Data Sheet

Freescale Semiconductor
Technical Data
Digital X-Axis or Z-Axis
Accelerometer
The MMA81XXEG (Z-axis) and MMA82XXEG/MMA82XXTEG (X-axis) are
members of Freescale’s family of DSI 2.0-compatible accelerometers. These
devices incorporate digital signal processing for filtering, trim and data
formatting.
Document Number: MMA81XXEG
Rev 5, 04/2010
MMA81XXEG
MMA82XXEG
MMA82XXTEG
SERIES
Features
•
Available in 20g, 40g, 150g, and 250g (MMA82XXEG, X-axis),
50g and 100g (MMA82XXTEG, X-axis) and 40g, 100g, 150g, and
250g (MMA81XXEG, Z-axis). Additional g-ranges may be available upon
request
•
80 customer-accessible OTP bits
•
10-bit digital data output from 8 to 10 bit DSI output
•
6.3 to 30 V supply voltage
•
On-chip voltage regulator
•
Internal self-test
•
Minimal external component requirements
•
RoHS compliant (-40 to +125ºC) 16-pin SOIC package
•
Automotive AEC-Q100 qualified
•
DSI 2.0 Compliant
•
Z-axis transducer is overdamped
SINGLE-AXIS
DSI 2.0
ACCELEROMETER
EG SUFFIX (Pb-free)
16-LEAD SOIC
CASE 475-01
PIN CONNECTIONS
Typical Applications
N/C
1
16
VSS
•
Crash detection (Airbag)
N/C
2
15
VSS
•
Impact and vibration monitoring
•
Shock detection.
CREG
3
14
BUSRTN
VPP/TEST
4
13
BUSIN
CFIL
5
12
BUSOUT
DOUT
6
11
HCAP
VGND/DIN
7
10
VSS
CLK
8
9
16-PIN SOIC PACKAGE
© Freescale Semiconductor, Inc., 2009, 2010. All rights reserved.
CREG
ORDERING INFORMATION
Device Name
X-axis g-Level
Z-axis g-Level
Temperature Range
SOIC 16 Package
Packaging
MMA8225EGR2
250
—
-40 to +125°C
475-01
Tape & Reel
MMA8225EG
250
—
-40 to +125°C
475-01
Tubes
MMA8215EGR2
150
—
-40 to +125°C
475-01
Tape & Reel
MMA8215EG
150
—
-40 to +125°C
475-01
Tubes
MMA8210TEGR2
100
—
-40 to +125°C
475-01
Tape & Reel
MMA8210TEG
100
—
-40 to +125°C
475-01
Tubes
MMA8205TEGR2
50
—
-40 to +125°C
475-01
Tape & Reel
MMA8205TEG
50
—
-40 to +125°C
475-01
Tubes
MMA8204EGR2
40
—
-40 to +125°C
475-01
Tape & Reel
MMA8204EG
40
—
-40 to +125°C
475-01
Tubes
MMA8202EGR2
20
—
-40 to +125°C
475-01
Tape & Reel
MMA8202EG
20
—
-40 to +125°C
475-01
Tubes
MMA8125EGR2
—
250
-40 to +125°C
475-01
Tape & Reel
MMA8125EG
—
250
-40 to +125°C
475-01
Tubes
MMA8115EGR2
—
150
-40 to +125°C
475-01
Tape & Reel
MMA8115EG
—
150
-40 to +125°C
475-01
Tubes
MMA8110EGR2
—
100
-40 to +125°C
475-01
Tape & Reel
MMA8110EG
—
100
-40 to +125°C
475-01
Tubes
MMA8104EGR2
—
40
-40 to +125°C
475-01
Tape & Reel
MMA8104EG
—
40
-40 to +125°C
475-01
Tubes
SECTION 1 GENERAL DESCRIPTION
MMA81XXEG/MMA82XXEG/MMA82XXTEG family is a satellite accelerometer which is comprised of a single axis, variable capacitance sensing element with a single channel interface IC. The interface IC converts the analog signal to a digital format which
is transmitted in accordance with the DSI-2.0 specification.
1.1
OVERVIEW
Signal conditioning begins with a Capacitance to Voltage conversion (C to V) followed by a 2-stage switched capacitor amplifier.
This amplifier has adjustable offset and gain trimming and is followed by a low-pass switched capacitor filter with Bessel function.
Offset and gain of the interface IC are trimmed during the manufacturing process. Following the filter the signal passes to the
output stage. The output stage sensitivity incorporates temperature compensation.
The output of the accelerometer signal conditioning is converted to a digital signal by an A/D converter. After this conversion the
resultant digital word is converted to a serial data stream which may be transmitted via the DSI bus. Power for the device is
derived from voltage applied to the BUSIN/BUSOUT and VSS pins. Bus voltage is rectified and applied to an external capacitor
connected to the HCAP pin. During data transmissions, the device operates from stored charge on the external capacitor. An
integrated regulator supplies fixed voltage to internal circuitry.
A self-test voltage may be applied to the electrostatic deflection plate in the sensing element. Self-Test voltage is factory trimmed.
Other support circuits include a bandgap voltage reference for the bias sources and the self-test voltage.
A total of 128 bits of One-Time Programmable (OTP) memory, are provided for storage of factory trim data, serial number and
device characteristics. Eighty OTP bits are available for customer programming. These eighty OTP bits may be programmed via
the DSI Bus or through the serial test/trim interface. OTP integrity is verified through continuous parity checking. Separate parity
bits are provided for factory and customer programmed data. In the event that a parity fault is detected, the reserved value of
zero is transmitted in response to a Read Acceleration Data command.
A block diagram illustrating the major elements of the device is shown in Figure 1-1.
MMA81XXEG
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Freescale Semiconductor
REGULATOR
TRIM
HCAP
BUSIN
N/C
N/C
VSS
VSS
VSS
BUSRTN
11
INTERNAL
SUPPLY
VOLTAGE
13
3
12
CREG
CREG
BUSOUT
1
2
16
15
10
14
GROUND
LOSS
DETECTOR
BANDGAP
REFERENCE
LOGIC
COMMAND DECODE
STATE MACHINE
RESPONSE GENERATION
OSCILLATOR
SELFTEST
TRIM
OSC
TRIM
SELFTEST
VOLTAGE
7
4
OTP
PROGRAMMING
INTERFACE
6
8
SELF-TEST ENABLE
A-TO-D
CONVERTER
g-CELL
9
VOLTAGE
REGULATOR
C-TO-V
CONVERTER
GAIN
TRIM
OFFSET
TRIM
VPP/TEST
DOUT
CLK
SWITCHES SHOWN
IN NORMAL OPERATING
CONFIGURATION
5
LOW-PASS
FILTER
VGND/DIN
CFIL
TCS
TRIM
Figure 1-1. Overall Block Diagram
MMA81XXEG
Sensors
Freescale Semiconductor
3
1.2
PACKAGE PINOUT
The pinout for this 16-pin device is shown in Figure 1-2.
+Z
+X
N/C
1
16
VSS
N/C
2
15
VSS
CREG
3
14
BUSRTN
VPP/TEST
4
13
BUSIN
CFIL
5
12
BUSOUT
DOUT
6
11
HCAP
VGND/DIN
7
10
VSS
CLK
8
9
-Z
-X
CREG
16-PIN SOIC PACKAGE
ACTIVATION OF Z-AXIS SELF-TEST
CAUSES OUTPUT TO
BECOME MORE POSITIVE
PROJECTION
ACTIVIATION OF X-AXIS SELF-TEST
CAUSES OUTPUT TO
BECOME MORE POSITIVE
CASE: 475-01
N/C: NO INTERNAL CONNECTION
Output response to displacement in the direction of arrows.
+1 g
+1 g
0g
0g
-1 g
0g
0g
TO CENTER OF
GRAVITATIONAL FIELD
-1 g
Response to static orientation within 1 g field.
Figure 1-2. Device Pinout
MMA81XXEG
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Freescale Semiconductor
1.3
PIN FUNCTIONS
The following paragraphs provide descriptions of the general function of each pin.
1.3.1
HCAP and VSS
Power is supplied to the ASIC through BUSIN or BUSOUT and BUSRTN. The supply voltage is rectified internally and applied
to the HCAP pin. An external capacitor connected to HCAP forms the positive supply for the integrated voltage regulator. VSS is
supply return node. All VSS pins are internally connected to BUSRTN. To obtain specified performance, all VSS nodes should be
connected to the BUSRTN node on the PWB. To ensure stability of the internal voltage regulator and meet DFMEA requirements,
the connection from HCAP to the external capacitor should be as short as possible and should not be routed elsewhere on the
printed wiring assembly.
The voltage on HCAP is monitored. If the voltage falls below a specified level, the device will return the value zero in response to
a short word Read Acceleration Data command, and report the undervoltage condition by setting the Undervoltage (U) flag.
Should the undervoltage condition persist for more than one millisecond, the internal Power-On Reset (POR) circuit is activated
and the device will not respond until the voltage at HCAP is restored to operating levels and the device has undergone post-reset
initialization.
1.3.2
BUSIN
The BUSIN pin is normally connected to the DSI bus and supports bidirectional communication with the master.
The MMA81XXEG, MMA82XXEG and MMA82XXTEG supports reverse initialization for improved system fault tolerance. In the
event that the DSI bus cannot support communication between the master and BUSIN pin, communication with the master may
be conducted via the BUSOUT pin and the BUSIN pin can be used to access other DSI devices.
1.3.3
BUSOUT
The BUSOUT pin is normally connected to the DSI bus for daisy-chained bus configurations. In support of fault tolerance at the
system level, the BUSOUT pin can be used as an input for reverse initialization and data communication.
The internal bus switch is always open following reset. The bus switch is closed when data bit D6 is set when an Initialization or
Reverse Initialization command is received.
1.3.4
BUSRTN
This pin provides the common return for power and signalling.
1.3.5
CREG
The internal voltage regulator requires external capacitance to the VSS pin for stability. This should be a high grade capacitor
without excessive internal resistance or inductance. An optional electrolytic capacitor may be required if a longer power down
delay is required.
Figure 1-3 illustrates the relationship between capacitance, series resistance and voltage regulator stability. Two CREG pins are
provided for redundancy. It is recommended that both CREG pins are connected to the external capacitor(s) for best system
reliability.
STABLE, UNACCEPTABLE
NOISE PERFORMANCE
UNSTABLE
700 mΩ
ESR
STABLE
0
1 μF
100 μF
CREG
Figure 1-3. Voltage Regulator Capacitance and Series Resistance
MMA81XXEG
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Freescale Semiconductor
5
1.3.6
CFIL
The output of the sensor interface circuitry can be monitored at the CFIL pin. An internal buffer is provided to provide isolation
between external signals and the input to the A/D converter. If CFIL monitoring is desired, a low-pass filter and a buffer with high
input impedance located as close to this pin as possible are required. The circuit configuration shown in Figure 1-5 is
recommended.
MMA81XXEG/MMA82XXEG//MMA82XXTEG
RIN ≥ 1 MΩ
50 kΩ
CFIL
5
680 pF
Figure 1-4. CFIL Filter and Buffer Configuration
This pin may be configured as an input to the A/D converter when the MMA81XXEG, MMA82XXEG and MMA82XXTEG devices
are in test mode. Refer to Appendix A for further details regarding test mode operation.
