CMA3000-D01DEMO

Doc.Nr. 8281000.12 Product Family Specification CMA3000-D0X Series 3-axis accelerometer CMA3000-D0X Series TABLE OF CONTENTS 1 General Description ........................................................................................................... 5 1.1 Introduction ................................................................................................................................5 1.2 Functional Description ..............................................................................................................5 1.2.1 Sensing element..................................................................................................................5 1.2.2 Interface IC...........................................................................................................................5 1.2.3 Factory calibration ..............................................................................................................5 1.2.4 Supported features .............................................................................................................6 1.2.5 Operation modes.................................................................................................................6 1.2.5.1 1.2.5.2 1.2.5.3 1.2.5.4 Power Down .................................................................................................................................6 Measurement................................................................................................................................6 Motion Detection..........................................................................................................................6 Free-Fall Detection ......................................................................................................................6 1.2.6 1.2.7 Interrupt................................................................................................................................6 Operational flow chart ........................................................................................................7 2 Reset and power up, Operation Modes, HW functions and Clock ................................. 8 2.1 2.2 Reset and power up...................................................................................................................8 Power Down mode.....................................................................................................................8 2.3 Measurement Mode ...................................................................................................................8 2.3.1 Description...........................................................................................................................8 2.3.2 Usage....................................................................................................................................8 2.4 Motion Detection Mode .............................................................................................................8 2.4.1 Description...........................................................................................................................8 2.4.2 Usage....................................................................................................................................9 2.4.3 Example..............................................................................................................................10 2.5 Free-Fall Detection...................................................................................................................10 2.5.1 Description.........................................................................................................................10 2.5.2 Usage..................................................................................................................................10 2.5.3 Example..............................................................................................................................10 2.6 Interrupt function (INT-pin) .....................................................................................................11 2.6.1 Usage..................................................................................................................................11 2.7 Clock .........................................................................................................................................11 3 Addressing Space ............................................................................................................ 12 3.1 3.2 3.3 Register Description................................................................................................................12 Non-volatile memory ...............................................................................................................12 Registers...................................................................................................................................12 4 Serial Interfaces ............................................................................................................... 17 4.1 SPI Interface .............................................................................................................................17 2/ 35 Rev. 0.12 VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 CMA3000-D0X Series 4.1.1 4.1.2 4.1.3 SPI frame format................................................................................................................17 Examples of SPI communication.....................................................................................18 Example of register read...........................................................................................................18 4.1.2.1 Multiple slave devices in SPI bus ....................................................................................18 4.2 I2C Interface ..............................................................................................................................19 4.2.1 I2C frame format.................................................................................................................19 4.2.1.1 4.2.1.2 I2C write mode ............................................................................................................................19 I2C read mode.............................................................................................................................19 4.2.2 Examples of I2C communication......................................................................................19 5 Electrical Characteristics ................................................................................................ 