A couple more instructions are left to fulfill the instructions set summary of the PIC 16F88 devices:

Now, let's see the instructions one by one:

This is the No Operation instructions. When this is executed, nothing will happen at all. It has no occurrence to anything on the chip or program. This instructions is commonly used to create time delays for synchronization or other purposes.

          nop    ;This program will do nothing at all
          nop
          nop

This instructions will clear the Watchdog timer. The Watchdog timer is a very useful independent on-chip timer that is used to ensure the chip is operating normally. When the Watchdog Timer is enabled, it will then require periodically a Watchdog Timer software reset via this instruction. The programmer needs to have put this instructions in strategically positions where it will periodically reset the Watchdog Timer. If the timer is not reseted within a preselected time period, the Watchdog Timer will reset the PIC and the program will start over, because it will assume that the program flow is interrupted of fallen into an infinitude loop. The Watchdog Timer will be extensively explained on the advanced book pages.

          .
          .
          CLRWDT     ;The Watchdog Timer is reseted
          .
          .

This instruction will put the chip into Sleep mode. Sleep mode is a state where the PIC will draw as low as 0.1uA current, and it will only have some basic operations still running for waking it up. The Sleep mode is basically for power maintenance.

When the SLEEP instruction is excecuted, the Watchdog timer and it's prescaller are cleared. The Power Down bit (-PD) is also cleared, and the Time Out Status bit (-TO) is set. The chip then goes into Sleep mode and the oscillator stops.

          .
          .
          SLEEP     ;The chip is gone into Sleep mode
          .
          .

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Basics       What will you need       Choosing the right PICThe 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 PICSection 1: Beginner's theoryMemory Organization       The Data Memory Organization       The Program Memory OrganizationThe instructions       General knowledge about instructions       Value Loading Instructions       Program Flow Instructions       Mathematic Instructions       Logic Function Instructions       Bit Orientated Instructions       Byte Orientated Instructions       Miscellaneous InstructionsThe Basic Special Function Registers       The Status Register       The Option_Reg Register       The TRIS and PORT registersBeginner'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 ButtonSection 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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