1.3.7
Trim/Test Pins (VPP/TEST, CLK, DOUT)
These pins are used for programming the device during manufacturing. These pins have internal pull-up or pull-down devices to
drive the input when left unconnected. The following termination is recommended for these pins in the end application:
Table 1-1
PIN
Termination
VPP/TEST
Connect to ground
CLK
Leave unconnected
DOUT
Leave unconnected
CLK may be connected to ground, however this is not advised if the GLDE bit in DEVCFG2 is set, as a short between the adjacent
VGND/DIN pin and ground prevents ground loss detection.
1.3.8
GND Detect Pin (VGND/DIN)
VGND/DIN may be used to detect an open condition between the satellite module and chassis. The ground loss detector circuit
supplies a constant current through VGND/DIN and measures resulting voltage. This determines the resistance between VGND/
DIN and the system’s virtual ground. A fault condition is signalled if the resistance exceeds specified limits. This pin has no internal
pull-down device and must be connected as shown in Figure 1-5.
Ground loss detection circuitry is enabled when the GLDE bit is programmed to a logic ‘1’ state in DEVCFG2. Ground loss
detection is not available when the master operates in differential mode. VGND/DIN must be directly connected to BUSRTN if the
DSI bus is configured for differential operation. VGND/DIN connection options are illustrated in Figure 1-5.
When ground loss detection is enabled, a constant current is sourced and the voltage at VGND is continuously monitored. An
open connection between VSS and chassis ground will cause the voltage to rise. If the voltage indicates that the connection
between chassis ground and VSS has opened, a 14-bit counter is enabled. This counter will reverse if the voltage falls below the
detection threshold. Should the counter overflow, a ground loss condition is indicated. The counter acts as a digital low-pass filter,
to provide immunity from spurious signals.
This pin functions as the SPI data input when the device is in test mode.
MMA81XXEG
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Freescale Semiconductor
GROUND-LOSS DETECTION DISABLED
MMA81XXEG/MMA82XXEG/MMA82XXTEG
1
2
3
4
5
6
7
8
N/C
VSS
N/C
VSS
CREG
BUSRTN
VPP/TEST
CFIL
BUSIN
BUSOUT
DOUT
VGND/DIN
CLK
HCAP
VSS
CREG
GROUND-LOSS DETECTION ENABLED
(SINGLE-ENDED SYSTEMS ONLY)
MMA81XXEG/MMA82XXEG/MMA82XXTEG
16
1
15
2
14
3
13
4
12
5
11
6
10
7
BUSRTN
8
9
N/C
VSS
N/C
VSS
CREG
BUSRTN
VPP/TEST
CFIL
BUSIN
BUSOUT
HCAP
DOUT
VGND/DIN
VSS
CLK
CREG
16
15
14
BUSRTN
13
12
11
10
9
1.00 kΩ, 1%
CHASSIS
1 nF
Figure 1-5. VGND/DIN Connection Options
1.4
MODULE INTERCONNECT
A typical satellite module configuration supporting daisy-chain configuration is shown in Figure 1-6. Capacitors C1 and C2
form a filter network for the internal voltage regulator. Two capacitors are shown for redundancy; this configuration improves
reliability in the event of an open capacitor connection. A single 1 μF capacitor may be used in place of C1 and C2, however
connection from the capacitor to both CREG pins is required. CHOLD stores energy during signal transitions on BUSIN and
BUSOUT. The value of this capacitor is typically 1 μF; however, this depends upon data rates and bus utilization.
MMA81XXEG/MMA82XXEG/MMA82XXTEG
1
2
3
4
5
SEE NOTE
N/C
6
7
8
N/C
VSS
N/C
VSS
CREG
VPP/TEST
CFIL
DOUT
VGND/DIN
CLK
C1
1 μF
BUSRTN
BUSIN
BUSOUT
HCAP
VSS
CREG
16
15
14
13
BUSIN
12
BUSOUT
11
10
9
C2
1 μF
CHOLD
BUSRTN
NOTE: LEAVE OPEN OR CONNECT TO SIGNAL MONITOR.
Figure 1-6. Typical Satellite Module Diagram
1.5
DEVICE IDENTIFICATION
Thirty-two OTP bits are factory-programmed with a unique serial number during the manufacturing and test. Five additional bits
are factory-programmed to indicate the full-scale range and axis of sensitivity. Device identification data may be read at any time
while the device is active.
MMA81XXEG
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Freescale Semiconductor
7
SECTION 2 SUPPORT MODULES
2.1
MASTER OSCILLATOR
A temperature-compensated internal oscillator provides a stable timing reference for the device. The oscillator is factory-trimmed
to operate at a nominal frequency of 4 MHz.
2.2
VOLTAGE REGULATION
The internal voltage regulator has minimum voltage level detection, which will hold the device in reset and prevent data
transmission should the regulator output fall during operation. The regulator also has an input voltage clamp to limit the power
dissipated in the regulator during voltage spikes on the HCAP pin which might come from the two or three wire satellite bus.
2.3
BESSEL FILTER
180-Hz, 2-pole and 400 Hz 4-pole Bessel filter options are provided. The low-pass filter is implemented within a two stage
switched capacitor amplifier. The overall gain of the Bessel filter is set to a fixed value. The output of the Bessel filter output acts
as the input to the A/D converter and is also buffered and made available at the CFIL pin.
2.4
STATUS MONITORING
A number of abnormal conditions are detected by MMA81XXEG/MMA82XXEG/MMA82XXTEG and the behavior of the device
altered if a fault is detected. Detected fault conditions and consequent device behavior is summarized in the table below. Certain
conditions, e.g. ground loss, are qualified by device configuration. Figure 2-1 provides a representation of fault conditions, applicable qualifiers and effects.
Table 2-1 Fault Condition Response Summary
Condition
Undervoltage, CREG
Sustained Undervoltage, HCAP
Frame Timeout
Transient Undervoltage, HCAP
Description
Internally regulated voltage below operating
level
Device Behavior
Device continuously undergoes reset, bus switch
open, no response to DSI commands
Voltage at HCAP below operating level for more
than 1 ms
Bus voltage remains below frame threshold
(tTO) longer than specified time.
Voltage at HCAP below operating level for less Undervoltage (U) flag set, short-word Read
than 1 ms
Acceleration Data response value equals zero
Fuse Fault
OTP fuse threshold failure
Parity Fault
Parity failure detected in factory or customer
programmed OTP data
Ground Fault
Ground loss detected for more than 4.096 ms
Accelerometer Status (S) flag set, short-word Read
Acceleration Data response value equals zero
Accelerometer Status (S) and Ground Fault (GF) flags
set, short-word Read Acceleration Data response
value equals zero
MMA81XXEG
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Freescale Semiconductor
ST
STDIS
S
1
D
SHORT WORD
ACCELERATION
DATA = 0
Q
DDIS
R
FUSE ERROR
TRANSIENT
UNDERVOLTAGE
CONDITION
GF
GLDE
U
LOCK1
PAR1 FAULT
LOCK2
PAR2 FAULT
KEY:
DDIS
DEVICE DISABLE BIT, DEVCFG2[4]
FUSE FAULT
OTP FUSE THRESHOLD FAILURE
GLDE
GROUND LOSS DETECTION BIT, DEVCFG2[5]
GF
GROUND FAULT DETECTION CONDITION
LOCK1
FACTORY PROGRAMMED OTP LOCK BIT
LOCK2
CUSTOMER PROGRAMMED OTP LOCK BIT
PAR1 FAULT
FACTORY PROGRAMMED OTP PARITY FAULT CONDITION
PAR2 FAULT
CUSTOMER PROGRAMMED OTP PARITY FAULT CONDITION
S
ACCELEROMETER STATUS FLAG
ST
SELF-TEST ACTIVATION CONDITION
STDIS
SELF-TEST DISABLE
U
UNDERVOLTAGE FLAG
Figure 2-1. Status Logic Representation
The signal STDIS in Figure 2-1 is set when self-test lockout is activated through the execution of two consecutive Disable SelfTest Stimulus commands, as described in Section 4.6.6. If self-test lockout has been activated, a DSI Clear command or poweron reset is required to clear a fault condition which results in reset of the D flip-flop.
MMA81XXEG
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Freescale Semiconductor
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SECTION 3 OTP MEMORY
MMA81XXEG/MMA82XXEG/MMA82XXTEG family features One-Time-Programmable (OTP) memory implemented via a fuse
array. OTP is organized as an array of 96 bits which contains the trim data, configuration data, and serial number for each device.
Sixteen bits of the OTP array may be programmed by the customer through the DSI Bus.
3.1
INTERNAL REGISTER ARRAY AND OTP MEMORY
Contents of OTP memory are transferred to a set of registers following power-on reset, after which the OTP array is powereddown. Contents of the register array are static and may be read at any time following the transfer of data from the OTP memory.
Write operations to OTP mirror registers are supported when the device is in test mode, however any data stored in the register
will be lost when the device is powered down. The mirror registers are also restored when an OTP read operation is performed.
In addition to the registers which mirror OTP memory contents, several other registers are provided. Among these are the OTP
Control Registers which controls OTP programming operations and may be used to restore the registers from the OTP memory.
CLK
SERIAL
PERIPHERAL
INTERFACE
DOUT
TO DIGITAL
INTERFACE
REGISTER
ARRAY
DIN
OTP
ARRAY
VPP/TEST
Figure 3-1. OTP Interface Overview
3.2
OTP WORD ASSIGNMENT
Customer-accessible OTP bits are shown in Table 3-1. Unprogrammed OTP bits are read as logic ‘0’ values. DEVCFG1,
DEVCFG2 and registers REG-8 through REG-F are programmed by the customer. Other bits are programmed and locked during
manufacturing. There is no requirement to program any bits in DEVCFG1 or DEVCFG2 for the device to be fully operational.
Table 3-1 Customer Accessible Data
Location
Bit Function
Address
Register
7
6
5
4
3
2
1
0
$00
SN0
S7
S6
S5
S4
S3
S2
S1
S0
$01
SN1
S15
S14
S13
S12
S11
S10
S9
S8
$02
SN2
S23
S22
S21
S20
S19
S18
S17
S16
$03
SN3
S31
S30
S29
S28
S27
S26
S25
S24
$04
TYPE
ORDER
0
AXIS
0
0
RNG2
RNG1
RNG0
$05
RESERVED
0
0
0
0
0
0
0
0
$06
DEVCFG1
AT1
AT0
$07
DEVCFG2
AD1
AD0
$08
REG-8
Customer Defined
LOCK2
PAR2
GLDE
DDIS
AD3
AD2
Customer Defined
$09
REG-9
Customer Defined
$0A
REG-A
Customer Defined
$0B
REG-B
Customer Defined
$0C
REG-C
Customer Defined
$0D
REG-D
Customer Defined
$0E
REG-E
Customer Defined
$0F
REG-F
Customer Defined
MMA81XXEG
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Freescale Semiconductor
3.2.1
Device Serial Number
A unique serial number is programmed into each device during manufacturing. The serial number is composed of the following
information.
Table 3-2 Serial Number Assignment
Bit Range
Content
S12 - S0
Serial Number
S31 - S13
Lot Number
Lot numbers begin at 1 for all devices produced and are sequentially assigned. Serial numbers begin at 1 for each lot, and are
sequentially assigned. No lot will contain more devices than can be uniquely identified by the 13-bit serial number. Not all allowable lot numbers and serial numbers will be assigned.
3.2.2
Type Byte
The Type Byte is programmed at final trim and test to indicate the axis of orientation of the g-cell and the calibrated range of the
device.