20 5.1 5.2 Absolute maximum ratings.....................................................................................................20 Power Supply ...........................................................................................................................20 5.3 Digital I/O Specification...........................................................................................................20 5.3.1 Digital I/O DC characteristics ...........................................................................................20 5.3.2 Digital I/O level shifter.......................................................................................................20 5.3.3 SPI AC characteristics ......................................................................................................21 5.3.4 I2C AC characteristics .......................................................................................................21 6 Package Characteristics.................................................................................................. 22 6.1 Dimensions...............................................................................................................................22 7 Application information ................................................................................................... 23 7.1 7.2 7.3 7.4 7.5 7.6 Pin Description.........................................................................................................................23 Recommended circuit diagram ..............................................................................................23 Recommended PWB layout ....................................................................................................24 Mounting recommendations...................................................................................................24 Assembly instructions ............................................................................................................25 Tape and reel specifications...................................................................................................25 8 Data sheet references ...................................................................................................... 26 8.1 Offset.........................................................................................................................................26 8.1.1 Offset calibration error .....................................................................................................26 8.1.2 Offset temperature error...................................................................................................26 8.2 Sensitivity .................................................................................................................................26 8.2.1 Sensitivity calibration error..............................................................................................27 8.2.2 Sensitivity temperature error ...........................................................................................27 8.3 8.4 8.5 8.6 Linearity ....................................................................................................................................27 Noise .........................................................................................................................................28 Bandwidth.................................................................................................................................29 Cross-axis sensitivity ..............................................................................................................29 VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 3/ 35 Rev. 0.12 CMA3000-D0X Series 8.7 Turn-on time .............................................................................................................................30 9 Known issues ................................................................................................................... 31 9.1 Acceleration data reading via I2C bus....................................................................................31 9.1.1 Interrupt based acceleration reading ..............................................................................31 9.1.2 Acceleration reading without interrupts .........................................................................32 9.2 Leakage current when VDD - DVIO > 0.3 V ............................................................................32 10 Order Information............................................................................................................. 33 11 Document Change Control.............................................................................................. 34 12 Contact Information ......................................................................................................... 35 VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 4/ 35 Rev. 0.12 CMA3000-D0X Series 1 1.1 General Description Introduction CMA3000-D0X is a three axis accelerometer family targeted for high volume products requiring small size, low price and low power consumption. It consists of a 3D-MEMS sensing element and a signal conditioning ASIC in a wafer level package. Block diagram of CMA3000-D0X is shown in Figure 1 below. C/V Analog calibration & ADC DEMUX 1:3 Low-pass Filter Low-pass Filter Low-pass Filter SCK/SCL SPI & I2C i/f MISO MOSI/SDA CSB Oscillator & clock Reference NonVolatile Memory Motion detector Free fall detector Control & INT INT Figure 1. CMA3000-D0X block diagram with digital SPI and I2C interface This document, no. 8281000, describes the product specification (e.g. operation modes, user accessible registers, electrical properties and application information) for the CMA3000-D0X family. The specification for an individual sensor is available in the corresponding data sheet. 1.2 1.2.1 Functional Description Sensing element The sensing element is manufactured using proprietary bulk 3D-MEMS process, which enables robust, stable and low noise & power capacitive sensors. The sensing element consists of three acceleration sensitive masses. Acceleration will cause a capacitance change that will be then converted into a voltage change in the signal conditioning ASIC. 1.2.2 Interface IC CMA3000 includes an internal oscillator, reference and non-volatile memory that enable the sensor's autonomous operation within a system. The sensing element is interfaced via a capacitance-to-voltage (CV) converter. Following calibration in the analog domain, the signal is A/D-converted and then digitally filtered. Sensor output is user selectable digital SPI or I2C interface. In measurement mode acceleration data can be read via the serial bus and in power down mode the device is in-active. Other supported features are motion and free-fall detection. In these modes, the sensor will generate an interrupt when a pre-defined condition has been met. Measurement range can be selected by register command. 1.2.3 Factory calibration Sensors are factory calibrated. Trimmed parameters are gain, offset, internal current reference and frequency of the internal oscillator. Calibration parameters will be read automatically from the internal non-volatile memory during sensor startup. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 5/ 35 Rev. 0.12 CMA3000-D0X Series 1.2.4 Supported features Supported features are listed in Table 1 below. Table 1. CMA3000-D0X devices’ summary. Features Supply voltage I/O voltage Measuring range (selectable) Resolution (2g /8g range) Sensitivity (2g /8g range) Motion detection Free fall detection Interface Clock CMA3000-D01 1.7 V – 3.6 V 1.7 V – 3.6 V ±2 g, ±8 g 17 mg / 67 mg 56 counts/g / 14 counts/g User enabled User enabled SPI max 500 kHz, I2C fast mode 400 kHz Internal 1.2.5 1.2.5.1 Operation modes Power Down In Power Down (PD) mode device's volatile register keep their contents and the current consumption is minimized. Power down mode is the default mode after start up. 1.2.5.2 Measurement In Measurement mode (Meas) the sensor offers acceleration information via the digital SPI/I2C interface. Interrupt can be activated via INT-pin, when each xyz-acceleration sample is ready to be read. Measurement range and sample rate are user selectable according to Table 2. Measurement mode can be activated by detected motion. 1.2.5.3 Motion Detection Motion Detection (MD) mode is intended to be used to save system level power consumption. In this mode, CMA3000-D0X activates the interrupt via the INT-pin when motion is detected. Motion sensitivity level can be configured via the SPI or I2C bus. Moreover, duration of the motion to be detected can be user defined. Once the interrupt has happened, the detected direction can be read out from the corresponding status register. Low sample rate (10 Hz) band-pass filtered acceleration information is available in MD mode. The device can be configured to switch automatically into the measurement mode with highest sampling rate after motion detection. 1.2.5.4 Free-Fall Detection Free-Fall Detection (FFD) is intended to be used to save system resources. This feature activates the interrupt via the INT-pin when free-fall is detected. Acceleration information is available when the FFD is enabled. 1.2.6 Interrupt The CMA3000 has a dedicated output pin (INT) to be used as the interrupt for the master controller. Interrupt conditions can be activated and deactivated via the SPI or I2C bus. Once the interrupt has happened, the interrupt source can be read out from the corresponding status register. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 6/ 35 Rev. 0.12 CMA3000-D0X Series 1.2.7 Operational flow chart CMA3000 power up CMA3000 power down mode can 2 be activated via SPI/I C bus CMA3000 in power down mode CMA3000 operation mode can be 2 changed via SPI/I C bus Activate CMA3000 operation 2 mode via SPI/I C bus Measurement mode Low pass filtered XYZ acceleration data available Ranges and data rates: 2g: 400Hz, 100Hz 8g: 400Hz, 100Hz, 40Hz INT-pin gives interrupt when new data is available Additional configuration option: • INT-pin data ready functionality can be disabled Free fall mode Low pass filtered XYZ acceleration data available Ranges and data rates: 2g: 400Hz, 100Hz 8g: 400Hz, 100Hz INT-pin gives interrupt when free fall is detected Additional configuration option: • Free fall trigger conditions can be configured (time & acceleration) Motion detection mode Band pass filtered XYZ acceleration data available Ranges and data rates: 8g: 10Hz INT-pin gives interrupt when motion is detected Additional configuration option: • Motion detection trigger conditions can be configured (time & acceleration) • CMA3000 can be configured to switch to measurement mode with 400Hz output data rate after motion is detected CMA3000 operation in application Figure 2. CMA3000 operational flow chart. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 7/ 35 Rev. 0.12 CMA3000-D0X Series 2 2.1 Reset and power up, Operation Modes, HW functions and Clock Reset and power up The CMA3000 has internal power-on reset circuit. It releases the internal reset-signal once the power supplies will be within the specified range. After releasing the internal reset, the CMA3000 will read configuration and calibration data from the non-volatile memory to volatile registers. Then the CMA3000 will make parity check to the read memory content. The STATUS register's PERR-bit="0" shows successful memory read operation. Device can be externally reset by writing the sequence 02h, 0Ah, 04h into the RSTR-register. 2.2 Power Down mode The CMA3000-D0X enters the power down mode by default after power-on reset and initialization of the volatile registers. PD can also be set by writing MODE[2:0] = 000b (or MODE[2:0] = 111b) to CTRL register. Output registers will keep their content in the power down mode. 2.3 2.3.1 Measurement Mode Description The CMA3000-D0X is set to a measurement mode by writing MODE[2:0] = 0XXb to CTRL register. Data will be reliable in the output registers after the product specific turn-on time. Default sample rate is 400 Hz (MODE[2:0] = 010b). Other data rates are 100 Hz (MODE[2:0] = 001b) and 40 Hz (MODE[2:0] = 011b). Table 2. CMA3000-D0X measurement ranges and output sample rates Measurement range Output sample rates 2g 8g 400 Hz, 100 Hz 400 Hz, 100 Hz, 40 Hz INT-pin gives an interrupt by default when new data is available. 2.3.2 Usage Acceleration data can be read from data output registers DOUTX, DOUTY and DOUTZ. See section 2.6 for INT-pin configuration details. 2.4 2.4.1 Motion Detection Mode Description In MD mode the device works at 10 Hz sample rate and the fixed measurement range is 8 g. Signal is band pass filtered and fed to threshold level programmable digital comparator and a configurable trigger function. Filtered signal is also available at output registers. The device can be configured to switch automatically into the measurement mode with highest sampling rate (400Hz) after motion is detected. The measurement range used will be defined by G_RANGE bit. Nominal BPF's -3 dB high-pass frequency is 1.3 Hz and -3 dB low-pass frequency is 3.8 Hz. See Figure 3 below. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 8/ 35 Rev. 0.12 CMA3000-D0X Series Figure 3. The MD band-pass filter's frequency response. Threshold level can be controlled by MDTHR[6:0] bits and the time condition – how long the threshold should be exceeded to trigger – by MDTMR[3:0] bits. Acceleration X, Y or Z Acceleration exceeds the threshold level due to motion ∆T period of time ∆T +TL T1 -TL T2 T3 T4 T5 T6 T7 T8 Time INT output " 1" " 0" T1 T2 T3 T4 T5 T6 T7 T8 Figure 4. Motion detector operation 2.4.2 Usage The MD mode can be enabled by setting the MODE[2:0] bits in the MODE register to "100". The trigger condition, threshold and duration, can be defined by setting MDTHR and MDFFTMR registers respectively. The device can be configured to switch automatically into 400Hz measurement mode by setting the MDET_EXIT bit in CTRL register. See section 3.3 register and section 2.6 for the interrupt functionality details. In MD mode, band pass filtered acceleration data with 10Hz output data rate is available in registers DOUTX, DOUTY and DOUTZ. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 9/ 35 Rev. 0.12 CMA3000-D0X Series 2.4.3 Example Below is a simple example of motion detection usage: 1. Write "00001000" (08h) into the MODE register (enable motion detection mode, MODE[2:0] bits = '100'). 2. Band pass filtered acceleration data at 10 Hz sample rate is available at the output registers. 3. The INT-pin is activated when motion is detected; see section 2.6 for detailed INT-pin information. 