MMA7456LT Freescale Semiconductor, MMA7456LT Datasheet - Page 13

• Manufacturer Part Number: MMA7456LT
• Description: Board Mount Accelerometers 3-AXIS DIGTL 12C&SP1
• Manufacturer: Freescale Semiconductor
• Series: -r

Specifications of MMA7456LT

• Sensing Axis: X, Y, Z
• Acceleration: 2 g, 4 g, 8 g
• Sensitivity: 64 count/g, 32 count/g, 16 count/g
• Package / Case: LGA-14
• Output Type: Digital
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 2.4 V
• Supply Current: 400 uA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Axis: X, Y, Z
• Acceleration Range: ± 2g, 4g, 8g
• Voltage - Supply: 2.4 V ~ 3.6 V
• Bandwidth: 6kHz - XY, 3.4kHz - Z
• Interface: I²C, SPI
• Mounting Type: Surface Mount
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

$1B: Pulse Detection Threshold Limit Value (Read/Write)
CASE 2: Freefall Detection: X and Y and Z < Pulse Threshold for Time > Latency Time
For freefall detection, set in pulse mode. PDPL in Register $19 =1 for “AND” freefall condition. The Pulse threshold must be set
in Register $1B and the pulse latency time window must also be set using Register $1D. All three axes must remain below the
threshold longer than the time window for the interrupt to trigger.
$1D: Latency Time Value (Read/Write)
Sensors
Freescale Semiconductor
PDTH[7]
LT[7]
D7
D7
0
0
PDTH[6]
LT[6]
D6
D6
0
0
PDTH[5]
LT[5]
D5
D5
0
0
G
INT pin
Single Pulse Detection ($19 PDPL=0 indicating motion detection)
Time Window for 2
G
th
Figure 5. Freefall Detection in Pulse Mode
PDTH[4]
Figure 4. Single Pulse Detection
LT[4]
D4
D4
0
0
Pulse Detection
Time duration
nd
pulse $1E TW =0 indicating single pulse
*Note there is up to
1.6ms delay on the
interrupt signal
PDTH[3]
LT[3]
D3
D3
0
0
PDTH[2]
LT[2]
Time
Time
D2
D2
0
0
PDTH[1]
LT[1]
D1
D1
0
0
PDTH[0]
LT[0]
D0
D0
1
0
MMA7456L
Reg $1D
Function
Reg $1B
Function
Default
Default
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