16f877 A/D help

[3adam]

hi
im new user in this forum.And my english is not good.I hope you can understand me.:)
ı use the 16f877 and this code:TRISA = %00001011
trisb=1
portb=0

' Allocate variables
x var byte
y var byte
z var byte

ADCON1 = 4 ' Set PortA 0, 1, 3 to A/D inputs

Low PORTE.2 ' LCD R/W line low (W)
Pause 100 ' Wait for LCD to start

Goto mainloop ' Skip subroutines


' Subroutine to read a/d converter
getad:
Pauseus 50 ' Wait for channel to setup

ADCON0.2 = 1 ' Start conversion
Pauseus 50 ' Wait for conversion

Return

' Subroutine to get pot x value
getx:
ADCON0 = $41 ' Set A/D to Fosc/8, Channel 0, On
Gosub getad
x = ADRESH
Return

' Subroutine to get pot y value
gety:
ADCON0 = $49 ' Set A/D to Fosc/8, Channel 1, On
Gosub getad
y = ADRESH
Return

' Subroutine to get pot z value
getz:
ADCON0 = $59 ' Set A/D to Fosc/8, Channel 3, On
Gosub getad
z = ADRESH
Return


mainloop:
Gosub getx ' Get x value
Gosub gety ' Get y value
Gosub getz ' Get z value
pwm portb.0,x,1
pwm portb.1,y,1
pwm portb.2,z,1

Goto mainloop ' Do it forever

End
ı connect the 3 led from the portb.0 portb.1 and portb.2
its working but its not come to 0v.All led is not come to off.This problem is burn to code or hardware please help me
thx

[skimask]

hi
im new user in this forum.And my english is not good.I hope you can understand me.:)
ı use the 16f877 and this code:

ı connect the 3 led from the portb.0 portb.1 and portb.2
its working but its not come to 0v.All led is not come to off.This problem is burn to code or hardware please help me
thx

16F877 or 16F877A? Not that it matters much in the hardware for this application...but the mistake has been made before.

Are you sure you voltage inputs are actually going to 0v? Ground them out to make sure.

X,Y,Z....looks like an accelerometer input to me. Don't forget that just because an accelerometer isn't moving, doesn't mean it's not sensing something...if this is actually an accelerometer. And some accelerometer outputs are ratiometric and have outputs on the order of mV, and need to be amplified correctly to get a 0-5v output signal.