![](http://datasheet.mmic.net.cn/280000/MPX2202GVP_datasheet_16098581/MPX2202GVP_366.png)
3–220
Motorola Sensor Device Data
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PURPOSE
This evaluation system, shown in Figure 1, demonstrates
the ease of operation and interfacing of the Motorola
MPX5100 series pressure sensors with on–chip temperature
compensation, calibration and amplification. The board may
be used to evaluate the sensor’s suitability for a specific
application.
DESCRIPTION
The DEVB–114 evaluation board is constructed on a small
printed circuit board. It is powered from a single +5 Vdc
regulated power supply. The system will display the pressure
applied to the MPX5100 sensor in pounds per square inch.
The range is 0 PSI through 15 PSI, resolved to 0.1 PSI. No
potentiometers are used in the system to adjust the span and
offset. The sensor’s zero offset voltage with no pressure
applied to the sensor is empirically computed each time power
is applied to the system and stored in RAM. The sensitivity of
the MPX5100 is repeatable from unit to unit. There is a facility
for a small “rubbering” of the slope constant built into the
program. It is accomplished with jumpers J1 and J2, and is
explained in the Operation section. The board contents are
further described in the schematic, silk screen plot, and parts
list that appear in Figures 2, 3 and Table 1.
BASIC CIRCUIT
The evaluation board consists of three basic subsystems:
an MPX5100GP pressure sensor, a four digit liquid crystal
display (only three digits and a decimal are used) and a
programmed microprocessor with the necessary external
circuitry to support the operation of the microprocessor.
30
1
29
2
28
3
27
4
26
5
25
6
24
7
31
0
38
1
37
2
36
3
35
4
34
5
33
6
32
7
48
45
44
5 4 3
42
7
43
6
46
47
2 1
49
0
44
VSS
~
.302 V
~
4.85 V
15 OHM
1%
453 OHM
1%
22 pF
C3
100
μ
F
52
50
TD0
RDI
5
PORTA
PORTB
PORTC
GND
VPP6
15
1%
30.1 OHM
XDCR1
MPX5100
RESET
IN
U1
U2
34064P–
5
.1
+
10K
10K
4.7K
22 pF
C4
10MEG
4 MHz
Y1
C2
C1
R7
R6
R5
R4
R3
R2
R1
J3
GND
MC68HC705B5FN
+5
OUT
VCC
TCAP2
21 22 23
TCAP1
D/A
PD5
PD0
13
PD1
PD2
11
PD3
PD4
VDD
9
+5
PD7
3
PD6
17
16
OSC2
OSC1
+5
8
7
VRH
VRL
+5
+5
18
RESET
IRQ
19
4
J2
J1
+5
1–4, 33
39, 38, 40
28
BP
IEE PART NUMBER LCD5657 OR EQUAL
LIQUID CRYSTAL DISPLAY
26
3736
35
34
32
31
30
29
27
25
24
23
22
21
20
19
14
12
11
17
18
16
15
13
10
9
8
7
6
5
14
12
10
LCD
Figure 2. DEVB–114 System Schematic
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F
Freescale Semiconductor, Inc.
n
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