SCA31X0

SCA8X0/21X0/3100 Series Product Family Specification VTI Automotive Digital Accelerometer Platform SCA8X0 / 21X0 / 31X0 Accelerometers SCA8X0/21X0/3100 Series TABLE OF CONTENTS Table of Contents .....................................................................................................................2 General Description..................................................................................................................5 1.1 1.2 1.3 1.4 Introduction ................................................................................................................................5 Features ......................................................................................................................................5 Typical applications...................................................................................................................6 Functional Description ..............................................................................................................6 Sensing element ...................................................................................................................................6 Interface IC............................................................................................................................................6 Capacitance to voltage conversion.......................................................................................................6 Analog to digital conversion ..................................................................................................................7 Signal conditioning and filtering ............................................................................................................7 Temperature measurement ..................................................................................................................7 Memory .................................................................................................................................................7 SPI ........................................................................................................................................................7 Self diagnostics.....................................................................................................................................7 Power supply interface..........................................................................................................................7 Factory calibration.................................................................................................................................7 1.4.1 1.4.2 1.4.3 1.4.4 1.4.5 1.4.6 1.4.7 1.4.8 1.4.9 1.4.10 1.4.11 2 Operation Modes .................................................................................................................8 2.1 2.2 2.3 Measurement mode ...................................................................................................................8 Temperature output ...................................................................................................................8 Self-diagnostic functions ..........................................................................................................8 2.3.1 Memory self-diagnostic .........................................................................................................................8 2.3.2 Signal path self-diagnostic ....................................................................................................................8 2.3.2.1 SCA8X0 – single axis accelerometers ..........................................................................................8 2.3.2.2 SCA21X0 and SCA31X0 – multi axis accelerometers ..................................................................8 2.4 2.5 2.6 2.7 Power Down mode.....................................................................................................................9 Recommended start-up sequence ...........................................................................................9 Recommended operation sequence ......................................................................................10 Recommended procedures or optional features ..................................................................11 2.7.1 SCA8x0/SCA21x0/SCA31x0 ..............................................................................................................11 2.7.1.1 Read back procedure ..................................................................................................................11 2.7.1.2 Checksum during operation.........................................................................................................11 2.7.1.3 Saturated data .............................................................................................................................11 2.7.1.4 Noiseless output ..........................................................................................................................11 2.7.1.5 Component ID..............................................................................................................................11 2.7.2 SCA8x0 ...............................................................................................................................................11 2.7.2.1 Mass deflection during operation.................................................................................................11 2.7.2.2 Monitor acceleration data during mass deflection .......................................................................12 3 Addressing Space .............................................................................................................12 3.1 Output registers .......................................................................................................................12 3.1.1 X axis acceleration output...................................................................................................................12 3.1.1.1 X_LSB..........................................................................................................................................12 3.1.1.2 X_MSB.........................................................................................................................................13 3.1.2 Y axis acceleration output...................................................................................................................13 3.1.2.1 Y_LSB..........................................................................................................................................13 VTI Technologies Oy www.vti.fi 2/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 3.1.2.2 Y_MSB.........................................................................................................................................13 3.1.3 Z axis acceleration output ...................................................................................................................13 3.1.3.1 Z_LSB ..........................................................................................................................................13 3.1.3.2 Z_MSB .........................................................................................................................................13 3.1.4 Output data conversion.......................................................................................................................14 3.1.4.1 2g products ..................................................................................................................................14 3.1.4.2 6 g products .................................................................................................................................15 3.1.4.3 1 g products .................................................................................................................................15 3.1.5 Temperature output ............................................................................................................................15 3.1.5.1 Temperature Register Low (TEMP_LSB)....................................................................................15 3.1.5.2 Temperature Register High (TEMP_MSB) ..................................................................................16 3.1.6 Status Register (STATUS)..................................................................................................................17 