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Lecture 8 Digital waveform generator using u-controller

Lecture 8 Digital waveform generator using u-controller. 2007/11/09 Prof. C.M. Kyung. Experimental Goal. GOAL is to get familiar with.. Intel 8051 microcontroller The concept of D/A converter The concept of Timer Function generator Sine wave, square wave. D/A Converter : DAC0800.

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Lecture 8 Digital waveform generator using u-controller

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  1. Lecture 8Digital waveform generator using u-controller 2007/11/09 Prof. C.M. Kyung

  2. Experimental Goal • GOAL is to get familiar with.. • Intel 8051 microcontroller • The concept of D/A converter • The concept of Timer • Function generator • Sine wave, square wave

  3. D/A Converter : DAC0800 • Fast settling output current: 100 ns • Full scale error: ±1 LSB • Nonlinearity over temperature: ±0.1% • Full scale current drift: ±10 ppm/°C • High output compliance: −10V to +18V • Complementary current outputs • Interface directly with TTL, CMOS, PMOS and others • 2 quadrant wide range multiplying capability • Wide power supply range: ±4.5V to ±18V • Low power consumption: 33 mW at ±5V • Low cost

  4. D/A Converter : DAC0800 • Top Architecture of DAC

  5. DAC Interface Circuit Oscilloscope 0101100 8051 MCU 74F573 Flip-Flop DAC0800 DAC Digital Value Latched Digital Value Analog Output

  6. DAC Interface Circuit

  7. DAC Interface Circuit • C100H mapping • cmpact51.h 참조 • unsigned char xdata DAC_0800 _at_ 0xC100; • 수학함수 library 이용 • Sine function 이용 @ <math.h> • Floating point 연산  속도 느림 • Specification에 알맞은 방법 찾아보기

  8. Timer / Counter • Count the machine cycle (1/12 of internal system cycle) or external clock / event • When the 8bit or 16bit timer overflows, timer interrupt occurs • 8051 has 2 timers – Timer0, Timer1 • Timers are controlled by TMOD, TCON registers • 4 modes are available

  9. Timer Module • Timer Interface Circuit

  10. Timer Mode • Mode0 • 8bit TH0 / lower 5bit TL0 • Mode1 • 16bit timer TH0/TL0 • Mode2 • 8bit timer with auto reload • Mode3 • Separated 8bit TH0 / 8bit TL0

  11. Timer Mode

  12. Timer Mode • Mode2 • TL 8bit counter 사용 • Auto reload 지원 • Overflow bit setting  • 사용자가 TF clear • TH에 저장되어 있는 값이 TL로 auto reload • Auto reload는 수동 reload보다 정확하다. • Timer 주기가 짧은 경우에만 사용 가능

  13. Timer Registers

  14. Problem State 1 • Sine wave generation • 한 주기 내에 샘플의 개수 선택, 또는 타이머 인터럽트 주기 결정 • COMPACT51 보드로 만들 수 있는 정현파의 최대주파수 • 버튼을 누를 때마다 주파수가 바뀌는 정현파 발생기 만들어보기

  15. Problem State 2 • Square wave generation • 한 주기 내에 샘플의 개수 선택, 또는 타이머 인터럽트 주기 결정 • COMPACT51 보드로 만들 수 있는 구형파의 최대주파수 • 버튼을 누를 때마다 주파수가 바뀌는 구형파 발생기 만들어보기

  16. Experiment Requirements • COMPACT51 보드 • KEIL uVisionII 프로그램 • PC • PC 와 COMPACT51 보드를 연결하기 위한 UART cable • Oscilloscope

  17. References & Contact • Textbook • 8051 user’s manual • 8255 user’s manual • 8051 & C Programming, 문왕환, 도서출판 세화 • DAC0800/DAC0804 manual • COMPACT51 실험보드 회로도 • cmpt51.h 헤더파일 • KEIL uVisionIII 매뉴얼 (HELP) • 7th Week T.A. E-mail • Lecture Homepage • http://wink.kaist.ac.kr/course/ee306/

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