Counter/Timer/PWM

incoming Lab. Counter counter is a device which stores the number of times a particular event or process has occurred synchronous/asynchronous pulse up counter/down Counter DCBA count 범위 : 0~2 N -1

incoming Lab. Timer timer is a specialized type of clock synchronous counter with fixed frequency clock T clk = 1/f clk DCBA T clk T clk T clk T clk T clk T clk Timer 의 최소단위 : T clk 최대 측정 시간 : (2 N -1)T clk

incoming Lab. Example counter : how many tablet ? timer : how long ?

incoming Lab. Counter/Timer in Atmega128 8-bit Timer/Counter TCNT0, TCNT2 Counting 범위 : 0~ bit Timer/Counter TCNT1H & TCNT1L, TCNT3H & TCNT3L Counting 범위 : 0~2 16 – 1 = 65535

incoming Lab. 8-bit Timer/Counter Block Diagram

incoming Lab. Basic Operation prescaler Counter/timer (TCNTn) clk f clk T clk = 1/f clk 8 bit / 16 bit f timer = f clk /N T timer = N/f clk f clk = 1 Mhz, N(prescale) = 100 T clk = 1 uSec f timer = f clk /N = 10 kHz T timer = 100 uSec

incoming Lab. Basic Operation & Timer Interrupt normal mode : overflow interrupt clear time on compare match (CTC) mode : output compare interrupt

incoming Lab. 8 bit Timer/Counter Register 관련 Register TCCRn : Timer/Counter Control Register 예 ) TCCR0 = 0x05  f timer = f clk /128 = /128 = Hz  T timer = 1/57600

incoming Lab. 8 bit Timer/Counter Register 관련 Register TCNTn : Timer/Counter Register Overflow Interrupt 예 ) TCNT0 = 0x27  구간 = 0xFF-0x27 = 0xD8 = 216  216 * T timer 마다 인터럽트 발생이 가능함

incoming Lab. 8 bit Timer/Counter Register 관련 Register OCRn : Output Compare Register Output Compare Interrupt 예 ) OCR0 = 0xA2  구간 = 0xA2 = 162  162 * T timer 마다 인터럽트 발생이 가능함

incoming Lab. 8 bit Timer/Counter Register 관련 Register TIMSK : Timer/Counter Interrupt Mask Register TOIE0 bit : Overflow Interrupt Enable OCIE0 bit : Output Compare Interrupt Enable ETIMSK : Extended Timer/Counter Interrupt Mask Register

incoming Lab. 16-bit Timer/Counter Block Diagram

incoming Lab. 16 bit Timer/Counter Register 관련 Register Timer/Counter Control Register TCCRnA TCCRnB TCCRnC

incoming Lab. 16 bit Timer/Counter Register 관련 Register Clock Selection Bit : CSn0 ~ CSn2 in TCCRnB

incoming Lab. 16 bit Timer/Counter Register 관련 Register TCNTnH & TCNTnL

incoming Lab. 16 bit Timer/Counter Register 관련 Register Output Compare Register OCRnAH & OCRnAH OCRnBH & OCRnBH OCRnCH & OCRnCH

incoming Lab. Timer Interrupt Example Mode : normal mode (overflow interrupt) Interrupt 간격 : 500mSec f clk = Hz  0.5 초 :  16bit counter = 2 16 – 1 = prescale : 1024  /1024 = 3600 => 0xE10  0xFFFF-0xE10 = 0xF1EF TCCR1A = 0x00; TCCR1B = 0x05; TCCR1C = 0x00; TCNT1H = 0xF1; TCNT1L = 0xEF; TIMSK = 0x04;

incoming Lab. Timer Interrupt Example #include int main(){ DDRD = 0x18; TCCR1A = 0x00; TCCR1B = 0x05; TCCR1C = 0x00; TCNT1H = 0xF1; TCNT1L = 0xEF; TIMSK = 0x04; sei(); while(1); return 0; }

incoming Lab. Timer Interrupt Service Routine ISR(TIMER1_OVF_vect) { static char cnt = 0; // static 은 이전 값을 유지 함 cnt++; cnt %= 2; if( cnt == 0 ) PORTD &= 0xEF; else PORTD |= 0x10; TCNT1H = 0xF1; TCNT1L = 0xEF; }

incoming Lab. 연습 다양한 시간으로 lamp 구동 1 초 간격으로 left motor 전진 right motor 전진 left motor 정지 left motor 후진 right motor 정지 right motor 후진 left motor 정지 right motor 정지 이하 반복

incoming Lab. Timer Interrupt Example (II) Mode : clear time on compare match (CTC) mode (output compare interrupt) Interrupt 간격 : 250mSec f clk = Hz  0.25 초 :  16bit counter = 2 16 – 1 = prescale : 1024  /1024 = 1800 => 0x0708 TCCR1A = 0x00; TCCR1B = 0x0D; TCCR1C = 0x00; OCR1A =0x0708; (OCR1AH = 0x07; OCR1AL = 0x08; ) TIMSK = 0x10;

incoming Lab. CTC mode (output compare interrupt) Which counter ? TCNT0, TCNT1, TCNT2, TCNT3 ? Timer/Counter Control Register TCCRnA / TCCRnB / TCCRnC = ? Output Compare Register OCRnA / OCRnB / OCRnC = ? Timer/Counter Interrupt Mask Register TIMSK ?

