Xtrinsic MMA52xxAKW PSI5 Inertial Sensor - Data Sheet

Document Number: MMA52xxAKW
Rev. 0, 09/2012
Freescale Semiconductor
Data Sheet: Technical Data
Xtrinsic MMA52xxAKW
PSI5 Inertial Sensor
MMA52xxAKW
The MMA52xxAKW family, a SafeAssure solution, includes the PSI5 Version 1.3
asynchronous mode compatible overdamped X-axis satellite accelerometers.
Features
Bottom View
•
•
•
•
±60g to ±480g Full-Scale Range
400 Hz, 3-Pole Low-Pass Filter
Single Pole, High-Pass Filter with Fast Startup and Output Rate Limiting
PSI5 Version 1.3 Asynchronous Mode Compatible
– PSI5-A10P-228/1L Compatible
– Baud Rate: 125 kBaud
– 10-bit Data
– Even Parity Error Detection
• 16 μs Internal Sample Rate, with Interpolation to 1 μs
• Pb-Free 16-Pin QFN, 6 by 6 Package
• Qualified AECQ100, Revision G, Grade 1 (-40°C to +125°C)
(http://www.aecouncil.com/)
16-PIN QFN
CASE 2086-01
VBUF
• Airbag Front and Side Crash Detection
TEST
VSSA
Typical Applications
NC
Top View
16 15 14 13
VCC 1
12 VSSA
17
VSS 2
IDATA
Package
Shipping
MMA5206AKW
X
60g
2086-01
Tubes
MMA5212AKW
X
120g
2086-01
Tubes
MMA5224AKW
X
240g
2086-01
Tubes
MMA5248AKW
X
480g
2086-01
Tubes
MMA5206AKWR2
X
60g
2086-01
Tape & Reel
MMA5212AKWR2
X
120g
2086-01
Tape & Reel
MMA5224AKWR2
X
240g
2086-01
Tape & Reel
MMA5248AKWR2
X
480g
2086-01
Tape & Reel
© 2012 Freescale Semiconductor, Inc. All rights reserved.
VSS 4
9 VREG
5
6
7
8
DIN
Range
DOUT
Axis
NC
Device
10 CS
SLCK
ORDERING INFORMATION
11 VREGA
3
PIN CONNECTIONS
Application Diagram
VVBUF
VBUF
VCC
VREG
IDATA
VREGA
C4
C5
C6
VCE
R1
R2
MMA51xx
C2
C3
C1
VSSA
CS
SCLK
VSS
VSS
DO
Note: Pin names and references
may differ from PSI5 V1.3
pin names and references
DI
Figure 1. Application Diagram
External Component Recommendations
Ref Des
Type
Description
Purpose
C1
Ceramic
2.2 nF, 10%, 50V minimum, X7R
VCC Power Supply Decoupling and Signal Damping
C3
Ceramic
470 pF, 10%, 50V minimum, X7R
IDATA Filtering and Signal Damping
C2
Ceramic
15 nF, 10%, 50V minimum, X7R
VCC Power Supply Decoupling
C4, C5, C6
Ceramic
1 μF, 10%, 10V minimum, X7R
Voltage Regulator Output Capacitor(s)
R1
General Purpose
82Ω, 5%, 200 PPM
VCC Filtering and Signal Damping
R2
General Purpose
27Ω, 5%, 200 PPM
IDATA Filtering and Signal Damping
xxxxxxx
xxxxxxx
X: 0g
X: +1g
xxxxxxx
xxxxxxx
xxxxxxx
xxxxxxx
Device Orientation
X: 0g
xxxxxxx
xxxxxxx
X: -1g
X: 0g
X: 0g
EARTH GROUND
Figure 2. Device Orientation Diagram
MMA52xxAKW
2
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Freescale Semiconductor, Inc.
Internal Block Diagram
VCC
Buffer
Voltage
Regulator
Reference
Voltage
VBUF
VBUF
VREF
Digital
Voltage
Regulator
VREG
Analog
Voltage
Regulator
VREGA
CS
VREG
VREGA
VBUF
VSSA
SCLK
Low Voltage
Detection
SPI
DIN
Sync Pulse
Detection
Control
Logic
DOUT
VCC
Programming
Interface
IDATA
OTP
Serial
Encoder
Array
VSS
VREG
Self-Test
Interface
VREGA
VREG
Control
In
Status
Out
DSP
g-cell
ΣΔ
Converter
SINC Filter
IIR
LPF
Compensation
Offset
Monitor
HPF
Figure 3. Block Diagram
MMA52xxAKW
Sensors
Freescale Semiconductor, Inc.
3
VBUF
TEST
NC
Pin Connections
VSSA
1
16 15 14 13
VCC 1
12 VSSA
17
VSS 2
11 VREGA
IDATA 3
10 CS
5
6
7
8
SLCK
DOUT
DIN
9 VREG
NC
VSS 4
Figure 4. Top View, 16-Pin QFN Package
Table 1. Pin Description
Pin
Pin
Name
Formal Name
Definition
1
VCC
Supply
This pin is connected to the PSI5 power and data line through a resistor and supplies power to the device. An external capacitor must be connected between this pin and VSS. Reference Figure 1.
2
VSS
Digital GND
3
IDATA
Response
Current
4
VSS
Digital GND
5
NC
Not Connected
6
SCLK
SPI Clock
This input pin provides the serial clock to the SPI port for test purposes. An internal pulldown device is connected to this pin.
This pin must be grounded or left unconnected in the application.
7
DOUT
SPI Data Out
This pin functions as the serial data output from the SPI port for test purposes. This pin must be left unconnected in the application.
8
DIN
SPI Data In
This pin functions as the serial data input to the SPI port for test purposes. An internal pulldown device is connected to this
pin. This pin must be grounded or left unconnected in the application.
9
VREG
Digital
Supply
This pin is connected to the power supply for the internal digital circuitry. An external capacitor must be connected between
this pin and VSS. Reference Figure 1.
10
CS
Chip Select
This input pin provides the chip select to the SPI port for test purposes. An internal pullup device is connected to this pin.This
pin must be left unconnected in the application.
11
VREGA
Analog
Supply
This pin is connected to the power supply for the internal analog circuitry. An external capacitor must be connected between
this pin and VSSA. Reference Figure 1.
12
VSSA
Analog GND
13
VBUF
Power
Supply
14
TEST
Test Pin
15
NC
Not Connected
16
VSSA
Analog GND
PAD
Die Attach Pad
Corner
Pads
Corner Pads
17
This pin is the power supply return node for the digital circuitry.
This pin is connected to the PSI5 power and data line through a resistor and modulates the response current for PSI5 communication. Reference Figure 1.
This pin is the power supply return node for the digital circuitry.
This pin must be left unconnected in the application.
This pin is the power supply return node for the analog circuitry.
This pin is connected to a buffer regulator for the internal circuitry. The buffer regulator supplies both the analog (VREGA) and
digital (VREG) supplies to provide immunity from EMC and supply dropouts on VCC. An external capacitor must be connected
between this pin and VSS. Reference Figure 1.
This pin is must be grounded or left unconnected in the application.
This pin must be left unconnected in the application.
This pin is the power supply return node for the analog circuitry.
This pin is the die attach flag, and is internally connected to VSS.
The corner pads are internally connected to VSS.
MMA52xxAKW
4
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Freescale Semiconductor, Inc.
2
Electrical Characteristics
2.1
Maximum Ratings
Maximum ratings are the extreme limits to which the device can be exposed without permanently damaging it.
