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The Option_Reg Register

The Option_Reg register is a Readable and Writable register that is used to control some modules of the PIC. This register is only available from bank 1 and bank 3. The bits of the Option_Reg register as as follows:


Bit # 7 6 5 4 3 2 1 0
Access R/W R/W R/W R/W R/W R/W R/W R/W
Initial 1 1 1 1 1 1 1 1
Name -RBPU INTEDG TOCS TOSE PSA PS2 PS1 PS0



The Option_Reg Register bits

Bit <2:0> - PS<2:0>: Prescaller rate selection

    Those bits are Readable and Writable and after a reset they will get the value '1'. They are used to set the Prescaller rate. The values it can get are:



    Bit 3 - PSA: Prescaller Assignment

      This bit is Readable and Writable and after a reset it will get the value 1. This bit is used to assign the prescaller to to the Watchdog timer or the Timer 0 module. The values it can get are:

    • 0: The prescaller is assigned to the Timer 0 module (TMR0)
    • 1: The prescaller is assigned to the Watchdog timer (WDT)


    Bit 4 - TOSE: Timer 0 Source Edge Select

      This bit is Readable and Writable and after a reset it will get the value 1. It is used to select the RA4/TOCKI pin clock edge (High to Low or Low to High) on which the Timer 0 will count. The values it can get are:

    • 0: Increment on Low to High
    • 1: Increment on High to Low


    Bit 5 - T0CS: Timer 0 Clock Source Select

      This bit is Readable and Writable and after a reset it will get the value 1. This bit will define the Timer 0 module clock source. It can be either the RA4/TOCKI pin or the Internal Instruction Cycle Clock (CLKO). The values it can get are:

    • 0: Timer 0 clock source is the Internal instruction cycle clock (CLKO)
    • 1: Timer 0 clock source is the RA4/TOCKI pin


    Bit 6 - INTEDG: RB0/INT pin Interrupt Edge Select

      This bit is Readable and Writable and after a reset it will get the value 1. By altering this bit, you can select the RB0/INT pin pulse edge that the RB0/INT interrupt will occur. The values it can get are:

    • 0: The RB0/INT interrupt will occur on the falling edge of the RB0/INT pin
    • 1: The RB0/INT interrupt will occur on the rising edge of the RB0/INT pin


    Bit 7 - -RBPU: PORTB Pull-up Enable

      This bit is Readable and Writable and after a reset it will get the value 1. The RB ports have an internal programmable pull-up resistor to minimize the use of external pull-up resistors when needed. This bit will enable or disable those resistors. The values it can get are:

    • 0: The RB pull-up resistors are enabled
    • 1: The RB pull-up resistors are disabled











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    Bit value TMR0 Rate WDT Rate
    000 1:2 1:1
    001 1:4 1:2
    010 1:8 1:4
    011 1:16 1:8
    100 1:32 1:16
    101 1:64 1:32
    110 1:128 1:64
    111 1:256 1:128
     

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    BEFORE you post a comment: Long comments or comments of general interest are NOT to be posted here. Please use the forum instead. You will receive a reply much faster.


          

  • At 27 July 2013, 11:51:01 user Kifaru Malale wrote:   [reply @ Kifaru Malale]
    • Thanks a lot guys for the very good posts, it realy added something in my head...........


  • At 12 June 2012, 7:56:32 user Giorgos Lazaridis wrote:   [reply @ Giorgos Lazaridis]
    • @kamran alam basically, i need to re-write this whole tutorial from the beginning, and make also more sophisticated videos. I'm not sure if i have the time to make for another PIC also, but the basic assembly programming can be applied for the 877 as well.
      As for the "student", i do not see how can this happen. I have never tried teaching through internet. You live in India right? I live in Greece. But you can use the forum to ask your questions, and if i can answer be sure that i will:

      http://www.pcbheaven.com/forum/


  • At 12 June 2012, 6:37:31 user kamran alam wrote:   [reply @ kamran alam]
    • hii buddy. i m really impressed from ur work. great job dude!
      i have a request that plz publish pic tutorial of PIC16F877A. I'll hope u'll do so. i m eagerly waiting.......

      i have a question for you.....
      can i be ur student

      thanking you
      with regards
      Kamran Alam
     






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 HOT in heaven!


  • Disclaimer
  • Book Contents
  • Discussion forum

  • Basics
  • What will you need
  • Choosing the right PIC
  • The MPLAB
  • Getting familiar with the MPLAB environment
  • Creating a new project
  • Open and close projects
  • Creating new files and including them in the project
  • Your very first assembly program
  • Compile a program and transfer to the PIC
  • Section 1: Beginner's theory
  • Memory Organization
  • The Data Memory Organization
  • The Program Memory Organization
  • The instructions
  • General knowledge about instructions
  • Value Loading Instructions
  • Program Flow Instructions
  • Mathematic Instructions
  • Logic Function Instructions
  • Bit Orientated Instructions
  • Byte Orientated Instructions
  • Miscellaneous Instructions
  • The Basic Special Function Registers
  • The Status Register
  • The Option_Reg Register
  • The TRIS and PORT registers
  • Beginner's PIC Tutorials
  • How to use our PIC Tutorials
  • A Pushbutton turning an LED on and off
  • A Simple LED Flasher
  • Interfacing Multiple Switches - The internal Pull-Up resistors
  • An LED Sequencer
  • Interface a Single 7seg Digit
  • Interface Multiple 7seg Digits
  • A 3-digits Decimal Counter
  • A Clever Button
  • Section 2: Intermediate theory
  • Instruction Cycle Duration and Calculated Delays
  • The Timer Modules - Timer0
  • The Timer Modules - Timer1
  • The Timer Modules-Timer2



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    New Theory: Basic Transistor Circuits






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