2.5 2.5.1 Free-Fall Detection Description During free-fall in the gravitation field, all 3 orthogonal acceleration components are ideally equal to zero. Due to practical non-idealities, detection must be done using Threshold Level (TL) greater than 0. When enabled, the Free-Fall Detection (FFD) will monitor the measured acceleration in the X, Y and Z directions. If all measured XYZ acceleration values stay within the TL longer than time TFF (Figure 5 below), the FFD will generate an interrupt to the INT-pin. TL can be controlled by FFTHR [6:0] and TFF by FFTMR [3:0] bits. Acceleration X, Y and Z +TL T1 -TL T2 T3 T4 T5 T6 T7 T8 Time INT output "1" TFF "0" T1 T2 T3 T4 T5 T6 T7 T8 Time Figure 5. Free Fall condition 2.5.2 Usage Free-fall detection can be enabled by setting MODE[2:0] bits in the CTRL register to "101" (sample rate 100 Hz) or to "110" (sample rate 400 Hz). See section 3.3 for MODE register details. Acceleration data is available in registers DOUTX, DOUTY and DOUTZ as in measurement mode. See section 3.3 for output register and section 2.6 for interrupt functionality details. 2.5.3 Example Below is a simple example of free-fall detection usage: 1. Write "00001100" (0Ch) into the MODE register (enable 400 Hz free fall detection mode, MODE[2:0] bits = '110'). 2. Acceleration data can be read normally 3. INT-pin is activated when free fall is detected. See section 2.6 for detailed INT-pin information. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 10/ 35 Rev. 0.12 CMA3000-D0X Series 2.6 2.6.1 Interrupt function (INT-pin) Usage Depending on the CMA3000 operational configuration, the INT-pin can give an interrupt in following cases: 1. Normal measurement mode: INT-pin gives interrupt when new data is available 2. Free fall detection mode: INT-pin gives an interrupt to signal that free fall is detected 3. Motion detection mode: INT-pin gives an interrupt to signal that motion is detected Interrupt polarity (active high/low) can be configured with CTRL register's INT_LEVEL bit. If the CMA3000 is in normal measurement mode, the INT pin is automatically cleared by reading the acceleration output data. INT-pin data ready functionality can be disabled by setting the CTRL register's INT_DIS bit. If INT-pin gives an interrupt in free fall or motion detection mode, the INT_STATUS register must be read to acknowledge and clear the interrupt. In motion detection mode the INT_STATUS register content gives information of which XYZ directions have exceed the trigger conditions. See section 3.3 for CTRL and INT_STATUS register details. 2.7 Clock The CMA3000 has an internal factory trimmed oscillator and clock generator. Internal frequencies vary product by product. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 11/ 35 Rev. 0.12 CMA3000-D0X Series 3 Addressing Space The CMA3000 register contents and bit definitions are described in more detail in the following sections. 3.1 Register Description The CMA3000 addressing space is presented in Table 3 below. Table 3. List of registers Address 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0Ch 0Dh-19h Name WHO_AM_I REVID CTRL STATUS RSTR INT_STATUS DOUTX DOUTY DOUTZ MDTHR MDFFTMR FFTHR I2C_ADDR Description Identification register ASIC revision ID, fixed in metal Configuration (por, operation modes) Status (por, EEPROM parity) Reset Register Interrupt status register Mode (R, RW, NV) R R RW R RW R R R R RW RW RW R Reg. type Output Output Conf Output Conf Output Output Output Output Conf Conf Conf Conf X channel output data register Y channel output data register Z channel output data register Motion detection threshold value register Free fall and motion detection time register Free fall threshold value register I C device address Reserved 2 Address is the register address in hex format. RW – Read / Write register, R – Read-only register, NV – non-volatile register content. 3.2 Non-volatile memory The CMA3000 has an internal non-volatile memory for calibration and configuration data. Memory content will be programmed during production and is not user configurable. Initial configuration values mirrored to volatile registers after reset can be found in the following section 3.3. 3.3 Registers Address: 00h Register name: WHO_AM_I, Identification register Initial Bits Mode Name Description Value 7 R 0 Reserved 6:0 R xxh Identification register Address: 01h Register name: REVID, ASIC revision ID Initial Bits Mode Name Value 7:4 R 1h REVMAJ 3:0 R 0h REVMIN Description Major revision number Minor revision number (metal mask change) VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 12/ 35 Rev. 0.12 CMA3000-D0X Series Address: 02h Register name: CTRL, Control register Initial Bits Mode Name Value 7 RW 0 G_RANGE Description 0 – 8g measurement range is selected 1 – 2g measurement range is selected 6 RW 0 INT_LEVEL 0 – INT is active when INT pin is set to logic high 1 – INT is active when INT pin is set to logic low 5 RW 0 MDET_EXIT 0 – Device goes to measurement mode after motion is detected (400Hz ODR) 1 – Device remains in motion detection mode after motion is detected. 4 RW 0 I2C_DIS 0 – I2C interface enabled 1 – I2C interface disabled. 3:1 RW 0 MODE[2:0] 000 – Power down mode, default mode. 001 – Measurement mode, 100 Hz ODR. 010 – Measurement mode, 400 Hz ODR. 011 – Measurement mode, 40 Hz ODR. 100 – Motion detection mode, 10 Hz ODR. 101 – Free fall detection mode, 100 Hz ODR. 110 – Free fall detection mode, 400 Hz ODR. 111 – Power down mode 0 RW 0 INT_DIS 0 – Interrupts enabled • Measurement mode: data ready • Motion detection mode: motion detected • Free fall detection mode: free fall detected 1 – Interrupts disabled Note that after changing MODE bits it may take some time to recover the target operating state. ODR = Output Data Rate. Address: 03h Register name: STATUS, Status register Initial Bits Mode Name Value 7:4 0h 3 R 0 PORST 2:1 0 0h 0 Description Reserved 1 means Power-on-Reset state. Reading the register sets always bit to 0. Reserved 0 – No EEPROM Parity Error 1 – EEPROM Parity Error R PERR Address: 04h Register name: RSTR, Reset register Initial Bits Mode Name Value 7:0 RW 0h RSTR Description Writing 02h, 0Ah, 04h in this order resets ASIC. Other sequences reserved. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 13/ 35 Rev. 0.12 CMA3000-D0X Series Address: 05h Register name: INT_STATUS, Interrupt status register Initial Bits Mode Name Description Value 7:3 0h Reserved 2 R 0 FFDET 1 – Free fall detected (i.e. 0 g acceleration) 0 – Free fall not detected 1:0 R 0h MDET 00 – No motion detected 01 – Trigger on X-axis 10 – Trigger on Y-axis 11 – Trigger on Z-axis Note: Contents of INT_STATUS [2:0] is set to '000' always after reading of this register. Address: 06h Register name: DOUTX, X-channel output register Initial Bits Mode Name Description Value 7:0 R 0h DOUTX See SPI data frame description for more info. Address: 07h Register name: DOUTY, Y-channel output register Initial Bits Mode Name Description Value 7:0 R 0h DOUTY See SPI data frame description for more info. Address: 08h Register name: DOUTZ, Z-channel output register Initial Bits Mode Name Description Value 7:0 R 0h DOUTZ See SPI data frame description for more info. The bit level description for acceleration data from DOUTX ... DOUTZ registers is presented in Table 4 below. The acceleration data is presented in 2's complement format. At 0 g acceleration the output is ideally 0h. Table 4. Bit level description in [mg] for acceleration registers of CMA3000-D01. Range 2g 2g 8g 8g s = sign bit G_RANGE 1 1 0 0 Output sample B7 rate 400 Hz, 100 Hz s 40 Hz, 10 Hz s 400 Hz, 100 Hz s 40 Hz, 10 Hz s B6 B5 B4 B3 143 571 571 571 B2 71 286 286 286 B1 36 143 143 143 B0 1/56 = 18 mg 1/14 = 71 mg 1/14 = 71 mg 1/14 = 71 mg 1142 571 286 4571 2286 1142 4571 2286 1142 4571 2286 1142 VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 14/ 35 Rev. 0.12 CMA3000-D0X Series Address: 09h Register name: MDTHR, Motion detection threshold value register Initial Bits Mode Name Description Value Reserved 7 0 6:0 RW 8h MDTHR[6:0] Motion detection threshold level absolute value. See detailed bit level weighting in Table 5 (bits [6:0]) Table 5. Bit level description in [mg] for motion detection threshold of CMA3000-D01. Range 8g x=not used bit G_RANGE 0 B7 x B6 4571 B5 2286 B4 1142 B3 571 B2 286 B1 143 B0 1/14 = 71 mg Address: 0Ah Register name: MDFFTMR, Motion and free fall detection time register Initial Value Bits Mode Name Description Motion detection timer bits 7:4 RW 3h MDTMR[3:0] 3:0 RW 3h FFTMR [3:0] Free fall detection timer bits The LSB bit weighting for MDTMR and FFTMR bits are converted to seconds by using the currently configured CMA3000 output data rate (ODR), as follows: MDTMRLSB[sec] = 1 / ODR[Hz], and FFTMRLSB[sec] = 1 / ODR[Hz] Were the ODR is the currently configured CMA3000 output data rate, which is defined by MODE bits (bits [3:1] in CTRL register). An example for CMA3000-D01 timer bit weighting is presented in Table 6 below. Table 6. An example for CMA3000-D01 MDTMR and FFTMR bit level descriptions in [ms]. Timer Register bit number Timer bit number B7 MDTMR b3 MDTMR B6 MDTMR b2 B5 MDTMR B1 B4 MDTMR b0 B3 FFTMR b3 FFTMR B2 FFTMR b2 B1 FFTMR B1 B0 FFTMR b0 CMA3000-D01, MODE bits x10 ODR: 400Hz CMA3000-D01, MODE bits x01 ODR: 100Hz CMA3000-D01, MODE bits 100 ODR: 10Hz x=not used bit x x x x x 400 x x 200 x x 1/10s = 100 ms 20 80 x 10 40 x 5 20 x 1/400s = 2,5 ms 1/100s = 10 ms x VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 15/ 35 Rev. 0.12 CMA3000-D0X Series Address: 0Bh Register name: FFTHR, Free fall threshold value register Initial Bits Mode Name Description Value Reserved, write these bits to '000' 7:5 0h 4:0 RW 8h FFTHR[5:0] Free fall detection threshold level absolute value. See detailed bit level weighting in Table 7 below. Table 7. Bit level description in [mg] for free fall detection threshold of CMA3000-D01. Range 2g 8g x=not used bit G_RANGE 1 0 B5 143 x B4 71 x B3 36 571 B2 1/56=18 mg 286 B1 x 143 B0 x 1/14 = 71 mg Address: 0Ch Register name: I2C_ADDR, Device address for I2C bus Initial Bits Mode Name Description Value Reserved 7 0 6:0 RW 1Ch ADDR[6:0] 7-bit device address for I2C bus. Register content is non-volatile. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 16/ 35 Rev. 0.12 CMA3000-D0X Series 4 Serial Interfaces Communication between the CMA3000 sensor and master controller is based on serial data transfer and a dedicated interrupt line (INT-pin). Two different serial interfaces are available for the CMA3000 sensor: SPI and I2C (Phillips specification V2.1). Selection between these two interfaces is done using the chip select signal. The I2C interface can be also disabled by re-configuring register content. The CMA3000 acts as a slave on both the SPI and I2C bus. 4.1 SPI Interface SPI bus is a full duplex synchronous 4-wire serial interface. It consists of one master device and one or more slave devices. The master is defined as a micro controller providing the SPI clock, and the slave as any integrated circuit receiving the SPI clock from the master. The CMA3000 sensor always operates as a slave device in master-slave operation mode. A typical SPI connection is presented in Figure 6. MASTER MICROCONTROLLER DATA OUT (MOSI) DATA IN (MISO) SERIAL CLOCK (SCK) SS0 SS1 SS2 SS3 SI SO SCK CS SI SO SCK CS SI SO SCK CS SLAVE SI SO SCK CS Figure 6. Typical SPI connection The data transfer uses the following 4-wire interface: MOSI MISO SCK CSB master out slave in master in slave out serial clock chip select (low active) µC → CMA3000 CMA3000 → µC µC → CMA3000 µC → CMA3000 4.1.1 SPI frame format CMA3000 SPI frame format and transfer protocol is presented in Figure 7. CSB SCK MO SI MISO A5 1 A4 2 A3 3 A2 PO R ST 4 A1 5 A0 6 7 RB/W 8 9 DI7 DO 7 10 D I6 DO6 11 DI5 DO 5 12 DI4 DO4 13 DI3 DO 3 14 DI2 D O2 15 DI1 DO 1 16 DI0 DO0 Figure 7. SPI frame format Each communication frame contains 16 bits. The first 8 bits in MOSI line contains info about the register address being accessed and the operation (read/write). The first 6 bits define the 6 bit address for the selected operation, which is defined by bit 7 (‘0’ = read ‘1’ = write), which is followed by one zero bit. The later 8 bits in the MOSI line contain data for a write operation and are VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 17/ 35 Rev. 0.12 CMA3000-D0X Series ‘don’t-care’ for a read operation. CMA3000 samples bits in from MOSI line on the rising edge of SCK and bits out to MISO line on falling edge of SCK. After the two constant '0' bits in the MISO line are the PORST status bits. All three PORST status bits have the same value as the PORST bit in register STATUS. Bits 6 and 8 are always '0'. Bit 7 is always ‘1’. The later 8 bits contain data for a read operation. For write commands, data is written into the addressed register after the rising edge of CSB. For read commands, data is latched into the internal SPI output register (shift register) on the 8th rising edge of SCK. The output register is shifted out MSB first over MISO output. When the CSB is high state between data transfers, the MISO line is in the high-impedance state. 4.1.2 4.1.2.1 Examples of SPI communication Example of register read An example of X-axis and Y-axis acceleration read command is presented in Figure 8. The master gives the register address to be read via the MOSI line: '06' in hex format and '000110' in binary format, register name is DOUTX). 7th bit is set to '0' to indicate the read operation. The sensor replies to a requested operation by transferring the register content via MISO line. After transferring the asked DOUTX register content, the master gives next register address to be read: '07' in hex format and '000111' in binary format, register name is DOUTY. The sensor replies to the requested operation by transferring the register content MSB first. CSB SCLK MOSI MISO 0001100 PO RST DX5 DX4 DX3 DX2 DX 1 LS B DX0 MS B DX7 DX6 0001110 PO RST MSB DY 7 DY 6 DY 5 DY 4 DY 3 DY2 DY1 LSB DY 0 Figure 8. An example of SPI read communication. 4.1.3 Multiple slave devices in SPI bus Since both SPI and I2C interfaces are enabled by default, certain precautions should be taken care of when the CMA3000 is connected to a SPI bus with multiple slave devices. In case of multiple devices on same SPI bus, it's important to prevent MOSI_SDA pin changes during SCK_SCL pin high state. If the MOSI_SDA pin state is changed when the SCK_SCL pin is in high state, the I2C transmission is engaged, see Figure 9 below. Figure 9. MOSI_SDA pin change during SCK_SCL high state engages I2C transmission. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 18/ 35 Rev. 0.12 CMA3000-D0X Series In cases with multiple slaves in SPI bus it is recommended that I2C transmission is disabled by setting I2C_DIS bit to '1' in CRTL register. After CMA3000 start up the I2C_DIS bit is always 0 (I2C transmission enabled). 4.2 I2C Interface I2C is a 2-wire serial interface. It consists of one master device and one or more slave devices. The master is defined as a micro controller providing the serial clock (SCL), and the slave as any integrated circuit receiving the SCL clock from the master. The CMA3000 sensor always operates as a slave device in master-slave operation mode. When using an SPI interface, a hardware addressing is used (slaves have dedicated CSB signals), the I2C interface uses a software based addressing (slave devices have dedicated bit patterns as addresses). The default I2C device address for CMA3000 is 00011100b (1Ch) (pre-programmed during CMA3000 production). The CMA3000 is compatible to the Philips I2C specification V2.1. Main used features of the I2C interface are: - 7-bit addressing, CMA3000 I2C device address is 1Ch - Supports standard mode and fast mode - Start / Restart / Stop - Slave transceiver mode - Designed for low power consumption 4.2.1 4.2.1.1 I2C frame format I2C write mode In I2C write mode, the first 8 bits after device address define the CMA3000 internal register address to be written. 4.2.1.2 I2C read mode The read mode operates as described in Philips I2C specification. I2C read operation returns the content of the register which address is defined in I2C read frame. Read data is acknowledged by I2C master. 4.2.2 Examples of I2C communication Examples of I2C communication are presented below in Figure 10. Address byte includes 7 device address bits (1Ch=0011100b) followed by the R/W bit. Figure 10 I2C format VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 19/ 35 Rev. 0.12 CMA3000-D0X Series 5 Electrical Characteristics All voltages are reference to ground. Currents flowing into the circuit have positive values. 5.1 Absolute maximum ratings The absolute maximum ratings of the CMA3000 are presented in Table 8 below. Table 8. Absolute maximum ratings of the CMA3000 Parameter Supply voltage (Vdd, DVIO) DVIO Voltage at input / output pins ESD (Human body model) Storage temperature Storage / operating temperature Mechanical shock * Exposure to ultrasonic energy (e.g. ultra sonic washing or welding) * 1 m drop on concrete may cause >>10000 g shock. Value -0.3 to +3.6 Vdd+0.2 -0.3 to (Vdd + 0.3) ±2 -40 ... +125 -40 ... +85 < 10 000 Not allowed Unit V V V kV °C °C g 5.2 Power Supply Please refer to the corresponding product datasheet. 5.3 5.3.1 Digital I/O Specification Digital I/O DC characteristics Table 9. DC characteristics of digital I/O pins. No. Parameter Conditions Input: CSB, SCL with pull up SDA, SCK and MOSI without pull up / pull down Pull up current: VIN = 0V 2 CSB, SCL VIN = DVIO 2a. Input Leakage Input high voltage 3 Input low voltage 4 Hysteresis 5 Output terminal: MISO, SDA, INT Output high voltage I > -1 mA 7 Output low voltage I < 1 mA 8 Tristate leakage 0 < VMISO < DVIO 9 Symbol Min Typ Max Unit µA 0.035 0.82*Dvio 0.38*Dvio 0.63*Dvio Dvio 0.3*Dvio 0.0063 µA V V V V V µA IPU IIN VIH VIL VHYST VOH VOL ILEAK -0.35 0.54*Dvio 0.18*Dvo 0.16*Dvio 0.7*Dvio 0 5.3.2 Digital I/O level shifter All the CMA3000 products have an internal level shifter that can be used to interface e.g. a micro controller using lower supply than the CMA3000. The level shifter is "programmed" by providing the supply voltage of the interfaced device to the DVIO-pin. Please refer to the corresponding product data sheet for details. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 20/ 35 Rev. 0.12 CMA3000-D0X Series 5.3.3 SPI AC characteristics The AC characteristics of the CMA3000 SPI interface are defined in Figure 11 and in Table 10. TLS1 CSB SCK TCH TCL TLS2 TLH THOL MOSI MSB in DA T A in TSET LSB in TVAL1 MISO MSB out TVAL2 DATA out LSB out TLZ Figure 11. Timing diagram for SPI communication. Table 10. AC characteristics of SPI communication. No. Parameter Time from CSB (10%) to (1 SCK (90%) Time from SCK (10%) to (1 CSB (90%) SCK low time SCK high time SCK Frequency Load capacitance at MISO < 50 pF Load capacitance at MISO < 50 pF Conditions Symbol TLS1 TLS2 Min 0.80* Tper/2 0.80* Tper/2 0.80* Tper/2 0.80* Tper/2 Tper/2 Tper/2 0.5 Typ Max Unit ns ns Terminal CSB, SCK 1 2 Terminal SCK 3 4 5 TCL TCH fsck = 1/Tper TSET Tper/4 ns ns MHz Terminal MOSI, SCK 6 Time from changing MOSI (10%, 90%) to SCK (90%) Data setup time Time from SCK (90%) to changing MOSI (10%, 90%) Data hold time Time from CSB (10%) to stable MISO (10%, 90%) Time from CSB (90%) to high impedance state of (1 MISO . Time from SCK (10%) to (1 stable MISO (10%, 90%) . Load capacitance at MISO < 50 pF Load capacitance at MISO < 50 pF ns 7 THOL Tper/4 ns Terminal MISO, CSB 8 9 TVAL1 TLZ Tper/4 Tper/4 ns ns Terminal MISO, SCK 10 Load capacitance at MISO < 50 pF TVAL2 1.5*Tper/4 ns Terminal MOSI, CSB Time between SPI cycles, CSB at high level (90%) 1) Tper is SCK period 11 TLH 11 * Tper ns 5.3.4 I2C AC characteristics Please, see Phillips Semiconductors, The I2C bus specification, Version 2.1, January 2000, pp. 3133. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 21/ 35 Rev. 0.12 CMA3000-D0X Series 6 6.1 Package Characteristics Dimensions The package dimensions are presented in Figure 12 below (dimensions in millimeters [mm] with ±50 µm tolerance). Figure 12. Package dimensions in mm with ±50 µm tolerance for reference only. Please check the corresponding data sheet for details. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 22/ 35 Rev. 0.12 CMA3000-D0X Series 7 7.1 Application information Pin Description CMA3000 pin numbers are presented in Figure 14 below and pin descriptions in Table 11. Z X Y Figure 13. CMA3000 sensing directions Table 11. CMA3000 pin descriptions Pin # 1 2 3 4 5 6 7 8 Name VDD VSS DVIO MISO SCK_SCL MOSI_SDA CSB INT CMA3000-D01 Figure 14. CMA3000 pin numbers Supply voltage Ground I/O Supply SPI Serial Data Output (MISO) SPI Serial Clock (SCK) / I2C Serial Clock (SCL) SPI Serial Data Input (MOSI) / I2C Serial Data (SDA) Chip select / I2C enable Interrupt 7.2 Recommended circuit diagram 1. Connect 100 nF SMD capacitor between each supply voltage and ground level. 2. Use separate regulator for digital IO supply (DVIO). 3. Serial interface (SPI or I2C) logical '1' level is determined by DVIO supply voltage level. Recommended circuit diagram for the CMA3000 with SPI interface is presented in Figure 15 below. SPI I2C INT CSB 8 7 6 5 INT CSB MOSI DVIO SCK VDD 1 2 VDD VSS DVIO MISO VDD 1 2 3 4 VDD VSS DVIO MISO INT CSB MOSI_SDA SCK_SCL 8 7 6 5 INT DVIO MISO 100n 100n 3 4 MOSI_SDA SCK_SCL SDA SCL 100n 100n Figure 15 Recommended circuit diagrams for CMA3000-D0X VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 23/ 35 Rev. 0.12 CMA3000-D0X Series 7.3 Recommended PWB layout General PWB layout recommendations for CMA3000 products (refer to Figure 15 and Figure 16): 1. Locate 100 nF SMD capacitors right next to the CMA3000 package 2. Ensure low impedance by maximizing the ground plane under the component. Recommended PWB pad layout for CMA3000 is presented in Figure 16 below (dimensions in micrometers, [µm]). Figure 16. Recommended PWB pad layout for CMA3000. Recommended PWB layout for the CMA3000-D0X is presented in Figure 17 below (circuit diagram presented in Figure 15 above). Note the symmetrical ground plane under the component. Figure 17. Recommended PWB layout for CMA3000-D0X with SPI interface (not actual size, for reference only). 