#
Rating
Symbol
Value
Unit
VCC_REV
VCC_MAX
VCC_TRANS
-0.7
+20.0
+25.0
V
V
V
(3)
(3)
(9)
1
2
3
Supply Voltage (VCC, IDATA)
Reverse Current ≤ 160 mA, t ≤ 80 ms
Continuous
Transient (< 10 μs)
4
VBUF, Test
-0.3 to +4.2
V
(3)
5
VREG, VREGA, SCLK, CS, DIN, DOUT
-0.3 to +3.0
V
(3)
6
Powered Shock (six sides, 0.5 ms duration)
gpms
±2000
g
(3)
7
Unpowered Shock (six sides, 0.5 ms duration)
gshock
±2500
g
(3)
8
Drop Shock (to concrete, tile or steel surface, 10 drops, any orientation)
hDROP
1.2
m
(5)
9
10
11
12
Electrostatic Discharge (per AECQ100)
External Pins (VCC, IDATA, VSS, VSSA), HBM (100 pF, 1.5 kΩ)
HBM (100 pF, 1.5 kΩ)
CDM (R = 0Ω)
MM (200 pF, 0Ω)
VESD
VESD
VESD
VESD
±4000
±2000
±1500
±200
V
V
V
V
(5)
(5)
(5)
(5)
13
14
Temperature Range
Storage
Junction
Tstg
TJ
-40 to +125
-40 to +150
°C
°C
(3)
(9)
15
Thermal Resistance
θJC
2.5
°C/W
(9, 14)
2.2
Operating Range
VL ≤ (VCC - VSS) ≤ VH, TL ≤ TA ≤ TH, ΔT ≤ 25 K/min, unless otherwise specified.
#
16
17
Characteristic
Supply Voltage
Symbol
Min
VCC
VL
4.2
VCC_UV
TA
TA
Operating Temperature Range
18
19
Typ
Max
Units
VVCC_UV_F
—
—
VH
17.0
VL
V
V
(1)
(9)
TL
-40
-40
⎯
⎯
TH
+105
+125
°C
°C
(1)
(3)
MMA52xxAKW
Sensors
Freescale Semiconductor, Inc.
5
2.3
Electrical Characteristics - Supply and I/O
VL ≤ (VCC - VSS) ≤ VH, TL ≤ TA ≤ TH, ΔT ≤ 25 K/min, unless otherwise specified.
#
Characteristic
Symbol
Min
Typ
Max
Units
20
Quiescent Supply Current
*
IIDLE
4.0
—
8.0
mA
(1)
21
Modulation Supply Current
*
IMOD
IIDLE+ 22.0
IIDLE+ 26.0
IIDLE+ 30.0
mA
(1)
22
Inrush Current (Power On until VBUF, VREG, VREGA Stable)
IINRUSH
—
—
30
mA
(3)
23
24
25
Internally Regulated Voltages
VBUF
VREG
VREGA
VBUF
VREG
VREGA
3.60
2.425
2.425
3.80
2.50
2.50
4.00
2.575
2.575
V
V
V
(1)
(1)
(1)
VVCC_UV_F
VBUF_UV_F
VREG_UV_F
VREGA_UV_F
3.40
2.95
2.15
2.15
3.70
3.15
2.25
2.25
4.0
3.35
2.35
2.35
V
V
V
V
(3, 6)
(3, 6)
(3, 6)
(3, 6)
VCC_HYST
VBUF_HYST
VREG_HYST
VREGA_HYST
0.10
0.05
0.05
0.05
0.25
0.10
0.10
0.10
0.40
0.15
0.15
0.15
V
V
V
V
(3)
(3)
(3)
(3)
26
27
28
29
30
31
32
33
Low Voltage Detection Threshold
VCC Falling
VBUF Falling
VREG Falling
VREGA Falling
Hysteresis
VCC
VBUF
VREG
VREGA
*
*
*
34
35
External Capacitor (VBUF, VREG, VREGA)
Capacitance
ESR (including interconnect resistance)
ESR
500
0
1000
—
1500
200
nF
mΩ
(9)
(9)
36
Output High Voltage (DO)
ILoad = 100 μA
VOH
VREG - 0.1
—
—
V
(9)
37
Output Low Voltage (DO)
ILoad = 100 μA
VOL
—
—
0.1
V
(9)
38
Input High Voltage
CS, SCLK, DI
VIH
0.7 * VREG
—
—
V
(9)
39
Input Low Voltage
CS, SCLK, DI
VIL
—
—
0.3 * VREG
V
(9)
40
41
Input Current
High (at VIH) (DI)
Low (at VIL) (CS)
IIH
IIL
-100
10
—
—
-10
100
μA
μA
(9)
(9)
42
Pulldown Resistance (SCLK)
RPD
20
æ
100
kΩ
(9)
MMA52xxAKW
6
Sensors
Freescale Semiconductor, Inc.
2.4
Electrical Characteristics - Sensor and Signal Chain
VL ≤ (VCC - VSS) ≤ VH, TL ≤ TA ≤ TH, ΔT ≤ 25 K/min, unless otherwise specified.
#
Characteristic
Symbol
Min
Typ
Max
Units
*
*
*
*
SENS
SENS
SENS
SENS
—
—
—
—
8
4
2
1
—
—
—
—
LSB/g
LSB/g
LSB/g
LSB/g
(1)
(1)
(1)
(1)
*
*
ΔSENS_240
ΔSENS_240
ΔSENS_240
ΔSENS_480
ΔSENS_480
ΔSENS_480
-5
-7
-7
-5
-7
-7
—
—
—
—
—
—
+5
+7
+7
+5
+7
+7
%
%
%
%
%
%
(1)
(1)
(9)
(1)
(1)
(9)
*
OFF10Bit
OFF10Bit
-52
-52
0
0
+52
+52
LSB
LSB
(1)
(9)
*
*
OFF10Bit
OFF10Bit
-1
-2
0
0
+1
+2
LSB
LSB
(1)
(9)
47
48
49
50
51
52
Sensitivity (10-bit output @ 100 Hz, referenced to 0 Hz)
±60g Range
±120g Range
±240g Range
±480g Range
Total Sensitivity Error (including non-linearity)
TA = 25°C, ≤ ±240g
TL ≤ TA ≤ TH, ≤ ±240g
TL ≤ TA ≤ TH, ≤ ±240g, VVCC_UV_F ≤ VCC ≤ VL
TA = 25°C, > ±240g
TL ≤ TA ≤ TH, > ±240g
TL ≤ TA ≤ TH, > ±240g, VVCC_UV_F ≤ VCC ≤ VL
53
54
Digital Offset Before Offset Cancellation
10-bit
10-bit, TL ≤ TA ≤ TH, VVCC_UV_F ≤ VCC ≤ VL
55
56
Digital Offset After Offset Cancellation
10-bit, 0.3 Hz HPF or 0.1 Hz HPF
10-bit, 0.04 Hz HPF
57
Continuous Offset Monitor Limit
10-bit output, before compensation
OFFMON
-66
—
+66
LSB
(3)
58
Range of Output (10-bit Mode)
Acceleration
RANGE
-480
—
+480
LSB
(3)
59
60
Cross-Axis Sensitivity
Z-axis to X-axis
Y-axis to X-axis
*
*
VZX
VYX
-5
-5
—
—
+5
+5
%
%
(3)
(3)
61
System Output Noise Peak (10-bit Mode, 1 Hz - 1 kHz, All Ranges)
*
nPeak
-4
—
+4
LSB
(3)
62
System Output Noise RMS (10-bit mode, 1 Hz - 1 kHz, All Ranges)
*
nRMS
—
—
+1.0
LSB
(3)
63
64
Non-linearity
10-bit output, ≤ ±240g
10-bit output, > ±240g
NLOUT_240g
NLOUT_480g
-2
-2
—
—
+2
+2
%
%
(3)
(3)
43
44
45
46
*
*
MMA52xxAKW
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Freescale Semiconductor, Inc.