Table 3-3 Device Type Register
Location
Bit Function
Address
Register
7
6
5
4
3
2
1
0
$04
TYPE
ORDER
0
AXIS
0
0
RNG2
RNG1
RNG0
3.2.2.1
Filter Characteristic Bit (ORDER)
This bit denotes the low-pass filter characteristic.
0 - 400 Hz, 4-pole
1 - 180 Hz, 2-pole
3.2.2.2
Bit 6
Bit 6 is reserved. It will always be read as a logic ‘0’ value.
3.2.2.3
Axis of Sensitivity Bit (AXIS)
The AXIS bit indicates direction of sensitivity
0 - Z-axis
1 - X-axis
3.2.2.4
Bit 4, Bit 3
Bit 4 and Bit 3 are reserved. They will always be read as a logic ‘0’ value.
3.2.2.5
Full-Scale Range Bits (RNG2 - RNG0)
These three bits define the calibrated range of the device as follows:
Table 3-4
RNG2
RNG1
RNG0
Range
0
0
0
Unused
0
0
1
20g
0
1
0
40g
0
1
1
50g
1
0
0
100g
1
0
1
150g
1
1
0
250g
1
1
1
Unused
MMA81XXEG
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Freescale Semiconductor
11
3.2.3
Configuration Bytes
Two customer-programmable configuration bytes are assigned.
3.2.4
Device Configuration Byte 1 (DEVCFG1)
Table 3-5 Device Configuration Byte 1
Location
Address
Register
$06
DEVCFG1
Bit Function
7
6
5
4
3
2
Customer Defined
1
0
ATT1
ATT0
Configuration Byte 1 contains three defined bit functions, plus five bits that can be programmed by the customer to designate any
coding desired for packaging axis, model, etc.
3.2.5
Attribute Bits (AT1, AT0)
These bits may be assigned by the customer as desired. They are transmitted by MMA81XXEG/MMA82XXEG/MMA82XXTEG
in response to Request Status, Disable Self-Test Stimulus or Enable Self-Test Stimulus commands, as described in Section 4.
3.2.6
Device Configuration Byte 2 (DEVCFG2)
Table 3-6 Device Configuration Byte 2
Location
Bit Function
Address
Register
7
6
5
4
3
2
1
0
$07
DEVCFG2
LOCK2
PAR2
GLDE
DDIS
AD3
AD2
AD1
AD0
Configuration Byte 2 contains six bits that can be programmed by the customer to control device configuration, along with parity
and lock bits for DEVCFG1 and DEVCFG2.
3.2.6.1
Customer Data Lock Bit (LOCK2)
The bits in configuration bytes 1 and 2 are frozen when the LOCK2 bit is programmed. The LOCK2 bit is not included in the parity
check. Locking does not take effect after this bit is programmed until the device has been subsequently reset.
0 - Customer-programmed data area unlocked.
1 - Programming operations inhibited.
The DDIS bit is not affected by LOCK2 and may be programmed at any time.
3.2.6.2
Customer Data Parity Bit (PAR2)
The PAR2 parity bit is used for detecting changes in configuration bytes 1 and 2 along with registers REG-8 through REG-F
(addresses $06 through $0F, inclusive). A fault condition is indicated if a change to parity-protected register data is detected. The
PAR2 bit follows an “even” parity scheme (number of logical HIGH bits including parity bit is even).
If an internal parity error is detected, the device will respond to Read Acceleration Data commands with zero in the data field, as
described in Section 4.5.4. The Status (S) bit will be set in either short word or long word responses to indicate the fault condition.
A parity fault may result from a bit failure within the OTP or the registers which store an image of the OTP during operation. In
the latter case, power-on reset will clear the fault when the registers are re-loaded. A parity fault associated with the OTP array
is a non-recoverable failure.
The parity status of customer programmed data is not monitored if the LOCK2 bit is not programmed to a logic ‘1’ state.
3.2.6.3
Ground Loss Detection Enable (GLDE)
When this bit is programmed to a logic ‘1’ value, ground loss errors will be reported if a ground fault condition is detected.
1 - Ground-loss detection circuitry enabled
0 - Ground-loss detection disabled.
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3.2.6.4
Device Disable Bit (DDIS)
This bit may be programmed at any time, regardless of the state of LOCK2. This bit is intended to be programmed when a module
has been determined by the DSI Bus Master to be defective. Programming this bit after LOCK2 has been set will cause the device
to respond to short word Read Acceleration Data commands with a zero response. Acceleration results are not affected by this
bit when long word Read Acceleration Data commands are executed, however the Status (S) bit will be set in the response.
1 - Device responds to Read Acceleration Data command with zero value
0 - Device responds normally to Read Acceleration Data command
3.2.6.5
Device Address (AD3 - AD0)
These bits define the pre-programmed DSI Bus device address.
3.3
OTP PROGRAMMING
Two different methods of programming the eighty customer defined bits are supported. In test mode, these may be programmed
in the same manner as factory programmed OTP bits. Additionally, the Read Write NVM DSI bus command may be used. Test
mode programming operations are described in Appendix A.3. Read Write NVM command operation is described in
Section 4.6.3.
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SECTION 4 PHYSICAL LAYER AND PROTOCOL
MMA81XXEG/MMA82XXEG/MMA82XXTEG family is compliant with the DSI Bus Standard, Version 2.0. MMA81XXEG/
MMA82XXEG/MMA82XXTEG is designed to be compatible with either DSI Version 2 or DSI Version 1.1 compliant bus masters.
4.1
DSI NETWORK PHYSICAL LAYER INTERFACE
Refer to Section 3 of the DSI Bus Standard for information regarding the physical layer interface.
4.2
DSI NETWORK DATA LINK LAYER
Refer to Section 4 of the DSI Bus Standard for information regarding the DSI network data link layer interface. Both standard
and enhanced command structures are supported for short word and long word commands.
4.3
DSI BUS COMMANDS
DSI Bus Commands which are recognized by MMA81XXEG and the MMA82XXEG/MMA82XXTEG are summarized in
Table 4-1. Detailed descriptions of each supported command are described in subsequent sections of this document. If a CRC
error is detected, or a reserved or unimplemented command is received, the device will not respond.
Following all messages, MMA81XXEG and the MMA82XXEG/MMA82XXTEG disregards the DSI bus voltage level for approximately 18.5 μs. Within this time, all supported commands except Initialization and Reverse Initialization are guaranteed to be
executed and the device will be ready for the next message. When the bus voltage falls below the signal high logic level (see
Section 5) after the 18.5 μs period has elapsed, the device will respond as appropriate to a command sent to it in the previous
message. Exactly one response is attempted; if a noise spike or corrupted transfer occurs, the response is not retried.
If an Initialization or Reverse Initialization command is executed and the Bus Switch (BS) bit is set, MMA81XXEG, MMA82XXEG
and MMA82XXTEG will disregard the bus voltage level for a nominal period of 180 μs. This interval allows for the bus voltage to
recover following closure of the bus switch, while the hold capacitor of a downstream slave charges.
Table 4-1 DSI Bus Command Summary
Command
Data
Binary
Size
Hex
Description
C3
C2
C1
C0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
$0
Initialization
LW
NV
BS
B1
B0
PA3
PA2
PA1
PA0
0
0
0
1
$1
Request Status
SW
—
—
—
—
—
—
—
—
0
0
1
0
$2
0
0
1
1
$3
Read Acceleration Data
SW
—
—
—
—
—
—
—
—
Not Implemented
N/A
0
1
0
0
$4
Request ID Information
SW
—
—
—
0
1
0
1
$5
Not Implemented
N/A
0
1
0
1
1
0
$6
Not Implemented
N/A
1
1
$7
Clear
SW
—
—
—
1
0
0
0
$8
Not Implemented
N/A
1
0
0
1
$9
Read Write NVM
LW
RA3
RA2
RA1
RA0
RD2
RD1
RD0
1
0
1
0
$A
Format Control
LW
R/W
FA2
FA1
FA0
FD3
FD2
FD1
FD0
1
0
1
1
$B
Read Register Data
LW
0
0
0
0
RA3
RA2
RA1
RA0
1
1
0
0
$C
Disable Self-Test Stimulus
SW
—
—
—
—
—
—
—
—
1
1
0
1
$D
Activate Self-Test Stimulus
SW
—
—
—
—
—
—
—
—
1
1
1
0
$E
Reserved
N/A
1
1
1
1
$F
Reverse Initialization
LW
NV
BS
B1
PA2
PA1
PA0
Not Applicable
—
—
—
—
—
Not Applicable
Not Applicable
—
—
—
—
—
Not Applicable
RD3
Not Applicable
B0
PA3
Legend:
BS: Bus Switch Control (0: open, 1: close)
NV: Nonvolatile memory control (1: program NVM)
PA3 - PA0: Device address assigned during Initialization or Reverse Initialization
RA3 - RA0: Internal user data register address
FA2 - FA0: Format register address
FD3 - FD0: Format register data content
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4.4
COMMAND RESPONSE SUMMARIES
The device incorporates an analog-to-digital converter which translates the low-pass filtered acceleration signal to a 10-bit binary
value. The 10-bit digital result is referred to as AD9 through AD0 in the response tables which follow.
4.4.1
Short Word Response Summary
Short word responses for all commands are summarized below. Detailed DSI command descriptions may be found in
Section 4.5.
Table 4-2 Short-Word Response Summary
Command
Hex
Description
Response
D7
D6
D5
D4
D3
D2
D1
D0
AT0
S
GF
1
0
0
$0
Initialization
Not Applicable
$1
Request Status
$2
Read Acceleration Data
$3
Not Implemented
$4
Request ID Information
$5
Not Implemented
No Response
$6
Not Implemented
No Response
$7
Clear
No Response
$8
Not Implemented
No Response
$9
Read/Write NVM
Not Valid
$A
Format Control
Not Valid
$B
Read Register Data
Not Valid
$C
Disable Self-Test Stimulus
NV
U
ST
BS
AT1
AT0
S
GF
$D
Activate Self-Test Stimulus
NV
U
ST
BS
AT1
AT0
S
GF
$E
Reserved
$F
Reverse Initialization
NV
U
ST
BS
AT1
See Section 4.5.4
No Response
V2
V1
V0
0
0
No Response
Not Valid
Legend:
AT1 - AT0: Attribute codes (see Section 4.5.1.3)
NV: State of fuse program control bit
BS: State of Bus Switch (0: open, 1: closed)
S: Accelerometer status flag (1: internal error)
ST: Self-Test flag (1: self-test active)
U - Undervoltage condition
V2 - V0: Version ID
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4.4.2
Long Word Response Summary
Long word responses for all commands are summarized below. Detailed DSI command descriptions may be found in Section 4.5.
