L06_Interrupt

Report
Interrupt
Interrupt
an asynchronous signal indicating the need for attention
hardware interrupt/software interrupt
call “interrupt service routine”(interrupt handler, interrupt
routine)
interrupt source/interrupt vector/interrupt priority
incoming Lab.
생활 속에 인터럽트
영화 감상
스팸
문자
interrupt
Gom player
cell phone
1
2
3
4
interrupt
1
2
3
4
5
중요
영화 정지
답신
재생
시간
5
6
7
8
…
incoming Lab.
program with or without interrupt
without interrupt
b = *ADC0;
c = *ADC1;
a = b+c;
i=0;
while(i<10){
a += b;
i++;
}
with interrupt
b = *ADC0;
c = *ADC1;
a = b+c;
if ( a>10 ) a = c;
else a = b;
i=0;
while(i<10){
a += b;
i++;
}
interrupt
service
routine(ISR)
incoming Lab.
interrupt is an asynchronous event
b = *ADC0;
b = *ADC0;
c = *ADC1;
a = b+c;
if ( a>10 ) a = c;
else a = b;
if ( a>10 ) a = c;
else a = b;
i=0;
while(i<10){
a += b;
i++;
}
ISR
c = *ADC1;
a = b+c;
i=0;
while(i<10){
a += b;
i++;
}
ISR
incoming Lab.
c.f.) function in program
b = *ADC0;
c = *ADC1;
a = b+c;
func();
i = 0;
while(i<10){
a += b;
i++;
}
b = *ADC0;
c = *ADC1;
a = b+c;
void func(){
if ( a>10 ) a = c;
else a = b;
}
i=0
while(i<10){
a += b;
i++;
}
incoming Lab.
ATmega128 interrupt Source (I)
35 개
incoming Lab.
ATmega128 interrupt Source (II)
incoming Lab.
Interrupt 처리 과정
Interrupt request from an interrupt source
예) INT0 Signal
If masked, ignore the interrupt.
Program counter(PC) is saved.
PC is changed to the program address according to the
interrupt source
예) PC <= 0x0002
Jump to the Interrupt Service Routine (ISR)
예) jmp EXT_INT0 (PC <= EXT_INT0)
After the end of ISR, PC is restored.
incoming Lab.
Interrupt Vector Table
memory address of an interrupt service routine
incoming Lab.
External Interrupt : INT0~INT7
INT0~INT3 : PD0~PD3 (Port D)
INT4~INT7 : PE4~PE7 (Port E)
incoming Lab.
Global Interrupt Enable
SREG(Status Register)
I (7 bit) : Global Interrupt Enable
전체 인터럽트를 허용하도록 설정하는 비트
‘1’ : interrupt enable
‘0’ : interrupt disable
SEI : ‘1’ 로 변경 (interrupt enable)
CLI : ‘0’으로 변경 (interrupt disable)
incoming Lab.
EIMSK register
External Interrupt MaSK register
External Interrupt (INT0~INT7)의 허용 여부를 제어
‘1’ : enable
‘0’: disable
예) EIMSK = 0xA4;
address : 0x59
incoming Lab.
External Interrupt Control Register (EICRA,
EICRB)
Interrupt Trigger
Level trigger
 low level : ‘0’ 상태이면 interrupt trigger
 high level : ‘1’ 상태이면 interrupt trigger
Edge trigger
 rising edge : ‘0’ -> ‘1’ 이면 interrupt trigger
 falling edge : ‘1’ -> ‘0’ 이면 interrupt trigger
EICRA, EIRCB
0x6A
0x5A
incoming Lab.
EICRA, EICRB
incoming Lab.
예) Enable Interrupt
INT0, rising edge
DDRD &= 0xFE; /* PD0 : interrupt source, input */
EICRA = 0x03;
EIMSK = 0x01;
sei(); /* global interrupt enable */
 SEI instruction의 C code, mnemonic code
 cli(); /* global interrupt disable */
INT7, falling edge;
DDRE &= 0xEF; /* PE7 : interrupt source, input */
EICRB = 0x80;
EIMSK = 0x80;
sei(); /* global interrupt enable */
incoming Lab.
Interrupt Service Routine
ISR(vector, attributes)
Format of WinAVR
 C:\WinAVR-20100110\doc\avr-libc\avr-libc-usermanual.pdf 의 p.233 ~
vector : interrupt source
 p.237의 표 참조
 예) INT0_vect : external interrupt 0 (PD0)
attributes : interrupt 속성, 생략 가능
예) ISR(INT0_vect) {
…
} /* external interrupt 0 (PD0)가 발생할 때 ISR */
incoming Lab.
Interrupt Vector Table Initialize
WinAVR :
ISR(vector, attributes)
ISR의 시작 번지가 자동으로 해당 vector table에 저장
in general (예)
unsigned int *ivt;
ivt = (unsigned int *)0x0002;
*ivt = int_service_routine;
 /* C program에서는 함수의 이름이 주소를 나타냄 */
…
…
void int_service_routine(){ /* interrupt service routine */
…
}
incoming Lab.
