I'm trying to write a program that blinks LEDs in a pattern. The pattern is P0, P0 and P1, P1 and P2, etc... until it gets to P6 and P7. Each set of LEDs is supposed to blink 10 times and then move on to the next set in the pattern. It works fine the first time through, but when it returns to P0 after P6 and P7, P0 blinks 20 times. The rest of the LEDs blink 10 times, so I am confused as to why it does this for P0. Can someone explain why or help me fix it?
In the code the semicolon (;) means it's a comment. Here is the code:
#include <p16F887.inc>
__CONFIG _CONFIG1, _LVP_OFF & _FCMEN_OFF & _IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT
__CONFIG _CONFIG2, _WRT_OFF & _BOR21V
cblock 0x20 ;start of general purpose registers
count1 ;used in delay routine
counta ;used in delay routine
countb ;used in delay routine
count2
Num1
Num2
Num3
Num4
Num5
Num6
Num7
Num8
endc
LEDPORT Equ PORTD ;set constant LEDPORT = 'PORTB'
LEDTRIS Equ TRISD ;set constant for TRIS register
org 0x0000 ;org sets the origin, 0x0000 for the 16F628,
;this is where the program starts running
movlw 0x07
bsf STATUS, RP0 ;select bank 1
movlw b'00000000' ;set PortB all outputs
movwf LEDTRIS
bcf STATUS, RP0 ;select bank 0
clrf LEDPORT ;set all outputs low
Loop
movlw d'10'
movwf Num1
movlw d'10'
movwf Num2
movlw d'10'
movwf Num3
movlw d'10'
movwf Num4
movlw d'10'
movwf Num5
movlw d'10'
movwf Num6
movlw d'10'
movwf Num7
movlw d'10'
movwf Num8
call LOOP1
call LOOP2
call LOOP3
call LOOP4
call LOOP5
call LOOP6
call LOOP7
call LOOP8
LOOP1:
movlw b'00000001'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num1,1
goto LOOP1
clrf Num1
movlw d'10'
movwf Num1
return
LOOP2:
movlw b'00000011'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num2,1
goto LOOP2
;clrf Num2
movlw d'10'
movwf Num2
return
LOOP3:
movlw b'00000110'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num3,1
goto LOOP3
;clrf Num3
movlw d'10'
movwf Num3
return
LOOP4:
movlw b'00001100'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num4,1
goto LOOP4
movlw d'10'
movwf Num4
return
LOOP5:
movlw b'00011000'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num5,1
goto LOOP5
movlw d'10'
movwf Num5
return
LOOP6:
movlw b'00110000'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num6,1
goto LOOP6
movlw d'10'
movwf Num6
return
LOOP7:
movlw b'01100000'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num7,1
goto LOOP7
movlw d'10'
movwf Num7
return
LOOP8:
movlw b'11000000'
movwf LEDPORT
call Delay ;this waits for a while!
movlw b'00000000'
movwf LEDPORT
call Delay
DECFSZ Num8,1
goto LOOP8
movlw d'10'
movwf Num8
return
Delay ;movlw d'4'
;movwf count2
movlw d'250' ;delay 250 ms (4 MHz clock)
movwf count1
d1 movlw 0xC7
movwf counta
movlw 0x01
movwf countb
Delay_0
decfsz counta, f
goto $+2
decfsz countb, f
goto Delay_0
decfsz count1 ,f
goto d1
;decfsz count2 ,f
;goto d1
retlw 0x00
end
Your last led blink
call LOOP8
LOOP1:
falls through into LOOP1: but it should jump back to Loop. This causes the execution to reach return at the end of LOOP1: function, but as there is no return address on the internal call stack, the device places the reset address in the program counter. Thus, LOOP1 appears to execute twice. You should have
call LOOP8
goto Loop
LOOP1: