need helps

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1

Hello everybody
I’m trying to make a robot but I’ve got few problem with servo controls.
i’m driving a servo by a pic16f84A but i’m not sure that my program is coccect.
I want to move the servo in the middle position so I give it a signal that is high(5V) for 1.5ms and low for 18.5ms and then I repeat.

This program put the min RA0 to high and than by many useless function it wait 1.5ms: I calculated 8000000^ -1 to check out the time that the pic need to do an instruction and than I made it count till it west 1.5 ms.

PROCESSOR 16F84A
RADIX DEC
INCLUDE “P16F84A.INC”
;ERROR LEVEL -302
__CONFIG 3FF1H

ORG 0CH

COUNT RES 2

ORG 00H

BSF STATUS,RP0

CLRF TRISA
CLRF TRISB

BCF STATUS,RP0

MAIN
BSF PORTA,0
MOVLW 00101111
MOVWF COUNT
MOVLW 00000000
MOVWF COUNT+1
CALL DELAY

BCF PORTA,0

CLRF COUNT
CLRF COUNT+1
CALL DELAY

CLRF COUNT
CLRF COUNT+1
CALL DELAY

MOVWF 00000001
MOVLW COUNT
MOVWF 01000010
MOVLW COUNT+1
CALL DELAY

MOVLW 00000001
MOVWF COUNT
MOVLW 10010100
MOVWF COUNT+1
CALL DELAY

GOTO MAIN

DELAY

DELAYLOOP

DECFSZ COUNT,1
GOTO DELAYLOOP
DECFSZ COUNT+1,1
GOTO DELAYLOOP

RETURN

END

I wrote this program but it doesn’t work but I don’t understand why.
Can some help me?

2

Haven’t read the entire code, the only thing that stood out to me is that you’re not reloading COUNT in your delay loop, so it’s gonna have a value of 0xFF everytime except in the first loop.

Dunno if that’s the point, but if you’re having timing problems that could be a hint.

3

it is crrect because in every loop it goeg in over(i don’t know how it’s called): it pass from 0 to 255 because i tell hit to decrese

4

i’ve understoold!!! in the delay rootime that i used i didn’t cauculated the time of “goto delay” so the time of delay is very differenct from what i calculated. thank you everydody!!!

5

Well, did it work?