7
2.5
Electrical Characteristics - Self-Test and Overload
VL ≤ (VCC - VSS) ≤ VH, TL ≤ TA ≤ TH, ΔT ≤ 25 K/min, unless otherwise specified.
#
Characteristic
Symbol
Min
Typ
Max
Units
gST10_60X
gST10_120X
gST10_240X
gST10_480X
120
40
56
8
—
—
—
—
280
160
184
112
LSB
LSB
LSB
LSB
(3)
(3)
(3)
(3)
65
66
67
68
10-Bit Output During Active Self-Test (TL ≤ TA ≤ TH)
±60g Range
±120g Range
±240g Range
±480g Range
69
Acceleration (without hitting internal g-cell stops)
±60g Range Positive/Negative
gg-cell_Clip60X
400
456
500
g
(9)
70
Acceleration (without hitting internal g-cell stops)
±120g Range Positive/Negative
gg-cell_Clip120X
400
456
500
g
(9)
71
Acceleration (without hitting internal g-cell stops)
±240g Range Positive/Negative
gg-cell_Clip240X
1750
2065
2300
g
(9)
72
Acceleration (without hitting internal g-cell stops)
±480g Range Positive/Negative
gg-cell_Clip480X
1750
2065
2300
g
(9)
73
ΣΔ and Sinc Filter Clipping Limit
±60g Range Positive/Negative
gADC_Clip60X
191
210
233
g
(9)
74
ΣΔ and Sinc Filter Clipping Limit
±120g Range Positive/Negative
gADC_Clip120X
353
380
410
g
(9)
75
ΣΔ and Sinc Filter Clipping Limit
±240g Range Positive/Negative
gADC_Clip240X
928
1055
1218
g
(9)
76
ΣΔ and Sinc Filter Clipping Limit
±480g Range Positive/Negative
gADC_Clip480X
1690
1879
2106
g
(9)
*
*
*
*
MMA52xxAKW
8
Sensors
Freescale Semiconductor, Inc.
2.6
Dynamic Electrical Characteristics - PSI5
VL ≤ (VCC - VSS) ≤ VH, TL ≤ TA ≤ TH, ΔT ≤ 25 K/min, unless otherwise specified
#
Characteristic
Symbol
Min
Typ
Max
Units
tPSI5_INIT1
tPSI5_INIT2_10a0
tPSI5_INIT3_10a0
tOC1
tOC2
tST1
tST2
tST3
ST_RPT
tPME
—
—
—
—
—
—
—
—
0
—
532000 / fOSC
512 * tASYNC
19 * tASYNC
320000 / fOSC
280000 / fOSC
128000 / fOSC
128000 / fOSC
128000 / fOSC
—
300000 / fOSC
—
—
—
—
—
—
—
—
5
—
s
s
s
s
s
s
s
s
s
(7)
(7)
(7, 12)
(7)
(7)
(7)
(7)
(7)
(7, 12)
(7)
tBIT_LOW
7.6000
8.0000
8.4000
μs
(7)
tRISE
324
463
602
ns
(3)
77
78
79
80
81
82
83
84
85
86
Initialization Timing
Phase 1
Phase 2 (10-Bit, Asynchronous Mode 0, k = 8)
Phase 3 (10-Bit, Asynchronous Mode 0, ST_RPT = 0)
Offset Cancellation Stage 1 Operating Time
Offset Cancellation Stage 2 Operating Time
Self-Test Stage 1 Operating Time
Self-Test Stage 2 Operating Time
Self-Test Stage 3 Operating Time
Self-Test Repetitions
Programming Mode Entry Window
87
Data Transmission Single Bit Time (PSI5 Low Bit Rate)
88
Modulation Current (20% to 80% of IMOD - IIDLE)
Rise Time
89
Position of bit transition (PSI5 Low Baud Rate)
*
tBittrans_LowBaud
49
50
51
%
(7)
90
Asynchronous Response Time
*
tASYNC
—
912 / fOSC
—
s
(7)
2.7
*
Dynamic Electrical Characteristics - Signal Chain
VL ≤ (VCC - VSS) ≤ VH, TL ≤ TA ≤ TH, ΔT ≤ 25 K/min, unless otherwise specified
#
Characteristic
Symbol
Min
Typ
Max
Units
91
Internal Oscillator Frequency
*
fOSC
3.80
4
4.20
MHz
(1)
92
93
DSP Low-Pass Filter (Note15)
Cutoff frequency LPF0 (referenced to 0 Hz)
Filter Order LPF0
*
*
fC_LPF0
OLPF0
⎯
⎯
400
3
⎯
⎯
Hz
1
(7)
(7)
94
95
96
97
98
99
100
101
102
103
104
105
DSP Offset Cancellation Low-Pass Filter (Note 15)
Offset Cancellation Low-Pass Filter Input Sample Rate
Stage 1 Cutoff frequency, Startup Phase 1
Stage 1 Filter Order, Startup Phase 1
Stage 2 Cutoff frequency, Startup Phase 1
Stage 2 Filter Order, Startup Phase 1
Cutoff frequency, Option 0
Filter Order, Option 0
Offset Cancellation Output Update Rate (10-Bit Mode)
Offset Cancellation Output Step Size (10-Bit Mode)
Offset Monitor Update Frequency
Offset Monitor Count Limit
Offset Monitor Counter Size
tOC_SampleRate
fC_OC10
OOC10
fC_OC03
OOC03
fC_OC0
OOC0
tOffRate_10
OFFStep_10
OFFMONOSC
OFFMONCNTLIMIT
OFFMONCNTSIZE
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
256
10.0
1
0.300
1
0.100
1
fOSC / 2e6
0.5
fOSC/2000
4096
8192
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
μs
Hz
1
Hz
1
Hz
1
s
LSB
Hz
1
1
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
(7)
106
107
108
109
Sensing Element Natural Frequency
±60g
±120g
±240g
±480g
fgcell_X60
fgcell_X120
fgcell_X240
fgcell_X480
12651
12651
26000
26000
⎯
⎯
⎯
⎯
13871
13871
28700
28700
Hz
Hz
Hz
Hz
(9)
(9)
(9)
(9)
110
111
112
113
Sensing Element Rolloff Frequency (-3 db)
±60g
±120g
±240g
±480g
fgcell_X60
fgcell_X120
fgcell_X240
fgcell_X480
938
938
3952
3952
⎯
⎯
⎯
⎯
2592
2592
14370
14370
Hz
Hz
Hz
Hz
(9)
(9)
(9)
(9)
114
115
116
117
Sensing Element Damping Ratio
±60g
±120g
±240g
±480g
ζgcell_X60
ζgcell_X120
ζgcell_X240
ζgcell_X480
2.760
2.760
1.260
1.260
⎯
⎯
⎯
⎯
6.770
6.770
3.602
3.602
⎯
⎯
⎯
⎯
(9)
(9)
(9)
(9)
118
119
120
121
Sensing Element Delay (@100 Hz)
±60g
±120g
±240g
±480g
fgcell_delay_X60
fgcell_delay_X120
fgcell_delay_X240
fgcell_delay_X480
63
63
13
13
⎯
⎯
⎯
⎯
170
170
40
40
μs
μs
μs
μs
(9)
(9)
(9)
(9)
122
Package Resonance Frequency
fPackage
100
⎯
⎯
kHz
(9)
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Freescale Semiconductor, Inc.