7.4 Mounting recommendations For the best sensor stability mechanical stresses due to mounting should be minimized. Potential causes of mechanical stress to be avoided are • • • • Contact with other structures due to too small mechanical tolerances. Placement under or next to mechanical push button contacts. Locations near hot spots (micro controller, power amplifier etc) due to temperature effects. Mounting close to PWB attachment point e.g. screw or snap. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 24/ 35 Rev. 0.12 CMA3000-D0X Series • • PWB areas that can bend or vibrate. The use of under fill or coating. Please note that under fill or coating the neighboring component should not be in contact with the sensor. Due to sampled signal conditioning strong magnetic or electric fields may cause noise in the sensor output. Therefore mounting near strong magnetic or electric fields is not recommended. 7.5 Assembly instructions The Moisture Sensitivity Level (MSL) of the CMA3000 component is 2 according to the IPC/JEDEC J-STD-020D. Please refer to the document TN68_CMA3000_Assembly_Instructions for more detailed information about CMA3000 assembly. 7.6 Tape and reel specifications Please refer to the document TN68_CMA3000_Assembly_Instructions for tape and reel specifications. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 25/ 35 Rev. 0.12 CMA3000-D0X Series 8 8.1 Data sheet references Offset CMA3000's offset will be calibrated in X = 0 g, Y = 0 g, and Z = +1 g (Z measuring axis is parallel to earth’s gravitation) position, see Figure 18. Z-axis in +1 g position Y X Earth’s gravitation Pin #1 Figure 18. CMA3000 offset (0 g) position. 8.1.1 Offset calibration error Offset calibration error is the difference between the sensor's actual output reading and the nominal output reading in calibration conditions. Error is calculated by Equation 1 Offset X −axisCalibEr = Output X −axis − Output ⋅ 1000 , Sens where OutputX-axisCalibEr is sensor’s X-axis calibration error in [mg], OutputX-axis is sensor’s X-axis output reading [counts], Output is sensor’s nominal output in 0 g position and Sens sensor’s nominal sensitivity [counts/g]. 8.1.2 Offset temperature error Offset temperature error is the difference between the sensor's output reading in different temperatures and the sensor’s calibrated offset value at room temperature. Error is calculated by Equation 2 Offset X − axisTempEr @ T = Output X − axis @ T − Output X − axis @ RT Sens ⋅1000 , where OutputX-axisTempEr@T is sensor’s X-axis temperature error in [mg] in temperature T, OutputX-axis@T is sensor’s X-axis output reading [counts] in temperature T, OutputX-axis@T X-axis output reading [counts] at room temperature RT and Sens sensor’s nominal sensitivity [counts/g]. Sensor is in 0 g position for every measurement point. 8.2 Sensitivity During sensitivity calibration, the sensor is placed in ±1 g positions having one of the sensor’s measuring axes at a time parallel to the earth’s gravitation, see Figure 19. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 26/ 35 Rev. 0.12 CMA3000-D0X Series Pin #1 Y-axis in +1 g position X Z Z X Earth’s gravitation Y-axis in -1 g position Pin #1 Figure 19. CMA3000 positions for Y-axis sensitivity measurement. Sensitivity is calculated by Equation 3 SensY − axis = OutputY − axis @ +1g − OutputY − axis @ −1g 2g , where SensY-axis is sensor’s Y-axis sensitivity in [counts/g], OutputY-axis@+1g sensor’s Y-axis output reading [counts] in +1 g position and OutputY-axis@-1g is sensor’s Y-axis output reading [counts] in -1 g position. 8.2.1 Sensitivity calibration error Sensitivity calibration error is the difference between sensor’s measured sensitivity and the nominal sensitivity at room temperature conditions. Error is calculated by Equation 4 SensY − axisCalibE r = SensY − axis − Sens ⋅100% , Sens where SensY-axisCalibEr is sensor’s Y-axis sensitivity calibration error in [%], SensY-axis sensor’s Y-axis sensitivity [counts/g] at room temperature conditions and Sens is sensor’s nominal sensitivity [counts/g]. 8.2.2 Sensitivity temperature error Sensitivity temperature error is the difference between sensor’s sensitivity at different temperatures and the calibrated sensitivity. Error is calculated by Equation 5 SensY − axisTempEr @T = SensY − axis @ T − SensY − axis @ RT SensY − axis @ RT ⋅100% , where SensY-axisTempEr@T is sensor’s Y-axis sensitivity temperature error in [%] in temperature T, SensYaxis@T is sensor’s measured Y-axis sensitivity [counts/g] at temperature T and SensY-axis@RT is sensor’s measured Y-axis sensitivity [counts/g] at room temperature RT. 8.3 Linearity The needed accurate input acceleration in linearity characterization is generated using centrifugal force in centrifuge, see Figure 20. The RPM of the centrifuge is swept so that wanted input acceleration values are applied in parallel to the sensor’s measuring axis. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 27/ 35 Rev. 0.12 CMA3000-D0X Series X Z Centrifugal acceleration for Z-axis Y Pin #1 Figure 20. Centrifugal acceleration applied for CMA3000 Z-axis. Linearity error is the deviation from the best bit straight line. See Figure 21. Acceleration reading from CMA3000 [g] CMA3000 linearity error in [g] at input acceleration acc -FS +FS CMA3000 output readings Sensor’s ideal output acc Input acceleration [g] (centrifugal acceleration in parallel to CMA3000 measuring axis) Possible offset error is not included into linearity error Figure 21. CMA3000’s linearity error at input acceleration acc. Linearity error is calculated by Equation 6 LinErZ −axis @ acc = Output Z −axis @ acc − Output@ acc Sens ⋅ FS ⋅100% , where LinErZ-axis@acc is sensor’s Z-axis linearity error [%FS] on input acceleration acc, OutputZ-axis@acc is sensor’s measured Z-axis output [counts] on input acceleration acc, Output@acc is sensor’s nominal output [counts] on input acceleration acc, Sens is sensor’s nominal sensitivity [counts/g] and FS is sensor’s full scale measuring range [g] (for example for CMA3000-D01 with ±2g setting → FS = 2 g). Sensor’s ideal output Output@acc (in Equation 6) is calculated by fitting a straight line to measured accelerations from –FS to FS. 8.4 Noise Output noise nX, nY and nZ in X,Y and Z directions is the measured standard deviation of the output values when the sensor is in 0 g position at room temperature. Average noise/axis is calculated by VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 28/ 35 Rev. 0.12 CMA3000-D0X Series Equation 7 n= 12 2 2 n X + nY + nZ , 3 ( ) where n is sensor’s noise [g] per axis, nX is sensor’s X-axis noise [g], nY is sensor’s Y-axis noise [g] and nZ is sensor’s Z-axis noise [g]. CMA3000 demo-kit design can be used as a reference design for noise measurements, refer to “CMA3000 DEMO KIT User Manual 8288400”. 