Lister - HW5

;===============================================================================;Name: Julio Sanchez with changes by Peter Seid;Class: AME 487;Date: 04/25/2015;Exercise: Homework 5 - The Digital Clock;Description: Create a Digital Clock;MCU: PIC16F84A;References: See Homework_5.pdf for further information;===============================================================================;===========================; switches;===========================; Switches used in __config directive:; _CP_ON Code protection ON/OFF; * _CP_OFF; * _PWRTE_ON Power-up timer ON/OFF; _PWRTE_OFF; _WDT_ON Watchdog timer ON/OFF; * _WDT_OFF; _LP_OSC Low power crystal oscillator; * _XT_OSC External parallel resonator/crystal oscillator; _HS_OSC High speed crystal resonator (8 to 10 MHz); Resonator: Murate Erie CSA8.00MG = 8 MHz; _RC_OSC Resistor/capacitor oscillator (simplest, 20% error); |; |_____ * indicates setup values

processor 16f84Ainclude <p16f84A.inc>__config _XT_OSC & _WDT_OFF & _PWRTE_ON & _CP_OFF

;=====================================================; variables in PIC RAM;=====================================================; Declare variables at 3 memory locations used for delay loopj equ 0x0ck equ 0x0di equ 0x0e

;========================================================; m a i n p r o g r a m;========================================================

org 0 ; start at address 0goto main

;=============================; space for interrupt handler;=============================

org 0x04;=============================; main program;=============================main:; Initialize all lines in port B for output (bits 0-6 are for 7 segment display)

movlw B'00000000' ; w = 00000000 binarytris PORTB ; Set up port B for output

; Make sure 7-Segment displays 'zero' from the start movlw B'01101111' movwf PORTB

; Initialize all lines in port A for outputmovlw B'00000000' ; w = 00000000 binarytris PORTA ; Set up port A for output

; Make sure both LEDs start OFF movlw B'00000000' movwf PORTA

minuteLoop:; Display 0 on 7 segment for 5 seconds movlw B'01101111' ; Byte for #0

movwf PORTB ; Set port B pins to display #0 call wait5Seconds

; Display 1 on 7 segment for 5 seconds movlw B'00000110' ; Byte for #1 movwf PORTB ; Set port B pins to display #1 call wait5Seconds




; toggle second LED to indicate 1 hour has passed btfss PORTA,1 ; if second LED is already on, skip this call toggleOn ; otherwise, turn it on

btfsc PORTA,1 ; if second LED is already off, skip this call toggleOff ; otherwise, turn it off

goto minuteLoop ; start the cycle over infinitely

;==========================================================; 5 second delay routine while flashing first LED on/off;==========================================================wait5Seconds: movlw B'00000001' ; turn first LED on for 1 second movwf PORTA call delay

movlw B'00000000' ; turn first LED off for 1 second movwf PORTA call delay

movlw B'00000001' ; turn first LED on for 1 second movwf PORTA call delay

movlw B'00000000' ; turn first LED off for 1 second movwf PORTA call delay

movlw B'00000001' ; turn first LED on for 1 second movwf PORTA call delay

movlw B'00000000' ; turn first LED off movwf PORTA

return

;================================; turn second LED on;================================toggleOn: movlw B'00000010' movwf PORTA return

;================================; turn second LED off;================================toggleOff: movlw B'00000000' movwf PORTA return

;================================; 1 second delay sub-routine;================================delay: movlw .8 ; w = 8 decimal movwf i ; i = w movlw .204 ; w = 204 decimal movwf j ; j = w

iloop: movwf j ; j = wjloop: movwf k ; k = w

kloop: decfsz k,f ; k = k-1, skip next if zero goto kloop decfsz j,f ; j = j-1, skip next if zero goto jloop decfsz i,f ; i = i-1, skip next if zero goto iloop return

end

Lister - HW5

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