensor Corporation SENtral Technical Data Sheet 0x32 0x54 0x33 Along with GyroRate establishes output data rate for 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 Scaled sensor data 2 HPRoutput 1 Heading pitch and roll output in QX QY amp QZ QW 0 0 0 Quaternion outputs 1 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 6 Reserved 7 Reserved Doc 1018049 R02 Page 20 Perform the following e 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 Ox1E 304 OxOA 104 and 0x14 204 o The actual accelerometer and gyro ODRs are limited to the ODRs supporte
26. guration File image as discussed in Appendix I Configuration File Image Format The file is sent one byte at a time using the UploadData register Data can be burst uploaded Each group of 4 bytes should be sent in byte reverse order i e little Endian format Table 5 3 provides an example PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 19 Byte Order in Config File Image Table 5 3 Sample Host Upload Data Order i i 1 i 2 i 3 i 4 i 5 i 6 i 7 Config File Image Example 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 Byte Order During Host Upload 3 i 2 i 1 i i 7 i 6 i 5 i 4 Example Bye Sent during Upload 0x04 0x03 0x02 0x01 0x08 0x07 0x06 0x05 e Read the CRCHost register Compare this to the host calculated CRC 32 to confirm a successful upload e After the reset write value 0x00 to the HostControl register which clears the HostUpload bit and places SENtral in Initialized State 5 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 5 4 Register Name MagRate Address 0x55 Table 5 4 Registers for Initial Set Up Register Value Requested magnetometer output data rate AccelRate 0x56 Requested accelerometer output data rate divided by 10 GyroRate 0x57 R
27. h Level Output Current Von Vpp 0 3V lou 1 mA Low Level Output Current Vo 0 3V lov 1 mA TE Current Normal Operation 100 300 HA Consumption Pass Through State 45 uA 18 Vos Standby State 7 uA Host Bus 3400 kbits sec C Interface Data Bate Sensor Bus 1000 kbits sec Pass Through 400 kbits sec Decoupling Capacitor ESR lt 20 Creg 0 33 0 5 1 8 uF Operating Temperature Top 40 25 85 C Footnotes Doc 1018049 R02 Page 7 3 Layout 3 1 System Layout Figure 3 1 provides a basic reference schematic for connecting SENtral with the host system and the various sensors AGND DRDY Gyroscope HH G dei a TT Figure 3 1 SENtral System Reference Schematic A few points on system layout SENtral communicates with the sensors as the master via a dedicated DC sensor bus The layout shows a discrete magnetometer accelerometer and gyroscope SENtral also works with combo sensors such as a single 9 axis sensor or a combo gyro accel with a discrete magnetometer SENtral acts as a slave on the host system s PC bus This does not need to be a dedicated bus although it is shown this way in the schematic SAO establishes SENtral s slave address when communicating with the host It is shown set to ground but can be set HIGH instead See Section 4 2 The pull up resistance on the FC lines depends on the number of devices on the bus and the bus speed Normally 4 7 kQ is appropriate for Standard or Fast modes l
28. h are fixed for all SENtral Configuration Files and if these match then it automatically uploads the SENtral Configuration File Once the upload is complete SENtral enters Initialized State and waits for instructions from the host If an EEPROM is not detected SENtral enters Unprogrammed State The host should confirm a successful EEPROM upload by following the steps below Read the value from the SentralStatus register Check bit 0 the EEPROM bit to ensure an EEPROM is detected by SENtral 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 try the following Reinitialize SENtral and retry the process Send a Reset command by writing 0x01 to the ResetReq register Upload the Configuration File from the host as discussed in the next section Download the Configuration File from the EEPROM and verify its contents as given in Appendix I Configuration File Image Format Reload the Configuration File from the host into the EEPROM PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 18 5 1 2 Configuration File Upload from Host If an EEPROM is not used for storing the Configuration File then SENtral will enter Unprogrammed State after failing to