9
2.8
Dynamic Electrical Characteristics - Supply and SPI
VL ≤ (VCC - VSS) ≤ VH, TL ≤ TA ≤ TH, ΔT ≤ 25 K/min, unless otherwise specified
#
Characteristic
Symbol
Min
Typ
Max
Units
tSET
⎯
⎯
5
ms
(3)
tINT_INIT
⎯
16000 / fOSC
⎯
s
(7)
tVCC_MICROCUTmin
tVCC_MICROCUT
tVCC_RESET
30
50
⎯
⎯
⎯
⎯
⎯
⎯
1000
μs
μs
μs
(3)
(3)
(3)
123
Quiescent Current Settling Time (Power Applied to Iq = IIDLE ± 2mA)
124
Reset Recovery Internal Delay (After internal POR)
125
126
127
VCC Micro-cut (CBUF=CREG=CREGA=1 μF)
Survival Time (VCC disconnect without Reset, CBUF=CREG=CREGA=700 nF)
Survival Time (VCC disconnect without Reset, CBUF=CREG=CREGA=1 μF)
Reset Time (VCC disconnect above which Reset is guaranteed)
128
129
VBUF, Capacitor Monitor Disconnect Time (Figure 9)
POR to first Capacitor Test Disconnect
Disconnect Delay, Asynchronous Mode (Figure 9)
tPOR_CAPTEST
tCAPTEST_ADLY
⎯
⎯
12000 / fOSC
688 / fOSC
⎯
⎯
s
s
(7)
(7)
130
131
VREG, VREGA Capacitor Monitor
POR to first Capacitor Test Disconnect
Disconnect Rate
tPOR_CAPTEST
tCAPTEST_RATE
⎯
⎯
12000 / fOSC
256 / fOSC
⎯
⎯
s
s
(7)
(7)
132
133
134
135
136
137
138
139
140
141
142
143
144
145
Serial Interface Timing (See Figure 6, CDOUT ≤ 80 pF, RDOUT ≥ 10 kΩ)
Clock (SCLK) period (10% of VCC to 10% of VCC)
Clock (SCLK) high time (90% of VCC to 90% of VCC)
Clock (SCLK) low time (10% of VCC to 10% of VCC)
Clock (SCLK) rise time (10% of VCC to 90% of VCC)
Clock (SCLK) fall time (90% of VCC to 10% of VCC)
CS asserted to SCLK high (CS = 10% of VCC to SCLK = 10% of VCC)
CS asserted to DOUT valid (CS = 10% of VCC to DOUT = 10/90% of VCC)
Data setup time (DIN = 10/90% of VCC to SCLK = 10% of VCC)
DIN Data hold time (SCLK = 90% of VCC to DIN = 10/90% of VCC)
DOUT Data hold time (SCLK = 90% of VCC to DOUT = 10/90% of VCC)
SCLK low to data valid (SCLK = 10% of VCC to DOUT = 10/90% of VCC)
SCLK low to CS high (SCLK = 10% of VCC to CS = 90% of VCC)
CS high to DOUT disable (CS = 90% of VCC to DOUT = Hi Z)
CS high to CS low (CS = 90% of VCC to CS = 90% of VCC)
tSCLK
tSCLKH
tSCLKL
tSCLKR
tSCLKF
tLEAD
320
120
120
⎯
⎯
60
⎯
20
10
0
⎯
60
⎯
1000
⎯
⎯
⎯
15
15
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
⎯
40
28
⎯
60
⎯
⎯
⎯
50
⎯
60
⎯
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
(9)
(9)
(9)
(9)
(9)
(9)
(9)
(9)
(9)
(9)
(9)
(9)
(9)
(9)
tACCESS
tSETUP
tHOLD_IN
tHOLD_OUT
tVALID
tLAG
tDISABLE
tCSN
1. Parameters tested 100% at final test.
2. Parameters tested 100% at wafer probe.
3. Verified by characterization
4. * Indicates critical characteristic.
5. Verified by qualification testing.
6. Parameters verified by pass/fail testing in production.
7. Functionality guaranteed by modeling, simulation and/or design verification. Circuit integrity assured through IDDQ and scan testing. Timing
is determined by internal system clock frequency.
8. N/A.
9. Verified by simulation.
10. N/A.
11. Measured at VCC pin; VSYNC guaranteed across full VIDLE range.
12. Self-Test repeats on failure up to a ST_RPTMAX times before transmitting Sensor Error Message.
13. N/A.
14. Thermal resistance between the die junction and the exposed pad; cold plate is attached to the exposed pad.
15. Filter cutoff frequencies are directly dependent upon the internal oscillator frequency.
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VCC_UV_f + VCC_HYST
VCC_UV_f
Response Terminated if in process
VCC
VBUF_UV_f + VBUF_HYST
VBUF_UV_f
VBUF
VREG_UV_f + VREG_HYST
VREG_UV_f
VREG
VREGA_UV_f+VREGA_HYST
VREGA_UV_f
VREG
POR
Time
Figure 5. Powerup Timing
CS
tLEAD
tSCLKR
tSCLK
tSCLKF
tCSN
tSCLKH
SCLK
tSCLKL
tLAG
tACCESS
tVALID
tHOLD_OUT
tDISABLE
DOUT
tHOLD_IN
tSETUP
DIN
Figure 6. Serial Interface Timing
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3
Functional Description
3.1
User Accessible Data Array
A user accessible data array allows for each device to be customized. The array consists of an OTP factory programmable
block, an OTP user programmable block, and read-only registers for device status. The OTP blocks incorporate independent
error detection circuitry for fault detection (reference Section 3.2). Portions of the factory programmable array are reserved for
factory-programmed trim values. The user accessible data is shown in Table 2.
Table 2. User Accessible Data
Byte
Addr
(XLong
Msg)
Register
$00
SN0
$01
$02
Bit Function
Nibble
Addr
(Long
Msg)
Bit Function
Nibble
Addr
(Long
Msg)
Type
7
6
5
4
3
2
1
0
$01
SN[7]
SN[6]
SN[5]
SN[4]
$00
SN[3]
SN[2]
SN[1]
SN[0]
SN1
$03
SN[15]
SN[14]
SN[13]
SN[12]
$02
SN[11]
SN[10]
SN[9]
SN[8]
SN2
$05
SN[23]
SN[22]
SN[21]
SN[20]
$04
SN[19]
SN[18]
SN[17]
SN[16]
$03
SN3
$07
SN[31]
SN[30]
SN[29]
SN[28]
$06
SN[27]
SN[26]
SN[25]
SN[24]
$04
DEVCFG1
$09
0
0
1
0
$08
0
RNG[2]
RNG[1]
RNG[0]
$05
DEVCFG2
$0B
0
0
0
0
$0A
0
0
0
0
$06
DEVCFG3
$0D
0
0
0
0
$0C
0
0
0
0
$07
DEVCFG4
$0F
0
0
0
0
$0E
0
0
0
0
$08
DEVCFG5
$11
0
0
0
0
$10
0
0
0
0
R
$09
DEVCFG6
$13
0
1
0
0
$12
0
0
0
0
$0A
DEVCFG7
$15
0
0
0
0
$14
0
0
0
0
$0B
DEVCFG8
$17
1
0
1
0
$16
0
0
0
0
$0C
SC
$19
0
TM_B
RESERVED
IDEN_B
$18
OC_INIT_B
IDEF_B
OFF_B
0
$0D
MFG_ID
$1B
0
0
0
0
$1A
0
0
0
0
Type codes
R: Readable register via PSI5
3.1.1
Device Serial Number Registers
A unique serial number is programmed into the serial number registers of each device during manufacturing. The serial number is composed of the following information:
Bit Range
Content
SN[12:0]
Serial Number
SN[31:13]
Lot Number
Serial numbers begin at 1 for all produced devices in each lot and are sequentially assigned. Lot numbers begin at 1 and are
sequentially assigned. No lot will contain more devices than can be uniquely identified by the 13-bit serial number. Depending on
lot size and quantities, all possible lot numbers and serial numbers may not be assigned.
