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Chapter 3
Microcomputer Basics 1
8-bit timer operation III−37
3.6 8-bit timer operation
3.6.1 Counting rising edges using the event count
■ Overview
This program uses Timer 1 to count the rising edges of the external signal input from the TM1IO input pin with a
binary counter.
When the external input signal is detected 5 times, an interrupt is generated and LED connected to P44 flashes.
The setting stored in the base register determines the number of rising edge detections that is counted until an
interrupt is generated.
■ Hardware allocation list
Source frequency fosc (10 MHz)
Ports used Port 3 (P31) Event input pin
Timers used Timer 1 Event count timer
Count clock source TIM0IO input
Interrupts used Timer 1 interrupt LED connected to P44 flashes
Interrupt level 0
Interrupt source Binary counter underflow