CT-161-CD Fujitsu Semiconductor America Inc, CT-161-CD Datasheet - Page 71

• 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

© Fujitsu
5.3
Explained next is the procedure for using pin INT5 as an external interrupt pin. To use pin
INT5 for the input of external interrupt, you should set the I-O direction of the pin to input by
using the port 2 register "DDR2." Handling of DDR2 was described in Chapter 3. Write '0'
to the bit 5 of DDR2. You should also set necessary values in external interrupt registers
"EIRR," "ENIR," and "ELVR" for using pin INT5 as the external interrupt input pin. EIRR
is an 8-bit register that indicates external interrupt factors. ENIR is an 8-bit register that
enables and disables external interrupts.
conditions for external interrupt detection.
Assume the processing to detect the SW1 operation from the off state to the on state by using
an interrupt. When SW1 is pressed, the signal input to pin INT5 changes from the high level
to the low level (as described before). When values are set in external interrupt registers in
steps (1) to (4) below, the external interrupt function enables the microcomputer to detect the
change (falling edge) of the signal input to pin INT5 from the high level to the low level. In
this way, the on operation of SW1 can be detected as the generation of an interrupt.
This section explains how to create a program to detect switch operation by an external
interrupt. The program is also designed to operate an LED to enable you to visually see the
detection of switch operation. The program incorporates the method to turn on an LED
explained in Chapter 2.
(1) Write '0' to the bit 5 of both EIRR and ENIR (to disable the external interrupt via
(2) Write '1' to the bits 10 and 11 of ELVR (to generate an external interrupt when a
(3) Write '0' to the bit 13 of both EIRR and ENIR (to clear the INT5 interrupt factor)
(4) Write '1' to the bit 5 of both EIRR and ENIR (to enable the external interrupt via
5.3.1
How to create and execute a program to control the LED by switch Input operation
Let's create a program to better understand the operation of interrupt processing. This
program will be very similar in contents to the LED control program created in Chapter
2, except that this program will have an additional portion to process the interrupt
generated by switch operation. The main operation by the program is as described
INT5)
falling edge is detected)
INT5)
Outline of the program to be created
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ELVR is a 16-bit register that specifies the