incoming Lab. CTC mode (output compare interrupt) Timer/Counter Control Register TCCRnA TCCRnB TCCRnC prescale Timer/counter mode

incoming Lab. CTC mode (output compare interrupt) Timer/counter Mode of Operation

incoming Lab. CTC mode (output compare interrupt) Output Compare Register OCRnA / OCRnB / OCRnC = ? TIMSK : Timer/Counter Interrupt Mask Register

incoming Lab. Timer Interrupt Example #include int main(){ DDRD = 0x18; TCCR1A = 0x00; TCCR1B = 0x0D; TCCR1C = 0x00; OCR1A = 0x0708 TIMSK = 0x10; sei(); while(1); return 0; }

incoming Lab. Timer Interrupt Service Routine ISR(TIMER1_COMPA_vect) { static char cnt = 0; // static 은 이전 값을 유지 함 cnt++; cnt %= 2; if( cnt == 0 ) PORTD &= 0xEF; else PORTD |= 0x10; }

incoming Lab. Timer/Counter 의 Input & Output Input Counter : asynchronous pulse Timer : external clock Output Waveform PWM : Pulse Width Modulation External Input/Output I/O Port 에 배정

incoming Lab. Timer/Counter 의 Input & Output TCNT0 : 8bit Counter No input Output : OC0 (PB4) TCNT1 : 16bit Counter Input : T1 (PD6) Output : OC1A(PB5), OC1B (PB6), OC1C(PB7) TCNT2 : 8bit Counter Input : T2(PD7) Output : OC2 (PB7) TCNT3 : 16bit Counter Input : T3 (PE6) Output : OC3A(PE3), OC3B (PE4), OC3C(PE5)

incoming Lab. Timer/Count Mode normal mode : overflow interrupt clear time on compare match (CTC) mode : output compare interrupt Fast PWM Mode

incoming Lab. Timer/Count Mode Phase Correct PWM Mode

incoming Lab. DC 모터의 가감속 제어 DC 모터의 속도제어 DC 모터의 전달함수 정상 상태 속도는 입력 전압에 비례

incoming Lab. Pulse Width Modulation (PWM, 펄스폭 변조 ) commonly used technique for controlling power to an electrical device power delivery, voltage regulation, telecommunication, … 신호 크기에 비례하는 pulse width or duty cycle

incoming Lab. Pulse Width Modulation (PWM, 펄스폭 변조 ) Why PWM ? difficult to amplify a voltage with appropriate power compact and low cost means for applying adjustable power for many devices Principle of PWM 전달되는 power 는 duty cycle 에 비례 PWM frequency

incoming Lab. PWM in ATmega128 Fast PWM mode/Phase Correct PWM Mode TCNT0  OC0 (PB4) TCNT1  OC1A(PB5), OC1B (PB6), OC1C(PB7) TCNT2  OC2 (PB7) TCNT3 : 16bit Counter  OC3A(PE3), OC3B (PE4), OC3C(PE5) OC1B (PB6) : Left Motor Enable OC1C (PB7) : Right Motor Enable TCNT1 => PWM 으로 사용

incoming Lab. PWM Example PWM mode : Fast PWM 10 bit mode PWM frequency motor 와 motor driver 의 주파수 특성 : ? f clk = Hz N(prescale) = 8 TOP =

incoming Lab. PWM Example

incoming Lab. PWM Example Timer/Counter Control Register TCCRnA TCCRnB TCCRnC prescale Timer/counter mode

incoming Lab. PWM Example

incoming Lab. PWM Example #include int main(){ DDRB = 0xCF; PORTB = 0x06; TCCR1A = 0x2B; TCCR1B = 0x0A; TCCR1C = 0x00; OCR1B = 0x00; /* 원하는 속도를 기입 0x000 ~ 0x3FF */ OCR1C = 0x00; /* 원하는 속도를 기입 0x000 ~ 0x3FF */ while(1); return 0; }

incoming Lab. 실습 과제 좌우 모터에 대해 저속 / 중속 / 고속을 정의 전진 / 후진 / 정지를 정의 Left/Right Switch 를 이용하여 Motor Disable (Interrupt) USART 통신을 이용하여 제어 (Interrupt)