A/D converter fails?

[Bruce]

ADCON0.0 = 1 ' <-- Turn ON A/D module

[egberttheone]

ADCON0.0 = 1 ' <-- Turn ON A/D module

please read before replying; i told that all these bits are set AND i sad that it works without the pause command or do you want to say that beacause i added the command line "pause 50" that the a/d conversion module shuts off?

[Bruce]

Sorry. It's hard to "guess" how you're configuring things if you don't show it in your code.

I'm sure this isn't what the rest of your own application is doing, but it works fine with the
pause 50 in there;

    @ DEVICE HS_OSC, WDT_ON, LVP_OFF, PROTECT_OFF
    DEFINE OSC 20
    
    SYMBOL AD_Progress = ADCON0.2
    SYMBOL ADON = ADCON0.0
    SYMBOL LED = PORTB.0
  
    Sound_Level VAR WORD
    
    TRISA.0 = 1     ' A/D input
    PORTB.0 = 1     ' LED on at boot
    TRISB.0 = 0     ' LED output
      
    ADCON0 = 128 ' A/D clock Fosc/32, RA0/AN0, A/D disabled
    ANSEL = 1       ' RA0 analog
    ADCON1.7 = 1  ' right justify for 10-bit

Main:
    ADON = 1        ' turn on A/D module
    PAUSE 50        ' wait
    AD_Progress = 1 ' start conversion
    
    WHILE AD_Progress = 1 : WEND
    Sound_Level.lowbyte = ADRESL
    Sound_Level.highbyte = ADRESH
    LED = LED ^ 1    ' toggle LED for visual
    GOTO Main
    
    END

I left the WDT enabled just to be sure PBP was handling it during the pause periods.

[egberttheone]

this code works but if you change the input port of the a/d convertor and then add a pause in the line between changing and a/d conversions start then it stucks.

example:

'retrieve sound level
ADCON0.5 = 0
ADCON0.4 = 0
ADCON0.3 = 0
pause 50
AD_Progress = 1
while AD_Progress = 1: wend
Sound_Level.lowbyte = ADRESL
Sound_Level.highbyte = ADRESH

'retrieve negative level
ADCON0.5 = 0
ADCON0.4 = 0
ADCON0.3 = 1
pause 50
AD_Progress = 1
while AD_Progress = 1: wend
Negative_Voltage.lowbyte = ADRESL
Negative_Voltage.highbyte = ADRESH

'retrieve positieve level
ADCON0.5 = 0
ADCON0.4 = 1
ADCON0.3 = 0
pause 50
AD_Progress = 1
while AD_Progress = 1: wend
Positive_Voltage.lowbyte = ADRESL
Positive_Voltage.highbyte = ADRESH

[Bruce]

That's odd. It works for me without getting stuck.

I modified your version to include 3 LED's in the last section of each channel read routine,
and all 3 LED's blink right along.

It doesn't appear to be getting getting stuck at any point.

    @ DEVICE HS_OSC, WDT_ON, LVP_OFF, PROTECT_OFF
    DEFINE OSC 20
    
    SYMBOL AD_Progress = ADCON0.2
    SYMBOL ADON = ADCON0.0
    SYMBOL LED1 = PORTB.0
    SYMBOL LED2 = PORTB.1
    SYMBOL LED3 = PORTB.2
  
    Sound_Level VAR WORD
    Negative_Voltage VAR WORD
    Positive_Voltage VAR WORD
    
    TRISA.0 = 1         ' A/D input
    PORTB = %00000111   ' LED's on at boot
    TRISB = 0           ' LED outputs
      
    ADCON0 = 128    ' A/D clock Fosc/32, RA0/AN0, A/D disabled
    ANSEL = 1       ' RA0 analog
    ADCON1.7 = 1    ' right justify for 10-bit

Main:
    ADON = 1        ' turn on A/D module
    PAUSE 50        ' wait
    AD_Progress = 1 ' start conversion 
    WHILE AD_Progress = 1: WEND
    Sound_Level.lowbyte = ADRESL
    Sound_Level.highbyte = ADRESH
    LED1 = LED1 ^ 1    ' toggle LED for visual
    
    'retrieve negative level
    ADCON0.5 = 0
    ADCON0.4 = 0
    ADCON0.3 = 1
    PAUSE 50
    AD_Progress = 1
    WHILE AD_Progress = 1: WEND
    Negative_Voltage.lowbyte = ADRESL
    Negative_Voltage.highbyte = ADRESH
    LED2 = LED2 ^ 1    ' toggle LED for visual
    
    'retrieve positieve level
    ADCON0.5 = 0
    ADCON0.4 = 1
    ADCON0.3 = 0
    PAUSE 50
    AD_Progress = 1
    WHILE AD_Progress = 1: WEND
    Positive_Voltage.lowbyte = ADRESL
    Positive_Voltage.highbyte = ADRESH
    LED3 = LED3 ^ 1    ' toggle LED for visual
    GOTO Main
    
    END

Are you reading 0-5 VDC voltage levels?

[egberttheone]

yes, i'm reading voltage's between 0-5VDC. i found out that it doesn't mather where i place the pause command(in the interrupt routine); it instant freez the pic forever. The AD routine is placed in a interrupt routine is it not possible to place a pause periode into a interrupt handel?

note: timer0, timer1 and serial interrupt are activated.

[egberttheone]

any one ?