The serial number registers are included in the factory programmed OTP CRC verification. Reference Section 3.2 for details
regarding the CRC verification. Beyond this, the contents of the serial number registers have no impact on device operation or
performance, and are only used for traceability purposes.
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3.1.2
Factory Configuration Register (DEVCFG1)
The factory configuration register is a factory programmed, read-only register which contains user specific device configuration
information. The factory configuration register is included in the factory programmed OTP CRC verification.
Location
Bit
Address
Register
$04
DEVCFG1
7
Factory Default
3.1.2.1
6
5
4
3
2
1
0
0
0
1
0
0
RNG[2]
RNG[1]
RNG[0]
0
0
1
0
0
0
0
0
Range Indication Bits (RNG[2:0])
The range indication bits are factory programmed and indicate the full-scale range of the device as shown below.
3.1.3
RNG[2]
RNG[1]
RNG[0]
Full-Scale Acceleration
Range
g-Cell Design
PSI5 Init Data
Transmission (D9)
Reference Table 9
0
0
0
Reserved
N/A
0001
0
0
1
±60g
Medium-g
0111
0
1
0
Reserved
N/A
0010
0
1
1
±120 g
Medium-g
1000
1
0
0
Reserved
N/A
0011
1
0
1
±240 g
High-g
1001
1
1
0
Reserved
N/A
0100
1
1
1
±480 g
High-g
1010
Status Check Register (SC)
The status check register is a read-only register containing device status information.
Location
Bit
Address
Register
7
6
5
4
3
2
1
0
$0C
SC
0
TM_B
RESERVED
IDEN_B
OC_INIT_B
IDEF_B
OFF_B
0
3.1.3.1
Test Mode Flag (TM_B)
The test mode bit is cleared if the device is in test mode.
3.1.3.2
TM_B
Operating Mode
0
Test Mode is active
1
Test Mode is not active
Internal Data Error Flag (IDEN_B)
The internal data error bit is cleared if a register data error detection mismatch is detected in the user accessible OTP array.
A device reset is required to clear the error.
IDEN_B
Error Condition
0
Error detection mismatch in user programmable OTP array
1
No error detected
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3.1.3.3
Offset Cancellation Init Status Flag (OC_INIT_B)
The offset cancellation initialization status bit is set once the offset cancellation initialization process is complete, and the filter
has switched to normal mode.
3.1.3.4
OC_INIT_B
Error Condition
0
Offset Cancellation in initialization
1
Offset Cancellation initialization complete (tOC1 and tOC2 expired)
Internal Factory Data Error Flag (IDEF_B)
The internal factory data error bit is cleared if a register data CRC fault is detected in the factory programmable OTP array. A
device reset is required to clear the error.
3.1.3.5
IDEF_B
Error Condition
0
CRC error in factory programmable OTP array
1
No error detected
Offset Error Flag (OFF_B)
The offset error flag is cleared if the acceleration signal reaches the offset limit.
3.2
OFF_B
Error Condition
0
Offset error detected
1
No error detected
OTP Array Error Detection
The Factory programmed OTP array is verified for errors with a 3-bit CRC. The CRC verification is enabled only when the
factory programmed array is locked. The CRC verification uses a generator polynomial of g(x) = X3 + X + 1, with a seed
value = ‘111’.
The CRC is continuously calculated on the factory programmable array with the exception of the factory lock bits. Bits are fed
in from right to left (LSB first), and top to bottom (lower addresses first) in the register map. The calculated CRC is then compared
against the stored 3 bit CRC. If a CRC error is detected in the OTP array, the IDEF_B bit is cleared in the SC register.
The CRC verification is completed on the memory registers which hold a copy of the fuse array values, not the fuse array values.
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3.3
Voltage Regulators
The device derives its internal supply voltage from the VCC and VSS pins. Separate internal voltage regulators are used for the
analog (VREGA) and digital circuitry (VREG). The analog and digital regulators are supplied by a buffer regulator (VBUF) to provide
immunity from EMC and supply dropouts on VCC. External filter capacitors are required, as shown in Figure 1.
The voltage regulator module includes voltage monitoring circuitry which holds the device in reset following power-on until the
internal voltages have increased above the undervoltage detection thresholds. The voltage monitor asserts internal reset when
the external supply or internally regulated voltages fall below the undervoltage detection thresholds. A reference generator provides a reference voltage for the ΣΔ converter.
VCC
VREF
VBUF
VOLTAGE
REGULATOR
VBUF
VREGA = 2.50 V
VOLTAGE
REGULATOR
VREGA
TRIM
BANDGAP
REFERENCE
BIAS
GENERATOR
VREF
TRIM
TRIM
REFERENCE VREF_MOD = 1.250 V
GENERATOR
VBUF
VREF
VREGA
OSCILLATOR
TRIM
ΣΔ
CONVERTER
OTP
ARRAY
VOLTAGE
REGULATOR
VREG = 2.50 V
VREG
DIGITAL
LOGIC
DSP
VCC
COMPARATOR
Micro-cut
VBUF
COMPARATOR
POR
VREG
VREGA
VREF
COMPARATOR
COMPARATOR
Figure 7. Voltage Regulation and Monitoring
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3.3.1
VBUF, VREG, and VREGA Regulator Capacitor
The internal regulators require an external capacitor between each of the regulator pins (VBUF, VREG, or VREGA) and the associated the VSS / VSSA pin for stability. Figure 1 shows the recommended types and values for each of these capacitors.
3.3.2
VCC, VBUF, VREG, and VREGA Undervoltage Monitor
A circuit is incorporated to monitor the supply voltage (VCC) and all internally regulated voltages (VBUF, VREG, and VREGA). If
any of internal regulator voltages fall below the specified undervoltage thresholds in Section 2, the device will be reset. If VCC
falls below the specified threshold, PSI5 transmissions are terminated for the present response. Once the supply returns above
the threshold, the device will respond to the next detected sync pulse. Reference Figure 8.
VCC micro-cut occurs
VCC
VBUF
VCC undervoltage detected
VREG
VREGA
Response Terminated
IDATA
POR
Time
Figure 8. VCC Micro-Cut Response
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3.3.3
VBUF, VREG, and VREGA Capacitance Monitor
A monitor circuit is incorporated to ensure predictable operation if the connection to the external VBUF, VREG, or VREGA, capacitor becomes open.
The VBUF regulator is disabled tCAPTEST_ADLY seconds after each data transmission for a duration of tCAPTEST_TIME seconds.
If the external capacitor is not present, the regulator voltage will fall below the internal reset threshold, forcing a device reset.
The VREG and VREGA regulators are disabled at a continuous rate (tCAPTEST_RATE), for a duration of tCAPTEST_TIME seconds.
If either external capacitor is not present, the associated regulator voltage will fall below the internal reset threshold, forcing a
device reset.
IDATA
tCAPTEST_TIME
tCAPTEST_ADLY
Capacitor Present
Capacitor Open
CAP_Test
VBUF
VBUF_UV_f
POR
Time
Figure 9. VBUF Capacitor Monitor - Asynchronous Mode
tCAPTEST_RATE
tCAPTEST_TIME
CAP_Test
VREG
Capacitor Present
Capacitor Open
VPORVREG_f
POR
Time
Figure 10. VREG Capacitor Monitor
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tCAPTEST_RATE
tCAPTEST_TIME
CAP_Test
VREGA
Capacitor Present
Capacitor Open
VPORREGA_f
POR
Time
Figure 11. VREGA Capacitor Monitor
3.4
Internal Oscillator
A factory trimmed oscillator is included as specified in Section 2.
