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Application of Interrupt and Timer : Measurement of Motor Speed.

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Presentation on theme: "Application of Interrupt and Timer : Measurement of Motor Speed."— Presentation transcript:

1 Application of Interrupt and Timer : Measurement of Motor Speed

2 incoming Lab. Rotary Encoder A ( rotary) encoder is an electro-mechanical device that converts the angular position of a shaft or axle to digital code or digital pulse absolute/ incremental

3 incoming Lab. DC motor

4 incoming Lab. Encoder Incremental Encoder 13 pulses/round/channel 1 pulse = 360/13 도 (motor), 360/50/13 도 (wheel) Motor Speed  rpm (round per minute) –rad/sec = rpm*2pi/60  102 rpm (wheel) = 5100 rpm (motor) direction  A/B channel 의 위상을 비교 A Ch. B Ch. A Ch. B Ch.

5 incoming Lab. DC Motor RB-35GM 제어전압 : DC 12V 감속비 [Reduction ration] : 1/50 정격토크 [Rated torque](Kg-cm): 2.0 정격회전수 [Rated speed](rpm):102 Rated torque 60 g-cm, 5100 rpm, current 470 mA 이하, 3.14 W No load speed 6200 rpm, No load current 120 mA 이하

6 incoming Lab. Measurement of motor speed (I) pulse 간의 시간 측정 Example)

7 incoming Lab. Measurement of motor speed (I) pulse 간의 시간 측정 예 ) f clk = 1 Mhz, N(prescale) = 100  f timer = f clk /N=10kHz, T timer = 100uSec  timer_diff = 100 =>  10 mSec timer_diff

8 incoming Lab. Measurement of motor speed (I) External Interrupt INT 5 : Left motor A channel (PE5) INT 7 : Right motor A channel (PE7) external interrupt 간 timer 비교 EICRB = 0x88; EIMSK = 0xA0; A Ch. tcnt1tcnt2 timer_diff = tcnt2 – tcnt1

9 incoming Lab. 바퀴구동체 도면

10 incoming Lab. External interrupt Setting EIMSK : external Interrupt MaSK register EICRB 1 0 1 0 0 0 0 0 1 0

11 incoming Lab. Measurement of motor speed (I) timer for external interrupt TCNT0 : 8 bit timer/counter TCNT1 : Motor Speed Control TCNT2, TCNT3 : same prescaler with TCNT1 normal mode no timer interrupt f clk = 7372800 Hz & prescale : 256  f timer = 7372800/256 = 28800  T timer = 1/28800 = 34.72 uSec  예상 ) 102 rpm => 904.9 uSec => 26 (= timer_diff ) TCCR0 = 0x06;

12 incoming Lab. Measurement of motor speed (I) TCCRn : Timer/Counter Control Register 1 1 0

13 incoming Lab. Interrupt Service Routine (INT5, Left Motor) ISP(INT5_vect) { static unsigned char timer_cur = 0, timer_prev = 0; timer_cur = TCNT0; Left_timer_diff = timer_cur – timer_prev; timer_prev; = timer_cur; if ( (PINE & 0x10) == 0 ) Dir_L = 0; // forward else Dir_L = 1; // backward }

14 incoming Lab. Speed Measurement Program (I) #include void txd_char(unsigned char data){ while( (UCSR0A & 0x20) == 0 ); UDR0 = data; } unsigned char Left_timer_diff, Right_timer_diff; unsigned char Dir_L, Dir_R; int main(){ unsigned char i, time_diff; unsigned char text[] = "\r Left : ";

15 incoming Lab. Speed Measurement Program (I) DDRB = 0xCF; DDRD = 0x18; DDRE = 0x01; PORTB = 0x01; /* 원하는 방향을 기입 */ EICRB = 0x08; // EICRB = 0x88; EIMSK = 0x20; // EIMSK = 0xA0; TCCR1A = 0x2B; TCCR1B = 0x0A; TCCR1C = 0x00; OCR1B = 0x00; /* 원하는 속도를 기입 0x000 ~ 0x3FF */ // OCR1C = 0x00; /* 원하는 속도를 기입 0x000 ~ 0x3FF */ TCCR0 = 0x06; EIMSK = 0x20; /* Left interrupt 만 enable */ sei();

16 incoming Lab. Speed Measurement Program (I) while(1){ i=0; while(text[i] != '\0') txd_char(text[i++]); if( Dir_L == 1 ) txd_char('+'); // 부호 출력 else txd_char('-'); time_diff = Left_timer_diff; // 임시 저장 txd_char(time_diff/100 + '0'); // 백의 자리 출력 txd_char((time_diff/10)%10 + '0'); // 십의 자리 출력 txd_char(time_diff%10 + '0'); // 일의 자리 출력 txd_char('\r'); return 0; }

