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MCU Micro Controller Unit

MCU Micro Controller Unit. 23/11/2005 – 14/12/2005 Andrea Aizza. Contenuti. Lezione 1 Introduzione ai microcontrollori MCU Microchip PIC16F877 Caratteristiche (prima parte) Set di istruzioni (prima parte) Pratica: come iniziare Hardware: configurazione ‘minima’

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MCU Micro Controller Unit

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  1. MCUMicro Controller Unit 23/11/2005 – 14/12/2005 Andrea Aizza

  2. Contenuti Lezione 1 • Introduzione ai microcontrollori • MCU Microchip • PIC16F877 • Caratteristiche (prima parte) • Set di istruzioni (prima parte) • Pratica: come iniziare • Hardware: configurazione ‘minima’ • Software: ‘Hello World’ • Tools: programmatore A. Aizza - 23/11/05

  3. Contenuti Lezione 2 • PIC16F877 • Caratteristiche (seconda parte) • Set di istruzioni (seconda parte) • Semplici tecniche di codifica • Tools: • Tools: ICD – In Circuit Debugger • Compilatore ANSI C per PIC18 A. Aizza - 23/11/05

  4. Contenuti Lezione 3 • Pratica: esperienza di laboratorio • LED + pulsante • LED + pulsante + anti-rimbalzo (hardware/software) • Misuratore di tensione con indicatore a LED • Trasmissione su porta seriale A. Aizza - 23/11/05

  5. Introduzione ai microcontrollori Microcontrollers: - Use internal RAM and ROM, so the external busses are available for general purpose I/O. Each bit can be assigned as an input or output. - Are generally used in very simple or lowcost designs. - Often have special ports: A/D converters, PWM outputs, USART, ...and so on. Microprocessors: - Use external RAM and ROM and require address and data busses to access them. - Are used for designs that require more I/O and memory. A. Aizza - 23/11/05

  6. MCU Microchip • Harvard Architecture • Instruction Pipelining • Long Word Instructions • Single Cycle Instructions • Single Word Instructions • Large Register File • Reduced Instruction Set • Orthogonal Instruction Set A. Aizza - 23/11/05

  7. MCU Microchip - Architecture • Traditional Von Neumann Architecture: • Fetches instructions and data from a single memory space • Limits operating bandwidth • Harvard Architecture: • Uses two separate memory spaces for program instructions and data • Improved operating bandwidth • Allows for different bus widths X12 = PIC16C5x, PIC12C5xx x14 = PIC16Cxxx, PIC14Cxxx, PIC12C6xx x16 = PIC17Cxxx x16 Enhanced = PIC18Cxxx A. Aizza - 23/11/05

  8. MCU Microchip - Pipelining Pipelining • In most micro controllers, instructions are fetched and executed sequentially • The pipelined architecture overlaps fetch and execution, making single cycle execution possible A. Aizza - 23/11/05

  9. MCU Microchip – Long Word Instruction Long Word Instruction • Separate instruction/data bus allows different bus widths • PIC16 word length optimized to 14-bits • Harvard architecture allows single word/single cycle instructions • 2k x 16 program memory on PICmicro roughly equivalent to 4k x 8 on other 8-bit microcontrollers • Single cycle access increases execution bandwidth A. Aizza - 23/11/05

  10. MCU Microchip - Register File Concept Register File Concept • Register File Concept: Unlike other RISC processors, all of data memory is part of the register file, so any location in data memory may be operated on directly • All peripherals are mapped into data memory as a series of registers • Orthogonal Instruction Set: ALL instructions can operate on ANY data memory location • The Long Word Instruction format allows a directly addressable register file Function Examples: addwf MyReg,w ; WREG = WREG + MyReg addwf MyReg,f ; MyReg = WREG + MyReg A. Aizza - 23/11/05

