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Freescale Semiconductor Energy Efficient Solutions Xtrinsic MMA8452Q, Технические данные: Техническая информация

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MMA8452Q

Sensors
Freescale Semiconductor, Inc.

31

0x1F: TRANSIENT_THS Register

The Transient Threshold register sets the threshold limit for the detection of the transient acceleration. The value in the 

TRANSIENT_THS register corresponds to a g value which is compared against the values of High-Pass Filtered Data. If the High-
Pass Filtered acceleration value exceeds the threshold limit, an event flag is raised and the interrupt is generated if enabled.

The threshold THS[6:0] is a 7-bit unsigned number, 0.063g/LSB. The maximum threshold is 8g. Even if the part is set to full 

scale at 2g or 4g this function will still operate up to 8g. If the Low-Noise bit is set in Register 0x2A, the maximum threshold to be 
reached is 4g.

Note:

 If configuring the transient detection threshold for less than 1g, the high-pass filter will need some settling time. The settling 

time will vary depending on selected ODR, high-pass frequency cutoff and threshold. For more information, please refer to 
Freescale application note, AN4071.

0x20: TRANSIENT_COUNT

The TRANSIENT_COUNT sets the minimum number of debounce counts continuously matching the condition where the 

unsigned value of high-pass filtered data is greater than the user specified value of TRANSIENT_THS.

The time step for the transient detection debounce counter is set by the value of the system ODR and the Oversampling mode.

0x1F: TRANSIENT_THS Register (Read/Write)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

DBCNTM

THS6

THS5

THS4

THS3

THS2

THS1

THS0

Table 33. TRANSIENT_THS Description

DBCNTM

Debounce counter mode selection. Default value: 0. 0: increments or decrements debounce; 1: increments or clears counter.

THS[6:0]

Transient Threshold: Default value: 000_0000.

0x20: TRANSIENT_COUNT Register (Read/Write)

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

D7

D6

D5

D4

D3

D2

D1

D0

Table 34. TRANSIENT_COUNT Description

D[7:0]

Count value. Default value: 0000_0000.

Table 35. TRANSIENT_COUNT Relationship with the ODR

 ODR (Hz)

 

Max Time Range (s)

Time Step (ms)

Normal

LPLN

HighRes

LP

Normal

LPLN

HighRes

LP

800

0.319

0.319

0.319

0.319

1.25

1.25

1.25

1.25

400

0.638

0.638

0.638

0.638

2.5

2.5

2.5

2.5

200

1.28

1.28

0.638

1.28

5

5

2.5

5

100

2.55

2.55

0.638

2.55

10

10

2.5

10

50

5.1

5.1

0.638

5.1

20

20

2.5

20

12.5

5.1

20.4

0.638

20.4

20

80

2.5

80

6.25

5.1

20.4

0.638

40.8

20

80

2.5

160

1.56

5.1

20.4

0.638

40.8

20

80

2.5

160

Содержание Energy Efficient Solutions Xtrinsic MMA8452Q

Страница 1: ...nterface Two programmable interrupt pins for six interrupt sources Three embedded channels of motion detection Freefall or Motion Detection 1 channel Pulse Detection 1 channel Transient Detection 1 ch...

Страница 2: ...MOD 10 5 Functionality 11 5 1 Device Calibration 12 5 2 8 bit or 12 bit Data 12 5 3 Low Power Modes vs High Resolution Modes 12 5 4 Auto WAKE SLEEP Mode 12 5 5 Freefall and Motion Detection 12 5 6 Tra...

Страница 3: ...ction i e fast motion transient Orientation with Set Hysteresis and Z lockout Shake Detection through Motion Threshold Auto WAKE Auto SLEEP Configurable with debounce counter and multiple motion inter...

Страница 4: ...are described in detail in the register setting section Figure 3 Landscape Portrait Orientation Figure 4 Application Diagram Top View PU Earth Gravity Pin 1 Xout 0g Yout 1g Zout 0g Xout 1g Yout 0g Zo...

Страница 5: ...refore require a pullup resistor as shown in the application diagram in Figure 4 1 1 Soldering Information The QFN package is compliant with the RoHS standard Please refer to AN4077 Table 1 Pin Descri...

Страница 6: ...ehavior is also seen when changing from 800 Hz to any other data rate in the Normal Low Noise Low Power or High Resolution mode Soa 2 64 Sensitivity Change vs Temperature FS 1 0 set to 00 2g Mode TCSo...

Страница 7: ...ass Cap VDD 2 5V Idd Boot 1 mA Value of Capacitor on BYP Pin 40 C 85 C Cap 75 100 470 nF STANDBY Mode Current 25 C VDD 2 5V VDDIO 1 8V STANDBY Mode IddStby 1 8 5 A Digital High Level Input Voltage SCL...

Страница 8: ...t stretch the LOW period tLOW of the SCL signal s SDA setup time tSU DAT 100 ns SCL clock low time tLOW 1 3 s SCL clock high time tHIGH 0 6 s SDA and SCL rise time tr 20 0 1 Cb 3 3 Cb total capacitanc...

