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PIC18F

PIC18F. Architecture. PIC18F Architecture. PIC18F. Harvard Architecture Program Memory : Flash 4KB to 128KB Data Memory : SRAM 256 to 3968 bytes Data EEPROM: 128 bytes to 1KB if any 18 to 100 Pins I/O Pins : 16 to 70 25 MHz to 48 MHz.

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PIC18F

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  1. PIC18F Architecture

  2. PIC18F Architecture

  3. PIC18F • Harvard Architecture • ProgramMemory: Flash 4KB to 128KB • Data Memory: SRAM 256 to 3968 bytes • Data EEPROM: 128 bytes to 1KB ifany • 18 to 100 Pins • I/O Pins: 16 to 70 • 25 MHz to 48 MHz

  4. MCU-MicrocontrollerUnitBlock Diagram

  5. MPU-MicroprocessorUnit & MemoryBlock Diagram

  6. PIC18F Architecture

  7. Program & Data Memories

  8. Data MemoryshowingAccess Bank & AddressRange

  9. I/O Ports • Five I/O ports • PORT A through PORT E • Most I/O pins are multiplexed • Generally have eight I/O pins with a few exceptions • Addresses already assigned to these ports in the design stage • Each port is identified by its assigned SFR

  10. I/O Ports

  11. Processes of Data Transfer

  12. MCU SupportDevices • Timers • CCP Modules: Capture, Compare and PWM • Serial Communications • MSSP: Master Synchronous Serial Port • Addressable USART • A/D converter • PSP: Parallel Slave Port • Data EEPROM

  13. MCU SupportDevices

  14. PIC18F SpecialFeatures • Sleep Mode • WDT: Watchdog Timer • Code Protection • In-Circuit Serial Programming • In-Circuit Debugger

  15. PIC18F Architecture

  16. PIC18F Instructions and Assembly Language • Has 77 instructions • Earlier PIC family of microcontrollers have either 33 or 35 instructions. Upward Compatible. • In PIC18F instruction set, all instructions are 16-bit word length except four instructions that are 32-bit length

  17. Instruction Description • Copy (Move) 8-bit number (Literal) into W register • Mnemonics: MOVLW 8-bit • Binary format: 0000 1110 XXXX XXXX (any 8-bit number) • Copy (Move) contents of W register into PORTC (File) • Mnemonics: MOVWF PORTC, a • (‘a’ indicates that PORTC is in the Access Bank) • Binary format: 0110 1110 1000 0010 (82H is PORTC address)

  18. Illustrative Program: Displaying a Byte at an I/O Port • Problem statement: • Write instructions to light up alternate LEDs at PORTC • Hardware: • PORTC • bidirectional (input or output) port; should be setup as output port for display • Logic 1 will turn on an LED

  19. Interfacing LEDs to PORTC

  20. Program • Logic 0 to TRISC sets up PORTC as an output port • Byte 55H turns on alternate LEDs • MOVLW 00 ;Load W register with 0 • MOVWF TRISC,0 ;Set up PORTC as output • MOVLW 0x55 ;Byte 55H to turn on LEDS • MOVWF PORTC,0 ;Turn on LEDs • SLEEP ;Power down

  21. AssembledProgram

  22. Execution of the instruction MOVWF PORTC

  23. MPLAB IDE Simulator

  24. EmbeddedSystem Microcontroller-based Time and Temperature System

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