4507_M Datasheet, PDF (132/216 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 4500 SERIES

4507 Group
APPLICATION
2.2 Interrupts
2.2.3 Interrupt application examples
(1) INT interrupt
The INT pin is used for external 0 interrupt, of which valid waveforms can be chosen, which can
recognize the change of both edges (“H”→“L” or “L”→“H”).
Outline: An external 0 interrupt can be used by dealing with the change of edge (“H”→“L” or
“L”→“H”) in both directions as a trigger.
Specifications: An interrupt occurs by the change of an external signals edge (“H”→“L” or “L”→“H”).
Figure 2.2.1 shows an operation example of an external 0 interrupt, and Figure 2.2.2 shows a setting
example of an external 0 interrupt.
(2) Timer 1 interrupt
Constant period interrupts by a setting value to timer 1 can be used.
Outline: The constant period interrupts by the timer 1 underflow signal can be used.
Specifications: Prescaler and timer 1 divide the system clock frequency f(XIN) = 4.0 MHz, and the
timer 1 interrupt occurs every 1 ms.
Figure 2.2.3 shows a setting example of the timer 1 constant period interrupt.
(3) Timer 2 interrupt
Constant period interrupts by a setting value to timer 2 can be used.
Outline: The constant period interrupts by the timer 2 underflow signal can be used.
Specifications: Timer 2 and prescaler divide the system clock frequency (= 4.0 MHz), and the timer
2 interrupt occurs every about 1 ms.
Figure 2.2.4 shows a setting example of the timer 2 constant period interrupt.
“H”
P13/INT
“L”
“H”
P13/INT
“L”
An interrupt occurs after the valid waveform “falling” is detected.
An interrupt occurs after the valid waveform “rising” is detected.
Fig. 2.2.1 INT interrupt operation example
Rev.2.01 Feb 04, 2005
REJ09B0195-0201
2-17