Table 4-3 Long-Word Response Summary
Command
Hex
Description
Response
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
$0
Initialization
A3
A2
A1
A0
0
0
0
BF
NV
BS
B1
B0
PA3 PA2 PA1 PA0
D3
D2
$1
Request Status
A3
A2
A1
A0
0
0
0
0
NV
U
ST
BS
AT1
$2
Read Acceleration Data
A3
A2
A1
A0
GF
S
$3
Not Implemented
$4
Request ID Information
A3
A2
A1
A0
0
0
$5
Not Implemented
No Response
$6
Not Implemented
No Response
$7
Clear
No Response
$8
Not Implemented
No Response
$9
Read/Write NVM
A3
A2
A1
A0
$A
Format Control
A3
A2
A1
A0
AT0
D1
S
D0
GF
AD9 AD8 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
No Response
0
0
V2
V1
V0
0
0
1
0
0
See Section 4.6.3
0
1
1
0
R/W FA2
FA1 FA0 FD3 FD2 FD1 FD0
$B
Read Register Data
A3
A2
A1
A0
$C
Disable Self-Test Stimulus
A3
A2
A1
A0
RA3 RA2 RA1 RA0 RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0
0
0
0
0
NV
U
ST
BS
AT1
AT0
S
GF
$D
Activate Self-Test Stimulus
A3
A2
A1
A0
0
0
0
0
NV
U
ST
BS
AT1
AT0
S
GF
$E
Reserved
$F
Reverse Initialization
BS
B1
B0
PA3 PA2 PA1 PA0
No Response
A3
A2
A1
A0
0
0
0
BF
NV
Legend:
A3 - A0: Device address
AD9 - AD0: 10-bit acceleration data result
AT1 - AT0: Attribute codes (see Section 4.5.1.3)
BF: Bus Fault flag (1: bus fault)
BS: State of Bus Switch (0: open, 1: closed)
FA2 - FA0: Format register address
FD3 - FD0: Format register data content
GF: Ground fault detected
NV: State of fuse program control bit
PA3 - PA0: Device address assigned during Initialization/Reverse Initialization
RA3 - RA 0: Internal user data register address
RD7 - RD0: Internal user data register contents
R/W: Read/Write flag for Format Control Register access
S: Accelerometer Status Flag (1: internal error)
ST: Self-Test Flag (1: self-test active)
U - Undervoltage condition
V2 - V0: Version ID
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4.5
DSI COMMAND DETAIL
Detailed descriptions of command formats and responses are provided in this section.
4.5.1
DSI COMMAND AND RESPONSE BIT DESCRIPTIONS
The following abbreviations are used in the descriptions of DSI commands and responses.
4.5.1.1
DSI Device Address - (A3 - A0)
DSI device address. This address will be set to the pre-programmed device address following reset, or zero if no pre-programmed
address has been assigned. If zero, the device address may be assigned during initialization or reverse initialization.
4.5.1.2
Acceleration Data - (AD9 - AD0)
Ten-bit acceleration result produced by the device. This value is returned by the Read Acceleration Data command, described in
Section 4.5.4.
4.5.1.3
Attribute Code Bits (AT1, AT0)
These bits indicate the contents of DEVCFG1 bits 1 and 0 in response to a Request Status, Activate Self-Test Stimulus or Disable
Self-Test Stimulus command.
Table 4-4 Attribute Code Bit Assignments
4.5.1.4
LOCK2
DEVGFG1[1]
DEVGFG1[0]
AT1
AT0
0
X
X
1
0
1
0
0
0
0
0
1
0
1
1
0
1
0
1
1
1
1
Bank Select (B1, B0)
These bits are assigned during initialization or reverse initialization to select specific fields within the customer accessible data
registers. Bank selection affects Read/Write NVM command operation. Invalid combinations of B1 and B0 result in no response
from the device to the associated initialization or reverse initialization command.
Refer to Section 4.6.3 for further details regarding register programming and bank selection.
4.5.1.5
Bus Fault Bit (BF)
This bit indicates the success or failure of the bus test which is performed as part of an Initialization or Reverse Initialization command.
1 - Bus fault detected
0 - Bus test passed
4.5.1.6
Bus Switch Control/Status Bit (BS)
This bit controls the state of the bus switch during an Initialization or Reverse Initialization command. It also indicates the state
of the bus switch in response to the Initialization, Request Status, Disable Self-Test Stimulus, Activate Self-Test Stimulus and
Reverse Initialization commands.
1 - Close bus switch, or bus switch closed
0 - Leave bus switch open, or bus switch opened
4.5.1.7
Format Control Register Address (FA2 - FA0)
This three-bit field selects one of eight format control registers. Format control registers are described in Section 4.6.4.3.
4.5.1.8
Format Register Data (FD3 - FD0)
Contents of a format control register. This is the data to be written to the register by a Format Control command, or the contents
read from the register in response to a Format Control command.
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4.5.1.9
Ground Fault Flag (GF)
If ground loss detection has been enabled and a ground fault condition is detected, this bit will be set in the response to Request
Status, Read Acceleration Data, Disable Self-Test Stimulus or Activate Self-Test Stimulus commands. If ground loss detection is
not enabled, this bit will always be read as a logic ‘0’ value.
1 - Ground fault condition detected
0 - Ground connection within specified limits, or ground loss detection disabled.
4.5.1.10 Nonvolatile Memory Program Control Bit (NV)
This bit enables programming of customer-programmed OTP locations when set during an Initialization or Reverse Initialization
command. Data to be programmed are transferred to the device during subsequent Read Write NVM commands.
1 - Enable OTP programming
0 - OTP programming circuitry disabled
4.5.1.11 Assigned Device Address (PA3 - PA0)
This field contains the device address to be assigned during an Initialization or Reverse Initialization command. The address
assigned is reported by the device in response to the Initialization or Reverse Initialization command.
4.5.1.12 Register Address (RA3 - RA0)
This field determines the register associated with a Read Write NVM or Read Register Data command. The two Bank Select bits
(B1, B0) are used to additionally specify a nibble or bit when a Read Write NVM command is executed.
4.5.1.13 Register Data (RD7 - RD0)
RD3 - RD0 contain data to be written to an OTP location when a Read Write NVM command is executed if the NV bit is set. RD3
- RD0 contain the data read from the selected register in response to a Read Write NVM command if the NV bit is cleared. RD7
- RD0 indicate the contents of the selected register in response to a Read Register Data command.
4.5.1.14 Format Control Register Read/Write Bit (R/W)
This bit controls the operation performed by a Format Control command.
1 - Write Format Control register selected by FA2 - FA0
0 - Read Format Control register unless global command
4.5.1.15 Accelerometer Status Flag (S)
This bit provides a cumulative indication of the various error conditions which are monitored by the device.
1 - Either one or more error conditions have been detected and/or the internal Self-Test stimulus circuitry is active
0 - No error condition has been detected
The following conditions will cause the status flag to be set:
*Internal Self-Test stimulus circuitry is active
OTP array parity fault
OTP fuse threshold fault (partially-programmed fuse)
Transient undervoltage condition
Ground fault (if GLDE bit in DEVCFG2 is set)
4.5.1.16 Self-Test State (ST)
This bit indicates whether internal self-test stimulus circuitry is active in response to Request Status, Disable Self-Test Stimulus
and Activate Self-Test Stimulus commands.
1 - Self-Test stimulus active
0 - Self-Test stimulus disabled
4.5.1.17 Undervoltage Flag (U)
This flag is set if the voltage at HCAP is below a specified threshold. Refer to Section 1.3.1 and Section 5 for further details.
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4.5.2
Initialization Command
The initialization command conforms to the description provided in Section 6.2.1 of the DSI Bus Standard, Version 2.0. At powerup the device is fully compliant with the DSI 1.1 protocol. The initialization command must be transmitted as a DSI 1.1 compliant
long command structure. Features of the DSI 2.0 protocol can not be accessed until a valid DSI 1.1 compliant initialization
sequence is performed and the enhanced mode format registers are properly configured.
Table 4-5 Initialization Command Structure
Data
Address
Command
CRC
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
NV
BS
B1
B0
PA3
PA2
PA1
PA0
A3
A2
A1
A0
0
0
0
0
4 bits
Figure 4-1 illustrates the sequence of operations performed following negation of internal Power-On Reset (POR) and execution
of a DSI Initialization command. Initialization commands are recognized only at BUSIN. The BUSOUT node is tested for a bus
short to battery high voltage condition, and the Bus Fault (BF) flag set if an error condition is detected. If no bus fault condition is
detected and the BS bit is set in the command structure, the bus switch will be closed. If the BS bit is set, the DSI bus voltage
level is disregarded for approximately 180 μs following initialization to allow the hold capacitor on a downstream slave to charge.
If the device has been pre-programmed, PA3 - PA0 and A3 - A0 must match the pre-programmed address. If no device address
has been previously programmed into the OTP array, PA3 - PA0 contain the device address, while A3 - A0 must be zero. If any
addressing condition is not met, the device address is not assigned, the bus switch will remain open and the device will not
respond to the Initialization command.
Table 4-6 Initialization Command Response
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
0
0
BF
NV
BS
B1
B0
A3
A2
A1
A0
4 bits
In the response, bits D15 - D12 and D3 - D0 will contain the device address. If the device was unprogrammed when the
initialization command was issued, the device address is assigned as the command executes. Both fields will contain the value
PA3 - PA0 to indicate successful device address assignment.
Initialization or reverse initialization commands which attempt to assign device address zero are ignored.
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POR
NEGATED
LOAD REGISTERS
FROM FUSE ARRAY
INITIALIZATION
COMMAND AT
BUSIN?
N
N
Y
REVERSE
INITIALIZATION
COMMAND AT
BUSOUT?
N
BS == 1?
Y
N
Y
BS == 1?
ENABLE IRESP CURRENT
DRIVE AT BUSOUT
Y
DELAY 10 μs
ENABLE IRESP CURRENT
DRIVE AT BUSIN
MEASURE
BUSOUT VOLTAGE
DELAY 10 μs
N
VBUSOUT < VTHH?
Y
MEASURE
BUSIN VOLTAGE
SET BF
FLAG
SET BF
FLAG
N
VBUSIN < VTHH?
CLOSE BUS SWITCH
Y
CLOSE BUS SWITCH
WAIT FOR NEXT DSI
BUS COMMAND
Figure 4-1. Initialization Sequence
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4.5.3
Request Status Command
The Request Status command may be transmitted as either a DSI long command structure or a DSI short command structure of
any length. The data field in the command structure is ignored but is included in the CRC calculation. No action is taken if this
command is sent to the DSI Global Device Address.
Table 4-1 Request Status Command Structure
Address
Command
CRC
A3
A2
A1
A0
C3
C2
C1
C0
A3
A2
A1
A0
0
0
0
1
0 to 8 bits
Table 4-2 Short Response Structure - Request Status Command
Response
Response
Length
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
NV
U
ST
BS
D3
D2
D1
D0
S
GF
8
9
10
11
12
13
14
0
15
0
0
0
0
0
0
AT1 AT0
Table 4-3 Long Response Structure - Request Status Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
0
0
0
NV
U
ST
BS
AT1
AT0
S
GF
4.5.4
0 to 8 bits
Read Acceleration Data Command
The Read Acceleration Data command may be transmitted as either a DSI long command structure or a DSI short command
structure of any length. The data field in the command structure is ignored but is included in the CRC calculation. No action is
taken if this command is sent to the DSI Global Device Address.
Table 4-4 Read Acceleration Data Command Structure
Address
Command
CRC
A3
A2
A1
A0
C3
C2
C1
C0
A3
A2
A1
A0
0
0
1
0
0 to 8 bits
Table 4-5 Short Response Structure - Read Acceleration Data Command
Response
Length
Response
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
8
AD9 AD8 AD7 AD6 AD5 AD4 AD3 AD2
9
AD9 AD8 AD7 AD6 AD5 AD4 AD3 AD2 AD1
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Table 4-5 Short Response Structure - Read Acceleration Data Command
Response
Response
Length
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
10
11
12
13
14
DEVCFG1[1]
15
DEVCFG1[0]
ST
S
GF
AD9 AD8 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
Table 4-6 Long Response Structure - Read Acceleration Data Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
GF
S
AD9
AD8
AD7
AD6
AD5
AD4
AD3
AD2
AD1
AD0
0 to 8 bits
Data returned in response to a Read Acceleration Data command varies, as illustrated in Table 4-5 and Table 4-6. The result is
also affected by the state of the self-test circuitry and internal parity. If the self-test circuitry is enabled, the ST bit will be set in
data bit D12 of a short word response. If a transient undervoltage condition, parity fault, ground fault or device disable condition
exists, the reserved data value of zero will be reported in response to a short word command structure to indicate that a fault
condition has been detected. The data value is not affected by a fault condition when a long word response is reported, however
the S and GF bits will be set as appropriate.
