Accelerometer; Figure 3-43. Gps Block Diagram (Uhf1 And Uhf2); Figure 3-44. Directions Of The Detectable Accelerations - Motorola APX 5000 Service Manual

3-62
RF-VOCON-Exp
RF Board
Ant
3.0V
SAW LNA
3.4

Accelerometer

3.4.1 General Overview
Accelerometer capabilities are achieved by the 3-axes "nano" accelerometer IC (LIS331DL) located
on the expansion board. The LIS331DL is a digital output linear accelerometer in a LGA package. It
is powered by the 3.3 LDO regulator placed in the expansion board. The complete device includes a
sensing element and an IC interface to provide the signal to the AVR IC. When acceleration is
applied to the sensor, an imbalance in capacitance is produced. This imbalance is measured and
converted to an analog voltage that is finally available to the user by an analog to digital converter.
The acceleration data is accessed through an SPI interface and presented to the AVR.
NOTE: Please refer to User Guide and CPS for further details.
Interconnect
SAW LNA

Figure 3-43. GPS Block Diagram (UHF1 and UHF2)

Y

Figure 3-44. Directions of the Detectable Accelerations

External Regulators
2.8V
LNA Enable
GPS_EXT_LNA_EN (H6)
GPS_LNA_IN (L2)
SAW
Z
X
Theory of Operation
Expansion Board
3.6V 1.8V
(VSW_3.6) (VCC_1.85)
VBAT VDDS
VDD_TCXO (G1)
TCXO_CLK_LV (F1)
GPS IC
TI NL5500
GPS Tx
GPS_UART_TX (F5)
GPS Rx
GPS_UART_RX (E3)
32kHz RTC
RTC_CLK (H9)
Reset
GPS_NSHUTDOWN (D5)
: Accelerometer
TCXO
26MHz,
<0.5ppm
[OMAP 1710]
UART2 Rx (R9)
UART2 Tx (M18)
[CPLD]
IO74 (E2)
IO91 (D12)