3.5
Acceleration Signal Path
3.5.1
Transducer
The transducer is an overdamped mass-spring-damper system defined by the following transfer function:
where:
2
ωn
H ( s ) = --------------------------------------------------------2
2
s + 2 ⋅ ξ ⋅ ωn ⋅ s + ωn
ζ = Damping Ratio
ωn = Natural Frequency = 2 ∗ Π ∗ fn
Reference Section 2.7 for transducer parameters.
3.5.2
ΣΔ Converter
A sigma delta modulator converts the differential capacitance of the transducer to a 1 MHz data stream that is input to the DSP
block.
g-CELL
α1=
CTOP
VX
FIRST
INTEGRATOR
CINT1
z-1
1-z
CBOT
SECOND
INTEGRATOR
α2
1-BIT
QUANTIZER
z-1
-1
ΣΔ_OUT
1 - z-1
ADC
ΔC = CTOP - CBOT
V = ΔC x VX / CINT1
β1
β2
DAC
V = ±2 × VREF
Figure 12. ΣΔ Converter Block Diagram
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3.5.3
Digital Signal Processing Block
A Digital Signal Processing (DSP) block is used to perform signal filtering and compensation. A diagram illustrating the signal
processing flow within the DSP block is shown in Figure 13.
B
A
ΣΔ_OUT
DOWNSAMPLING
D
C
LOW-PASS FILTER
SINC FILTER
COMPENSATION
OFFSET
OFFSET CANCELLATION CANCELLATION
LOW-PASS FILTER
OUTPUT
RATE LIMITING
E
F
OUTPUT
H
G
SCALING
INTERPOLATION OUTPUT
Figure 13. Signal Chain Diagram
Table 3. Signal Chain Characteristics
A
Description
Sample
Time
(μs)
Data
Width
(Bits)
SD
1
1
Over
Range
(Bits
Signal
Width
(Bits)
Signal
Noise
(Bits)
Signal
Margin
(Bits)
Typical Block Latency
1
Reference
Section 3.5.2
203/fosc
B
SINC Filter
16
20
13
C
Low-Pass Filter
16
26
4
10
3
9
D
Compensation
16
26
4
10
3
9
E
Down Sampling
16
26
4
10
3
9
F
High-Pass Filter
16
26
4
10
3
9
Reference Section 3.5.3.2
Section 3.5.3.2
Section 3.5.3.2
68/fosc
Reference Section 3.5.3.3
Section 3.5.3.3
DSP Sampling
G
16
10
4/fosc
Section 3.5.3.5
1
10
64/fosc
Section 3.5.3.5
10-Bit Output Scaling
H
3.5.3.1
Interpolation
Decimation Sinc Filter
The serial data stream produced by the ΣΔ converter is decimated and converted to parallel values by a 3rd order 16:1 sinc
filter with a decimation factor of 16.
3
1 – z –16
H ( z ) = ------------------------------------16 × ( 1 – z – 1 )
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Figure 14. Sinc Filter Response, tS = 16 μs
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3.5.3.2
Low-Pass Filter
Data from the Sinc filter is processed by an infinite impulse response (IIR) low-pass filter.
( n 11 ⋅ z 0 ) + ( n 12 ⋅ z – 1 ) + ( n 13 ⋅ z – 2 ) ( n 21 ⋅ z 0 ) + ( n 22 ⋅ z – 1 ) + ( n 23 ⋅ z – 2 )
H ( z ) = a 0 ⋅ ------------------------------------------------------------------------------------------------- ⋅ ------------------------------------------------------------------------------------------------( d 11 ⋅ z 0 ) + ( d 12 ⋅ z – 1 ) + ( d 13 ⋅ z – 2 ) ( d 11 ⋅ z 0 ) + ( d 22 ⋅ z – 1 ) + ( d 23 ⋅ z – 2 )
Table 4. Low-Pass Filter Coefficients
Description
Filter Coefficients
Group Delay
a0
5.189235225042199e-02
n11
1.629077582099646e-03
d11
1.0
n12
1.630351547919014e-03
d12
-9.481076477495780e-01
0
d13
0
n21
2.500977520825902e-01
d21
1.0
n22
4.999999235890745e-01
d22
-1.915847097557409e+00
n23
2.499023243303036e-01
d23
9.191065266874253e-01
400 Hz, 3-Pole LPF n13
2816/fosc
Note: Low-Pass Filter values do not include g-cell frequency response.
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Figure 15. Low-Pass Filter Characteristics: fC = 400 Hz, 3-Pole, tS = 16 μs
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3.5.3.3
Offset Cancellation
The device provides an offset cancellation circuit to remove internal offset error. A block diagram of the offset cancellation is
shown in Figure 16.
INPUT DATA
INC/DEC
OFFSET CANCELLATION
LOW-PASS FILTER
n + ( n ⋅ z–1 )
1
2
a ⋅ ------------------------------------0
d + ( d ⋅ z–1 )
1
2
TO_OUTPUT SCALING
OUT
COUNTER
0.5 Hz (Derived from fOSC)
Input Data downsampled to 256μs
CLK
OFFMONNEG
INC/DEC
OUT
OFF_ERR
UP/DOWN
COUNTER
OFFMONPOS
2 kHz (Derived from fOSC)
OFFMONCNTLIMIT
CLK
Figure 16. Offset Cancellation Block Diagram
The transfer function for the offset LPF is:
no 1 + ( no 2 ⋅ z – 1 )
H ( z ) = ao 0 ⋅ ---------------------------------------------do 1 + ( do 2 ⋅ z – 1 )
Response parameters are specified in Section 2 and the offset LPF coefficients are specified in Table 6.
During startup, two phases of the offset LPF are used to allow for fast convergence of the internal offset error during initialization. The timing and characteristics of each phase are shown in Table 5 and Table 6 and specified in Section 2. For more information regarding the startup timing, reference the PSI5 initialization information in Section 4.4. The offset low-pass filter used in
normal operation is selected by the OC_FILT bit as shown in Table 5.
During the Initialization Self-Test phase, the offset cancellation circuit output value is frozen.
During normal operation, output rate limiting is applied to the output of the high-pass filter. Rate limiting updates the offset cancellation output by OFFStep_xx LSB every tOffRate_xx seconds.
Table 5. Offset Cancellation Startup Characteristics and Timing
Offset Cancellation
Startup Phase
Offset LPF
Output Rate Limiting
Total Time for Phase
1
10 Hz
Bypassed
80 ms
2
0.3 Hz
Bypassed
70 ms
Self-Test
0.3 Hz
Bypassed (Frozen during ST2)
96 ms per Self-Test Sequence (up to 6 repeats)
Complete
0.1 Hz
Enabled
N/A
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Table 6. High-Pass Filter Coefficients
Description
10 Hz HPF
0.3 Hz HPF
0.1 Hz HPF
Coefficients
Group Delay
ao0
0.015956938266754
no1
0.499998132328277
do1
1.0
no2
0.499998132328277
do2
-0.984043061733246
ao0
0.000482380390167
no1
0.499938218213271
do1
1.0
no2
0.499938218213271
do2
-0.999517619609833
ao0
0.0001608133316040
no1
0.4999999403953552
do1
1.0
no2
0.4999999403953552
do2
-0.9998391270637512
16.384 ms
537.6 ms
1591ms
Figure 17. 10 Hz Offset Cancellation Low-Pass Filter Characteristics
Figure 18. 0.1 Hz Offset Cancellation Low-Pass Filter Characteristics
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3.5.3.4
Offset Monitor
The device includes an offset monitor circuit. The output of the single pole low-pass filter in the offset cancellation block is
continuously monitored against the offset limits specified in Section 2.4. An up/down counter is employed to count up If the output
exceeds the limits, and to count down if the output is within the limits. The output of the counter is compared against the count
limit OFFMONCNTLIMIT. If the counter exceeds the limit, the OFF_B flag in the SC register is cleared. The counter rails once the
max counter value is reached (OFFMONCNTSIZE). The offset monitor is disabled during Initialization Phase 1, Phase 2, and
Phase 3.
