PIC16F877A, How to add timer delays on output?

[cncmachineguy]

@ DEVICE pic16f877a,WDT_ON, PWRT_ON, BOD_ON
DEFINE OSC 4
define ADIN_RES 10
DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50

RLH VAR word
SLM var word
position var word
COUNT1 VAR BYTE ' COUNTER FOR PORTD.5
COUNT2 VAR BYTE ' COUNTER FOR PORTD.6
TRISA = %00000011
TRISB = %00000000
TRISD.0 = %0
TRISD.1 = %0
ADCON0 = %11000101
ADCON1 = %10000000
low portd.7

COUNT1 = 0
COUNT2 = 0

START:

ADCIN 0 , RLH
ADCIN 1 , SLM

IF (PORTD.5=1) AND (COUNT1<50) THEN SKIP1 '50 LOOPS WILL BE ~1 SEC
IF RLH =< 621 then
  high PORTD.5
  else
  low PORTD.5
endif
COUNT1 = 0

SKIP1:
IF (PORTD.6=1) AND (COUNT2<50) THEN SKIP2
IF SLM => 621 then
    high PORTD.6
    position = 100
    else 
    low PORTD.6
    position = 170
endif
COUNT2 = 0

SKIP2:

PULSOUT PORTD.7, position
pause 18
COUNT1 = COUNT1 + 1
COUNT2 = COUNT2 + 1
GOTO START

QUOTE]
I made some assumptions here. I assumed if you wanted to keep them high, you didn't need to check the sensor readings.

I used 50 for the loop count because of this: pulseout will be between 1-2 mSec, then an 18mSec pause. this is 19-20 mSec. * 5= .1sec * 10 = 1 sec. This won't be exact, but you can play with the numbers to get it right

[joseph]

thanks cncmachineguy! the code posted above works i just change the byte variable into a word and i can time upto my requirements




however i have another similar project that is having problem, the code is:

@ DEVICE pic16f877a,WDT_ON, PWRT_ON, BOD_ON
DEFINE OSC 8
define ADIN_RES 10
DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50

TMP VAR word
SLM var word
delay var word


COUNT1 VAR word ' COUNTER FOR PORTD.5
TRISA = %00000011
TRISB = %00000000
TRISD.0 = %0
TRISD.1 = %0
ADCON0 = %11000101
ADCON1 = %10000000


COUNT1 = 0


START:
delay = 0
ADCIN 0 , SLM
ADCIN 1 , TMP

delay  =((tmp * (46/200)) + 8)*384
if tmp =< 30 THEN                    
   DELay = 3625
   ELSE 
    IF tmp => 80 THEN
   delay = 10244
      ELSE
     delay = 384 * ((tmp * (46/200)) + 8) / 2
     ENDIF
ENDIF  
 
IF(PORTb.5=1) AND (COUNT1<delay) THEN skip1 
IF SLM => 621 then
 high PORTb.5
 else
 low PORTb.5
endif
COUNT1 = 0



SKIP1:
pause 20
COUNT1 = COUNT1 + 1


GOTO START

i need to vary the output delay based on the ambient temperature, but the result is inaccurate

[joseph]

UP! :

@ DEVICE pic16f877a,WDT_ON, PWRT_ON, BOD_ON
DEFINE OSC 8
define ADIN_RES 10
DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50

TMP VAR word
SLM var word
delay var word


COUNT1 VAR word ' COUNTER FOR PORTD.5
TRISA = %00000011
TRISB = %00000000
TRISD.0 = %0
TRISD.1 = %0
ADCON0 = %11000101
ADCON1 = %10000000


COUNT1 = 0


START:
delay = 0
ADCIN 0 , SLM
ADCIN 1 , TMP

 
if tmp =< 30 THEN                    
   DELay = 3625
   ELSE 
    IF tmp => 80 THEN
   delay = 10244
      ELSE                               
     delay = 384 * (tmp * (46/200) + 8)
     ENDIF
ENDIF  
 
IF SLM => 621 then
 high PORTb.5
 else
 low PORTb.5
endif
COUNT1 = 0

lod:
IF (PORTb.5=1) AND (COUNT1<DELAY) THEN skip1 
goto start
SKIP1:
pause 100
COUNT1 = COUNT1 + 1
goto lod

tried the code posted above with no luck

[cncmachineguy]

Can you give us any clues? What does it do or not do?

[joseph]

the circuit has two analog inputs, SLM and TMP, if SLM reaches the value 621 then PORTB.5 is turned on for a period of time proportional to TMP with the formula 384 * (tmp * (46/200) + 8)

the minimum time is 3625 seconds if TMP is less than 30, maximum is 10244 if TMP is equal or higher than 80

vref is set to VDD