2–104
Motorola Sensor Device Data
For More Information On This Product,
Go to: www.freescale.com
Prepared by: Leticia Gomez and Raul Figueroa
Sensor Products Division
Systems and Applications Engineering
INTRODUCTION
This application note describes the Motorola Accelerometer
Evaluation Board (Figure 1). The Accelerometer Evaluation
Board is a small circuit board intended to serve as an aid in
system design with the capability for mounting the following
devices: MMA1220D, MMA1201P, MMA1200D, MMA2201D.
This evaluation board is useful for quickly evaluating any of
these three devices. It also provides a means for
understanding the best mounting position and location of an
accelerometer in your product.
CIRCUIT DESCRIPTION
Figure 2 is a circuit schematic of the evaluation board. The
recommended decoupling capacitor at the power source and
recommended RC filter at the output, are included on the
evaluation board. This RC filter at the output of the
accelerometer minimizes clock noise that may be present
from the switched capacitor filter circuit. No additional
components are necessary to use the evaluation board.
Refer to the respective datasheet of the device being used
for
specifications
and
technical
accelerometer.
The evaluation board has a 4–pin header (
J1
in Figure 1) for
interfacing to a 5 volt power source or a 9 to 15 volt power
operation
of
the
source (for example, 9 V battery). Jumper
JP1
(see Figure 1)
must have the following placement: on
PS
if a 5 V supply is
being used or on
BATT
if a 9 V to 15 V supply is used. A 5 V
regulator (
U1
in figure 1) supplies the necessary power for the
accelerometer in the
BATT
option.
The power header also provides a means for connecting to
the accelerometer analog output through a wire to another
breadboard or system. Four through–hole sockets are
included to allow access to the following signals: VDD, GND,
ST and STATUS. These sockets can be used as test points or
as means for connecting to other hardware.
The ON/OFF switch (
S1
) provides power to the
accelerometer and helps preserve battery life if a battery is
being used as the power source.
S1
must be set towards the
“ON” position for the accelerometer to function. The green
LED (D1) is lit when power is supplied to the accelerometer.
A self–test pushbutton (
S2
) on the evaluation board is a
self–test feature that provides verification of the mechanical
and electrical integrity of the accelerometer. The
STATUS
pin
is an output from the fault latch and is set high if one of the fault
conditions exists. A second pressing of the pushbutton (
S2
)
resets the fault latch, unless of course one or more fault
conditions continue to exist.
Figure 1. Motorola Accelerometer Evaluation Board
Jumper (JP1)
5 V Regulator
(U1)
Power Header
(J1)
On/Off Switch
(S1)
Power LED (D1)
Test Points
Self–Test
Pushbutton (S2)
MMA Device
Mounting
Hole (1 of 4)
PS
BATT
STATUS
Accelerometer Output
(Vout)
SEMICONDUCTOR APPLICATION NOTE
REV 0
F
Freescale Semiconductor, Inc.
n
.