3.5.3.5
Data Interpolation
The device includes 16 to 1 linear data interpolation to minimize the system sample jitter. Each result produced by the digital
signal processing chain is delayed one sample time.
3.5.3.6
Output Scaling
The 26-bit digital output from the DSP is clipped and scaled to a 10-bit word which spans the acceleration range of the device.
Figure 19 shows the method used to establish the output acceleration data word from the 26-bit DSP output.
Over Range
D25
D24
D23
10-bit Data Word
Signal
D22
Noise
D21
D20
D19
D18
D17
D16
D15
D14
D13
D12
D21
D20
D19
D18
D17
D16
D15
D14
D13
D12
D11
D10
Margin
D9
D8
...
D2
D1
D0
Using Rounding
Figure 19. 10-Bit Output Scaling Diagram
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3.6
Overload Response
3.6.1
Overload Performance
The device is designed to operate within a specified range. Acceleration beyond that range (overload) impacts the output of
the sensor. Acceleration beyond the range of the device can generate a DC shift at the output of the device that is dependent
upon the overload frequency and amplitude. The g-cell is overdamped, providing the optimal design for overload performance.
However, the performance of the device during an overload condition is affected by many other parameters, including:
• g-cell damping
• Non-linearity
• Clipping limits
• Symmetry
Figure 20 shows the g-cell, ADC and output clipping of the device over frequency. The relevant parameters are specified in
Section 2.
g-cellRolloff
Acceleration (g)
Region Clipped
by Output
LPFRolloff
R eg
ion
pe
Clip
d by
g-ce
ll
Determined by g-cell
roll-off and ADC clipping
e to
n du arity
o
i
t
r
e
to
in
e
l Dis on-L
lipp
igna and N
nC
S
o
i
f
g
o
Re
etr y
ion
Reg Asymm
gg-cell_Clip
A
d by
gADC_Clip
DC
Determined by g-cell
roll-off and full-scale range
gRange_Norm
Region of Interest
fLPF
Region of No Signal Distortion Beyond
Specification
fg-Cell
5kHz
10kHz
Frequency (kHz)
Figure 20. Output Clipping vs. Frequency
3.6.2
Sigma Delta Modulator Over Range Response
Over Range conditions exist when the signal level is beyond the full-scale range of the device but within the computational
limits of the DSP. The ΣΔ converter can saturate at levels above those specified in Section 2 (GADC_CLIP). The DSP operates
predictably under all cases of over range, although the signal may include residual high frequency components for some time
after returning to the normal range of operation due to non-linear effects of the sensor.
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4
PSI5 Layer and Protocol
4.1
Communication Interface Overview
The communication interface between a master device and the MMA52xx is established via a PSI5 compatible 2-wire interface. Figure 21 shows the PSI5 master to slave connections.
SATELLITE MODULE #1
MASTER DEVICE
MMA51xx
VCC
VSS
Discrete
Components
VCC
IData
VSS
Figure 21. PSI5 Satellite Interface Diagram
4.2
Data Transmission Physical Layer
The device uses a two wire interface for both its power supply (VCC), and data transmission. Data transmissions from the device to the PSI5 master are accomplished via modulation of the current on the power supply line.
4.3
Data Transmission Data Link Layer
4.3.1
Bit Encoding
The device outputs data by modulation of the VCC current using Manchester 2 Encoding. Data is stored in a transition occurring
in the middle of the bit time. The signal idles at the normal quiescent supply current. A logic low is defined as an increase in
current at the middle of a bit time. A logic high is defined as a decrease in current at the middle of a bit time. There is always a
transition in the middle of the bit time. If consecutive “1” or “0” data are transmitted, There will also be a transition at the start of
a bit time.
IMOD CURRENT
IDLE CURRENT
‘0’ BIT
tBIT
‘1’ BIT
SENSED HIGH
SENSED LOW
CONSECUTIVE
‘0’ DATA BITS
CONSECUTIVE
‘1’ DATA BITS
Figure 22. Manchester 2 Data Bit Encoding
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4.3.2
Data Transmission
Transmission frames are composed of two start bits, a 10-bit data word, and error detection bit(s). Data words are transmitted
least-significant bit (LSB) first. A typical Manchester-encoded transmission frame is illustrated in Figure 23.
Data Bit
SB1
SB0
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
PAR
‘0’
‘0’
‘1’
‘1’
‘1’
‘0’
‘0’
‘1’
‘1’
‘1’
‘1’
‘0’
‘1’
SB1
IMOD
Bit Value
tBIT
tTRAN = tBIT * 13
tFRAME
Figure 23. Example Manchester Encoded Data Transfer - PSI5-x10P
4.3.3
Error Detection
Error detection of the transmitted data is accomplished via a parity bit. Even parity is employed. The number of logic “1” bits
in the transmitted message must be an even number.
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4.3.4
Data Range Values
Table 8 shows the details for each data range.
Table 7. PSI5 Data Values
10-Bit Data Value
Decimal
Hex
+511
$1FF
•
•
•
•
•
•
+502
$1F6
+501
$1F5
+500
$1F4
+499
$1F3
•
•
•
•
•
•
Description
Reserved
Sensor Defect Error Message
Reserved
+489
$1E9
+488
$1E8
Sensor Busy
+487
$1E7
Sensor Ready
+486
$1E6
Sensor Ready, but Unlocked
+485
$1E5
•
•
•
•
•
•
+481
$1E1
+480
$1E0
•
•
•
•
•
•
+3
$03
+2
$02
+1
$01
0
0
-1
$3FF
-2
$3FE
-3
$3FD
•
•
•
•
•
•
-480
$220
-481
$21F
•
•
•
•
-496
$210
-497
$20F
•
•
•
•
-512
$200
Reserved
Maximum positive acceleration value
Positive acceleration values
0g level
Negative acceleration values
Maximum negative acceleration value
Initialization Data Codes
10-Bit Status Data Nibble 1 - 16 (0000 - 1111) (Dx)
Initialization Data IDs
Block ID 1 - 16 (10-bit Mode) (IDx)
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4.4
Initialization
Following powerup, the device proceeds through an initialization process which is divided into 3 phases:
• Initialization Phase 1: No Data transmissions occur
• Initialization Phase 2: Sensor self-test and transmission of configuration information
• Initialization Phase 3: Transmission of “Sensor Busy”, and “Sensor Ready” / “Sensor Defect” message
Once initialization is completed the device begins normal mode operation, which continues as long as the supply voltage remains within the specified limits.
IIDLE + IMOD
IIDLE
POR
INIT 1
NORMAL MODE
INIT 3
INIT 2
Figure 24. PSI5 Sensor 10-Bit Initialization
During PSI5 initialization, the device completes an internal initialization process consisting of the following:
• Power-on Reset
• Device Initialization
• Program Mode Entry Verification
• Offset Cancellation Initialization (2 Stages)
• Self-Test
Figure 25 shows the timing for internal and external initialization.