If the self-test circuitry is active, acceleration data is reported regardless of parity faults. The Status (S) bit will be set in either
short word or long word responses if a parity fault is detected.
4.5.4.1
ACCELERATION DATA REPRESENTATION
Acceleration values may be determined from the 10-bit digital output (DV) as follows:
a = sensitivity × (DV - 512)
Sensitivity is determined by nominal full-scale range (FSR), linear range of digital values and a scaling factor to compensate for
sensitivity error.
The linear range of digital values for MMA81XXEG/MMA82XXEG/MMA82XXTEG is 1 to 1023. The digital value of 0 is reserved
as an error
indicator.
For the linear ranges of digital values indicated, the nominal value of 1 LSB for each full-scale range is shown in the table below.
Table 4-7 Nominal Sensitivity (10-bit data)
Full-Scale Range (g)
Nominal Sensitivity (g/digit)
250
0.61
150
0.366
100
0.244
50
0.122
40
0.0976
20
0.0488
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4.6
ACCELERATION MEASUREMENT TIMING
Upon verification of the CRC associated with a Read Acceleration Data command, MMA81XXEG/MMA82XXEG/MMA82XXTEG
initiates an analog-to-digital conversion. The conversion occurs during the inter frame separation (IFS) and involves a delay
during which the BUSIN line is allowed to stabilize, a sample period and finally the translation of the analog signal level to a digital
result.
4.6.1
Request ID Information Command
The Request ID Information command may be transmitted as either a DSI long command structure or a DSI short command
structure of any length. The data field in the command structure is ignored but is included in the CRC calculation. No action is
taken by MMA81XXEG/MMA82XXEG/MMA82XXTEG if this command is sent to the DSI Global Device Address.
Table 4-8 Request ID Information Command Structure
Address
Command
CRC
A3
A2
A1
A0
C3
C2
C1
C0
A3
A2
A1
A0
0
1
0
0
0 to 8 bits
Table 4-9 Short Response Structure - Request ID Information Command
Response
Response
Length
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
V2
V1
V0
0
0
1
0
0
8
9
10
11
12
13
14
15
0
0
0
0
0
0
0
Table 4-10 Long Response Structure - Request ID Information Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
0
0
0
V2
V1
V0
0
0
1
0
0
4.6.2
0 to 8 bits
Clear Command
The Clear command may be transmitted as either a DSI long command structure or a DSI short command structure of any length.
The data field in the command structure is ignored but is included in the CRC calculation.
Table 4-11 Clear Command Structure
Address
Command
CRC
A3
A2
A1
A0
C3
C2
C1
C0
A3
A2
A1
A0
0
1
1
1
0 to 8 bits
When a Clear Command is successfully decoded and the address field matches either the assigned device address or the DSI
Global Device Address, the bus switch is opened and the device undergoes a full reset operation.
There is no response to the Clear Command.
MMA81XXEG
Sensors
Freescale Semiconductor
23
4.6.3
Read/Write NVM Command
The Read/Write NVM command must be transmitted as a DSI long command structure. No action is taken by MMA81XXEG/
MMA82XXEG/MMA82XXTEG if this command is sent to the DSI Global Device Address.
Table 4-12 Read Write NVM Command Structure
Data
Address
Command
CRC
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
RA3
RA2
RA1
RA0
RD3
RD2
RD1
RD0
A3
A2
A1
A0
1
0
0
1
0 to 8 bits
Table 4-13 Long Response Structure - Read/Write NVM Command (NV = 1)
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
RA3
RA2
RA1
RA0
1
1
B1
B0
RD3
RD2
RD1
RD0
0 to 8 bits
Table 4-14 Long Response Structure - Read/Write NVM Command (NV = 0)
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
0
0
0
1
1
1
1
A3
A2
A1
A0
0 to 8 bits
There is no response if the Read/Write NVM Command is received within a DSI short command structure.
OTP data are accessed by fields, where a field is a combination of register address (RA3 - RA0) and bank select (B1, B0) bits.
Bank select bits are assigned during an Initialization or Reverse Initialization command. Individual bits with predefined functions
(the upper four bits of DEVCFG2) each have their own field address. The remaining OTP data are grouped into four-bit fields.
Field addresses are shown in Table 4-15.
The structure of the OTP array results in data being programmed in 16-bit groups. DEVCFG1 and DEVCFG2 are in the same
group. As a result, a non-zero device address assigned during Initialization or Reverse Initialization will be permanently
programmed into the OTP array when any field within the two device configuration bytes is programmed.
To avoid programming a non-zero device address, ensure that device address 0 is assigned during Initialization or Reverse
Initialization before programming any other bit(s) in DEVCFG1 or DEVCFG2.
OTP programming operations occur when the Read/Write NVM command is executed after the NV bit has been set during a
preceding Initialization or Reverse Initialization command.
The minimum DSI Bus idle voltage must exceed 14 V when programming the OTP array.
When this command is executed while the NV bit is cleared, the DSI device address will be returned regardless of the state of
the register address and bank select bits. The Read Register Data command (described in Section 4.6.5) may be used to access
the full range of customer accessible data.
MMA81XXEG
24
Sensors
Freescale Semiconductor
Table 4-15 OTP Field Assignments
Register Address
Register
Definition
1
DEVCFG1[3:0]
User Defined
1
0
DEVCFG1[7:4]
0
0
DEVCFG2[7]
LOCK2
0
1
DEVCFG2[3:0]
DSI Bus Device Address
1
0
DEVCFG2[5]
GLDE
1
1
DEVCFG2[6]
PAR2
0
1
REG8[3:0]
User Defined
1
0
REG8[7:4]
0
1
REG9[3:0]
1
0
REG9[7:4]
0
1
REGA[3:0]
1
0
REGA[7:4]
0
1
REGB[3:0]
1
0
REGB[7:4]
0
1
REGC[3:0]
1
0
REGC[7:4]
0
1
REGD[3:0]
1
0
REGD[7:4]
0
1
REGE[3:0]
1
0
REGE[7:4]
0
1
REGF[3:0]
1
0
REGF[7:4]
1
1
DEVCFG[4]
RA3
RA2
RA1
RA0
B1
B0
0
1
1
0
0
0
4.6.4
Bank Select
1
1
1
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
User Defined
User Defined
User Defined
User Defined
User Defined
User Defined
User Defined
DDIS
Format Control Command
The Format Control command must be transmitted as a DSI long command structure. No change to the format registers occurs
if the Format Control Command is received within a DSI short command structure.
If this command is sent to the DSI Global Device Address, the format registers are updated, however there is no response.
The Format Control command conforms to the DSI 2.0 Specification.
Table 4-16 Format Control Command Structure
Data
Address
Command
CRC
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
R/W
FA2
FA1
FA0
FD3
FD2
FD1
FD0
A3
A2
A1
A0
1
0
1
0
4.6.4.1
0 to 8 bits
Format Register Read/Write Control Bit (R/W)
1 - Write Format Control register selected by FA2 - FA0
0 - Read Format Control register unless global command
MMA81XXEG
Sensors
Freescale Semiconductor
25
4.6.4.2
Format Control Register Selection (FA2 - FA0)
This three-bit field selects one of eight format control registers. Format control registers are described in Section 4.6.4.3.
Table 4-17 Long Response Structure - Format Control Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
1
1
0
R/W
FA2
FA1
FA0
FD3
FD2
FD1
FD0
0 to 8 bits
There is no response if the Format Control Command is received within a DSI short command structure.
4.6.4.3
Format Control Registers
The seven 4-bit format control registers defined in the DSI 2.0 Bus Specification are shown in Table 4-18 below. The default values assigned to each register following reset are indicated.
Table 4-18 Format Control Registers
Format Control Register
Default Value
Address
Name
Decimal
FA2
FA1
FA0
FD3
FD2
FD1
FD0
CRC Polynomial - Low Nibble
0
0
0
0
0
0
0
1
CRC Polynomial - High Nibble
1
0
0
1
0
0
0
1
Seed - Low Nibble
2
0
1
0
1
0
1
0
Seed - High Nibble
3
0
1
1
0
0
0
0
CRC Length (0 to 8)
4
1
0
0
0
1
0
0
Short Word Data Length (8 to 15)
5
1
0
1
1
0
0
0
Reserved
6
1
1
0
0
0
0
0
Format Selection
7
1
1
1
0
0
0
0
The following restrictions apply to format control register operations, in accordance with the DSI 2.0 Bus Specification:
•
•
•
Attempting to write a value greater than eight to the CRC Length Register will cause the write to be ignored. The contents
of the register will remain unchanged.
Attempting to write a value less than eight to the Short Word Data Length register will cause the write to be ignored. The
contents of the register will remain unchanged.
The contents of the Format Selection register determine whether standard DSI values or the values contained in the
remaining format control registers will be used. The values contained in the remaining format control registers become
effective when this register is successfully written to ‘1111’. If the register is currently cleared, and one of the data bits FD3
- FD0 is not received as a logic ‘1’, the data in the register will remain all zeroes and the device will continue to use
standard DSI format settings. If the register bits FD3 - FD0 are all set and one of the bits is received as a logic ‘0’ value,
the data in the register will remain ‘1111’ and the values contained in the remaining format control registers will continue
to be used.
MMA81XXEG
26
Sensors
Freescale Semiconductor
4.6.5
Read Register Data Command
The Read Register Data command must be transmitted as a DSI long command structure.
Table 4-19 Read Register Data Command Structure
Data
Address
Command
CRC
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
0
0
0
0
RA3
RA2
RA1
RA0
A3
A2
A1
A0
1
0
1
1
0 to 8 bits
Table 4-20 Long Response Structure - Read Register Data Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
RA3
RA2
RA1
RA0
RD7
RD6
RD5
RD4
RD3
RD2
RD1
RD0
0 to 8 bits
There is no response if the Read Register Data Command is received within a DSI short command structure or if this command
is sent to the DSI Global Device Address.
The sixteen registers shown in Table 3-1 may be accessed using this command. Register address combinations are listed below.
Table 4-21 Read Register Data Command Address Assignment
RA3
RA2
RA1
RA0
Register
0
0
0
0
SN0
0
0
0
1
SN1
0
0
1
0
SN2
0
0
1
1
SN3
0
1
0
0
TYPE
0
1
0
1
Reserved
0
1
1
0
DEVCFG1
0
1
1
1
DEVCFG2
1
0
0
0
REG-8
1
0
0
1
REG-9
1
0
1
0
REG-A
1
0
1
1
REG-B
1
1
0
0
REG-C
1
1
0
1
REG-D
1
1
1
0
REG-E
1
1
1
1
REG-F
MMA81XXEG
Sensors
Freescale Semiconductor
27
4.6.6
Disable Self-Test Stimulus Command
The Disable Self-Test Stimulus command may be transmitted as either a DSI long command structure or a DSI short command
structure of any length. The data field in the command structure is ignored but is included in the CRC calculation.
