ATMEGA128, CodeVisonAVR, TIMER, pwm_led

ATMEGA128, CodeVisonAVR, TIMER, pwm_led

출력 파형 주파수 foc = fclk / (scaler * 256)

0. 참고 자료

• http://www.academia.edu/8443016/AVR_ATmega128_Tutorial
• https://m.blog.naver.com/PostView.nhn?blogId=ga1267&logNo=220079623919&proxyReferer=https%3A%2F%2Fwww.google.co.kr%2F
  
• http://ww1.microchip.com/downloads/en/DeviceDoc/doc2467.pdf

1. 모듈

2. HW 구성

3. Timers > Timer1

Timer0 pwm을 사용하면 정확하게 1ms 등의 주기 설정이 되지 않아

Timer1을 사용하였습니다.

• Clock Source : System Clock
• Clock Value : 250.000 kHz
• Mode : Fast PWM top=ICR1
• Out A : Inverted
• connect with PORTB.5 Gpio
• Inp. Capture : f9
• f9 = 249
• 250000 Hz / 250 = 1kHz = 1ms
  
• Comp A : 7c
• 7c = 124
• 0.5ms, 50% duty

4.

5. SW 구성

• TCCR1A : 0xC2
• COM1A1 / COM1A0 / COM1B1 / COM1B0 / COM1C1 / COM1C0 / WGM11 / WGM10
• 
  
• TCCR1B : 0x1B
• ICNC1 / ICES1 / – / WGM13 / WGM12 / CS12 / CS11 / CS10
• 
  
• ICR1L : 0xF9
• max value 249
  
• OCR1AL : 0x7C
• center value 124

#include <mega128.h> #include <delay.h> // Declare your global variables here void main(void) {     // Declare your local variables here     unsigned char period = 0xF9;       // Port B initialization     // Func7=In Func6=In Func5=Out Func4=In Func3=In Func2=In Func1=In Func0=In     // State7=T State6=T State5=0 State4=T State3=T State2=T State1=T State0=T     PORTB=0x00;     DDRB=0x20;     // Timer/Counter 1 initialization     // Clock source: System Clock     // Clock value: 250.000 kHz     // Mode: Fast PWM top=ICR1     // OC1A output: Inverted     // OC1B output: Discon.     // OC1C output: Discon.     // Noise Canceler: Off     // Input Capture on Falling Edge     // Timer1 Overflow Interrupt: Off     // Input Capture Interrupt: Off     // Compare A Match Interrupt: Off     // Compare B Match Interrupt: Off     // Compare C Match Interrupt: Off     TCCR1A=0xC2; // 1100 0010     TCCR1B=0x1B; // 0001 1011     TCNT1H=0x00;     TCNT1L=0x00;     ICR1H=0x00;     ICR1L=0xF9; // 249     OCR1AH=0x00;     OCR1AL=0x7C; // 124     OCR1BH=0x00;     OCR1BL=0x00;     OCR1CH=0x00;     OCR1CL=0x00;     while (1)     {         // Place your code here         period--;         if (period <= 0)             period = 0xF9;                      OCR1AL = period;                  delay_ms(50);     } }

6. 소스

• https://github.com/sglee0223/atmega128/tree/master/pwm_led

7. 결과

pwm 1ms 주기에 50% duty입니다.

• pwm 주파수
  

https://youtu.be/hNvUKlGsanQ

• pwm led
  

https://youtu.be/dtNwq5BVWRM