POR
Internal
Delay
tINT_INIT
PSI5 Initialization
Phase 1
PSI5 Initialization
Phase 2
tPSI5_INIT1
tPSI5_INIT2
Self-Test
Offset Cancellation Offset Cancellation Raw Offset
Stage 1
Stage 2
Calculation
tOC1
tOC2
tST1
PSI5
PSI5 Initialization
Normal Mode
Phase 3
tPSI5_INIT3
Self-Test
Self-Test
Deflection Normal Data
Verification Calculation
tST2
tST3
Self-Test
Repeat
(If Necessary)
ST_RPT * tST
Figure 25. Initialization Timing
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4.4.1
PSI5 Initialization Phase 1
During PSI5 initialization phase 1, the device begins internal initialization and self checks, but transmits no data. Initialization
begins with the sequence below and shown in Figure 25:
• Internal Delay to ensure analog circuitry has stabilized (tINT_INIT)
• Offset Cancellation phase 1 Initialization (tOC1)
• Offset Cancellation phase 2 Initialization (tOC2)
4.4.2
PSI5 Initialization Phase 2
During PSI5 initialization phase 2, the device continues its internal self checks and transmits the PSI5 initialization phase 2
data. Initialization is transmitted using the initialization data codes and IDs specified in Table 9, and in the order shown in
Figure 26.
D1
ID11
D11
ID12
D12
D2
...
ID1k
Repeat k times
D1k
ID21
D21
ID22
D22
...
ID2k
D2k
Repeat k times
...
D32
...
ID321 D321 ID322 D322
...
...
ID32k D32k
Repeat k times
Figure 26. PSI5 Initialization Phase 2 Data Transmission Order (10-bit Mode)
The Initialization phase 2 time is calculated with the following equation:
t PHASE2 = TRANS NIBBLE × k × ( DataFields ) × t ASYNC
where:
• TRANSNIBBLE
• k
• Data Fields
• tS-S
= # of Transmissions per Data Nibble
2 for 10-bit Data: 1 for ID, and 1 for Data
= the repetition rate for the data fields
= 32 data fields for 10-bit data
= Sync Pulse Period
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4.4.2.1
PSI5 Initialization Phase 2
In PSI5 initialization phase 2, 10-bit mode, the device transmits a sequence of sensor specific configuration and serial number
information. The transmission data is in conformance with the PSI5 specification, Revision 1.3, Revision 1.10. The data content
and transmission format is shown in Table 8 and Table 9. Times are calculated using the equation in Section 4.4.2.
Table 8. Initialization Phase 2 Time
Operating Mode
Repetition Rate (k)
# of Transmissions
Nominal Phase 2 Time
Asynchronous Mode (228 μs)
8
512
116.7 ms
Table 9. PSI5 Initialization Phase 2 Data
PSI5 V1.2 PSI5 V1.2
Field ID # Nibble ID #
Page
Address
PSI5 Nibble
Address
Register Address
Description
Value
F1
D1
0000
Hard-coded
Protocol Revision = V1.3
0100
F2
D2, D3
0001, 0010
Hard-coded
Number of Data Blocks = 32
0010 0000
F3
D4, D5
0100, 0110
MFG_ID[7:0]
Manufacturer ID
0100 0110
F4
D6, D7
0101, 0110
Hard-coded
Sensor Type = Acceleration (high-g)
0000 0001
D8
0111
Factory Programmed
Axis
0000
1000
±60g: 0111
±120g: 1000
±240g: 1001
±480g: 1010
Range
Varies
F5
D9
0
F6
F7
F8
D10
1001
DEVCFG2[7:4]
Sensor Specific Information
0000
D11
1010
DEVCFG2[3:0]
Sensor Specific Information
0000
D12
1011
Hard-coded
Product Revision
Factory
D13
1100
Hard-coded
Product Revision
Factory
D14
1101
DEVCFG6[3:0]
Product Revision
0000
D15
1110
0001
D16
1111
0010
D17
0000
D18
0001
D19
0010
SN0 (High Nibble)
MMA52xx Serial Number
D20
0011
SN0 (Low Nibble)
MMA52xx Serial Number
Factory
D21
0100
SN1 (High Nibble)
MMA52xx Serial Number
Factory
D22
0101
SN1 (Low Nibble)
MMA52xx Serial Number
Factory
D23
0110
SN2 (High Nibble)
MMA52xx Serial Number
Factory
D24
F9
Factory Programmed
0000
0000
Factory
0111
SN2 (Low Nibble)
MMA52xx Serial Number
Factory
1000
SN3 (High Nibble)
MMA52xx Serial Number
Factory
D26
1001
SN3 (Low Nibble)
MMA52xx Serial Number
Factory
D27
1010
0000
D28
1011
0000
D29
1100
D25
1
Factory Programmed
0000
D30
1101
D31
1110
0000
0000
D32
1111
0000
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4.4.3
Internal Self-Test
During PSI5 Initialization Phase 2 and Phase 3, the device completes it’s internal self-test as described below and shown in
Figure 25.
• Self-Test Phase 1 - Raw Offset Calculation
– The average offset is calculated for tST1 (Self-Test Disabled).
• Self-Test Phase 2 - Self-Test Deflection Verification
–
–
–
–
–
The offset cancellation value is frozen for tST2 + 2ms
Self-Test is enabled
After tST2/2, the acceleration output value is averaged for tST2/2 to determine the self-test value
The self-test value is compared against the limits specified in Section 2.5
Self-Test is disabled
• Self-Test Phase 3 - Self-Test Normal Data Calculation
– The average offset is calculated for tST3
– If Self-Test passed, the device advances to normal mode
– If Self-Test failed, the device repeats Self-Test Phases 1 through 3 up to ST_RPT times.
4.4.4
Initialization Phase 3
During PSI5 initialization phase 3, the device completes it’s internal self checks, and transmits a combination of “Sensor Busy”,
“Sensor Ready”, or “Sensor Defect” messages as defined in Table 7. Self-Test is repeated on failure up to ST_RPT times to provide immunity to misuse inputs during initialization. Self-Test terminates successfully after one successful self-test sequence.
Table 10 shows the nominal Initialization Phase 3 times for self-test repeats. Times are calculated using the following equation.
( t INTINIT + t OC1 + t OC2 + ( t ST1 + t ST2 + t ST3 ) × ( STRPT + 1 ) ) – ( t PSI5INIT1 + t PSI5INIT2xx )
t PSI5INIT3 = ROUNDUP ⎛ --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 2⎞ × t ASYNC
⎝
⎠
t ASYNC
Table 10. Initialization Phase 3 Time
Operating Mode
10-Bit Asynchronous Mode 0 (228 μs)
4.5
Error Handling
4.5.1
Sensor Defect Message
Self-Test
Repetitions
# of Sensor Busy
Messages
# of Sensor Ready or Sensor
Defect Messages
Nominal Phase 3
Time (ms)
0
2
0.91
1
423
96.90
2
844
3
1265
2
192.89
288.88
4
1686
384.86
5
2107
480.85
The following failures will cause the device to transmit a “Sensor Defect” error message:
4.5.2
Error Condition
Error Type
Offset Error
Temporary (Normal transmissions continue once offset returns within limits)
Self-Test Failure
Latched until reset
IDEN_B, IDEF_B flag cleared
Latched until reset
No Response Error
The following failures will cause the device to stop transmitting:
Error Condition
Error Type
Undervoltage Failure (VCC)
Temporary: Normal transmissions continue once voltage returns above failure limit)
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5
Package
5.1
Case Outline Drawing
Reference Freescale Case Outline Drawing # 98ASA00090D
http://www.freescale.com/files/shared/doc/package_info/98ASA00090D.pdf
5.2
Recommended Footprint
Reference Freescale Application Note AN3111, latest revision:
http://www.freescale.com/files/sensors/doc/app_note/AN3111.pdf
Table 11. Revision History
Revision
number
Revision
date
0
09/2012
Description of changes
• Initial release.
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© 2012 Freescale Semiconductor, Inc.
Document Number: MMA52xxAKW
Rev. 0
09/2012