Table 4-22 Disable Self-Test Stimulus Command Structure
Address
Command
CRC
A3
A2
A1
A0
C3
C2
C1
C0
A3
A2
A1
A0
1
1
0
0
0 to 8 bits
Table 4-23 Short Response Structure - Disable Self-Test Stimulus Command
Response
Response
Length
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
NV
U
ST
BS
D3
D2
D1
D0
S
GF
8
9
10
11
12
13
14
15
0
0
0
0
0
0
0
AT1 AT0
Table 4-24 Long Response Structure - Disable Self-Test Stimulus Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
0
0
0
NV
U
ST
BS
AT1
AT0
S
GF
0 to 8 bits
This command will execute if either the device specific address or DSI global device address (address $0) is provided. A
secondary function, self-test lockout, is activated when two consecutive Disable Self-Test Stimulus commands are received.
Following self-test lockout, the internal self-test circuitry is disabled until a Clear command is received or the device undergoes
power-on reset.
4.6.7
Enable Self-Test Stimulus Command
The Enable Self-Test Stimulus command may be transmitted as either a DSI long command structure or a DSI short command
structure of any length. The data field in the command structure is ignored but is included in the CRC calculation. No action is
taken by the device if this command is sent to the DSI Global Device Address.
Table 4-25 Enable Self-Test Stimulus Command Structure
Address
Command
CRC
A3
A2
A1
A0
C3
C2
C1
C0
A3
A2
A1
A0
1
1
0
1
0 to 8 bits
MMA81XXEG
28
Sensors
Freescale Semiconductor
Table 4-26 Short Response Structure - Enable Self-Test Stimulus Command
Response
Response
Length
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
NV
U
ST
BS
D3
D2
D1
D0
S
GF
8
9
10
11
12
13
14
15
0
0
0
0
0
0
0
AT1 AT0
Table 4-27 Long Response Structure - Enable Self-Test Stimulus Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
0
0
0
NV
U
ST
BS
AT1
AT0
S
GF
0 to 8 bits
If self-test locking has been activated, the ST bit will be cleared in the response from the device. Self-Test locking is described in
Section 4.6.6.
4.6.8
Reverse Initialization Command
The reverse initialization command conforms to the description provided in Section 6.2.1 of the DSI Bus Standard, Version 2.0.
At power-up the device is fully compliant with the DSI 1.1 protocol. The initialization command must be transmitted as a DSI 1.1
compliant long command structure. Features of the DSI 2.0 protocol can not be accessed until a valid DSI 1.1 compliant initialization sequence is performed and the enhanced mode format registers are properly configured.
Table 4-28 Reverse Initialization Command Structure
Data
Address
Command
CRC
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
C3
C2
C1
C0
NV
BS
B1
B0
PA3
PA2
PA1
PA0
A3
A2
A1
A0
1
1
1
1
4 bits
Figure 4-1 illustrates the sequence of operations performed following negation of internal power-on reset (POR) and execution
of a DSI Reverse Initialization command. Reverse Initialization commands are recognized only at BUSOUT. The BUSIN node is
tested for a bus short to battery high voltage condition, and the bus fault (BF) flag set if an error condition is detected. If no bus
fault condition is detected and the BS bit is set in the command structure, the bus switch will be closed.
If the device has been pre-programmed, PA3 - PA0 and A3 - A0 must match the pre-programmed address. If no device address
has been previously programmed into the OTP array, PA3 - PA0 contain the device address, while A3 - A0 must be zero. If any
addressing condition is not met, the device address is not assigned, the bus switch will remain open and the device will not respond to the Reverse Initialization command. If the BS bit is set, the DSI bus voltage level is disregarded for approximately
180 μs following reverse initialization to allow hold capacitors on downstream slaves to charge.
Table 4-29 Long Response Structure - Reverse Initialization Command
Data
CRC
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
A3
A2
A1
A0
0
0
0
BF
NV
BS
B1
B0
A3
A2
A1
A0
4 bits
In the response, bits D15 - D12 and D3 - D0 will contain the device address. If the device was unprogrammed when the reverse
initialization command was issued, the device address is assigned as the command executes. Both fields will contain the value
PA3 - PA0 to indicate successful device address assignment.
Initialization or reverse initialization commands which attempt to assign device address zero are ignored.
MMA81XXEG
Sensors
Freescale Semiconductor
29
SECTION 5 PERFORMANCE SPECIFICATIONS
5.1
MAXIMUM RATINGS
Maximum ratings are the extreme limits to which the device can be exposed without permanently damaging it. The device
contains circuitry to protect the inputs against damage from high static voltages; however, do not apply voltages higher than those
shown in the table below.
Table 5-1
Ref
1
2
Rating
Supply Voltages
HCAP
BUSIN, BUSOUT
3 Voltage at Programming/Test Mode Entry pin
4 Voltage at CREG, DIN, CLK, CFIL, DOUT
Symbol
Value
Unit
VHCAP
VBUS
-0.3 to +40
-0.3 to +40
V
V
(3)
(3)
VPP/TEST
-0.3 to +11
V
(3)
VIN
-0.3 to +3.0
V
(3)
VGND
-0.3 to +3.0
V
(3)
IIN
IIN
400
200
mA
mA
(3)
(3)
I
±10
mA
(3)
gmax
gmax
gmax
±1400
±950
±2200
g
g
g
(3)
(3)
(3)
gpms
±1500
g
(3)
13 Unpowered Shock (six sides, 0.5 ms duration)
gshock
±2000
g
(3)
14 Drop Shock (to concrete surface)
hDROP
1.2
m
(3)
VESD
VESD
VESD
±2000
±500
±200
V
V
V
(3)
(3)
(3)
Tstg
TJ
-40 to +125
-40 to +150
°C
°C
(3)
(3)
5 Voltage at VGND
6
7
BUSIN, BUSOUT, BUSRTN and HCAP Current
Maximum duration 1 s
Continuous
8 Current Drain per Pin Excluding VSS, BUSIN, BUSOUT, BUSRTN
9
10
11
Acceleration (without hitting internal g-cell stops)
Z-axis g-cell
X-axis g-cell (40g, 70g)
X-axis g-cell (100g - 250g)
12 Powered Shock (six sides, 0.5 ms duration)
1.
2.
3.
4.
15
16
17
Electrostatic Discharge
Human Body Model (HBM)
Charge Device Model (CDM)
Machine Model (MM)
18
19
Temperature Range
Storage
Junction
Parameters tested 100% at final test.
Parameters tested 100% at unit probe.
Verified by characterization, not tested in production.
(*) Indicates a customer critical characteristic or Freescale important characteristic.
MMA81XXEG
30
Sensors
Freescale Semiconductor
5.2
Ref
20
5.3
THERMAL CHARACTERISTICS
Characteristic
Thermal Resistance
Symbol
Min
Typ
Max
Units
θJA
θJC
—
—
—
—
85
46
°C/W
°C/W
(3)
(3)
OPERATING RANGE
The operating ratings are the limits normally expected in the application and define the range of operation.
Ref
Symbol
Min
Typ
Max
Units
VHCAP
VBUS
VL
6.3
-0.3
—
—
VH
30
30
V
V
(1)
(1)
VLVD
VLVR
VLVH
—
—
—
—
—
100
6.2
6.3
—
V
V
mV
(1)
(1)
(3)
CREG Undervoltage Detection
(see Figure 5-2)
Undervoltage Detection Threshold
26
CREG Recovery Threshold
27
28
Hysteresis (VLVR - VLVD)
VLVD
VLVR
VLVH
—
—
—
2.25
2.35
100
—
—
—
V
V
mV
(3)
(3)
(3)
29 Test Mode Activation Voltage
VTEST
4.5
—
10
V
(3)
VPP/TEST
VBUS
7.5
14
8.0
—
8.5
30
V
V
(3)
(3)
IPROG
—
—
85
mA
(3)
TA
TL
-40
—
TH
+125
°C
(6)
21
22
Characteristic
Supply Voltage (Note 9)
VHCAP (Note 5)
BUSIN, BUSOUT
VHCAP Undervoltage Detection
(see Figure 5-1)
Undervoltage Detection Threshold
23
VHCAP Recovery Threshold
24
25
Hysteresis (VLVR - VLVD)
Programming Voltage
30
via SPI
31
via DSI
32 OTP Programming Current
33
Operating Temperature Range
Standard Temperature Range
1.
2.
3.
4.
5.
6.
Parameters tested 100% at final test.
Parameters tested 100% at unit probe.
Verified by characterization, not tested in production.
(*) Indicates a customer critical characteristic or Freescale important characteristic.
Minimum operating voltage may be reduced pending characterization.
Device fully characterized at +105 °C and +125 °C. Production units tested +105 °C, with operation at +125 °C guaranteed through
correlation with characterization results.
9. Maximum voltage characterized. Minimum voltage tested 100% at final test. Maximum voltage tested 100% to 24 V at final test.
MMA81XXEG
Sensors
Freescale Semiconductor
31
5.4
ELECTRICAL CHARACTERISTICS
The unit digit is defined to be 1 least significant bit (LSB) of the 10-bit digital value, or 1 LSB of the equivalent 8-bit value if explicitly
stated.
VL ≤ (VBUS - VSS) ≤ VH, VL ≤ (VHCAP - VSS) ≤ VH,TL ≤ TA ≤ TH, unless otherwise specified.
.
Ref
Characteristic
Min
Typ
Max
Units
*
*
*
*
*
*
SENS
SENS
SENS
SENS
SENS
SENS
—
—
—
—
—
—
0.0488
0.0976
0.122
0.244
0.366
0.610
—
—
—
—
—
—
g/digit
g/digit
g/digit
g/digit
g/digit
g/digit
(7)
(7)
(7)
(7)
(7)
(7)
*
*
*
*
*
*
SENS
SENS
SENS
SENS
SENS
SENS
—
—
—
—
—
—
20.1
10.0
8.02
4.01
2.67
1.60
—
—
—
—
—
—
mV/V/g
mV/V/g
mV/V/g
mV/V/g
mV/V/g
mV/V/g
(3)
(3)
(3)
(3)
(3)
(3)
*
*
ΔSENS
ΔSENS
-5
-7
0
0
+5
+7
%
%
(1)
(1)
*
*
OFF8
OFF8
OFF10
OFF10
122
116
488
464
128
128
512
512
134
140
536
560
digit
digit
digit
digit
(7)
(7)
(1)
(1)
FSR
FSR
FSR
FSR
FSR
FSR
21.0
42.0
52.5
105
158
263
24.9
49.9
62.3
124.7
187
312
26.6
53.4
66.7
133
200
334
g
g
g
g
g
g
(3)
(3)
(3)
(3)
(3)
(3)
46
47
Digital Output Sensitivity
20g Range
40g Range
50g Range
100g Range
150g Range
250g Range
CFIL Output Sensitivity (TA = 25 °C)
20g Range
40g Range
50g Range
100g Range
150g Range
250g Range
Sensitivity Error
TA = 25 °C
TL ≤ TA ≤ TH
48
49
50
51
Offset (measured in 0g orientation)
TA = 25 °C (8-bit)
TL ≤ TA ≤ TH (8-bit)
TA = 25 °C (10-bit)
TL ≤ TA ≤ TH (10-bit)
52
53
54
55
56
57
Full-Scale Range, including sensitivity and offset errors
20g Range
40g Range
50g Range
100g Range
150g Range
250g Range
58
59
60
Range of Output
Normal (10-bit)
Normal (8-bit)
Fault
RANGE
RANGE
FAULT
1
1
—
—
—
0
1023
255
—
digit
digit
digit
(3)
(3)
(8)
61
Nonlinearity
Measured at CFIL output, TA = 25 °C
NLOUT
-1
0
+1
%
(3)
VCREG
REGLINE
REGLOAD
2.37
—
0.45
2.5
—
—
2.63
6
2
V
mV
mV/mA
(1)
(3)
(3)
RR
CREG
ESR
60
0.9
—
—
—
—
—
—
700
dB
μF
mΩ
(3)
(3)
(3)
34
35
36
37
38
39
40
41
42
43
44
45
Internal Voltage Regulator
Output Voltage
Line regulation
Load regulation (IREG < 6 mA)
Ripple rejection
(DC ≤ fRIPPLE ≤ 10 kHz, CREG ≥ 0.9 μF)
65
66
CREG capacitance
67
Effective series resistance, CREG capacitor
62
63
64
1.
