Hardware Reference
In-Depth Information
Vcc
3.3v
GND
1
VSS (GND)
VDD (VCC)
V0
RS
2
3
PiGPIO
4
26
24
22
25
5
R/W
6
E
23
21
8
16
A0
Vcc
7
D80
7
15
LCD
A1
SDA
8
D81
6
14
A2
SCL
20
18
16
14
12
19
17
15
13
11
9
D82
5
13
P0
INT
10
PCF8574
D83
12
4
P1
P7
P6
P5
P4
11
D84
3
11
P2
12
D85
2
10
P3
13
D86
1
9
GND
14
D87
A
K
15
10
8
6
4
2
9
7
5
3
1
16
GND
Vcc
5.0v
Figure 4-11.
Circuit schematic diagram
■
Figure 4.11 is accurate according to the components i have used. please read your data sheets and cross-check
all connections. For example your register select pad on the lCD may be in a different location than mine. Check your
data sheets! it takes only a small glance to feel safe in the knowledge that you have made the right connections.
Warning
You now have all the information you need to start work! This is the fun part.
1.
Get your breadboard out and insert the PCF8574AN shift register into the center of the
board. You can see this neatly done in Figure
4-12
. Remember that the half-moon crescent
on the package indicates the top/pin1.
