Problems with 12F675

[fratello]

Hi to all !
I am still at the beginning of understanding the MCU's...After finalizing the project with Nokia 3310 display (thermometer & clock, see in this forum) I try to make another project ; one button for electric windows of my car.
If short pulse for up, the window roll-up till detecting over-charging of motor ; if short pulse for down, rolling-down till over-charge...
I use code from this forum ; I try the schematic in ISIS, but nothing happening !
I think I do something wrong...Can somebody help me, please ?! Thanks in advance for every suggestion !
btw : adval >=256 ; that means 4.00 Volts ?

[Darrel Taylor]

Try ...

  CHECK:
  ADCIN 3, adval

The 675 doesn't have an AN4.

[fratello]

I made this schematic.
I write this code.
I want this :
- if I push button on gpio.3, gpio.5 goes high UNTILL voltage at AN3 goes OVER 550 mV or I push again the button ;
- idem for gpio.2 -> gpio.0.
My problems are :
- AN1 must be on Vdd ?
- the calculation of vt (voltage at AN3) is correct ? ( I use 10 bit resolution, so 5000/1024= 4,88 -> con1 = 4 & con2 = 88). Can someone to explain me more accurate ? Maybe I must use 12 V for calculation ?!
Thanks in advance for every reply !

[fratello]

I use the information from here : http://www.picbasic.co.uk/forum/show...8&postcount=12
So, I need to detect the voltage from 0,48 V to 0,56 V ( load of 120 to 140W , using R1= 0,05 Ohmi) ; if voltage increase over 0.56 V, gpio.5 MUST go to 0 !
Thanks for attention...

[Darrel Taylor]

I want this :
- if I push button on gpio.3, gpio.5 goes high UNTILL voltage at AN3 goes OVER 550 mV or I push again the button ;

As it's written ... when a button is pressed, it checks the voltage ONE time then waits for the button to be released. That's all.
Not even close to what you "wanted".

The "Check's" need to be in a loop, or a couple loops since you want to look for a second button press.

Something like this might work ...

  if GPIO.3=1 AND GPIO.0 = 0 then 
    HIGH GPIO.5
    pause 20             ; debounce
         
    while GPIO.3 = 1 
      CALL CHECK         ; check while waiting for button release
    WEND
    pause 20

    WHILE GPIO.3 = 0
      CALL CHECK         ; continue checking input
      if GPIO.5 = 0 THEN ; IF LED was turned OFF in CHECK routine
        GP3PressDone     ;   we're done
      endif
    WEND                 ; stop if button is pressed again
    LOW  GPIO.5 

    while GPIO.3 = 1     ; wait for button release
    WEND
    pause 20

  endif

GP3PressDone:

Then do the same thing for the GP2 button.

I was bouncing back and forth from the code to the schematic, having a hard time figuring out what you were trying to do. With so many GPIO's spread throughout the program it's really, really hard.

It would be a lot easier to debug your programs if you used Aliases.
Instead of GPIO.0 etc ... give meaningful Names to each Pin ...

LED1   VAR GPIO.5
LED2   VAR GPIO.0
BUTN1  VAR GPIO.3
BUTN2  VAR GPIO.2

Then it would look like this, which is much easier to follow ...
Comments help too.

  if BUTN1 = 1 AND LED2 = 0 then 
    HIGH LED1
    pause 20             ; debounce
         
    while BUTN1 = 1 
      CALL CHECK         ; check while waiting for button release
    WEND
    pause 20

    WHILE BUTN1 = 0
      CALL CHECK         ; continue checking input
      if LED1 = 0 THEN   ; IF LED was turned OFF in CHECK routine
        GP3PressDone     ;   we're done
      endif
    WEND                 ; stop if button is pressed again
    LOW  LED1
     
    while BUTN1 = 1      ; wait for button release
    WEND
    pause 20

  endif

GP3PressDone:

You would have received an answer a lot quicker that way too.
<br>

[Darrel Taylor]

Also, for the Voltage conversion ...

The way you are doing it will overflow the variables and isn't very accurate.

A better way would be to use DIV32 ...

CHECK :
  ADCIN 3, ADVAL
  VT = ADVAL * 5000  ; 5V with 3 decimals
  VT = DIV32 1023    ; / maximum A/D reading

  IF VT > 550 THEN
    GPIO.5 = 0
    GPIO.0 = 0
  ENDIF
RETURN

hth,

[fratello]

THANK YOU !!!!
I will try the soft and I will keep You inform.