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Simple flashing LED

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Project description:   
An LED is connected to one of the port pins of a PIC microcontroller. The

LED is flashed continuously with 1-s interval.
 
This project is so simple that any type of PIC microcontroller can be used.

As shown in Figure 5.1, a PIC16F84 type microcontroller is chosen for this project. Bit 0 of PORTB (RB0) is connected to a small LED through a current-limiting resistor. The voltage drop across an LED is approxi- mately 2 V. Assuming an LED current of 10 mA, the value of the resistor can be calculated as



R      V I

   5     2       0.3 K
10 mA


the nearest value is 330  


 

 ‘*************************************************************
‘
‘                         LED FLASHING PROGRAM
‘                         ======================
‘
‘ This program flashes an LED connected to port RB0 of PORTB. The
‘ Led is flashed with 1 second intervals.
‘
‘ Author:            Dogan Ibrahim
‘ Date:               October, 2005
‘ Compiler:        PicBasic
‘ File:                 LED1.BAS
‘
‘ Modifications
‘ ==========
‘
‘*************************************************************
‘
‘ SYMBOLS
‘
Symbol LED     0                                                               ‘ Define RB0 as LED Symbol TRISB     $86                                                        ‘ TRISB address Symbol PORTB     $06                                                      ‘ PORTB address
‘
‘ START OF MAIN PROGRAM
‘
POKE TRISB, 0                                                    ‘ Set PORTB pins as outputs

AGAIN:
HIGH LED                                                            ‘ Turn ON LED PAUSE 1000                                                         ‘ Wait 1 second

LOW LED                                                             ‘ Turn OFF LED PAUSE 1000                                                         ‘ Wait 1 second

GOTO AGAIN                                                      ‘ Repeat

END                                                                      ‘ End of program






‘************************************************************
‘
‘                           LED FLASHING PROGRAM
‘                           ======================
‘
‘ This program flashes an LED connected to port RB0 of PORTB. The
‘ LED is flashed with 1 second intervals.
‘
‘ Author:           Dogan Ibrahim
‘ Date:               October, 2005
‘ Compiler:       PicBasic Pro
‘ File:                LED2.BAS
‘
‘ Modifications
‘ ==========
‘
‘*************************************************************
‘
‘ DEFINITIONS
‘
LED VAR PORTB.0                                                          ‘ Define RB0 as LED
‘
‘ START OF MAIN PROGRAM
‘
TRISB     0                                                                ‘ Set PORTB pins as outputs

AGAIN:
LED     1                                                                    ‘ Turn ON LED PAUSE 1000                                                              ‘ Wait 1 second

LED     0                                                                    ‘ Turn OFF LED PAUSE 1000                                                              ‘ Wait 1 second

GOTO AGAIN                                                     ‘ Repeat

END                                                                           ‘ End of program



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