2.
3.
4.
7.
8.
Symbol
Parameters tested 100% at final test.
Parameters tested 100% at unit probe.
Verified by characterization, not tested in production.
(*) Indicates a customer critical characteristic or Freescale important characteristic.
Tested 100% at 10-bit output. 8-bit value verified via scan.
Functionality verified 100% via scan.
MMA81XXEG
32
Sensors
Freescale Semiconductor
5.5
ELECTRICAL CHARACTERISTICS (continued)
VL ≤ (VBUS - VSS) ≤ VH, VL ≤ (VHCAP - VSS) ≤ VH,TL ≤ TA ≤ TH, unless otherwise specified.
.
Ref
Characteristic
Min
Typ
Max
Units
68
69
Input Voltage
LOW (CLK,DIN)
HIGH (CLK,DIN)
VIL
VIH
—
0.7xVCreg
—
—
0.3xVCreg
—
V
V
(3)
(3)
70
71
Output Voltage (IOUT = 200 μA)
LOW (DOUT)
HIGH (DOUT)
VOL
VOH
—
VCreg- 0.1
—
—
VSS+ 0.1
—
V
V
(3)
(3)
72
73
74
Output Loading, CFIL pin (Note 10)
Resistance to VCREG, VSS
Capacitance to VCREG, VSS
Output voltage range
RLOAD
CLOAD
VOUT
50
—
VSS + 50 mV
—
—
—
—
20
VCREG-50mV
kΩ
pF
V
(3)
(3)
(3)
75 Bus Switch Resistance
*
RSW
—
4.0
8.0
Ω
(1)
76 Rectifier Forward Resistance
*
RFWD
—
—
2.5
Ω
(3)
77 Rectifier Leakage Current
*
IRLKG
—
—
100
μA
(1)
*
*
VRECT
VRECT
—
—
—
—
1.0
1.2
V
V
(3)
(3)
VRECT
VRECT
—
—
—
—
1.0
1.2
V
V
(1)
(1)
IBIAS
IBIAS
—
—
—
—
100
20
mA
μA
(1)
(1)
80
81
BUSIN or BUSOUT to HCAP Rectifier Voltage Drop
(VBUS = 26 V)
IBUSIN or IBUSOUT = -15 mA
IBUSIN or IBUSOUT = -100 mA
(VBUS = 7 V)
IBUSIN or IBUSOUT = -15 mA
IBUSIN or IBUSOUT = -100 mA
82
83
BUSIN + BUSOUT Bias Current
VBUSIN or VBUSOUT = 8.0 V, VHCAP = 9.0 V
VBUSIN or VBUSOUT = 0.5 V, VHCAP = 24 V
84
85
BUSIN and BUSOUT Logic Thresholds
Signal Low
Signal High
*
*
VTHL
VTHH
2.7
5.4
3.0
6.0
3.3
6.6
V
V
(1)
(1)
86
87
BUSIN and BUSOUT Hysteresis
Signal
Frame
*
*
VHYSS
VHYSF
30
100
—
—
90
300
mV
mV
(3)
(3)
88
BUSIN + BUSOUT Response Current
VBUSIN and/or VBUSOUT = 4.0 V
IRESP
9.9
11
12.1
mA
(1)
IQ
—
—
7.5
mA
(1)
90 Internal pull-down resistance CLK
RPD
20
60
100
kΩ
(2)
91 Internal pull-down resistance VPP/TEST
RPD
kΩ
(2)
μA
kΩ
(1)
(1)
78
79
89 Quiescent Current
92
93
1.
2.
3.
4.
10.
Symbol
GND Loss Detect (with external 3 kΩ resistor)
Measurement Current
Detection Resistance
*
*
*
IGNDETC
RGNDDETC
437
309
1
340
—
371
10
Parameters tested 100% at final test.
Parameters tested 100% at unit probe.
Verified by characterization, not tested in production.
(*) Indicates a customer critical characteristic or Freescale important characteristic.
The external circuit configuration shown in Section 1.3.6 is recommended.
MMA81XXEG
Sensors
Freescale Semiconductor
33
5.6
ELECTRICAL CHARACTERISTICS (continued)
VL ≤ (VBUS - VSS) ≤ VH, VL ≤ (VHCAP - VSS) ≤ VH,TL ≤ TA ≤ TH, unless otherwise specified.
.
Ref
94
95
96
97
Characteristic
Min
Typ
Max
Units
nRMS
nP-P
—
—
—
—
2
8
digit
digit
(3)
(3)
nRMS
nP-P
—
—
—
—
2
7
digit
digit
(3)
(3)
VXY
VXZ
VYX
VYZ
-5
-5
-5
-5
—
—
—
—
+5
+5
+5
+5
%
%
%
%
(3)
(3)
(3)
(3)
INL
DNL
GAINERR
OFST
nRMS
nP-P
-2
-1
-1
-3
-1
-3
—
—
—
—
—
—
+2
+1
+1
+3
+1
+3
digit
digit
%FSR
digit
digit
digit
(3)
(3)
(2)
(3)
(3)
(3)
*
*
*
*
*
*
ΔDFLCT
ΔDFLCT
ΔDFLCT
ΔDFLCT
DDFLCT
DDFLCT
—
—
—
—
—
—
246
123
98
49
82
49
—
—
—
—
—
—
digit
digit
digit
digit
digit
digit
(7)
(7)
(7)
(7)
(7)
(7)
*
*
*
*
ΔDFLCT
ΔDFLCT
ΔDFLCT
ΔDFLCT
—
—
—
—
307
299
205
123
—
—
—
—
digit
digit
digit
digit
(7)
(7)
(7)
(7)
Total Noise (see Figure 5-3)
400 Hz, 4-pole filter, 20g range
RMS, 100 samples
P-P, 100 samples
180 Hz, 2-pole filter, 20g range
RMS, 100 samples
P-P, 100 samples
98
99
100
101
Cross-Axis Sensitivity
X-axis, X-axis to Y-axis
X-axis, X-axis to Z-axis
Y-axis, Y-axis to X-axis
Y-axis, Y-axis to Z-axis
102
103
104
105
106
107
Analog to digital converter
Relative accuracy
Differential nonlinearity
Gain error
Offset error (VIN = VCREG/2)
Noise (RMS, 100 samples)
Noise (peak)
108
109
110
111
112
113
Deflection
(Self-Test Output - Offset, average of 30 samples,
measured in 0g orientation, TA = 25° C)
X-axis, 20g Range
X-axis, 40g Range
X-axis, 50g Range
X-axis, 100g Range
X-axis, 150g Range
X-axis, 250g Range
114
115
116
117
Symbol
Z-axis, 40g Range
Z-axis, 100g Range
Z-axis, 150g Range
Z-axis, 250g Range
118
Self-Test deflection range, TA = 25 °C, measured in 0g
orientation
ΔDFLCT
-10
—
+10
%
(1)
119
Self-Test deflection range, TL ≤ TA ≤ TH, measured in
0g orientation
ΔDFLCT
-20
—
+20
%
(1)
1.
2.
3.
4.
7.
Parameters tested 100% at final test.
Parameters tested 100% at unit probe.
Verified by characterization, not tested in production.
(*) Indicates a customer critical characteristic or Freescale important characteristic.
Tested 100% at 10-bit output. 8-bit value verified via scan.
MMA81XXEG
34
Sensors
Freescale Semiconductor
POR NEGATED
POR ASSERTED
VLVR
VLVD
VHCAP
VLVH
UV
UV
UNDERVOLTAGE
tUVR
NORMAL
OPERATION
RESUMES
UV: UNDERVOLTAGE CONDITION
EXISTS
GND
Figure 5-1. VHCAP Undervoltage Detection
VCREG
INTERNAL RESET IS INITIALLY
ASSERTED UNTIL VCREG ≥ VLVR,
AND THEREAFTER WHEN
VCREG ≤ VLVD.
VLVR
VLVD
VLVH
LOW-VOLTAGE
CONDITION
DETECTED
POR ASSERTED
POR NEGATED
NORMAL
OPERATION
RESUMES
GND
Figure 5-2. VCREG Undervoltage Detection
MMA81XXEG
Sensors
Freescale Semiconductor
35
MASTER
UUT
DOH
BUSIN
BUSOUT
N/C
BUSRTN
DOL
DSI BUS CONFIGURATION
D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 A3 A2 A1 A0 C3 C2 C1 C0
0
0
0
0
0
0
0
0
0
0 A3 A2 A1 A0 0
0
1
0
COMMAND FORMAT
90 μs
20 μs
CMD 1
CMD 2
CMD 3
CMD 99
CMD 100
XXX
XXX
RESP 1
RESP 2
RESP 98
RESP 99
RESP 100
MEASUREMENT WINDOW (10910 μs)
MEASUREMENT TIMING
Figure 5-3. Total Noise Measurement Conditions
MMA81XXEG
36
Sensors
Freescale Semiconductor
5.7
CONTROL TIMING
VL ≤ (VBUS - VSS) ≤ VH, VL ≤ (VHCAP - VSS) ≤ VH,TL ≤ TA ≤ TH, unless otherwise specified.
Ref
Characteristic
Symbol
Min
Typ
Max
Units
120
VHCAP Undervoltage Reset Period
(see Figure 5-1)
VHCAP < VRA to POR assertion
tUVR
0.95
1.0
1.05
ms
(8)
121
122
123
Analog to digital converter (see Figure 5-4)
Sample time
Conversion time
Delay following bus idle
tSAMPLE
tCONVERT
tDELAY
4.28
7.13
2.85
4.5
7.5
3.0
4.73
7.88
3.15
μs
μs
μs
(8)
(8)
(8)
124
BUSIN and BUSOUT response current transition
1.0 mA to 9.0 mA, 9.0 to 1.0 mA
tITR
4.5
—
7.5
mA/μs
(3)
125
Initialization to Bus Switch Closing
tBS
89
—
138
μs
(3)
126
Signal Bit Transition Time
tBIT
5
—
200
μs
(3)
127
Loss of Signal Reset Time
Maximum time below frame threshold
tTO
—
—
10
ms
(8)
128
129
BUSIN or BUSOUT Timing to Response Current
BUSIN or BUSOUT ≤ VTHL to IBUS ≥ 7 mA
BUSIN or BUSOUT ≤ VTHH to IBUS ≤ 5 mA
tRSPH
tRSPL
—
—
—
—
3.0
3.0
μs
μs
(3)
(3)
tIFS
2
—
—
ms
(3)
tIFS
tIFS
tIFS
200
20
20
—
—
—
—
—
—
μs
μs
μs
(3)
(3)
(3)
360
162
400
180
440
198
Hz
Hz
(1)
(1)
cycles
ms
(8)
(8)
131
132
133
Interframe Separation Time (see Figure 5-5)
Following Read Write NVM Command
Following Initialization or Reverse Initialization
BS = 1
BS = 0
Following other DSI bus commands
134
135
Low Pass Filter
(4-pole, -3 db Rolloff Frequency)
(2-pole, -3 db Rolloff Frequency)
BWOUT
BWOUT
136
137
Ground Loss Detection Filter Time
Cycles of fOSC
Time
tGNDETC
tGNDETC
138
139
140
Reset Recovery Time
POR negated to Initialization Command
POR negated to 180 Hz Data Valid
POR negated to 400 Hz Data Valid
141
Internal Oscillator Frequency
142
143
Logic Duty Cycle
Logic ‘0’
Logic ‘1’
144
OTP Programming, SPI program control
130
1.