Страница 9: ...osing it to extensive mechanical stress 3 3 Self Test Self T est checks the transducer functionality without external mechanical stimulus When Self T est is activated an electrostatic actuation force...

Страница 10: ...ction of this document Table 7 Mode of Operation Description Mode I2 C Bus State VDD Function Description OFF Powered Down 1 8 V VDDIO Can be VDD The device is powered off All analog and digital block...

Страница 11: ...ith directional information 1 channel Portrait Landscape detection with trip points fixed at 30 and 60 for smooth transitions between orientations All functionality is available in 2g 4g or 8g dynamic...

Страница 12: ...at 1 56 Hz There is a trade off between low power and high resolution Low Power can be achieved when the oversampling rate is reduced The lowest power is achieved when MODS 11 or when the sample rate...

Страница 13: ...ere high frequency data is considered noise However there are many functions where the accelerometer must analyze dynamic acceleration Functions such as tap flick shake and step counting are based on...

Страница 14: ...ve for orientation detection as low as 29 from flat Figure 9 Illustration of Z Tilt Angle Lockout Transition Top View PU Earth Gravity Pin 1 Xout 0g Yout 1g Zout 0g Xout 1g Yout 0g Zout 0g Xout 0g You...

Страница 15: ...ctions of the device for Motion Freefall Transient Orientation and Pulse The registers embedded inside the MMA8452Q are accessed through the I2C serial interface Table 9 To enable the I2C interface VD...

Страница 16: ...mand begins on the falling edge of SCL After the eight clock cycles are used to send the command note that the data returned is sent with the MSB first once the data is received Figure 11 shows the ti...

Страница 17: ...0x39 Write 001110 0 0x1C 0 0x38 Read 001110 1 0x1D 1 0x3B Write 001110 1 0x1D 0 0x3A Single Byte Read Master ST Device Address 6 0 W Register Address 7 0 SR Device Address 6 0 R NAK SP Slave AK AK AK...

Страница 18: ...x80 Landscape Portrait configuration PL_COUNT 3 4 R 0x12 0x13 00000000 0x00 Landscape Portrait debounce counter PL_BF_ZCOMP 3 4 R 0x13 0x14 01000100 0x44 Back Front Z Lock Trip threshold P_L_THS_REG 3...

Страница 19: ...mode occurs 2 This register data is only valid in ACTIVE mode 3 Register contents are preserved when transition from ACTIVE to STANDBY mode occurs 4 Modification of this register s contents can only...

Страница 20: ...0x06 OUT_Z_LSB These registers contain the X axis Y axis and Z axis 12 bit output sample data expressed as 2 s complement numbers The sample data output registers store the current sample data OUT_X_...

Страница 21: ...SRC_TRANS Transient interrupt status bit Default value 0 Logic 1 indicates that an acceleration transient value greater than user specified threshold has occurred Logic 0 indicates that no transient e...

Страница 22: ...lementation on the high pass filter refer to Freescale application note AN4071 0x0D WHO_AM_I Device ID Register Read Only Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0 0 1 0 1 0 1 0 0x0E XYZ_DATA_...

Страница 23: ...0 16 Hz 16 Hz 8 Hz 4 Hz 2 Hz 0 5 Hz 0 5 Hz 0 5 Hz 0 1 8 Hz 8 Hz 4 Hz 2 Hz 1 Hz 0 25 Hz 0 25 Hz 0 25 Hz 1 0 4 Hz 4 Hz 2 Hz 1 Hz 0 5 Hz 0 125 Hz 0 125 Hz 0 125 Hz 1 1 2 Hz 2 Hz 1 Hz 0 5 Hz 0 25 Hz 0 06...

Страница 24: ...de selection Default value 1 0 Decrements debounce whenever condition of interest is no longer valid 1 Clears counter whenever condition of interest is no longer valid PL_EN Portrait Landscape Detecti...

Страница 25: ...nd or XEFE are set The event flags ZHE ZHP YHE YHP XHE and XHP are latched when the EA event bit is set The event flags ZHE ZHP YHE YHP XHE and XHP will start changing only after the FF_MT_SRC registe...

Страница 26: ...on detection where the magnitude of the X or Y or Z acceleration value is higher than the threshold value Figure 12 FF_MT_CFG High and Low g Level 0x16 FF_MT_SRC Freefall Motion Source Register 0x15 F...

Страница 27: ...longer true Figure 13 c until the debounce counter reaches 0 or the inertial event of interest becomes active Decrementing the debounce counter acts as a median enabling the system to filter out irre...

Страница 28: ...ce sample count depends on the ODR chosen and the Oversampling mode as shown in Table 30 0x18 FF_MT_COUNT_Register Read Write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 D7 D6 D5 D4 D3 D2 D1 D0 Ta...

Страница 29: ...tion High g Event on Count Threshold FF FFEA all 3 axis Motion Detect Counter Value High g Event on Count Threshold Debounce a all 3 axis Motion Detect Counter Value High g Event on Count Threshold De...

