CT-161-CD Fujitsu Semiconductor America Inc, CT-161-CD Datasheet - Page 55

• Manufacturer Part Number: CT-161-CD
• Description: KIT 16LX FOR MB90F387
• Manufacturer: Fujitsu Semiconductor America Inc
• Series: F²MC-16LXr
• Type: MCUr

Specifications of CT-161-CD

• Contents: Board, Cable, CD
• For Use With/related Products: MB90F387S
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 865-1103

3 “Let's try to control the LED by switch operation!”
© Fujitsu
This chapter explains how to control LEDs by operating the push switches on the board and how
to create a program that controls LEDs based on switch operations.
3.1
The board of the Starter Kit has two switches (SWs) as shown in Figure 3.1. The switches
are connected to pins P25 and P27 of the microcomputer. The following explains how the
microcomputer detects your operation of these switches.
Figure 3.2 shows a conceptual diagram of the connection of SW1 on the board. On the board,
SW1 is connected to pin P25, which is a general I-O port of the microcomputer. While SW1
is released (off state), the voltage applied to pin P25 of the microcomputer is Vcc (5 V), which
is the high-level input. When SW1 is pressed (on state), the input to pin P25 becomes the
low level because the voltage at pin P25 becomes GND. Thus, the input status at pin P25 of
the microcomputer changes depending on the state of SW1. The same mechanism applies to
SW2, except that SW2 is connected to pin P27, which is a general I-O port of the
microcomputer. Therefore, the input status at pin P27 changes when SW2 is operated.
How the microcomputer detects switch operation
■ When SW1 is off
Figure 3.2 Connection of SW1 to microcomputer pin (conceptual diagram)
Microcompute
PDR2 register
r
Pin P25
Figure 3.1 Switches on the Starter Kit board
GND
Vcc
-
49
SW1
-
■ When SW1 is on
Microcomputer
PDR2 register
SW1
Pin P25
SW2
GND
Vcc
SW1