NXP Semiconductors TWR-S08 User Manual

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NXP Semiconductors TWR-S08 User Manual Manual pdf 12 page image

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 0U S E R G U I D E12ACCELEROMETERThe TWR-S08 applies the MMA7361L, 3-axis, analog accelerometer for tilt and motion-senseapplications. The accelerometer supports 2 user selectable sensitivities - 1.5g / 6g. TheSLEEP* 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.ConfigurationAccelerometer sensitivity configuration is controlled manually using option select header JP2.The SLEEP* input is configurable manually or under MCU control. Figure 7 below shows thesetting to configure the accelerometer output.Figure 7: Accelerometer Sensitivity Select, JP6ShuntJP6 On Off3 ▪ ▪ Accel in SLEEP mode Disabled (*)2 ▪ ▪ Enable PTB5 control to Accel(*) Disabled1 ▪ ▪ Selects ±6g Sensitivity Disabled(*)(*) – Default positionCut-traces on the accelerometer output signals allow the user to disconnect the accelerometeroutput if necessary. Once cut, simply install a 1206 sized, 0-ohm resistor to reconnect theaccelerometer output. Figure 8 below shows how the accelerometer output connects to thetarget MCU.Figure 8: Accelerometer Output Cut-TracesSignal Cut-TraceMCU InputX CT2 PTA1/ADP5Y CT3 PTA2/ADP6Z CT4 PTA3/ADP7USER I/OUser I/O includes 1 piezo buzzer, 1 Light Sensor, 4 push-button switches, 4 green LEDs, and 1potentiometer for user I/O. Each user peripheral may be enabled or disabled using anassociated option header.