Страница 30: ...bled 1 Event flag latch enabled ZTEFE Event flag enable on Z transient acceleration greater than transient threshold event Default value 0 0 Event detection disabled 1 Raise event flag on measured acc...

Страница 31: ...r of debounce counts continuously matching the condition where the unsigned value of high pass filtered data is greater than the user specified value of TRANSIENT_THS The time step for the transient d...

Страница 32: ...vent flag latch enabled ZDPEFE Event flag enable on double pulse event on Z axis Default value 0 0 Event detection disabled 1 Event detection enabled ZSPEFE Event flag enable on single pulse event on...

Страница 33: ...ailable are dependent on the Oversampling mode and whether the Pulse Low Pass Filter option is enabled or not The Pulse Low Pass Filter is set in Register 0x0F 0x23 PULSE_THSX Register Read Write Bit...

Страница 34: ...1 0 159 10 2 5 20 0 625 40 0x27 PULSE_LTCY Register Read Write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 LTCY7 LTCY6 LTCY5 LTCY4 LTCY3 LTCY2 LTCY1 LTCY0 Table 44 PULSE_LTCY Description LTCY 7 0...

Страница 35: ...IND0 Table 47 PULSE_WIND Description WIND 7 0 Second Pulse Time Window Default value 0000_0000 Table 48 Time Step for PULSE Detection Window ODR and Power Mode Reg 0x0F Pulse_LPF_EN 1 ODR Hz Max Time...

Страница 36: ...can be enabled In order to WAKE the device four functions are provided Transient Orientation Pulse and the Motion Freefall The Auto WAKE SLEEP interrupt does not affect the WAKE SLEEP nor does the da...

Страница 37: ...ted the auto increment counter will skip over the LSB data bytes 0x2A CTRL_REG1 Register Read Write Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 ASLP_RATE1 ASLP_RATE0 DR2 DR1 DR0 LNOISE F_READ ACTI...

Страница 38: ...it 3 Bit 2 Bit 1 Bit 0 ST RST 0 SMODS1 SMODS0 SLPE MODS1 MODS0 Table 57 CTRL_REG2 Description ST Self Test Enable Default value 0 0 Self Test disabled 1 Self Test enabled RST Software Reset Default va...

Страница 39: ...LSE 0 Pulse function is bypassed in SLEEP mode Default value 0 1 Pulse function interrupt can wake up system WAKE_FF_MT 0 Freefall Motion function is bypassed in SLEEP mode Default value 0 1 Freefall...

Страница 40: ...ASLP 0 INT_CFG_TRANS INT_CFG_LNDPRT INT_CFG_PULSE INT_CFG_FF_MT 0 INT_CFG_DRDY Table 62 Interrupt Configuration Register Description Interrupt Configuration Description INT_CFG_ASLP INT1 INT2 Configur...

Страница 41: ...ZHP YHE YHP XHE XHP 17 FF_MT_THS Freefall Motion Threshold R W DBCNTM THS6 THS5 THS4 THS3 THS2 THS1 THS0 18 FF_MT_COUNT Freefall Motion Debounce R W D7 D6 D5 D4 D3 D2 D1 D0 1D TRANSIENT_CFG Transient...

Страница 42: ...4g 2 mg Range 8g 3 9 mg 0111 1111 1111 1 999g 3 998g 7 996g 0111 1111 1110 1 998g 3 996g 7 992g 0000 0000 0001 0 001g 0 002g 0 004g 0000 0000 0000 0 0000g 0 0000g 0 0000g 1111 1111 1111 0 001g 0 002g...

Страница 43: ...over any of the PCB landing pads as shown in Figure 14 7 No additional via nor metal pattern underneath package on the top of the PCB layer 8 Do not place any components or vias within 2 mm of the pac...

Страница 44: ...25 m The PCB should be rated for the multiple lead free reflow condition with a maximum 260 C temperature Use a standard pick and place process and equipment Do not use a hand soldering process Do not...

Страница 45: ...formation The MMA8451Q device is housed in a 16 lead QFN package case number 2077 8 1 Product identification markings 8 2 Tape and reel information Top View 263 8451 ALYW Traceability date code Assemb...

Страница 46: ...MMA8452Q Sensors 46 Freescale Semiconductor Inc 8 3 Package Description CASE 2077 02 ISSUE A 16 LEAD QFN...

Страница 47: ...MMA8452Q Sensors Freescale Semiconductor Inc 47 PACKAGE DIMENSIONS CASE 2077 02 ISSUE A 16 LEAD QFN...

Страница 48: ...MMA8452Q Sensors 48 Freescale Semiconductor Inc PACKAGE DIMENSIONS CASE 2077 02 ISSUE A 16 LEAD QFN...

Страница 49: ...espectively 8 07 2013 Table 2 Updated Self test Output Change row X Y and Z Typ values from 181 255 and 1680 to 44 61 and 392 respectively 8 1 10 2013 Table 3 Updated Parameter and Test Condition colu...

Страница 50: ...ims any and all liability including without limitation consequential or incidental damages Typical parameters that may be provided in Freescale data sheets and or specifications can and do vary in dif...

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