DMC73C167 datasheet(36/90 Pages) DAEWOO

36 / 90 page

8Bit Single Chip Microcontroller

DMC73C167

1) The port using as the interrupt input should be in the input mode. The output mode may

cause damage to the device. If the contents of the corresponding output port are changed

from 1 to 0, the interrupt flag will also set to 1.

2) If not used as the interrupt input, the corresponding interrupt enable should be disabled.

But even with the disabling of this interrupt enable, the interrupt flag will be changed.

The external interrupt timing is shown in Figure 5-6. The device needs additional circuitry

when INT1, INT3_0, and IN 5_0 are used as zero-cross detectors as shown in Figure 5-7.

The following conditions are needed :

1) The external interrupt level should be in the range from VCC +0.3V to VSS. The input

current must not exceed the specification.

2) Noise on the interrupt signal should be minimized because the noise debounce logic is not

implemented on chip. The function may fail due to continuous interrupts.

Caution :

It is possible that the INTn flag bits in the IOCNT registers could be unintentionally cleared by

using bit manipulation instructions (ANDP/ORP & XORP). To avoid these occurences, use

the MOVP and STA instructions when writing Data to IOCNT registers.

Figure 5-3. External Interrupt Timing

VCC

VSS

External

Input

VT+

VT-

Interrupt

Happen

Last

Happen

Interrupt

Execution

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DMC73C167 Datasheet(PDF) 36 Page - Daewoo Semiconductor