3.1.7 Interrupt Status Register (INT_STATUS) ...........................................................................................17 3.2 Operation control registers.....................................................................................................18 Control Register (CTRL) .....................................................................................................................18 Reset Register (RESET).....................................................................................................................19 Revision ID (REVID) ...........................................................................................................................19 Component ID (ID)..............................................................................................................................19 3.2.1 3.2.2 3.3 Identification registers ............................................................................................................19 3.3.1 3.3.2 4 SPI Interface ......................................................................................................................20 4.1 Output of Acceleration Data ...................................................................................................21 Register read operation ......................................................................................................................22 Decremented register read operation .................................................................................................22 MOSI data of SPI commands .............................................................................................................23 FRME-bit .............................................................................................................................................23 PORST-bit...........................................................................................................................................23 ST-bit (SCA21X0 / 3100) ....................................................................................................................24 SAT-bit (SCA21X0 / 3100)..................................................................................................................24 aPAR-bit (SCA21X0 / 3100) ...............................................................................................................24 dPAR-bit..............................................................................................................................................25 Fixed bits.............................................................................................................................................25 Output data .........................................................................................................................................25 4.1.1 4.1.2 4.1.3 4.2 Error Conditioning ...................................................................................................................23 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6 4.2.7 4.2.8 5 Electrical Characteristics .................................................................................................26 5.1 5.2 5.3 Absolute maximum ratings.....................................................................................................26 Power Supply ...........................................................................................................................26 Digital I/O Specification...........................................................................................................26 DC Characteristics ..............................................................................................................................26 AC Characteristics ..............................................................................................................................26 5.3.1 5.3.2 6 Application information ....................................................................................................28 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Package dimensions ...............................................................................................................28 Output to Angle Conversion ...................................................................................................29 Measuring Directions ..............................................................................................................30 Pin Description.........................................................................................................................31 Recommended circuit diagram ..............................................................................................31 Recommended PWB layout ....................................................................................................32 Assembly instructions ............................................................................................................34 VTI Technologies Oy www.vti.fi 3/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 6.8 Tape and reel specifications...................................................................................................34 7 Contact Information ..........................................................................................................35 8 Document Change Control...............................................................................................36 VTI Technologies Oy www.vti.fi 4/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series General Description 1.1 Introduction VTI Automotive Digital Accelerometer Platform is an accelerometer product concept based on VTI capacitive 3D-MEMS technology. The VTI ADP platform integrates high accuracy micromechanical acceleration sensing together with a flexible SPI digital interface. The products within the platform range from single axis accelerometers into two or three axis accelerometers. Dual Flat Lead (DFL) housing of the component guarantees robust operation over the product lifetime. The products are designed, manufactured and tested for high stability, reliability and quality requirements of automotive applications. The accelerometers have extremely stable output over wide range of temperature, humidity and mechanical noise. The components are qualified against AEC-Q100 standard and have several advanced self diagnostics features. The DFL housing is suitable for SMD mounting and the component is compatible with RoHS and ELV directives. This Product Family Specification describes the VTI Automotive Digital Accelerometer Platform common characteristics and how to operate with the products. Detail product specification is described in individual data sheets of each product. 1.2 Features Standard features of the VTI Automotive Digital Accelerometer Platform • Single, dual or three axis acceleration measurement • SPI digital interface • 3.3V supply voltage • Enhanced self diagnostics features • Internal temperature sensor • Size 7.6 x 3.3 x 8.6 mm (w x h x l) • RoHS compliant Dual Flat Lead (DFL) plastic package suitable for lead free soldering process and SMD mounting • Package, pin-out and SPI protocol compatible within the product family • Proven capacitive 3D-MEMS technology • Qualified according to AEC-Q100 standard Main characteristics of each product within the product family are listed in Table 1 below. Table 1: Digital platform summary Type SCA810 SCA820 SCA830 SCA2100 SCA2110 SCA2120 SCA3100 X Z Y X, Y X, Z Y, Z X, Y, Z Measuring directions Single axis Accelerometer Single axis Accelerometer Single axis Accelerometer Dual axis Accelerometer Dual axis Accelerometer Dual axis Accelerometer Three axis Accelerometer Figure 1: Measurement directions VTI Technologies Oy www.vti.fi 5/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 1.3 Typical applications VTI Automotive Digital Accelerometer Platform is targeted to automotive applications with high stability requirements. Typical applications include but are not limited to • Electronic Stability Control (ESC) • Hill Start Assist (HSA) • Electronic Parking Brake (EPB) • Roll Over • Active Suspension • Inclination • Industrial applications 1.4 Functional Description Basic product concept of the VTI Automotive Digital Accelerometer Platform is a two chip solution consisting of a single sensing element and one ASIC inside a pre-molded 12-pin housing. The interface to the application is a four wire digital SPI interface. In single axis products there is also Pulse Width Modulation output available. In addition to the supply voltage filtering the component does not require any other components to be connected to the device. Block diagram of SCA8X0/SCA21X0/31X0 1.4.1 Sensing element The sensing element of the product is manufactured by using VTI Technologies proprietary bulk 3D-mems process enabling a robust, stable and low noise capacitive sensor. Depending on the product type and measurement direction the sensing element type and orientation inside the housing can vary. Single axis products are equipped with single axis sensing elements and multi axis products are equipped with multi axis sensing elements. 1.4.2 Interface IC The main functional blocks of the interface ASIC are the following: 1.4.3 Capacitance to voltage conversion The acceleration is causing a capacitance change inside the sensing element. The capacitance change can be detected by the ASIC analog interface. The capacitance information is converted into an analog voltage that can be further processed easily inside the ASIC. VTI Technologies Oy www.vti.fi 6/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 1.4.4 Analog to digital conversion Analog voltage information is amplified and filtered and converted into digital information for signal processing inside the ASIC. 1.4.5 Signal conditioning and filtering The block filters and conditions the measurement information needed for the application 1.4.6 Temperature measurement The accelerometers contain a temperature sensor for temperature compensation purposes and for use in the application. 1.4.7 Memory Factory programmed calibration values are stored in a non-volatile memory 1.4.8 SPI SPI interface is a simple four wire interface for communication between the component and the application micro controller. 1.4.9 Self diagnostics The VTI Automotive Digital Platform contains several enhanced diagnostics features to allow timely and robust failure detection. 1.4.10 Power supply interface The products are equipped with separate power and ground pins for analog and digital functionality to allow high accuracy measurement. 1.4.11 Factory calibration VTI Automotive Digital Platform accelerometers are factory calibrated. No separate calibration is required in the application. Trimmed parameters during production include sensitivity, offset and frequency response. Calibration parameters are stored during the manufacturing of the part inside a non-volatile memory. The parameters are read automatically from the internal non-volatile memory during the startup of the sensor after power on. VTI Technologies Oy www.vti.fi 7/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 2 2.1 Operation Modes Measurement mode After the startup the acceleration data is immediately available through the SPI registers. There is no need to initialize the accelerometer before starting to use of it. If the application is requiring monitoring of the correctness of the operation there are several options available to monitor the operation status. 2.2 Temperature output The devices include a temperature measurement function. Temperature data can be read through the SPI interface. Temperature measurement is not calibrated for absolute accuracy. If absolute accuracy is needed, it can be achieved through measuring the temperature value in two temperature points in final application and storing them as a calibration value and calculating the absolute temperature value by using the two points. 2.3 Self-diagnostic functions VTI Automotive Digital Accelerometer Platform has a set of built-in self-diagnostic functions to support the application fail safety. The diagnostic functions cover the accelerometer sensing element functionality, accelerometer internal operation and signal path functionality 2.3.1 Memory self-diagnostic Factory calibrated values of the accelerometer are stored in a non-volatile memory. The calibrated values are read during the device power on into volatile registers that control the operation of the device. During the startup of the device the calculated sum of non-volatile registers is compared to the factory calibrated value. The test is done automatically after supplies are set on, after any reset state of component and after return from power-down mode. Test can also be started by a CTRLregister command. 2.3.2 2.3.2.1 Signal path self-diagnostic SCA8X0 – single axis accelerometers Sensor element and signal path is tested by deflecting the proof mass of the sensing element to both directions over a predefined dynamic range. The test is done automatically during start-up and it can be repeated by a CTRL-register command. The result of the test is a momentary mass deflection seen in the output of the device. During the test the accelerometer performs a comparison of the deflection result to a pre-defined threshold value. When the needed dynamics have been detected the device will return the result of a passed test in a register. By following the output of the device on SPI interface it is possible to detect failures through the signal path. 2.3.2.2 2.3.2.2.1 SCA21X0 and SCA31X0 – multi axis accelerometers Start-up Self Test (STS) During the application start up or when the accelerometer is affected by the gravity force only it is possible to detect possible sensing element anomalies by applying a start up self test. The test is done in a following way: a digitally calculated resultant acceleration of x, y and z-axis is compared to predefined threshold value. Test is started by CTRL-register command and it is done once when requested. Continuous Self Test (STC) During device operation the continuous self test is monitoring the sensing element performance. Digitally calculated self-diagnostic function is compared to predefined threshold value. Test is started by CTRL-register command and it is calculated continuously on background until disabled. Possible errors are indicated in an error status register and in SPI frame. 2.3.2.2.2 VTI Technologies Oy www.vti.fi 8/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 2.4 Power Down mode For low power applications it is possible to set the accelerometer into power down mode. During the power down mode the power consumption is minimized inside the device. This is achieved by stopping the internal clocks and resetting the control registers of the device. Please refer to the individual device data sheets for detail power consumption figures. 2.5 Recommended start-up sequence For correct device operation there are no specific configuration needed for the device before starting of measuring the acceleration. However if the device detail features are being used the following operations could be made after the powering on the device. Table 2: SCA8X0 start up sequence Item 1 Procedure Set Vdd=3.0...3.6V Functions • Set the power on to release part from reset and to start the operation • During the first 95ms the part is performing the memory read and selfdiagnostics. • Possible signal path selfdiagnostic test is carried out. • Settling of signal path • Check the self-test pass status • Check the memory checksum pass status • After device power on set PORST=0 to be able to detect any future occurring power failures • Start reading the acceleration data Check - 2 Wait 95ms - 3 Read CTRL-register 4 Read STATUS-register 5 Write CTRL=0000 0000 • • • • • • • • • CTRL.ST=0 SPI fixed bits dPAR, data parity STATUS.CSMERR=0 SPI fixed bits SPI FRME=0 dPAR, data parity SPI fixed bits SPI FRME=0 6 Read X_MSB, X_LSB – registers • • • • SPI fixed bits SPI FRME=0 SPI PORST=0 dPAR, data parity VTI Technologies Oy www.vti.fi 9/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series Table 3: SCA21X0 and SCA31X0 start up sequence Item 1 2 Procedure Set Vdd=3.0...3.6V Wait 35ms Functions • Release part from reset • Memory reading and self-diagnostic • Settling of signal path • Acknowledge for possible saturation (SAT-bit) • Checksum pass detected from SPI frame • • Set PORST=0 (abc) Start STC (ab) Check - 3 Read INT_STATUS • • SPI fixed bits SPI ST=0 4 5 6 Write CTRL=00001010 (a) or CTRL=00001000 (b) or CTRL=00000000 (c) Wait 10ms Read CTRL • • • • • • • • • • • • • • • • • • SPI fixed bits SPI FRME=0 SPI ST=0 SPI SAT=0 • Start STS (a) STS calculation • Check that STC is on, if enabled • Check that STS is over if enabled 7 