8.5 Bandwidth Signal bandwidth is measured in a shaker by sweeping the piston movement frequency with constant amplitude (Figure 22). Z Y Shaker movement in parallel to Z-axis Earth’s gravitation X Pin #1 Figure 22. CMA3000 movement in Z-axis bandwidth measurement. 8.6 Cross-axis sensitivity Cross-axis sensitivity is sum of the alignment and the inherent sensitivity errors. Cross-axis sensitivity of one axis is a geometric sum of the sensitivities in two perpendicular directions. Cross-axis sensitivity [%] of X-axis is given by Equation 8 S XY + S XZ ⋅ 100%, Cross X = ± SX 2 2 where SXY is X-axis sensitivity to Y-axis acceleration [Count/g], SXZ is X-axis sensitivity to Z-axis acceleration [Count/g] and SX is sensitivity of X-axis [Count/g]. Cross-axis sensitivity [%] of Y-axis is given by Equation 9 S + SYZ CrossY = ± YX ⋅100%, SY 2 2 where SYX is Y-axis sensitivity to X-axis acceleration [Count/g], SYZ is Y-axis sensitivity to Z-axis acceleration [Count/g] and SY is sensitivity of Y-axis [Count/g]. Cross-axis sensitivity [%] of Z-axis is given by VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 29/ 35 Rev. 0.12 CMA3000-D0X Series Equation 10 S + S ZY ⋅ 100%, Cross Z = ± ZX SZ 2 2 where SZX is Z-axis sensitivity to X-axis acceleration [Count/g], SZY is Z-axis sensitivity to Y-axis acceleration [Count/g] and SZ is sensitivity of Z-axis [Count/g]. Cross-axis sensitivity of CMA3000 family is measured in centrifuge over specified measurement range during qualification. Correct mounting position of component is important during the measurement of cross-axis sensitivity. 8.7 Turn-on time Turn-on time is the time when the last of one X, Y, Z axis output readings stabilizes into its final value after XRESET is pulled high. The final value limits in turn-on time measurements is defined to be ±1 % of the sensor’s full scale measuring range (for example for CMA3000-D01 ±2g → FS = 2 g). Turn-on time definition for Z-axis is presented in Figure 23 below. Acceleration Supply voltage reaches the minimum required level → CMA3000 starts CMA3000 output inside ±1% FS limits CMA3000 Z-axis output Turn on time Time scale Figure 23. Turn-on time definition for one axis. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 30/ 35 Rev. 0.12 CMA3000-D0X Series 9 9.1 Known issues Acceleration data reading via I2C bus CMA3000-D01 has a design issue (to be corrected) related to acceleration data reading via I2C bus: acceleration data reading during the INT-pin assertion (i.e. internal output register update) causes the data corruption. The following sections discuss how to overcome this. 9.1.1 Interrupt based acceleration reading Interrupt (INT-pin) based acceleration data reading can be used only in measurement mode. After interrupt signal activation the acceleration data has to be read before next interrupt activation. The allowed reading time depends on selected measurement mode. Detailed timing values are presented in Table 12 and Figure 24 below. Table 12. CMA3000-D01 maximum reading periods in interrupt based acceleration data reading. Output data rate CMA3000-D01, MODE bits x10 ODR: 400Hz CMA3000-D01, MODE bits x01 ODR: 100Hz CMA3000-D01, MODE bits 011 ODR: 40Hz ODR = Output Data Rate Maximum reading period, Tr 2.25 ms 9.0 ms 22.5 ms Interrupt activation INT-pin Reading period, Tr Acceleration reading ends Interrupt activation Interrupt initialized Figure 24. Interrupt based CMA3000 acceleration data read timing. If the above presented data read timing constraints are not met, the acceleration output data should be ignored. Valid data samples can be read after the next interrupt signal. VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 31/ 35 Rev. 0.12 CMA3000-D0X Series 9.1.2 Acceleration reading without interrupts Acceleration data reading without interrupts can be used in all operation modes. Acceleration data is read out faster than CMA3000 can updates the acceleration output registers. When two identical XYZ acceleration values are received, the data is considered valid. The maximum data reading periods in different operation modes are presented below in Table 13. Table 13. CMA3000-D01 maximum reading periods when interrupts are not detected. Output data rate CMA3000-D01, MODE bits x10 ODR: 400Hz CMA3000-D01, MODE bits x01 ODR: 100Hz CMA3000-D01, MODE bits 011 ODR: 40Hz CMA3000-D01, MODE bits 100 ODR: 10Hz ODR = Output Data Rate Maximum reading period for 3 samples, Tr 2.4 ms 9.9 ms 24.0 ms 90.0 ms Internal acceleration register update These two acceleration readings result identical acceleration values → This result is accepted Internal acceleration register update Acceleration reading → corrupted Acceleration reading Acceleration reading Acceleration reading → corrupted Acceleration data reading period for 3 samples, Tr Figure 25. Interrupt based CMA3000 acceleration data read timing. 9.2 Leakage current when VDD - DVIO > 0.3 V Due to design issue a switch will leak some current, if the VDD will be approx 300 mV higher than DVIO. Typical leakage currents are according to the Table 14 below. Table 14 CMA3000-D0X typical DVIO leakage current when VDD-DVIO>0.3V. VDD/DVIO [V] 2.5 / 1.7 3.6 / 1.7 Leakage current [µA] 25 100 VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 32/ 35 Rev. 0.12 CMA3000-D0X Series 10 Order Information Order code CMA3000-D01-1 CMA3000-D01-10 CMA3000-D01-30 CMA3000-D01 PWB CMA3000-D01DEMO Description 3-Axis accelerometer with SPI&I2C interface, +/- 2/8g, 100 pcs 3-Axis accelerometer with SPI&I2C interface, +/- 2/8g, 1000 pcs 3-Axis accelerometer with SPI&I2C interface, +/- 2/8g, 3000 pcs PWB assy 3-Axis accelerometer with SPI&I2C interface, +/- 2/8g CMA3000-D01 DEMOKIT Packing T&R T&R T&R Bulk Bulk Quantity 100 1000 3000 1 1 VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 33/ 35 Rev. 0.12 CMA3000-D0X Series 11 Document Change Control Version 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.10 0.11 0.12 Date 06-Sep-07 11-Jan-08 14-Feb-08 18-Apr-08 01-Jul-08 29-Aug-08 10-Dec-08 29-Dec-08 28-Jan-09 02-Mar-09 08-Jun-09 12-Jun-09 Change Description Initial draft. Major update. Minor updates, corrections Minor updates, section 'Known issues' added Figure 1,&12 updated, table 9 updated Sensitivities from 1/60 and 1/15 counts/g updated to 1/56 and 1/14 counts/g Figure 12 updated. Tables 4, 5, 7, 9, 10 updated. Sections 9.2 and 9.3 added. Launch version. Table 6 updated. Table 5, 7 & 10 updated. 2 Typo corrections, 3.3 register initial values updated, 4.2 I C address updated, 8.4 demo kit document number updated, preliminary tag removed, MSL level 3 -> 2, 7.2 removed reference to 1uF capacitor 2 Figure 4 updated, 4.2.2 I C address byte description updated Mounting recommendations (section 7.4) added. Device bandwidth updated to ODR/5 VTI Technologies Oy www.vti.fi Doc.Nr. 8281000.12 34/ 35 Rev. 0.12 CMA3000-D0X Series 12 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 Park Lane 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 Doc.Nr. 8281000.12 35/ 35 Rev. 0.12