29. identify an EEPROM The host now should upload the Configuration File from host memory The registers involved are given below Table 5 2 Configuration File Host Upload Registers Register Name Address Register Value 0 1 RunEnable HostControl 0x34 SNE S 1 1 HostUpload Enable UploadAddr 0x94 to 0x95 Initial RAM address 0x0000 UploadData 0x96 Data to be uploaded CRC32 of the uploaded data since Globe DET OLE host upload was enabled ResetReq 0x9B 0 1 Reset SENtral To upload the Configuration File from the host perform the following transactions e Write value 0x01 to the ResetReq register This results in a hard reset of SENtral This is unnecessary if SENtral has just been powered up or Reset e Verify the Configuration File image as given in Appendix I Configuration File Image Format Specifically o Ensure the Magic Numbers are correct o Ensure the Uploaded Image Length matches the Uploaded Firmware Image Size o Ensure the Upload Image Length is a multiple of 4 bytes e Write 0x02 to the HostControl register This sets the UploadEnable bit which enables uploading of the Configuration File e Write the initial RAM address 0x0000 into the UploadAddr register This normally is an unnecessary operation since the default after powering up or sending a ResetReq is 0x0000 e Upload the Configuration File to SENtral s program RAM This represents the range from 0x10 to 0x10 UIL 1 in the Confi
30. ing 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 1018049 R02 SENtral Technical Data Sheet Page 46
31. ion 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 O 0 707 0 707 E Qz Qw Qx Qy 0 0 0 707 0 707 C 0 707 0 707 0 d Qy Qx Qw Qz 0 707 0 707 0 0 Qx Qy 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 e Heading atan2 Qx Qy Qz Owi 2 QxQy QzQw e Pitch asin 2 QxQz QyQw e Roll atan2 Qx Qy Qz Qw 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 clockwise and the range is 90 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 40 Rotation Vector
32. ite Example The FC host interface supports both a read sequence using repeated START conditions shown in Figure 4 3 and a sequence in which the register address is sent in a separate sequence than the data shown in Figure 4 4 and Figure 4 5 START SLAVE ADDRESS RW ACK REGISTER ADDRESS N ACK START SLAVE ADDRESS RW ACK DATA FROM REGISTER N NACK STOP BB ve 4p o M NN Data Transferred n bytes acknowledge Figure 4 3 FC Slave Read Example with Repeated START START SLAVE ADDRESS RW ACK REGISTER ADDRESS N ACK STOP BESSER ROESER eee EN MO Figure 4 4 FC Slave Write Register Address Only START SLAVE ADDRESS RW ACK DATA FROM REG N ACK DATA FROM REG N 1 NACK STOP S A6 A5 A4A3 A2A1 A0 1 0 D7D6 D5 D4D3 D2 D1 DO 0 D7D6 D5 DA4D3 D2 D1 DO 1 p From Host to SENtral From SENtral to Host Figure 4 5 FC Slave read register from current address PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 14 4 3 TC Sensor Interface Sensor Bus SENtral communicates with the accelerometer gyroscope and magnetometer over the sensor bus where SENtral acts as the FC master and the sensors act as the DC slaves On the sensor bus SENtral initiates data transfer and generates the serial clock SENtral s FC sensor interface supports Standard mode with a rate up to 10
33. ld not be encountered as the Configuration File is automatically uploaded 5 3 3 Read Results The Results Registers addresses formats and full scale ranges are given below in Table 5 6 For an explanation of how to convert quaternions to the rotation vector the rotation matrix or heading pitch and roll Euler angles see Appendix II Converting Quaternions The resolution is 32 kHz for all timestamps Note AU 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 C bus Table 5 6 Results Registers EE Description Format Full Scale Range QX 00 03 Normalized Quaternion X or Heading Float32 0 0 1 0 or x QY 04 07 Normalized Quaternion Y or Pitch Float32 0 0 1 0 or 7 2 QZ 08 0B Normalized Quaternion Z or Roll Float32 0 0 1 0 or x QW OG OF Normalized Quaternion W or 0 0 Float32 0 0 1 0 QTime 10 11 Quaternion Data Timestamp Ulnt16 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 Ulnt16 0 2048 msec AX 1A 1B Linear Acceleration X Axis or Raw Accel Data I