Read Z_MSB, Z_LSB, Y_MSB, Y_LSB, X_MSB, X_LSB Read acceleration data CTRL.ST=1 CTRL.ST_CFG=0 SPI fixed bits SPI FRME=0 SPI PORST=0 SPI ST=0 SPI SAT=0 dPAR, data parity SPI fixed bits SPI FRME=0 SPI PORST=0 SPI ST=0 SPI SAT=0 dPAR, data parity 2.6 Recommended operation sequence Table 4: Reading of the acceleration data Item 1 Procedure Read acceleration data Functions Desired x, y, or/and z-data Check • SPI fixed bits • SPI FRME=0 • SPI PORST=0 • SPI ST=0 • SPI SAT=0 • dPAR, data parity • • • SPI fixed bits SPI FRME=0 SPI PORST=0 2 3 4 Repeat item 1 (N-1) times Calculate average (AVE) of N-samples Read acceleration data Noise averaging Noise averaging Desired x, y, or/and z-data (one read before sending VTI Technologies Oy www.vti.fi 10/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series Item Procedure Functions AVE forward to check SPI failure bits) - 5 6 Send calculated AVE forward Jump back to item 2 Check • SPI ST=0 • SPI SAT=0 • dPAR, data parity - For detailed SPI failure bit information see chapter 4.2 Error Conditioning 2.7 Recommended procedures or optional features Product family components have different features, which are not required during normal operation. However, they are recommended in some cases if they are seen important from system perspective. 2.7.1 2.7.1.1 SCA8x0/SCA21x0/SCA31x0 Read back procedure It is recommended to read back every write command to compare read data to the write command. This way it is detected very unlikely failures in MCU, in SPI wiring, in SPI interface, in system clock or inside state machine. 2.7.1.2 Checksum during operation Checksum is calculated for component register values that control the operation of product. Data is read from non-volatile memory to these registers during start-up and checksum is calculated automatically. It is possible to repeat checksum calculation during normal operation by CTRL register command and test result can be seen from STATUS register (see more info in 3.2.1 and 3.1.6). In multi-axis products test result can be seen also from SPI frame. By repeating checksum during normal operation, it is possible to detect very unlikely intermittent or static bit failures in register map. 2.7.1.3 Saturated data Output data saturates to predefined value if product dynamic range is exceeded. If output data has been saturated it should be considered invalid and it should not be used for system controlling. Output data saturation can also be indication of some very unlike component failure. 2.7.1.4 Noiseless output Valid acceleration output includes always some noise. If output data is constant, it can be indication of system error and data is not valid anymore. Therefore it is useful to monitor noise or deviation of output data. 2.7.1.5 Component ID Each product family component type has unique identification number, which is stored to nonvolatile memory (see 3.3.2). This number can be used for example in production line to check that correct component is mounted to the system. In some cases it may be used for MCU software controlling. 2.7.2 2.7.2.1 SCA8x0 Mass deflection during operation Mass deflection self-test is performed automatically to both direction in start-up. Mass deflection can be performed during operation if requested by user. Test is started and direction is controlled VTI Technologies Oy www.vti.fi 11/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series by CTRL register (see more info in 3.2.1). Note that acceleration output data is not valid during test and after test is started to one direction there has to be 50ms wait time before output data is used. 2.7.2.2 Monitor acceleration data during mass deflection Acceleration data can be read out from acceleration output registers during mass deflection selftest in start-up or during operation, in case that test is repeated by the request. Monitoring this data it is possible to determine product frequency response and check product timing properties. 3 Addressing Space Table 5 presents the registers of SCA8X0, SCA21X0 and SCA31X0 products. Table 5: Register address space Addr hex 00 01 02 03 04 05 06 07 08 09 0A ... 11 12 13 14 15 16 17 ... 26 27 28 ... 3F Name REVID CTRL STATUS RESET X_LSB X_MSB Y_LSB Y_MSB Z_LSB Z_MSB Description Mode (R/RW) R RW R RW R R R R R R R R R RW - ASIC revision ID number Control Status Reset component X-axis (or Y- or Z-axis in SCA8X0) LSB frame X-axis (or Y- or Z-axis in SCA8X0) MSB frame Y-axis LSB frame in multi-axis components Y-axis MSB frame in multi-axis components Z-axis LSB frame in multi-axis components Z-axis MSB frame in multi-axis components Reserved Reserved Reserved TEMP_LSB Temperature LSB frame TEMP_MSB Temperature MSB frame Reserved Reserved INT_STATUS Interrupt status register in multi-axis components Reserved Reserved Reserved ID Component ID Reserved Reserved Reserved 3.1 3.1.1 Output registers X axis acceleration output X_LSB Address: 4h Bits Mode 7:0 R Initial Value 00h Name DATA Description X-axis LSB frame (or Y-axis or Z-axis in SCA8X0) Read always X_MSB prior to X_LSB. 12/35 Doc. Nr. 82 694 00 C 3.1.1.1 VTI Technologies Oy www.vti.fi SCA8X0/21X0/3100 Series 3.1.1.2 X_MSB Address: 5h Bits Mode 7:0 R Initial Value 00h Name DATA Description X-axis MSB frame (or Y-axis or Z-axis in SCA8X0) Reading of this register latches X_LSB. 3.1.2 3.1.2.1 Y axis acceleration output Y_LSB Address: 6h Bits Mode 7:0 R Initial Value 00h Name DATA Description Y-axis LSB frame Read always Y_MSB prior to Y_LSB. 3.1.2.2 Y_MSB Address: 7h Bits Mode 7:0 R Initial Value 00h Name DATA Description Y-axis MSB frame Reading of this register latches Y_LSB. 3.1.3 3.1.3.1 Z axis acceleration output Z_LSB Address: 8h Bits Mode 7:0 R Initial Value 00h Name DATA Description Z-axis LSB frame Read always Z_MSB prior to Z_LSB. 3.1.3.2 Z_MSB Address: 9h Bits Mode 7:0 R Initial Value 00h Name DATA Description Z-axis MSB frame Reading of this register latches Z_LSB. The bit level description of acceleration data from X_LSB ... Z_MSB registers is presented below (Note that the available axis combination of xyz depends on product type). The acceleration data is presented in 2's complement format. At 0 g acceleration the output is ideally 0000h. VTI Technologies Oy www.vti.fi 13/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 3.1.4 3.1.4.1 Output data conversion 2g products DOUT MSB bits(7:0) 15 14 13 s 1137.8 568.9 0 0 1 1 1 0 0 1 1 1 0 0 DOUT LSB bits(7:0) 7 6 5 8.89 4.44 2.22 0 1 0 1 1 0 1 1 1 0 0 0 DOUT LSB bits(7:0) 7 6 5 35.56 17.78 8.89 0 0 0 1 1 1 1 1 1 0 0 0 12b 12b Bits (15:4) Bits (15:4) [Dec] [Hex] 900 384 -900 C7C 2047 7FF -2048 800 +/-2g product Bit number SCA8x0 +1g position -1g position +Full-scale -Full-scale 12 284.4 1 0 1 0 11 142.2 1 0 1 0 10 71.1 0 1 1 0 9 35.6 0 1 1 0 8 17.8 0 1 1 0 4 1.11 0 0 1 0 3 x x x x x 2 x x x x x 1 x x x x x 0 x x x x x [-] [mg] 1000 -1000 2274 -2275 +/-2g product DOUT MSB bits(7:0) Bit number 15 14 13 SCA31x0/SCA21x0 s 4551.1 2275.6 +1g position 0 0 0 -1g position 1 1 1 +Full-scale *) 0 0 0 -Full-scale *) 1 1 1 12 1137.8 0 1 1 0 11 568.9 1 0 1 0 10 284.4 1 0 1 0 9 142.2 1 0 1 0 8 71.1 0 1 1 0 4 4.44 1 1 1 0 3 2.22 0 0 1 0 2 1.11 0 0 1 0 1 x x x x x 0 x x x x x [-] [mg] 1000 -1000 2274 -2275 Bits (15:2) Bits (15:2) [Dec] [Hex] 900 384 -900 3C7C 2047 7FF -2048 3800 s = sign bit x = not used/defined bit *) = positive/negative full-scale or saturation limit of ±2 g product is 2.27 g. In SCA8X0 acceleration bits can be converted to mg acceleration (Acc) using following equation Acc[mg ] = 10 − s ⋅ 211 + b14 ⋅ 210 + b13 ⋅ 29 + b12 ⋅ 28 + b11 ⋅ 27 + b10 ⋅ 26 + b9 ⋅ 25 + b8 ⋅ 24 + b7 ⋅ 23 + b6 ⋅ 22 + b5 ⋅ 2 + b 4 9 [ ] and in SCA21X0/SCA31X0 13 12 11 10 9 8 ⎤, 10 ⎡ − s ⋅ 2 + b14 ⋅ 2 + b13 ⋅ 2 + b12 ⋅ 2 + b11 ⋅ 2 + b10 ⋅ 2 ⎢ ⎥ 7 6 5 4 3 2 9 ⎢ + b9 ⋅ 2 + b8 ⋅ 2 + b7 ⋅ 2 + b6 ⋅ 2 + b5 ⋅ 2 + b 4 ⋅ 2 + b3 ⋅ 2 + b 2⎥ ⎣ ⎦ Acc[mg ] = where bits are defined according to following table. Acceleration MSB-register: Address 5'hex / 7'hex / 9'hex Acceleration LSB-register: Address 4'hex / 6'hex / 8'hex DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0 DO7 DO6 DO5 DO4 DO3 DO2 DO1 DO0 b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 In data output registers of SCA21X0/SCA31X0 there is reserved room for different g-ranges. To make sure that same software works with different product types it is recommended to use bits(15:2) for data conversion. If dynamic output range of product does not require bits b14 or b13 they include copy of sign bit b15. If self-test (checksum, STC, STS) alarms it sets ST bit in SPI frame and forces output data to value 7FFF'hex (checksum fail) or to value FFFF'hex (STC/STS alarm). In SCA21X0/SCA31X0 there is also possible to use 1-extra lsb bit (b1) for calculation to improve resolution. In that case acceleration bits can be converted to mg acceleration (Acc) using following equation Acc[mg ] = 14 13 12 11 10 9 8 10 ⎡− s ⋅ 2 + b14 ⋅ 2 + b13 ⋅ 2 + b12 ⋅ 2 + b11 ⋅ 2 + b10 ⋅ 2 + b9 ⋅ 2 ⎤ . ⎢ ⎥ 18 ⎢+ b8 ⋅ 27 + b7 ⋅ 26 + b6 ⋅ 25 + b5 ⋅ 24 + b 4 ⋅ 23 + b3 ⋅ 22 + b 2 ⋅ 2 + b1 ⎥ ⎣ ⎦ VTI Technologies Oy www.vti.fi 14/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 3.1.4.2 +/-6g product Bit number SCA8x0 +1g position -1g position +Full-scale -Full-scale 6 g products DOUT MSB bits(7:0) 15 14 13 s 3150.8 1575.4 0 0 0 1 1 1 0 1 1 1 0 0 DOUT LSB bits(7:0) 7 6 5 24.6 12.31 6.15 0 1 0 1 0 1 1 1 1 0 0 0 DOUT LSB bits(7:0) 7 6 5 49.2 24.6 12.3 0 0 1 1 1 0 1 1 1 0 0 0 12b 12b Bits (15:4) Bits (15:4) [Dec] [Hex] 325 145 -325 EBB 2047 7FF -2048 800 12 787.7 1 0 1 0 11 393.8 0 1 1 0 10 196.9 1 0 1 0 9 98.5 0 1 1 0 8 49.2 0 1 1 0 4 3.08 1 1 1 0 3 x x x x x 2 x x x x x 1 x x x x x 0 x x x x x [-] [mg] 1000 -1000 6300 -6302 +/-6g product DOUT MSB bits(7:0) Bit number 15 14 13 SCA31x0/SCA21x0 s 6301.5 3150.8 +1g position 0 0 0 -1g position 1 1 1 +Full-scale *) 0 0 1 -Full-scale *) 1 1 0 12 1575.4 0 1 1 0 11 787.7 1 0 1 0 10 393.8 0 1 1 0 9 196.9 1 0 1 0 8 98.5 0 1 1 0 4 6.15 0 1 1 0 3 3.08 1 1 1 0 2 1.54 0 0 1 0 1 x x x x x 0 x x x x x [-] [mg] 1000 -1000 6300 -6302 Bits (15:2) Bits (15:2) [Dec] [Hex] 650 28A -650 3D76 4095 FFF -4096 3000 s = sign bit x = not used/defined bit *) = positive/negative full-scale or saturation limit of ±6 g product is 6.3 g. In SCA8X0 acceleration bits can be converted to mg acceleration (Acc) using following equation Acc[mg ] = 1000 − s ⋅ 211 + b14 ⋅ 210 + b13 ⋅ 29 + b12 ⋅ 28 + b11 ⋅ 27 + b10 ⋅ 26 + b9 ⋅ 25 + b8 ⋅ 24 + b7 ⋅ 23 + b6 ⋅ 22 + b5 ⋅ 2 + b 4 325 [ ] and in SCA21X0/SCA31X0 13 12 11 10 9 8 ⎤, 1000 ⎡− s ⋅ 2 + b14 ⋅ 2 + b13 ⋅ 2 + b12 ⋅ 2 + b11 ⋅ 2 + b10 ⋅ 2 ⎢ ⎥ 7 6 5 4 3 2 650 ⎢+ b9 ⋅ 2 + b8 ⋅ 2 + b7 ⋅ 2 + b6 ⋅ 2 + b5 ⋅ 2 + b 4 ⋅ 2 + b3 ⋅ 2 + b 2⎥ ⎣ ⎦ Acc[mg ] = 3.1.4.3 +/-1g product Bit number SCA8xx +1g position -1g position +Full-scale -Full-scale 1 g products DOUT MSB bits(7:0) 15 14 13 s 512,0 256,0 0 1 1 1 0 0 0 1 1 1 0 0 DOUT LSB bits(7:0) 7 6 5 4,00 2,00 1,00 0 0 0 0 0 0 1 1 1 0 0 0 16b 0 [-] Bits (15:0) [Dec] 0,03 [mg] 0 1000 32000 0 -1000 -32000 1 1023 32767 0 -1024 -32768 12 128,0 1 0 1 0 11 64,0 1 0 1 0 10 32,0 1 0 1 0 9 16,0 0 1 1 0 8 8,0 1 1 1 0 4 0,50 0 0 1 0 3 0,25 0 0 1 0 2 0,13 0 0 1 0 1 0,06 0 0 1 0 s = sign bit Acceleration bits can be converted to mg acceleration (Acc) using following equation 15 14 13 12 11 10 9 8 7 6 5 4 4 1 ⎡− s ⋅ 2 + b14 ⋅ 2 + b13 ⋅ 2 + b12 ⋅ 2 + b11 ⋅ 2 + b10 ⋅ 2 + b9 ⋅ 2 + b8 ⋅ 2 + b7 ⋅ 2 + b6 ⋅ 2 + b5 ⋅ 2 + b 4 ⋅ 2 + b3 ⋅ 2 ⎤ Acc[mg ] = ⎥ ⎢ 32 ⎢+ b 2 ⋅ 2 3 + b1 ⋅ 21 + b0 ⎥ ⎦ ⎣ 3.1.5 3.1.5.1 Temperature output Temperature Register Low (TEMP_LSB) Address: 12h Bits Mode 7:0 R Initial Value 00h Name DATA Description Data bits [7:0] of temperature sensor. Read always TEMP_MSB prior to TEMP_LSB. VTI Technologies Oy www.vti.fi 15/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 3.1.5.2 Temperature Register High (TEMP_MSB) Address: 13h Bits Mode 7:0 R Initial Value 00h Name DATA Description Data bits [15:8] of temperature sensor. Reading of this register latches TEMP_LSB. The bit level description of temperature data: In SCA8X0 temperature data is not factory calibrated and hence sensitivity and offset of temperature data varies from part to part. Temperature data is in 2's complement format and 14 bits (13:0) of TEMP_MSB/TEMP_LSB are used for temperature. Here is presented temperature calculation using 10bit but 4-extra LSB bit can be used to improve resolution in noise sense if needed. Table 6 Bit level description for SCA8X0 temperature registers Register TEMP_MSB Bit number B7:B6 B5 B4 B3 B2 B1 B0 Bit temperature weight [°C] xx sign ~82 ~41 ~21 ~10 ~5.1 Bit in temperature register xx t9 t8 t7 t6 T5 t4 x = not used bit r=reserved TEMP_LSB B7 B6 B5 B4 B3:B0 ~2.6 ~1.3 ~0.6 ~0.3 rrrr t3 t2 t1 t0 rrrr Temp[°C ] = (45 ± 32 )°C + Temp dec , LSB ko C where Temp[°C] is temperature in Celsius and Tempdec is temperature from TEMP_MSB and TEMP_LSB registers in decimal format, bits(t9:0). k is temperature slope factor specified as k Min 2.8 Typ 3.1 Max 3.5 Unit LSB/ oC In SCA21X0 and SCA31X0 offset of temperature data is factory calibrated but sensitivity of the temperature data varies from part to part. Temperature data is in unsigned format and 13 bits (13:1) of TEMP_MSB/TEMP_LSB are used for temperature. Here is presented temperature calculation using 10bit but 3-extra LSB bit can be used to improve resolution in noise sense if needed. Table 7 Bit level description for SCA21X0/31X0 temperature registers Register TEMP_MSB TEMP_LSB Bit number B7:B6 B5 B4 B3 B2 B1 B0 B7 B6 B5 B4 B3:B0 Bit temperature weight [°C] xx ~162 ~81 ~41 ~20 ~10 ~5.1 ~2.5 ~1.3 ~0.6 ~0.3 rrrx Bit in temperature register xx t9 t8 t7 T6 T5 t4 t3 t2 t1 t0 rrrx x = not used bit r=reserved Temperature registers’ typical output at +23 °C is 512 counts and 1 °C change in temperature typically corresponds to 3.2 LSB change in temperature output. Temperature information is converted to [°C] as follows VTI Technologies Oy www.vti.fi 16/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series Temp[°C ] = (23 ± 10 )°C + Temp dec − 512 LSB , LSB k °C where Temp[°C] is temperature in Celsius and Tempdec is temperature from TEMP_MSB and TEMP_LSB registers in decimal format, bits(t9:0). k is temperature slope factor specified as k Min 2.8 Typ 3.2 Max 3.6 Unit LSB/oC 3.1.6 Status Register (STATUS) Address: 2h Bits Mode 7:3 2 1 0 R R R Initial Value 0 0 0 Name ATEST CSMERR FRME Description Reserved Analog test mode status 1 – Test mode is active 0 – Test mode is not active EEPROM Checksum Error. In SCA21X0/SCA31X0 ST bit of SPI frame is also set if CSMERR is set. SPI frame error. Bit is reset, when next correct SPI frame is received. Bit is also visible in SPI frame. 3.1.7 Interrupt Status Register (INT_STATUS) Address: 16h Bits Mode 7 6 R R Initial Value 0 0 Name SAT Description Reserved Saturation status of output data 1 – Over range detected, one or 2-3 of xyz axis is saturated and output data is not valid. 0 – Data in range SAT bit is also visible in SPI frame. This bit can be active after start-up or reset stage before signal path settles to final value and it has to be acknowledged in start-up sequence (see Table 3) or after SW reset or after PORST stage. Status of gravitation based start-up self test 1 – Failure 0 – No failure STS sets also ST bit in SPI frame. Status of continuous self test 1 – Failure 0 – No failure STC sets also ST bit in SPI frame. Reserved 5 R 0 STS 4 R 0 STC 3:0 R 0000 The bits in this interrupt status register and corresponding SPI frame bits are cleared after register has been read. Register reading is treated as interrupt acknowledgement signal. These bits are kept active even failure condition is over if they are not acknowledged. This register is not defined in SCA8X0. VTI Technologies Oy www.vti.fi 17/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 3.2 3.2.1 Operation control registers Control Register (CTRL) Address: 1h Bits Mode 7 6 RW RW Initial Value 0 0 Name PORST Description Reserved 1 means reset state. Bit gets set to 1 when the digital gets reset by supply off control or under voltage control. Bit is set after supply off/on transition or startup. This bit can not be set by SPI but it can be reset to 0 by writing a 0 over the SPI. This bit is also sent as Bit3 of SPI output data frame on MISO. Set chip to power down mode Set chip to sleep mode. This bit can not be set to 1 if PDOW is already 1 or if PDOW is being set by the current SPI command. (bit is not used in SCA8X0) Set chip to self-test mode. SCA8X0: This bit starts mass deflection self-test (see also ST_CFG bit). This bit is set to 0, when test is passed. This bit can not be set to 1 if PDOW is already 1 or if PDOW is being set by the current SPI command. Test is done automatically during start-up and acceleration output data can be read during test. SCA21X0 and SCA31X0: Start continuous self-test calculation (STC). This bit can not be set to 1 if PDOW or SLEEP or MTST is already 1 or if PDOW or SLEEP or MTST is being set by the current SPI command. Use INT_STATUS.STC and ST bit of SPI frame for test result monitoring. Memory self-test function is activated, when user sets bit to ‘1’. This bit is reset to 0 when test is over. During memory self test, SPI access is prevented for 85us. This bit can not be set to 1 if PDOW or SLEEP is already 1 or if PDOW or SLEEP is being set by the current SPI command. Test is done automatically during start-up. Set other bits to zero in CTRL register by previous SPI command before starting memory self-test by CTRL.MST command. Use STATUS.CSMERR for test result monitoring and in SCA21X0/SCA31X0 ST bit in SPI frame. Self-test configuration. SCA8X0: Select direction of mass deflection. SCA21X0 and SCA31X0: Start gravitation based start-up self-test calculation (STS). This bit can not be set to 1 if PDOW or SLEEP or MTST is already 1 or if PDOW or SLEEP or MTST is being set by the current SPI command. STC and 5 4 3 RW RW RW 0 0 0 PDOW SLEEP ST 2 RW 0 MST 1 RW 0 ST_CFG VTI Technologies Oy www.vti.fi 18/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series Bits Mode Initial Value Name Description STS have same priority and they can be set and used simultaneously. This bit is set to 0 when test is over. Use INT_STATUS.STS and ST bit of SPI frame for test result monitoring. 