A/D conversion does not work

[DeonS]

Hi
I am trying to use the A/D conversion ports of the 12F683, 12F674 or 16F684 but obviously I do not have a clue how it works. The code uses AN0 for input of the voltage which I vary from 0.1 volt to ca 1.6 volt. However, I can vary the volts as much as I like; basically the pic (anyone of the three above) turns on the portA.4 and it stays on regardless the input voltage?

The pic is connected to a regulated power supply of 4.98V. Can anyone help? (If you are wondering I am extremely new to this!)

Regards
Deon

;Chip Settings

chip 16F684,8

;Variables
Dim volts As byte

'Set the input pin direction
Dir PORTA.0 In
Dir PORTA.1 Out
Dir PORTA.2 Out
Dir PORTA.3 In
Dir PORTA.4 Out
Dir PORTA.5 Out

'Program starts here
Main:
volts = ReadAD(AN0)
wait 1 s
if volts > 230 then
PORTA.1 = 1
PORTA.2 = 0
PORTA.4 = 0
PORTA.5 = 0
if volts > 180 and volts < 230 then
PORTA.1 = 0
PORTA.2 = 1
PORTA.4 = 0
PORTA.5 = 0
if volts > 153 and volts < 180 then
PORTA.1 = 0
PORTA.2 = 0
PORTA.4 = 1
PORTA.5 = 0
if volts > 112 and volts < 153 then
PORTA.1 = 0
PORTA.2 = 0
PORTA.4 = 0
PORTA.5 = 0
if volts > 0 and volts < 112 then
PORTA.1 = 0
PORTA.2 = 0
PORTA.4 = 1
PORTA.5 = 1
else
PORTA.1 = 1
PORTA.2 = 1
PORTA.4 = 1
PORTA.5 = 1
end if
end if
end if
end if
end if
goto main

[Anobium]

Hi and welcome.

Nested if's are not supported. Simply change your code are shown below.

~~~~
;Chip Settings

chip 16F684,8

;Variables
Dim volts As byte

'Set the input pin direction
Dir PORTA.0 In
Dir PORTA.1 Out
Dir PORTA.2 Out
Dir PORTA.3 In
Dir PORTA.4 Out
Dir PORTA.5 Out

'Program starts here
Main:
volts = ReadAD(AN0)

 if volts > 230 then
   PORTA.1 = 1
   PORTA.2 = 0
   PORTA.4 = 0
   PORTA.5 = 0
 end if

 if volts > 180 and volts < 230 then
   PORTA.1 = 0
   PORTA.2 = 1
   PORTA.4 = 0
   PORTA.5 = 0
 end if
 if volts > 153 and volts < 180 then
   PORTA.1 = 0
   PORTA.2 = 0
   PORTA.4 = 1
   PORTA.5 = 0
 end if
 if volts > 112 and volts < 153 then
   PORTA.1 = 0
   PORTA.2 = 0
   PORTA.4 = 0
   PORTA.5 = 0
 end if
 if volts > 0 and volts < 112 then
   PORTA.1 = 0
   PORTA.2 = 0
   PORTA.4 = 1
   PORTA.5 = 1
 end if

 if volts = 0  then
   PORTA.1 = 1
   PORTA.2 = 1
   PORTA.4 = 1
   PORTA.5 = 1
 end if

goto main

[DeonS]

Hi Anobium
Thanks so much. It works now on the 16F684. Tried the 12F683 and it does not work, but I will work on this still bit more before I ask again.
Anyway removing the nested if structure worked for the 16F684.

Thanks again!

[Anobium]

Do not struggle. Post your code if you want to.

[DeonS]

Hi Anobium

All three chips now working! Thanks again and thanks for the forum whoever needs to be thanked for it.

[Hugh Considine]

A clarification for anyone who finds this thread, nested ifs are usually supported. The issue with the first post is that if the condition on the outer If is true, then the condition on the inner If will always be false. So feel free to use nested Ifs, but just be careful with the conditions!