34. nal information http www nxp com documents user_manual UM 10204 pdf PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 15 5 Operation Figure 5 1 provides a flow chart of the initialization process and a detailed discussion of the initialization process follows in Section 5 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 C bus Power Up Watchdog Reset or I2C ResetReq Automatic Register Initialization EEPROM Detected Unprogrammed State Automatic EEPROM Host Uploads Configuration Upload of f File from Host Configuration RAM File Initialized State Set Sensor ODR amp EnableEvent Registers Run Enable Normal Operation Figure 5 1 SENtral Initialization Sequence PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 16 Prior to running SENtral the Configuration File must be uploaded into SENtral s Configuration RAM This file contains information regarding how the user s sensor system is configured such as sensor models sensor slave addresses GPIO pin assignments etc The Configuration File is generated with the SENtral Configuration Tool as discussed in Section 6 It may be stored in the host processor s non volatile memory or in a
35. nning Host Receives Interrupt from Sentral Host Reads EventStatus Register EventStatus Error Handle Error EventStatus CPUReset Initialize Sentral ventStatus Quaternion or Sensor Result Exit Interrupt Routine Figure 5 3 SENtral Normal Operation Flow Read Results PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 22 Table 5 5 Normal Operation Registers Register Name Address Register Value 0 1 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 0x01 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 d Interpret and act on the EventStatus register in the priority shown in Figure 5 3 If bit 1 the Error bit is 1 see Se
36. nt16 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 Ulnt16 0 2048 msec GX 22 23 Rotational Velocity X 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 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 24 5 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 5 7 provides the registers associated with Standby State Table 5 7 Standby Registers Register Name Address Register Value 0 1 StandbyEnable AlgorithmControl 0x54 0 Disable Standby State 0 1 SENtral in Standby State Agonthm status oe 0 SENtral not in Standby State The steps to enter and exit Standby State are given below e Write 0x01 to the AlgorithmControl register This places SENtral in Standby State e Read the AlgorithmStatus register If bit 0 is 1 then SENtral is in Standby State This step is optional e When you are ready to exit Standby State write 0x00 to the Algori
37. od 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 of the possibility of any such damages includ
38. out 1 of the power of a comparable sensor fusion microprocessor Note This revision of the SENtral Technical Datasheet applies to Configuration Files of revision 1 1 or higher The Configuration File is discussed in Sections 1 2 5 1 6 and Appendix I It is generated by the SENtral Configuration Tool and is uploaded into SENtral RAM after power up 1 1 SENtral Features and Benefits Features and benefits of the SENtral Motion Coprocessor include e Low power consumption Offloads sensor processing from the less efficient host CPU consuming lt 1 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 e Industry leading heading accuracy Unparalleled heading accuracy for consumer electronics applications e Continuous hard and soft iron magnetic auto calibration Provides continual background calibration of the sensors Leverages PNI s more than 20 years of experience and expertise in magnetic measurement e Magnetic anomaly compensation Heading and motion tracking is unaffected by magnetic anomalies such as rebar in buildings desks speakers etc that can easily throw off the accuracy SENtral recognizes and compensates for these anomalies e Sensor flexibility Works with common consumer electronic MEMS motion sensors so system designers can choose the sensors most appropriate for their systems e Small form fac
39. p 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 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 peri