Interrupt Priority & EIFR
인터럽트의 우선 순위
두 개 이상의 인터럽트가 동시에 발생될 경우
하위 주소의 인터럽트가 상위 주소의 인터럽트 보다 우선 순위가
높다
예) INT0 > INT1 > … > USART0 > …
interrupt flag register (EIFR)
External Interrupt (INT0~INT7)의 발생 여부를 나타냄
incoming Lab.
Interrupt 실습
#include <avr/io.h>
#include <avr/interrupt.h>
int main(){
DDRD = 0x18;
EICRA = 0x02; /* falling edge */
EIMSK = 0x01; /* left S/W interrupt enable */
sei();
/* SEI instruction의 C code, mnemonic code */
while(1);
return 0;
}
incoming Lab.
falling edge or rising edge
incoming Lab.
Interrupt Service Routine
ISP(INT0_vect)
{
PORTD |= 0x10;
}
incoming Lab.
In flash program memory
0x0000 : jmp 0x0054
Reset or Restart
0x0002 : jmp 0x00a0
INT0 (left S/W)
…
0x0054 : ….
…
main program
0x00a0 : ….
interrupt service routine
….
….
: reti
incoming Lab.
Interrupt 실습 : LED 다시 켜기, while 문만 변경
#include <avr/io.h>
#include <avr/interrupt.h>
int main(){
…
sei();
while(1) {
if( (PIND & 0x01) == 1 ) PORTD &= 0xEF;
}
return 0;
}
incoming Lab.
Interrupt 실습 : INT1 (RIGHT)
#include <avr/io.h>
#include <avr/interrupt.h>
int main(){
DDRD = ________;
EICRA = ________;
EIMSK =________;
sei();
while(1);
return 0;
}
incoming Lab.
Interrupt Service Routine
ISR(INT1_vect)
{
PORTD |= 0x10;
}
incoming Lab.
실습 : INT0, INT1 모두 사용
#include <avr/io.h>
#include <avr/interrupt.h>
int main(){
DDRD = ________;
EICRA = ________;
EIMSK =________;
sei();
while(1);
return 0;
}
incoming Lab.
실습 : INT0, INT1 모두 사용
ISP(INT0_vect) /* Left S/W => LED Off */
{
PORTD |= 0x10;
}
ISR(INT1_vect) /* Right S/W => LED On */
{
PORTD &= 0xEF;
}
incoming Lab.
main switch problem : wait-polling
int main()
{
…
while (1) {
unsigned char rxd_char() {
unsigned char data;
while( (UCSR0A & 0x80) == 0) ;
cmd = rxd_char();
if( main S/W is left) {
Motor Off;
}
else {
switch(cmd){
case …
}
data = UDR0 ;
return data ;
incoming Lab.
one possible solution : still polling
int main()
{
…
while (1) {
if( (UCSR0A & 0x80) != 0 ) cmd = UDR0 ;
if( main S/W is left) {
Motor Off;
}
else {
switch(cmd){
case …
incoming Lab.
solution with interrupt (I)
int main()
{
…
while (1) {
main S/W
interrupt
ISR(INT0_vect) {
cmd = rxd_char();
if( main S/W is left) {
Motor Disable;
}
else {
switch(cmd){
case …
Motor Disable;
}
incoming Lab.
solution with interrupt (II)
int main()
{
…
while (1) {
left S/W
interrupt
ISR(INT0_vect) {
Left Motor Disable;
}
cmd = rxd_char();
if( … ) {
Left Motor Disable;
}
else if (… ) {
RightMotor Disable;
}
else {
switch(cmd){
case …
right S/W
interrupt
ISR(INT1_vect) {
Right Motor Disable;
}
incoming Lab.
USART Interrupt
USART0 사용
USCR0B Register
RXCIE0 (7 bit) = ‘1’;
USCR0B : ’18’ -> ’98’
incoming Lab.
USART0 Interrupt Service Routine
ISR(USART0_RX_vect)
{
Cmd_U0 = UDR0; /* Cmd_U0 : global 변수 */
}
…
unsigned char Cmd_U0;
int main() {
/* global 변수 선언 위치 */
…
incoming Lab.
변수의 허용 범위
block : {}내의 선언문 및 실행문
block 내에서 선언된 변수는 block내에서 만 유효
Example)
int a = 2;
printf(“%d\n”,a);
{
int a = 3;
printf(“%d\n”,a);
}
printf(“%d\n”,a);
incoming Lab.
USART0 interrupt program
#include <avr/io.h>
#include <avr/interrupt.h>
unsigned char Cmd_U0;
int main(){
/* 초기화 code, Port I/O, USART0, Interrupt Enable */
while(1){
switch(Cmd_U0) {
case :
…
}
}
return 0;
}
incoming Lab.
USART0 interrupt 실습
‘n’ : LED on, ‘f’ : LED off
switch(Cmd_U0){
case ‘n’ :
PORTD &= 0xEF;
break;
case ‘f’ :
PORTD |= 0x10;
break;
default :
}
incoming Lab.
실습 과제
모든 input은 interrupt로 처리
Left S/W를 이용하여 left motor enable/disable
‘0’ : Disable ‘1’ : Enable
Right S/W를 이용하여 right motor enable/disable
‘0’ : Disable ‘1’ : Enable
UART 통신을 이용하여 Motor 제어
Key map 정의
 예) R : right forward, r : right backward
incoming Lab.

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