Interrupt

incoming Lab. 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 문자 영화 정지 답신 재생 중요 스팸 …5678… 시간 Gom playercell phone interrupt

incoming Lab. program with or without interrupt b = *ADC0; c = *ADC1; a = b+c; i=0; while(i<10){ a += b; i++; } b = *ADC0; c = *ADC1; a = b+c; i=0; while(i<10){ a += b; i++; } without interrupt with interrupt if ( a>10 ) a = c; else a = b; interrupt service routine(ISR)

incoming Lab. interrupt is an asynchronous event b = *ADC0; c = *ADC1; a = b+c; i=0; while(i<10){ a += b; i++; } if ( a>10 ) a = c; else a = b; b = *ADC0; c = *ADC1; a = b+c; i=0; while(i<10){ a += b; i++; } if ( a>10 ) a = c; else a = b; 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; i=0 while(i<10){ a += b; i++; } void func(){ if ( a>10 ) a = c; else a = b; }

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 0x5A 0x6A

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 instruction 의 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 \doc\avr-libc\avr-libc-user- manual.pdf 의 p.233 ~ vector : interrupt source  p.237 의 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) ISR 의 시작 번지가 자동으로 해당 vector table 에 저장 in general ( 예 ) unsigned int *ivt; ivt = (unsigned int *)0x0002; *ivt = int_service_routine;  /* C program 에서는 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 int main(){ DDRD = 0x18; EICRA = 0x02; /* falling edge */ EIMSK = 0x01; /* left S/W interrupt enable */ sei(); /* SEI instruction 의 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 0x0002 : jmp 0x00a0 … 0x0054 : …. … 0x00a0 : …. …. …. : reti Reset or Restart INT0 (left S/W) main program interrupt service routine

incoming Lab. Interrupt 실습 : LED 다시 켜기, while 문만 변경 #include int main(){ … sei(); while(1) { if( (PIND & 0x01) == 1 ) PORTD &= 0xEF; } return 0; }

incoming Lab. Interrupt 실습 : INT1 (RIGHT) #include 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 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) { cmd = rxd_char(); if( main S/W is left) { Motor Off; } else { switch(cmd){ case … unsigned char rxd_char() { unsigned char data; while( (UCSR0A & 0x80) == 0) ; 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) { cmd = rxd_char(); if( main S/W is left) { Motor Disable; } else { switch(cmd){ case … ISR(INT0_vect) { Motor Disable; } main S/W interrupt

incoming Lab. solution with interrupt (II) int main() { … while (1) { cmd = rxd_char(); if( … ) { Left Motor Disable; } else if (… ) { RightMotor Disable; } else { switch(cmd){ case … ISR(INT0_vect) { Left Motor Disable; } left S/W interrupt ISR(INT1_vect) { Right Motor Disable; } right S/W interrupt

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; /* global 변수 선언 위치 */ int main() { …

incoming Lab. 변수의 허용 범위 block : {} 내의 선언문 및 실행문 block 내에서 선언된 변수는 block 내에서 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 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 input 은 interrupt 로 처리 Left S/W 를 이용하여 left motor enable/disable ‘0’ : Disable ‘1’ : Enable Right S/W 를 이용하여 right motor enable/disable ‘0’ : Disable ‘1’ : Enable UART 통신을 이용하여 Motor 제어 Key map 정의  예 ) R : right forward, r : right backward