40. r EEPROM upload Bits 8 to 10 l2CClockSpeed 000 1 Mbit s 001 833 kbit s 010 400 kbit s 011 333 kbit s 100 100 kbit s Others 83 kbit s Bits 11 to 14 ROMVerExp 0001 version 0x7A8 0010 version OX9E6 0x04 to 0x07 CRC32 of uploaded image Stored in Little Endian Format 0x08 to OxOB Reserved 0x00000000 0x0C amp 0x0D Uploaded Image Length UIL Stored in Little Endian Format OxOE amp OxOF Reserved 0x0000 0x10 to Uploaded Image Instructions amp CRC32 is calculated over 0x10 UIL 46 Configuration File Data uploaded image 0x10 UIL 45 to Uploaded Image Config File 0x10 UIL 1 Data Structure See Table A1 2 PNI Sensor Corporation SENtral Technical Data Sheet Doc 1018049 R02 Page 38 Table A1 2 Configuration File Data Structure Byte Index Content Note 0x00 Signature Lower Byte Value is 0x8B Can be used to locate the data structure within the image 0x01 Signature Upper Byte Value is OxC8 Can be used to locate the data structure within the image 0x02 to 0x07 Reserved 0x08 amp 0x09 RAM Version Firmware version number 0x0A Version Configuration Structure Version 0x0B Boot Protocol Used for standalone applications 0x0C to 0x13 PinSelection Bit 0 3 Host IRQ pin selection Others reserved 0x14 to Ox1B PullSelection Bit 0 amp 1 GPIOO pull selection O no pulls 1 pull down 2 pull up 3 keep defaults Bit 2 amp 3 GPIO1 pull selection Bit 4 amp 5 GP
41. rmware to be generated Normally the latest revision is most desirable but prior revisions are retained for customers that have qualified older revisions 6 1 2 Host Interrupt Pin This establishes which GPIO pin is used to send an event interrupt to the host system The default is GPIO 6 but any of the GPIO pins can be used for this function 6 1 3 EEPROM Max Upload Speed If the user incorporates a dedicated EEPROM to store the SENtral s Configuration File then this field establishes the maximum data rate the configuration EEPROM can accommodate If there is no EEPROM this setting has no meaning SENtral automatically determines if a dedicated EEPROM is present 6 2 Configuration Tool Sensor Configuration The sensors attached to SENtral must be configured correctly for SENtral to properly function The magnetometer accelerometer and gyroscope are configured in a similar manner so the parameters discussed below apply to all three sensors 6 2 1 Sensor The drop down menus are used to select the sensor models incorporated into the user s system If a sensor is not listed then a driver has not been developed for that sensor 6 2 2 Interrupt Pin This drop down menu establishes which General Purpose IO pin is used to send a sensor interrupt signal to SENtral As shown in the reference schematic Figure 3 1 the default is to use GPIO 0 for the magnetometer GPIO 1 for the accelerometer and GPIO 2 for the gyroscope However
42. rom the magnetic anomaly determination and continuous auto calibration blocks to generate intelligent orientation updates The Kalman update involves a sophisticated multi state Kalman algorithm Continuous Hard and Soft Iron Auto Calibration SENtral is the only product in the market that auto calibrates for both hard iron and soft iron magnetic distortions While others may calibrate for hard iron distortion soft iron distortion is more difficult to correct for and it can be caused by EMI shielding tape and other shielding materials widely used in mobile and consumer electronic devices It is important to correct for soft iron distortions since these can contribute up to 90 of error Additionally since a host system s magnetic signature can change over time and temperature SENtral s continuous auto calibration ensures accuracy all the time PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 4 e Magnetic Anomaly Determination establishes if a transient magnetic distortion is present and accounts for it e Configuration RAM allows for customizing SENtral to match the specific sensors being used and allows the user to tailor certain parameters for their specific system The SENtral Configuration Tool generates the SENtral Configuration File and this is subsequently uploaded into SENtral s Configuration RAM e Pass Through allows for direct communication with devices on the sensor bus by connecting SENtral s DC Ho
43. sor 0x22 Accelerometer initialization failed connection or incorrect lC device 0x24 Gyroscope initialization failed address in the driver d Magnetomater rate failure This error indicates the given sensor 0x12 Accelerometer rate failure is unreliable and has stopped 0x14 Gyroscope rate failure producing Gate PNI Sensor Corporation SENtral Technical Data Sheet Doc 1018049 R02 Page 28 6 SENtral Configuration Tool Before using the SENtral Motion Coprocessor the SENtral Configuration File must be generated using the SENtral Configuration Tool As discussed in prior sections the Configuration File contains information on how the sensor system is configured in the user s system To access the SENtral Configuration Tool go to http www sentraltoolkit com The tool is for SENtral customers and registration is required Registration requests are reviewed at PNI Typically it takes less than one business day to activate a registration request The SENtral Configuration Tool provides an intuitive GUI which allows the user to easily generate the Configuration File A screen shot of the tool is given in Figure 6 1 and a discussion of the settings follows Once the various fields are correctly populated click lt Generate gt to create the SENtral Configuration File A zip file will automatically download onto your computer containing the Configuration File sentral rev mag accel gyro fw and a cfg file providing
44. ssseeeeee 8 Figure 4 1 c Timing Diagr m mva ae 12 Figure 4 2 TE Slave Write Examyple ctetu tttm nk oet ck conde dc EE 14 Figure 4 3 I C Slave Read Example with Repeated START 14 Figure 4 4 I C Slave Write Register Address Only nanne eenen 14 Figure 4 5 I C Slave read register from current address 14 Figure 5 1 SENtral Initialization Geouence sse 16 Figure 5 2 SENtral Operational States nnne 17 Figure 5 3 SENtral Normal Operation Flow nennen 22 Figure 6 1 SENtral Configuration Togo 29 Figure 7 1 Mechanical Drawing eene nennen 33 Figure 7 2 Tape Dimensions eseseeeseseseseessseeeeeen eene enne nnne nennen nennt entente nn 34 Figure 8 1 Typical Solder Mask and Land Pad Parameters sss 36 Figure 8 2 Typical Solder Reflow Profile 37 List of Tables Table 2 1 Performance Characteristics enne 6 Table 2 2 Absolute Maximum Ratings eeseeeeenene nennen ener 6 Table 2 3 Operating Conditions 7 Table 3 1 SENtral Pin Assignments sss nennen nennen nnne nen 9 Table 3 2 Recommended Power Line Distance from Magnetometer 11 Table 4 1 IC B ll else ut 13 Table 4 2 IC Pull Up Resistance Table enne 15 Table 5 1 Configuration File Upload from EEPROM Registers nnee ennen 18 Table 5 2 Configuration File Host Upload Registers sseeeene 19 Table 5 3 Sample Host Upload Data Order nnn aaan
45. st Interface to the Sensor Interface e Host Interface communicates with the host system Data is transmitted between the host and SENtral via the host IC bus in which the host acts as the master and SENtral acts as a slave device SENtral signals the host that new data is available by sending an interrupt signal on the host DRDY line e Sensor Interface communicates primarily with the sensors Sensor data is transmitted from the sensors to SENtral via the sensor C bus in which SENtral acts as the master and the sensors as the slave devices PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet 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 Voo 0 3 3 6 VDC Input Pin Voltage Vin GND 0 3 Vpp 0 3 VDC pem Human Body Model HBM 2000 2000 V Machine Model MM 200 200 V Storage Temperature 50 150 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
46. supply Connections I Digital Input IO Digital Input Output PU Pull Up PD Pull Down PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 9 3 3 Sensor Layout SENtral provides for considerable flexibility in sensor orientation and layout but there are some basic requirements as given below e All three axes of a sensor must be orthogonal to each other This is by design for most accelerometers gyroscopes and magnetometers e A sensor s X axis and Y axis should act parallel to the primary plane of the motherboard A sensor s Z axis should act perpendicular to the primary plane e Either a sensor s X axis or Y axis should align parallel to the line of sight of the motion tracking device e Itis NOT necessary that the gyroscope accelerometer and magnetometer have their same axis sensors i e all X axis sensors point in the same direction since sensor orientation is configured when running the SENtral Configuration Tool and stored in the SENtral Configuration File Assuming the Orientation Matrix is properly input in the SENtral Configuration Tool SENtral will output data conforming to a North East Down NED convention To convert to East North Up ENU see Appendix II Converting Quaternions In addition to the requirements listed above other recommendations regarding sensor layout are given below These represent good practices but are not mandatory e Accelerometer o Locate the accelerome
47. t and the z axis points down Recall that north is defined as the line of sight or direction of travel In this case the orientation matrix is the identity matrix as given below omz H oo oo oo omz Another common convention is east north up ENU where the x axis points east the y axis points north and the z axis points up in which case the orientation matrix and associated matrix math are given below N 0 1 OLIE E 11 0 Of IN D 0 0 1 U PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 31 The final example is west south down WSD This matrix would be appropriate for an ENU accelerometer since it incorporates the 1 multiplication factor The orientation matrix and associated matrix math are given below W omz O O 1 0 0 OIS 0 1 D 6 2 5 Cal Offsets Normally these fields will be 0 However if the user has information indicating a given model of sensor consistently has a fixed measurement offset then these fields allow the user to tailor the SENtral algorithm For example assume statistical data from a manufacturer regarding their accelerometer indicates their z axis sensor has an average reading of 1 1 g when actually experiencing 1 0 g of gravitational force In this case the user can enter an offset on the z axis of 0 1g for the accelerometer The fields are given in X Y Z order and the units are as follows e Magnetometer 1 0 50 uT e Accelerometer 1 0 41g e
48. t 400 kbit sec See Section 4 4 There are three dedicated sensor interrupt lines between the sensors and SENtral and one interrupt line between the host and SENtral The default GPIO assignments are shown but these can be altered with the SENtral Configuration Tool See Section 6 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 8 3 2 Pin Assignments SENtral s pin out is a 4x4 ball grid array as defined in Figure 7 1 The table below provides the pin assignments Table 3 1 SENtral Pin Assignments Pin Pin Name I O Type Description D1 Von PWR Supply voltage D3 VCAP PWR SE capacitor for internal core D2 GND PWR Ground C3 SA0 FC slave address bit 0 Bi SCLs IO IG host bus SCL clock line A1 SDAs lo IC host bus SDA data line B4 SCLy IO IG sensor bus SCL clock line A4 SDAu IO C sensor bus SDA data line D4 GPIO 0 IO PUPD General Purpose IO Default mag interrupt C4 GPIO 1 IO PUPD General Purpose IO Default accel interrupt A3 GPIO 2 IO PUPD General Purpose IO Default gyro interrupt B3 GPIO 3 IO PUPD General Purpose IO Default not connected A2 GPIO 4 IO PUPD General Purpose IO Default not connected B2 GPIO 5 IO PUPD General Purpose IO Default not connected C1 GPIO 6 IO PUPD General Purpose IO Default host interrupt C2 RES Not Used Connect to Ground VO Types are PWR Power
49. ter near the expected center of rotation of the device to minimize rotational accelerations being interpreted as linear accelerations e Magnetometer o Locate the magnetometer gt l cm away from magnetic sources hard iron such as speaker magnets or known magnetized metals If uncertain about whether a component is a magnetic source check it with a Gauss meter if possible o For non magnetic components try to avoid placing wireless antenna power capacitors inductors ferrite beads and components using ferromagnetic materials Fe Co Ni within 1 cm of the magnetometer Examples of components in a cell phone which typically contain ferromagnetic materials are the memory card slot battery frame electrical and magnetic noise shields connectors and hinges o Materials that are magnetically transparent and thus relatively safe include aluminum gold titanium copper brass and magnesium Most stainless steel alloys have relatively weak magnetic properties and are not as safe as those just listed but don t need as much attention as ferromagnetic materials Locate high frequency signal lines away from the magnetometer Locate power lines away from the magnetometer per the table below PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 10 Table 3 2 Recommended Power Line Distance from Magnetometer Recommended Distance mm Current mA 2 0 2 10 1 50 5 100 10 200 20 3 4 Dedicat
50. the data input into the Configuration Tool The cfg file can be opened with a text editor Additionally the cfg file can be uploaded into the Configuration Tool by clicking lt Load Config gt and then selecting the desired cfg file The GS and M amp M Configuration link opens a pop up window with the configurations for the various SENtral M amp M and GS modules PNI Sensor Corporation Inr x Sentral Configuration Tool x WN C O www sentraltoolkit com Cj unfiled CJ Market Research 7 Sensor Companies 3 Other bookmarks SEN a SENSOR FUSION COPROCESSOR General Settings Magnetometer Configuration SDK Revision Select Sensor Select Host Interrupt Pin GPIO B Interrupt Pin GPIO O EEPROM Max Upload Speed 100 kHz T bit Slave Address Select Orientation Matrix 1 D 1 0 a 0 a Cal Offsets Accelerometer Configuration Gyroscope Configuration Sensor Select Sensor Select Interrupt Pin GPIO 1 v Interrupt Pin GPIO 2 T bit Slave Address Select T bit Slave Address Select Orientation Matrix Orientation Matrix 1 0 0 1 0 1 1 0 lo 0 lo Cal Offsets 0 D Cal Offsets o 0 Generate Load Config GS and M amp M Configurations Figure 6 1 SENtral Configuration Tool PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 29 6 1 Configuration Tool General Settings 6 1 1 SDK Revision This establishes the revision of the fi
51. thmControl 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 5 5 Pass Through State SENtral can be configured so the host communicates directly with devices on the sensor bus by placing SENtral into Pass Through State In Pass Through State SENtral s sensor and host interfaces are connected by internal switches so the host system communicates directly with the sensors and or dedicated EEPROM To enter Pass Through State SENtral first should be in either Standby Initialized or Unprogrammed 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 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 25 Uses for the Pass Through State include e Direct control of sensors if desired e 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 Since oper
52. tor 1 6x1 6x0 5 mm chip scale package on 0 4 mm pitch Uses little PCB real estate allowing for painless integration e IC interface Uses the industry standard DC protocol 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 e Outputs SENtral outputs quaternions Euler angles heading pitch amp roll and sensor data rotational velocity linear acceleration amp magnetic field PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 3 1 2 SENtral Functional Description Figure 1 1 provides a diagram of SENtral s primary functional blocks and a brief description of these functional blocks follows Sensor 12C Bus Quaternion Host I2C Bus o DRDY from Gyro 8 Kalman Update _ Configuration 8 DRDY to Host DRDY from Accel i RAM 5 DRDY from Mag o z 5 I Availale GPIO SS Continuous Magnetic Anomaly Available GPIO Auto Calibration Determination Available GPIO Pass Through z 3 VCAP SA0 RES Figure 1 1 SENtral Block Diagram Quaternion generates the orientation output where the actual orientation outputs can be quaternions or Euler angles heading pitch amp roll The outputs are updated at a rate limited to the gyro output data rate ODR to a maximum of 400 Hz Kalman Update fuses data from the 3 axis gyroscope 3 axis accelerometer and 3 axis magnetometer plus data f
53. yroRate to 150 Hz e Write 0x01 to the QRateDivisor Register This sets the quaternion output data rate to equal the GyroRate For writing 0x01 this step is optional since the default also 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 PNI Sensor Corporation Doc 1018049 R02 SENtral Technical Data Sheet Page 21 e Write 0x07 to the EnableEvents register This sets up the host to receive interrupts from SENtral whenever the quaternion results registers are updated an error has been detected or when SENtral needs to be reset 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 a 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 the CalStatus MagTransient and AlgorithmSlow bits become undefined 5 3 Running in Normal Operation After performing the steps listed above SENtral is ready to start generating orientation data Below is a flow diagram for Normal Operation followed by the pertinent registers and then the steps to follow when ru

SENtral

Contents

Download Pdf Manuals

Related Search

Related Contents