2.
3.
4.
8.
—
—
*
*
16384
4.096
tRESET
tRESET
tRESET
—
—
—
—
5.3
2.4
100
—
—
μs
ms
ms
(8)
(3)
(3)
fOSC
3.80
4.0
4.20
MHz
(1)
DCL
DCH
10
60
33
67
40
90
%
%
(8)
(8)
tPROG
—
—
2
ms
(8)
Parameters tested 100% at final test.
Parameters tested 100% at unit probe.
Verified by characterization, not tested in production.
(*) Indicates a customer critical characteristic or Freescale important characteristics.
Functionality verified 100% via scan. Timing is directly determined by internal oscillator frequency.
MMA81XXEG
Sensors
Freescale Semiconductor
37
5.8
CONTROL TIMING (continued)
VL ≤ (VBUS - VSS) ≤ VH, VL ≤ (VHCAP - VSS) ≤ VH,TL ≤ TA ≤ TH, unless otherwise specified.
Ref
Characteristic
Symbol
Min
Typ
Max
Units
tCLK
tDC
tCDIN
—
—
—
—
—
—
—
20
ns
ns
ns
ns
(3)
(3)
(3)
(3)
145
146
147
148
SPI Timing (see Figure 5-6)
CLK period
DIN to CLK setup
CLK to DIN hold
CLK to DOUT
tCDOUT
500
50
50
—
149
150
151
Sensing Element Resonant Frequency
Z-axis g-cell
X-axis medium-g g-cell (20-50g)
X-axis high-g g-cell (100-250g)
fGCELL
fGCELL
fGCELL
—
11.2
18.0
22.0
12.8
20.6
—
15.3
24.2
kHz
kHz
kHz
(3)
(3)
(3)
152
153
154
Sensing Element Rolloff Frequency (-3 db)
Z-axis g-cell
X-axis medium-g g-cell (20-50g)
X-axis high-g g-cell (100-250g)
BWGCELL
BWGCELL
BWGCELL
—
—
—
1.58
19
32
—
—
—
kHz
kHz
kHz
(3)
(3)
(3)
155
156
Gain at Package Resonance
Z-axis
X-axis
Q
Q
—
—
10
12
—
—
kHz
kHz
(3)
(3)
157
158
Package Resonance
Z-axis
X-axis
f
f
—
—
45
9.5
—
—
kHz
kHz
(3)
(3)
1.
2.
3.
4.
8.
Parameters tested 100% at final test.
Parameters tested 100% at unit probe.
Verified by characterization, not tested in production.
(*) Indicates a customer critical characteristic or Freescale important characteristics.
Functionality verified 100% via scan. Timing is directly determined by internal oscillator frequency.
MMA81XXEG
38
Sensors
Freescale Semiconductor
BUSIN
tSAMPLE
tCONVERT
tDELAY
STABILIZATION
S/H
CONVERSION
Figure 5-4. A-to-D Conversion Timing
DSI BUS
COMMAND
BUSIN
tIFS
Figure 5-5. DSI Bus Interframe Timing
tCLK
CLK
tDC
tCDIN
DIN/VGND
tCDOUT
DOUT
DATA
VALID
Figure 5-6. Serial Interface Timing
MMA81XXEG
Sensors
Freescale Semiconductor
39
APPENDIX A TEST MODE OPERATION
Test mode is entered when certain conditions are satisfied after power is applied to the device. Communication with the device
is conducted using the SPI when in test mode. Two test mode operations are of interest to the customer. These operations are
described below. Test mode communication is conducted using the serial peripheral interface (SPI).
A.1
SPI DATA TRANSFER
A 16-bit SPI is available for data transfer when the voltage at VPP/TEST is raised above VTEST. Test mode is entered when the
sequence of data values shown above are transferred following reset. See Figure A-4 for details of 16-bit SPI packet.
The state of DIN is latched on the rising edge of CLK. DOUT changes on the falling edge of CLK. The interface conforms to
CPHA = 0, CPOL = 0 operation for conventional SPI devices.
A.2
ADC TEST MODE
A special device configuration useful for evaluating the performance of the analog-to-digital convertor block is available. When
selected, internal buffers which drive the CFIL pin and ADC input are disabled, and the input of the ADC is connected to the CFIL
pin, as illustrated in Figure A-1. The following sequence of operations must be performed to enter ADC Test Mode. Refer to
Appendix A.4 for details regarding register read and write operations.
1.
Apply VHCAP to the HCAP pin. This may be accomplished through BUSIN if desired.
2.
Apply VTEST to the VPP/TEST pin.
3.
Transfer the data value $AA to device register address $30 via the SPI.
4.
Transfer the data value $55 to device register address $30 via the SPI.
5.
Transfer the data value $1D to device register address $30 via the SPI.
Remove power or lower the voltage at VPP/TEST to exit ADC Test Mode.
MMA81XXEG
40
Sensors
Freescale Semiconductor
REGULATOR
TRIM
HCAP
BUSIN
N/C
N/C
VSS
VSS
VSS
BUSRTN
11
VOLTAGE
REGULATOR
INTERNAL
SUPPLY
VOLTAGE
13
9
3
12
CREG
CREG
BUSOUT
1
2
16
15
10
14
GROUND
LOSS
DETECTOR
BANDGAP
REFERENCE
LOGIC
COMMAND DECODE
STATE MACHINE
RESPONSE GENERATION
OSCILLATOR
SELFTEST
TRIM
OSC
TRIM
SELFTEST
VOLTAGE
7
4
OTP
PROGRAMMING
INTERFACE
6
8
SELF-TEST ENABLE
VGND/DIN
VPP/TEST
DOUT
CLK
A-TO-D
CONVERTER
g-CELL
C-TO-V
CONVERTER
GAIN
TRIM
5
LOW-PASS
FILTER
OFFSET
TRIM
CFIL
TCS
TRIM
Figure A-1. ADC Test Mode Configuration
MMA81XXEG
Sensors
Freescale Semiconductor
41
A.3
OTP PROGRAMMING OPERATIONS
The ten customer-programmed OTP locations (DEVCFG0, DEVCFG1 and REG-8 through REG-F) may be programmed when
the device is in test mode if the following sequence of operations is performed. Register access operations required for OTP programming are described in Appendix A.4.
1.
Apply VHCAP to the HCAP pin. This may be accomplished through BUSIN if desired.
2.
Apply VTEST to the VPP/TEST pin.
3.
Write the desired data values to the two registers via the SPI.
4.
Transfer the data value $AA to device register address $30 via the SPI.
5.
Transfer the data value $55 to device register address $30 via the SPI.
6.
Transfer the data value $C6 to device register address $30 via the SPI.
7.
Write the data value $00 to address $20 via the SPI. This will enable write access to the fuse mirror registers.
8.
Write register data to be programmed into fuse array.
9.
Write the data value $05 to address $20 via the SPI. The automatic programming sequence is initiated by this write
operation.
10. Delay a minimum of 32 μs to allow the programming sequence to begin.
11. Read data value from address $29 until bit 5 is set.
12. If bit 4 of value read from address $29 is set, the programming operation did not complete successfully.
Bits which are unprogrammed may be programmed to a logic ‘1’ state. The device may be incrementally programmed if desired,
however once a bit is programmed to a logic ‘1’ state, it may not be reset to logic ‘0’ in the OTP array. Once the LOCK2 bit has
been set, no further changes to the OTP array are possible. Setting LOCK2 also enables parity detection when the device operates in normal mode.
A.4
INTERNAL REGISTER ACCESS
Using the DIN /VGND, CLK, and DOUT pins, each address location of MMA81XXEG/MMA82XXEG/MMA82XXTEG can be read
and written from an external SPI interface shown in Figure A-2. The corresponding registers may be used to:
•
•
•
Program the OTP memory
Read the OTP memory
Access various internal signals of the MMA81XXEG/MMA82XXEG/MMA82XXTEG in Test mode
CLK
DOUT
DIN/VGND
SERIAL
PERIPHERAL
INTERFACE
REGISTER
ARRAY
TO DIGITAL
INTERFACE
OTP
ARRAY
Figure A-2. OTP Interface Overview
MMA81XXEG
42
Sensors
Freescale Semiconductor
A.4.1 Interface Data Bit Stream
The 16-bit SPI serial data consists of 6 bits for a data address, 1 bit for a data direction, and 8 bits for the data to be transferred
as shown below.
BIT
FUNCTION
15
14
13
12
11
10
9
8
A[5]
A[4]
A[3]
A[2]
A[1]
A[0]
RW
⎯
7
6
5
4
3
2
1
0
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
Figure A-3. Serial Data Stream
A[5:0]
Register array location to be read or written.
D[7:0]
Register array data. This is the data to be transferred to the register array during write operations, or the data contained in the
array at the associated address during read operations.
RW
Control of data direction during the clocking of D[7:0] data bits as follows:
RW = 1
Register array write. D[7:0] are transferred into the register array during subsequent transitions of the CLK input.
RW = 0
Register array read. Data are transferred from the register array during subsequent transitions of the CLK input.
A.4.2 Register Array Read Operation
Read operations are completed through16-bit transfers using the SPI as shown below. Data contained in the array at the associated address are presented at the DOUT pin during the 8th through 15th falling edges at the CLK input.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
CLK
DIN/VP2
A[5] A[4] A[3] A[2] A[1] A[0] RW
DOUT
D[7]
D[6] D[5] D[4] D[3] D[2] D[1] D[0]
Figure A-4. Serial Data Timing, Register Array Read Operation
Should the data transfer be corrupted by e.g., noise on the clock line, a device reset is required to restore the state of internal
logic.
MMA81XXEG
Sensors
Freescale Semiconductor
43
A.4.3 Register Array Write Operation
A write operation is completed through the transfer of a 16-bit value using the SPI as shown in the diagram below. Data present
at the DIN pin are transferred to the register at the associated address during the 9th through 16th rising edges at the CLK input.
Contents of the register at the time the write operation is initiated are presented at the DOUT pin during the 8th through 15th falling
edges of the CLK input.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
CLK
DIN/VP2
A[5] A[4] A[3] A[2] A[1] A[0] RW
DOUT
D[7]
D[6 D[5] D[4] D[3] D[2] D[1] D[0]
D[7]
D[6] D[5] D[4] D[3] D[2] D[1] D[0]
Figure A-5. Serial Data Timing, Register Array Write Operation
A.4.4 Internal Address Map Overview
OTP data is transferred to internal registers during the first sixteen clock cycles following oscillator startup and negation of internal
reset. When the device operates in test mode, OTP data in the mirror registers may be overwritten. Mirror register writes must
be enabled by setting the SPI_WRITE_ENABLE bit (address $29[5]). This bit may be set by writing the value $0 to address $20.
Internal register read and write operations are described in Section 3.
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PACKAGE DIMENSIONS
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