0 = Set MISO line to normal state (= High impedance state between SPI transfers, data out state during transfers) 1 = Set MISO like to a continuous high impedance state (same write command to multiple slaves, which share MISO line). 0 RW 0 MISO 3.2.2 Reset Register (RESET) Address: 3h Bits Mode 7:0 RW Initial Value 00h Name RST Description Writing 0C'hex, 05'hex, 0F'hex in this order resets component. 3.3 3.3.1 Identification registers Revision ID (REVID) Address: 0h Bits Mode 7:0 R Initial Value 23h 1) 22h 2) Name REVID Description ASIC revision identification number, each ASIC version has different REVID-number. 1) SCA8X0 2) SCA21X0/SCA31X0 3.3.2 Component ID (ID) Address: 27h Bits Mode 7:0 RW Initial Value Name ID Description Component identification number (write operation by user is possible to this register but not to non-volatile memory) The ID register contains information about the product version and value is loaded from nonvolatile memory. Each VTI Automotive Digital Accelerometer Platform product will have a unique identification number. Single axis products can be differentiated from multi axis products through this register. SCA8X0: SCA21X0: SCA31X0: MSB = 0 MSB = 1 MSB = 1 Please refer to the product data sheet for correct ID number. VTI Technologies Oy www.vti.fi 19/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 4 SPI Interface Serial peripheral interface (SPI) is a 4-wire synchronous serial interface. Data communication is enabled with active low Slave Select or Chip Select wire (CSB). Data is transmitted via 3-wire interface consisting of serial data input (MOSI), serial data output (MISO) and serial clock (SCK). Every SPI system consists of one master and one or more slaves, where the master is defined as the microcomputer that provides the SPI clock, and the slave is any integrated circuit that receives the SPI clock from the master. MASTER MICROCONTROLLER DATA OUT (MOSI) DATA IN (MISO) SERIAL CLK (SCK) CSB0 CSB1 CSB2 CSB3 SLAVE MOSI MISO SCK CSB MOSI MISO SCK CSB MOSI MISO SCK CSB MOSI MISO SCK CSB Figure 2: Typical SPI connection The SPI interface of VTI automotive series is designed to support almost any micro controller that uses software implemented SPI. However it is not designed to support any particular hardware implemented SPI found in many commercial micro controllers. SCA8X0/SCA21X0/SCA31X0 accelerometer operates always as a slave device in the master-slave operation mode. The data transfer between the master (µP test machine etc.) and accelerometer is performed serially with four wire system. MOSI MISO SCK CSB master out slave in master in slave out serial clock chip select (low active) µP → ASIC ASIC → µP µP → ASIC µP → ASIC Each transmission starts with a falling edge on CSB and ends with the rising edge. During the transmission, commands and data are controlled by SCK and CSB according to the following rules: • • • commands and data are shifted MSB first LSB last each output data/status-bits are shifted out on the falling edge of SCK (MISO line) each bit is sampled on the rising edge of SCK (MOSI line) and registers of the SPI communication transfers data between SPI master SCA8X0/SCA21X0/SCA31X0. Registers can be read and write. SPI communication is full duplex communication. Data is send and received simultaneously. VTI Technologies Oy www.vti.fi 20/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series SPI frame format and transfer protocol is presented in Figure 3. Figure 3: SPI frame format • MOSI • • • • MISO • • • A5:A0 RB/W aPAR DI7:DI0 Register address Read/Write selection, '0'=read Odd parity for bits A5:A0, RB/W Input data for data write • • • • • Bit 1 not defined bit FRME Frame error indication (previous frame) Bit 3-5 status bits • PORST Power On Reset Status • ST Self Test error, not defined in SCA8X0 • SAT Output SATuration indicator, not defined in SCA8X0 Bit 6 always ‘0’, fixed bit Bit 7 always ‘1’, fixed bit dPAR Odd parity for output data (DO7:DO0) DO7:DO0 Output data Each communication frame contains 16 bits. Please see Figure 3 for SPI bit definition. The first 8 bits in MOSI line contains info about the operation (read/write) and the register address being accessed. First 6 bits define 6 bit address for selected operation, which is defined by bit 7 (‘0’ = read ‘1’ = write), which is followed by odd parity bit (aPAR) for 8 bit pattern. The later 8 bits in MOSI line contain data for a write operation and are ignored in case of read operation. The first bits in MISO line are frame error bit (FRME, bit2) of previous frame, reset status bit (PORST, bit3), self-test status bit (ST, bit4), saturation status (SAT, bit5), fixed zero bit (bit6), fixed one bit (bit7) and odd parity bit of output data (dPAR, bit8)). Parity is calculated from data, which is currently sent. The later 8 bits contain data for a read operation. During the write operation, these data bits are previous data bits of addressed register. For write commands, data is written into the addressed register on the rising edge of CSB. If the command frame is invalid, data will not be written into the register. The output register is shifted out MSB first over MISO output. Attempt to read a reserved register outputs data of 00h. When CSB is high state between data transfers, MISO line is in high-impedance state. If bit CTRL.SDODIS is set to ‘1’, MISO line is always in high-impedance state. In multi-chip SPI bus master can send data to all slave chips simultaneously. 4.1 Output of Acceleration Data 16-bit data is sent in 8-bit data bytes during two frames. Each frame contains odd parity bit of data bits. Number format of acceleration data is two’s complement number. VTI Technologies Oy www.vti.fi 21/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 4.1.1 Register read operation An example of X-axis acceleration read command is presented in Figure 4. Master gives the register address to be read via MOSI line: '05' in hex format and '000101' in binary format, register name is X_MSB (X-axis MSB frame). 