NXP Semiconductors TWR-S08, User Manual, Page: 12 / 19

T W R - S 0 8 L L / L H U S E R G U I D E A P R I L 2 7 , 2 0 1 0
U S E R G U I D E
12
ACCELEROMETER
The TWR-S08 applies the MMA7361L, 3-axis, analog accelerometer for tilt and motion-sense
applications. The accelerometer supports 2 user selectable sensitivities - 1.5g / 6g. The
SLEEP* input allows the device to be placed in a low-power mode. Separate X-, Y-, and Z-
axis readings are routed to the MCU. Output filtering is applied to remove fast transients.
Configuration
Accelerometer sensitivity configuration is controlled manually using option select header JP2.
The SLEEP* input is configurable manually or under MCU control. Figure 7 below shows the
setting to configure the accelerometer output.
Figure 7: Accelerometer Sensitivity Select, JP6
Shunt
JP6 On Off
3
▪ ▪
Accel in SLEEP mode Disabled (*)
2
▪ ▪
Enable PTB5 control to Accel(*) Disabled
1
▪ ▪
Selects ±6g Sensitivity
Disabled
(*)
(*)
– Default position
Cut-traces on the accelerometer output signals allow the user to disconnect the accelerometer
output if necessary. Once cut, simply install a 1206 sized, 0-ohm resistor to reconnect the
accelerometer output. Figure 8 below shows how the accelerometer output connects to the
target MCU.
Figure 8: Accelerometer Output Cut-Traces
Signal Cut-
Trace
MCU Input
X CT2 PTA1/ADP5
Y CT3 PTA2/ADP6
Z CT4 PTA3/ADP7
USER I/O
User I/O includes 1 piezo buzzer, 1 Light Sensor, 4 push-button switches, 4 green LEDs, and 1
potentiometer for user I/O. Each user peripheral may be enabled or disabled using an
associated option header.