  11. PIC16F877 - Caratteristiche Caratteristiche principali • Velocita` massima: 20Mhz • Fino a 8K words (da 14bit) • Pinout compatibile con altri PIC16 • Internal timers (8bit e 16bit) • PWM (capture, compare) • SSP (SPI o IIC) • USART • PSP (slave) • Brown-out detection • 10bit A/D converter • Brown-out reset • Comparatore analogico • 256byte internal data EEPROM • Oscillatore configurabile • ICSP (debug/ICD) • Protezione del codice • Watch-dog timer • Modalita` SLEEP A. Aizza - 23/11/05

  12. PIC16F877 - Caratteristiche Caratteristiche principali • Descrizione generale • Piedinatura • Schema a blocchi • Oscillatore • Reset • Configuration Bits • Memoria dati • Memoria programma • Paging memoria programma • Registri speciali • Convertitore A/D • Interrupts • Manuale completo A. Aizza - 23/11/05

  13. PIC16F877 – Set di istruzioni Indirizzamento – Accesso alla Data Memory • Diretto: movwf <reg> • Indiretto: movwf INDF • Immediato (literal) movlw <const> A. Aizza - 23/11/05

  14. PIC16F877 – Set di istruzioni Indirizzamento – controllo di flusso • Assoluto: goto <addr> • Subroutine: call <addr> • Istruzioni ‘Skip’: btfss <reg>, <bit> A. Aizza - 23/11/05

  15. PIC16F877 – Set di istruzioni Classi di istruzioni: Control, Bit e Byte. A. Aizza - 23/11/05

  16. PIC16F877 – Set di istruzioni A. Aizza - 23/11/05

  17. Pratica – Configurazione hw minima Configurazione hardware minima • Alimentazione: +5Vdc (pin 11, 32), 0Vdc (pin 12, 31) • Clock: RC (pin 13) • Reset: +5Vdc  run, 0Vdc  reset (pin 1) Schema configurazione hardware minima A. Aizza - 23/11/05

  18. Pratica – Software Software: ‘Hello World’ Per far ‘funzionare’ un PIC serve: • Il codice da eseguire caricato nella program memory, • I configuration bits programmati in modo da rispecchiare le caratteristiche hardware. • ll file .hex, creato per esempio dall’assemblatore a partire dall’assembler o da un compilatore+assemblatore a partire dal linguaggio-C, contiene sempre il codice da eseguire assemblato. Puo` anche contenere i configuration bits. In caso contrario i configuration bits possono essere direttamente impostati tramite il programmatore. • Il codice da eseguire (e i configuration bits) vengono caricati nell’MCU tramite il programmatore. A. Aizza - 23/11/05

  19. Pratica – Software Multiple Source File Projects Relocatable Code Assembly Source File(s) Object File(s) Map File C Source File(s) Common Object File Format (COFF) Object Module File Used to generate HEX, COD and LST files: mp2cod.exe COD and LST mp2hex.exe HEX Library File (Collection of Pre-Compiled Object Files) Linker Script File A. Aizza - 23/11/05

  20. Pratica – Software ‘Hello World’ – ASM Software: ‘Hello World’ • Header: LIST P=16F877, F=INHX8M include <P16F877.inc> __CONFIG _CP_ALL & _DEBUG_OFF & ... errorlevel -302, -306, -202 radix dec • Inizio Codice: ASM – hello.asm org 0x00 goto Start org 0x04 goto ISR • Codice: Start ... A. Aizza - 23/11/05

  21. Pratica – Software – documenti utili Suggerimento... Quando si scrive codice ASM e` bene avere a disposizione: Manuale ASM: Quick ASM reference / ASM reference manual Il datasheet del PIC che si sta usando Il circuito per il quale si sta scrivendo il codice A. Aizza - 23/11/05

  22. Pratica – Tools: programmatore Come programmare un PIC? IC-Prog + JDM! Read, Write e Verify Codice in program memory Data EEPROM Configuration bits A. Aizza - 23/11/05

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