7th bit is set to '0' to indicate the read operation and 8th bit is 1 for odd parity. The sensor replies to asked operation by transferring the register content via MISO line. After transferring the asked X_MSB register content, master gives next register address to be read: '04' in hex format and '000100' in binary format, register name is X_LSB (X-axis LSB frame). The sensor replies to asked operation by transferring the register content MSB first. Figure 4: Example of 16 bit acceleration data transfer from registers DOUT2-1 (05h,04h). DO15…DO0 bits are acceleration data bits (DO15=MSB) and parity (dPAR) is odd parity of register of 8 data bits. FRME is possible frame error bit of previous frame, PORST is reset bit, ST is selftest status bit and SAT is output saturation status bit. 4.1.2 Decremented register read operation In Figure 5 is presented a decremented read operation where the content of four output registers is read by one SPI frame. After normal register addressing and one register content reading the µC keeps CSB line low and continues supplying the SCK pulses. After every 8 SCK pulses the output data address is decremented by one and the previous DOUT register's content is shifted out without parity bits. Parity bit is calculated and transferred only for the first data frame. From X_LSB register address the SCA21X0/SCA31X0 jumps to Z_MSB. Decremented reading is possible only for registers X_LSB ... Z_MSB in SCA21X0 and SCA31X0 series. Decremented read is not recommended in fail-safe critical applications because output data parity is only available for first 8bit data. Figure 5: An example of decremented read operation. VTI Technologies Oy www.vti.fi 22/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 4.1.3 MOSI data of SPI commands Table 8: MOSI data during SPI read command Register to be read REVID CTRL STATUS X_LSB X_MSB Y_LSB Y_MSB Z_LSB Z_MSB TEMP_LSB TEMP_MSB INT_STATUS ID Function Read ASIC revision ID Read CTRL register Read Status register Read acceleration on X-axis, LSB Read acceleration on X-axis, MSB Read acceleration on Y-axis, LSB Read acceleration on Y-axis, MSB Read acceleration on Z-axis, LSB Read acceleration on Z-axis, MSB Read temperature, LSB Read temperature, MSB Read INT_STATUS register Read product ID number MOSI (15:0) [bits] 000000 01 xxxxxxxx 000001 00 xxxxxxxx 000010 00 xxxxxxxx 000100 00 xxxxxxxx 000101 01 xxxxxxxx 000110 01 xxxxxxxx 000111 00 xxxxxxxx 001000 00 xxxxxxxx 001001 01 xxxxxxxx 010010 01 xxxxxxxx 010011 00 xxxxxxxx 010110 00 xxxxxxxx 100111 01 xxxxxxxx MOSI [hex] 01xx 04xx 08xx 10xx 15xx 19xx 1Cxx 20xx 25xx 49xx 4Cxx 58xx 9Dxx Table 9: MOSI data during write command Register to be written RESET RESET RESET CTRL CTRL CTRL CTRL Function Reset component (data C'hex ) Reset component (data 5'hex ) Reset component (data F'hex ) Set PORST to zero Set chip to power down mode Start self-diagnostic Start memory self-test MOSI (15:0) [bits] 000011 10 00001100 000011 10 00000101 000011 10 00001111 000001 11 00000000 000001 11 00100000 000001 11 00001000 000001 11 00000100 MOSI [hex] 0E0C 0E05 0E0F 0700 0720 0708 0704 4.2 4.2.1 Error Conditioning FRME-bit While sending a frame, if CSB is raised to 1 before sending 16 SCKs, the frame is considered invalid. In SCA8X0 the frame error is raised if number of SCK pulses is not 16. In SCA21X0/3100 the frame error is raised only if number of SCK pulses is not divisible by 8 to support decremented mode reading. When an invalid frame is received, the last command is simply ignored and the register contents are left unchanged. Status bit STATUS.FRME is set to indicate this error condition. During next SPI frame error bit send out as bit number 2. Bit STATUS.FRME will be reseted, if correct frame is received. 4.2.2 PORST-bit PORST length is 1bit in SPI frame. PORST bit is set if chip is reseted (HW reset by POR or supply on/off) or under-voltage is detected. PORST bit is also set after power-up because chip has been in reset state. PORST can be set to zero (reseted) by writing CTRL.PORST =0. Software (SW) reset does not set PORST. When CTRL.PORST bit is written to 0 via SPI, there is 300ns delay before register value is set to zero. VTI Technologies Oy www.vti.fi 23/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 4.2.3 ST-bit (SCA21X0 / 3100) Self-test frame status (ST) is set if STC or STS is alarmed or checksum is not passed. • CASE 1: Checksum fails and ST-frame bit is set 1. ST is set back to zero when (and only if) new checksum calculation is passed. • CASE 2: ST-frame bit is set because STC or STS is alarmed. In this case ST-frame bit can be cleared by INT_STATUS register reading. ST bit is not defined in SCA8X0 series. 4.2.4 SAT-bit (SCA21X0 / 3100) Saturation status (SAT) is set if any of axis xyz is saturated and it can be cleared by INT_STATUS register reading. This bit is kept active even failure condition is over if it is not acknowledged. Saturation limit varies between different product types. For example: • SCA2100 2 g product: x and y channel saturates to 2.27 g and SAT bit in SPI frame and in INT_STATUS register is set, if 2.27 g is exceeded. Additional to this, if acceleration to zdirection exceeds 4.54 g, SAT bit in SPI frame and in INT_STATUS register is set. In all cases INT_STATUS register reading is needed for acknowledgement and acceleration output data of any channel is not valid, when bit is active. SCA2110 2 g product: x and z channel saturates to 2.27 g and SAT bit in SPI frame and in INT_STATUS register is set, if 2.27 g is exceeded. Additional to this, if acceleration to ydirection exceeds 4.54 g, SAT bit in SPI frame and in INT_STATUS register is set. In all cases INT_STATUS register reading is needed for acknowledgement and acceleration output data of any channel is not valid, when bit is active. SCA2120 2 g product: y and z channel saturates to 2.27 g and SAT bit in SPI frame and in INT_STATUS register is set, if 2.27 g is exceeded. Additional to this, if acceleration to xdirection exceeds 4.54 g, SAT bit in SPI frame and in INT_STATUS register is set. In all cases INT_STATUS register reading is needed for acknowledgement and acceleration output data of any channel is not valid, when bit is active. • • SAT bit is not defined in SCA8X0 series, but output saturates to the calibrated level. For example acceleration output data of SCA8x0 2 g products saturates to 2.27 g. 4.2.5 aPAR-bit (SCA21X0 / 3100) aPAR is odd parity bit of input address+RB/W-bit. Master write it and slave check that bit. • If there is parity error and RB/W='1', write command is ignored and frame error bit is set to STATUS-register and to SPI frame. Next correct SPI frame will zero this bit. • If there is parity error and RB/W='0', read command is performed normally and frame error bit is set to STATUS-register and to SPI frame. Next correct SPI frame will zero this bit. aPAR bit is not checked in SCA8X0 series. Table 10: Address parity A5 0 1 1 0 A4 0 1 0 1 Address A3 A2 0 0 1 1 1 0 0 1 Notes A1 0 1 1 0 A0 0 1 0 1 RB/W 0 1 1 0 aPAR 1 0 1 0 correct frame correct frame correct frame correct frame VTI Technologies Oy www.vti.fi 24/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 4.2.6 dPAR-bit dPAR bit is odd parity bit of 8bit data that is currently sent in the frame. Master checks this bit and compares to received data. Using dPAR at least one bit errors in data transmission can be detected. 4.2.7 Fixed bits Bits 6 and 7 are always fixed in MISO line. Bit 6 should always be '0' and bit 7 always '1' 4.2.8 Output data 1. Reset stage: When component is in reset or under voltage state, PORST bit in SPI frame and CTRL.PORST bit is set. Furthermore, all register values are set to 00'hex. 2. Saturation: When acceleration exceeds measurement range, the output data is saturated to specified positive or negative full-scale. 3. Self-diagnostic failure: In SCA21X0 and 31X0 the ST bit in SPI frame is set when memory diagnostic or signal path diagnostic functions fail. Furthermore acceleration output data is forced to 7FFF'hex if memory diagnostic fails or to FFFF'hex if signal path diagnostic functions (STC/STS) fail. VTI Technologies Oy www.vti.fi 25/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 5 Electrical Characteristics All voltages are referenced to ground. Currents flowing into the circuit have positive values. 5.1 Absolute maximum ratings The absolute maximum ratings of Digital Family are presented in Table 11 below. Table 11: Absolute maximum ratings Parameter Supply voltage (Vdd) Voltage at input / output pins ESD (Human body model) Storage temperature Operating temperature Ultrasonic cleaning Value -0.3 to +3.6 -0.3 to (Vdd + 0.3) ±2 -40 ... +125 -40 ... +125 Not allowed Unit V V kV °C °C 5.2 5.3 5.3.1 Power Supply Digital I/O Specification DC Characteristics Unit µA V V V µA V V V V V uA Supply voltage is 3.3 V unless otherwise noted. Current flowing into the circuit has positive values. Parameter Conditions Symbol Min Typ Max Input terminal CSB 1 Pull up current VIN = 0 V IPU 10 50 DVDD 2 Input high voltage DVDD = 3.3 V VIH 2 3 Input low voltage DVDD = 3.3 V VIL 0.8 4 Hysteresis DVDD = 3.3 V VHYST 0.18 Input terminal MOSI, SCK 5 Pull down current VIN = 3.3 V IPD 10 50 DVDD 6 Input high voltage DVDD = 3.3 V VIH 2 7 Input low voltage DVDD = 3.3 V VIL 0.8 8 Hysteresis DVDD = 3.3 V VHYST 0.18 Output terminal MISO 9 Output high voltage I > -1mA VOH DVDD – DVDD = 3.3 V 0.5 10 Output low voltage I < 1 mA VOL 0.5 11 Tri-state leakage 0 < VMISO < 3.3 V ILEAK -3 3 5.3.2 AC Characteristics Parameter Terminal CSB, SCK Time from CSB (10%) to SCK (90%)1 Time from SCK (10%) to CSB (90%)1 Terminal SCK SCK low time Conditions Symbol TLS1 