17 incoming Lab. 연습 Right Motor 에 대해 속도 측정 code 완성 Left/Right motor 에 대해 다양한 속도에 대한 속도측정 RPM 단위로 출력 (UART)

18 incoming Lab. Measurement of motor speed (I)

19 incoming Lab. Interrupt Service Routine (INT5, Left Motor) ISR(INT5_vect) { static timer_cur = 0, timer_prev = 0; timer_cur = TCNT0; if (timer_cur >= timer_prev) Left_timer_diff = timer_cur – timer_prev; else Left_timer_diff = 255- timer_prev+timer_cur+1; timer_prev; = timer_cur; if ( (PINE & 0x20) == 0 ) Dir_L = 0; // forward else Dir_L = 1; // backward }

20 incoming Lab. Interrupt Service Routine (INT5, Left Motor) ISR(INT5_vect) { Left_timer_diff = TCNT0; TCNT0 = 0; if ( (PINE & 0x20) == 0 ) Dir_L = 0; // forward else Dir_L = 1; // backward }

21 incoming Lab. Measurement of motor speed (II) 일정한 시간 간격 동안 pulse 의 개수 측정 Example)

22 incoming Lab. Measurement of motor speed (II) clear time on compare match (CTC) mode (output compare interrupt) TCNT0 : 8 bit timer/counter f clk = 7372800 Hz & prescale : 1024  f timer = 7372800/1024 = 7200  T timer = 1/7200  OCR0 = 144 => 144*T timer = 1/50 = 20 mSec 마다 interrupt 발 생  예상 ) 102 rpm => 904.9 uSec => 22 개 pulse TCCR0 = 0x0F; TIMSK = 0x02;

23 incoming Lab. Measurement of motor speed (II) TCCRn : Timer/Counter Control Register TIMSK : Timer/Counter Interrupt Mask Register 1 1

24 incoming Lab. Interrupt Service Routine (INT5, Left Motor) ISP(INT5_vect) { Pulse_L++; if ( (PINE & 0x20) == 0 ) Dir_L = 0; // forward else Dir_L = 1; // backward }

25 incoming Lab. Interrupt Service Routine (Timer0) ISR(TIMER0_COMP_vect) { static unsigned char no_timer = 0; no_timer++; if ( no_timer >= 10 ) { // 20*10 = 200 mSec no_timer = 0; No_Pulse_L = Pulse_L; No_Pulse_R = Pulse_R; Pulse_L = Pulse_R = 0; }

26 incoming Lab. Interrupt Service Routine (Timer0) – 20mSec ISR(TIMER0_COMP_vect) { No_Pulse_L = Pulse_L; No_Pulse_R = Pulse_R; Pulse_L = Pulse_R = 0; }

27 incoming Lab. Speed Measurement Program (II) #include void txd_char(unsigned char data){ while( (UCSR0A & 0x20) == 0 ); UDR0 = data; } unsigned char Pulse_L, Pulse_R, No_Pulse_L, No_Pulse_R; unsigned char Dir_L, Dir_R; int main(){ unsigned char cmd, i=0, no_pulse_l; unsigned char text[] = "\r Left : ";

28 incoming Lab. Speed Measurement Program (II) /* UART0 초기화 추가 */ DDRB = 0xCF; DDRD = 0x18; DDRE = 0x01; PORTB = 0x01; /* 원하는 방향을 기입 */ EICRB = 0x08; // EICRB = 0x88; EIMSK = 0x20; // EIMSK = 0xA0; TCCR1A = 0x2B; TCCR1B = 0x0A; TCCR1C = 0x00; OCR1B = 0x00; /* 원하는 속도를 기입 0x000 ~ 0x3FF */ // OCR1C = 0x00; /* 원하는 속도를 기입 0x000 ~ 0x3FF */ OCR0 = 144; TCCR0 = 0x0F; /* CTC mode prescale = 1024 */ TIMSK = 0x02; /* Timer Interrupt */ sei();

29 incoming Lab. Speed Measurement Program (II) while(1){ i=0; while(text[i] != '\0') txd_char(text[i++]); if( Dir_L == 1 ) txd_char('+'); // 부호 출력 else txd_char('-'); no_pulse_l = No_Pulse_L; // 임시 저장 txd_char(no_pulse_l /100 + '0'); // 백의 자리 출력 txd_char((no_pulse_l /10)%10 + '0'); // 십의 자리 출력 txd_char(no_pulse_l %10 + '0'); // 일의 자리 출력 txd_char('\r'); return 0; }

30 incoming Lab. 연습 Right Motor 에 대해 속도 측정 code 완성 Left/Right motor 에 대해 다양한 속도에 대한 속도측정 RPM 단위로 출력 (UART)

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