Port Application Examples; Fig. 2.1.1 Key Input By Key Scan - Renesas 4513 User Manual

2.1.3 Port application examples

(1) Key input by key scan
Key matrix can be set up by connecting keys externally because port D output structure is an N-
channel open-drain and port P0 has the pull-up resistor.
Outline: The connecting required external part is just keys.
Specifications: Port D is used to output "L" level and port P0 is used to input 16 keys. Multiple key
Figure 2.1.1 shows the key input and Figure 2.1.2 shows the key input timing.
M34513/M34514

Fig. 2.1.1 Key input by key scan

inputs are not detected.
SW4
D
0
SW8
D
1
SW12
D
2
SW16
D
3
P0
0
P0
1
P0
2
P0
3
4513/4514 Group User's Manual
APPLICATION
SW3 SW2
SW7 SW6
SW11 SW10
SW15 SW14
2.1 I/O pins
SW1
SW5
SW9
SW13
2-7