SYNPWM datasheet(31/57 Pages) FEELING

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FM8P73B

Web site: http://www.feeling-tech.com.tw

Rev1.0 Nov 20, 2013

P.31/FM8P73B

FEELING

TECHNOLOGY

2.7

Interrupt

The FM8P73B has three kinds of interrupt sources:

8 External IOB<0:7> pin changed interrupt

3 Timers underflow interrupt (or PWM interrupt)

ADC conversion completion interrupt

INTFLAG is the interrupt flag register that recodes the interrupt requests to the relative flags.

A global interrupt enable bit, GIE (INTEN<7>), enables (if set) all un-masked interrupts or disables (if cleared) all

interrupts. Individual interrupts can be enabled/ disabled through their corresponding enable bits in INTEN

When an interrupt event occur with the GIE bit and its corresponding interrupt enable bit are all set, the GIE bit

will be cleared by hardware to disable any further interrupts, and the next instruction will be fetched from address

3FEh. The interrupt flag bits must be cleared by software before re-enabling GIE bit to avoid recursive interrupts.

The RETFIE instruction exits the interrupt routine and set the GIE bit to re-enable interrupt.

The flag bit in INTFLAG register is set by interrupt event regardless of the status of its mask bit.

2.7.1

PORTB<0:7> External Interrupt and Wakeup Function

The external interrupt on PORTB<0:7> are selected by INTPB<0:7> and PBIE (INTEN<5>). When the device is

in normal mode and the specified IO status changed, the interrupt event will be triggered and the program will

jump to 3FEh.

When the device is in sleep mode, those interrupts can also be used as an external wakeup signal. The device

will restart system clock and the program will jump to 3FEh after startup timer timeout.

Example 2.6: External IOB0 pin change interrupt

Address

Code

#include

<8P73B.ASH>

…

MOVIA

0xFF

n+1

MOVAR

IOSTB

;Set Port B as input

n+2

MOVIA

0xA0

n+3

MOVAR

INTEN

;Enable global & Port B interrupt

n+4

MOVIA

0xDF

n+5

MOVAR

INTFALG

;Clear PBIF flag(Note1)

n+6

MOVR

PORTB,R

;Update Port B pin status

n+7

MOVIA

0x01

n+8

MOVAR

INTPB

;Set IOB0 pin change

…

N/A

ISR:

;In this example, ISR define at 0x200

200

…

;User Port B pin change ISR code

200+n

MOVIA

0xDF

200+n+1

MOVAR

INTFLAG

;Clear PBIF flag(Note1)

200+n+2

RETFIE

3FE

GOTO

ISR

3FF

GOTO

START

Note : 1. BCR instruction is not recommended for Clear interrupt flag (INTFLAG register).

2. Interrupt save status code is not shown in this example.

1. IOB0 pin change

2. Return from ISR

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