TLS2 Load capacitance at MISO < 50 pF tr=rise time tf=fall time Load capacitance at MISO < 50 pF TCL Min Tper/2 Tper/2 60 Tper/2 – (tr+tf)/2 Typ Max Unit ns ns ns 1 2 3 4 SCK high time TCH 60 Tper/2 – (tr+tf)/2 ns VTI Technologies Oy www.vti.fi 26/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 5 6 SCK Frequency Terminal MOSI, SCK Time from changing MOSI (10%, 90%) to SCK (90%)1. Data setup time Time from SCK (90%) to changing MOSI (10%, 90%)1. Data hold time Terminal MISO, CSB Time from CSB (10%) to stable MISO (10%, 90%) Time from CSB (90%) to high impedance state of MISO1. Terminal MISO, SCK Time from SCK (10%) to stable MISO (10%, 90%)1. Terminal CSB Time between SPI cycles, CSB at high level (90%) fsck = 1/Tper TSET Tper/4 8 MHz ns 7 THOL Tper/4 ns 8 9 Load capacitance at MISO < 50 pF Load capacitance at MISO < 50 pF Load capacitance at MISO < 50 pF TVAL1 TLZ Tper/4 Tper/4 ns ns 10 TVAL2 1.3 x Tper/4 Tper ns 11 TLH ns TLS1 CSB SCK TCH TCL TLS2 TLH THOL MOSI TVAL1 MISO MSB out MSB in DATA in TSET LSB in TVAL2 DATA out LSB out TLZ Figure 6: Timing diagram of SPI communication VTI Technologies Oy www.vti.fi 27/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 6 6.1 Application information Package dimensions The package dimensions are presented in the Figure 7 below (measures in mm with ±0.1 mm tolerance). The part weights < 0.35 g. Figure 7: Package dimensions VTI Technologies Oy www.vti.fi 28/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 6.2 Output to Angle Conversion Product output is function of sin and it can be transferred to angle using the following equation for conversion: α = arcsin⎜ ⎜ ⎛ Output LSB − Offset 0 g Sensitivity ⎝ ⎞ ⎟, ⎟ ⎠ Where OutputLSB is output in g, Offset0g is offset at 0 g position and sensitivity is sensitivity of product. Nominal sensitivity is determined at datasheet of product and 0 g can be used in Offset0g if not measured after installation. To read output of product refer chapter Output Data Conversion. Angles close to 0° inclination can be estimated quite accurately with straight line conversion but for the best possible accuracy, arcsine conversion is recommended to be used. The following table shows the angle measurement error if straight line conversion is used. Straight line conversion equation: α =⎜ ⎜ ⎛ Output LSB − Offset 0 g Sensitivity ⎝ ⎞ ⎟, ⎟ ⎠ Where OutputLSB is output in g, Offset0g is offset at 0 g position and sensitivity is sensitivity of product. Tilt angle [°] 0 1 2 3 4 5 10 15 30 Straight line conversion error [°] 0 0.0027 0.0058 0.0094 0.0140 0.0198 0.0787 0.2185 1.668 VTI Technologies Oy www.vti.fi 29/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 6.3 Measuring Directions X [mg] ARCSIN(X) [o] Y [mg] ARCSIN(Y) [o] Z [mg] o ARCSIN(Z) [ ] 1 0 0 0 0 1000 90 2 0 0 -707 -45 707 45 3 0 0 -1000 -90 0 0 4 0 0 -707 -45 -707 -45 X [mg] ARCSIN(X) [o] Y [mg] ARCSIN(Y) [o] Z [mg] ARCSIN(Z) [o] 5 0 0 0 0 -1000 -90 6 0 0 707 45 -707 -45 7 0 0 1000 90 0 0 8 0 0 707 45 707 45 Measuring direction of Z and Y axis of ADP-product and output in mg and degree 1 X [mg] ARCSIN(X) [o] Y [mg] ARCSIN(Y) [o] Z [mg] o ARCSIN(Z) [ ] 1000 90 0 0 0 0 2 707 45 -707 -45 0 0 3 0 0 -1000 -90 0 0 4 -707 -45 -707 -45 0 0 5 X [mg] ARCSIN(X) [o] Y [mg] ARCSIN(Y) [o] Z [mg] ARCSIN(Z) [o] -1000 -90 0 0 0 0 6 -707 -45 707 45 0 0 7 0 0 1000 90 0 0 8 707 45 707 45 0 0 Measuring direction of Z and Y axis of ADP-product and output in mg and degree VTI Technologies Oy www.vti.fi 30/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 6.4 Pin Description 1 2 3 4 5 6 12 11 10 9 8 7 Figure 8: Component pinout Table 12: Component pinout Name Type 1) PD/PU 2) Reserved Reserved PD AVSS AI AVDD AI CSB DI PU MISO ZO SCK DI PD MOSI DI PD PWM ADO PD DVDD AI DVSS AI EGnd AI No. 1 2 3 4 5 6 7 8 9 10 11 12 Function Not used Factory use Negative power supply (analog) Positive power supply (analog) Chip select Data output Serial clock Data input Pulse Width Modulation output Positive power supply (digital) Negative power supply (digital) EMC ground Connect Gnd Gnd Gnd Vdd CSB MISO SCK MOSI N.C. or PWM 3) Vdd Gnd Gnd Notes: 1) A=Analog, D=Digital, I=Input, O=Output, Z=Tristate Output 2) PU=internal pullup, PD=internal pulldown 3) PWM output in some SCA8X0 products, N.C.= Not Connected 6.5 Recommended circuit diagram Recommended circuit diagram for all product family components with SPI interface is shown in Figure 9. Following design rules and recommendations should be considered to achieve maximum performance: Required: 1 Connect (C4) 100 nF (ESR < 1) capacitor between AVDD and AVSS 2 Connect (C5) 100 nF (ESR < 1) capacitor between DVDD and DVSS 3 Use one power supply VDD for AVDD and DVDD (AVDD voltage level has to be raised always same time or after DVDD during power up sequence) Recommended for improved PSRR (Note 1 in Figure 9): 4 Connect (C6) 10 µF capacitor between AVDD and AVSS 5 Connect serial resistance (R1) 10 Ω between VDD and AVDD/DVDD VTI Technologies Oy www.vti.fi 31/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 6 VDD • Specified operation voltage (VDD) range 3.05...3.6 V To achieve high EMC DPI performance, add serial inductance (L1) to VDD line before serial resistance (for example Murata: BLM18HG102S) Note 1 L1 R1 10 Ω C6 10 µF 1 2 3 4 5 6 NC NC AVSS AVDD CSB MISO SCA8x0 SCA21x0 SCA3100 EGND DVSS DVDD PWM MOSI SCK C4 CSB MISO 100 nF 12 11 10 9 8 7 C5 100 nF MOSI SCK Figure 9: Recommended circuit diagram 6.6 Recommended PWB layout Recommended PWB layout for all product family components with SPI interface is shown in Figure 10 and Figure 11. Following design rules and recommendations should be considered: Required: 1 Connect (C4) 100 nF SMD capacitor between AVDD and AVSS right next to component pins AVDD and AVSS 2 Connect (C5) 100 nF SMD capacitor between DVDD and DVSS right next to component pins DVDD and DVSS 3 Use separate ground levels AVSS and DVSS under and near the component but connect them together on the PCB, see Figure 10 4 Locate ground plate under component 5 Do not route signals or power supplies under the component on top layer 6 Ensure good ground connection of Egnd (pin12) to AVSS Recommended: 7 Locate digital ground under digital signal lines 8 Do not route digital signals one upon the other for long distance 9 Avoid crossing of AVDD path with digital signal especially between serial resistance R1 and AVDD pin 10 Do not route digital signals under the component on 2nd layer VTI Technologies Oy www.vti.fi 32/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series Figure 10: Recommended PWB layout for product family components with SPI interface (Top layer, Not actual size, for reference only) Figure 11: Recommended PWB layout for product family components with SPI interface (2nd layer, Not actual size, for reference only) VTI Technologies Oy www.vti.fi 33/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series Recommended PWB pad layout is presented in the Figure 12 below (dimensions in mm). Figure 12: Component pad layout 6.7 Assembly instructions The Moisture Sensitivity Level (MSL) of the component is 3 according to the IPC/JEDEC J-STD020C. Please refer to the document "TN53 Assembly Instructions for Dual Flat Lead Package" for more detailed information of the assembly. 6.8 Tape and reel specifications Please refer to the document "TN53 Assembly Instructions for Dual Flat Lead Package" for tape and reel specifications. VTI Technologies Oy www.vti.fi 34/35 Doc. Nr. 82 694 00 C SCA8X0/21X0/3100 Series 7 Contact Information Finland (head office) VTI Technologies Oy P.O. Box 27 Myllynkivenkuja 6 FI-01621 Vantaa Finland Tel. +358 9 879 181 Fax +358 9 8791 8791 E-mail: sales@vti.fi Japan VTI Technologies Oy Tokyo Office Tokyo-to, Minato-ku 2-7-16 Bureau Toranomon 401 105-0001 Japan Tel. +81 3 6277 6618 Fax +81 3 6277 6619 E-mail: sales.japan@vti.fi Germany VTI Technologies Oy Branch Office Frankfurt Rennbahnstrasse 72-74 D-60528 Frankfurt am Main, Germany Tel. +49 69 6786 880 Fax +49 69 6786 8829 E-mail: sales.de@vti.fi USA VTI Technologies, Inc. One ParkLane Blvd. Suite 804 - East Tower Dearborn, MI 48126 USA Tel. +1 313 425 0850 Fax +1 313 425 0860 E-mail sales@vtitechnologies.com China VTI Technologies Shanghai Office 6th floor, Room 618 780 Cailun Lu Pudong New Area 201203 Shanghai P.R. China Tel. +86 21 5132 0417 Fax +86 21 513 20 416 E-mail: sales.china@vti.fi To find out your local sales representative visit www.vti.fi VTI Technologies Oy www.vti.fi 35/35 Doc. Nr. 82 694 00 C