I am trying to do analog to digital conversion. When I read any analog input
ANx I get the value present at pin AN0. For example, I have AN0 connected to
2v, AN1 connected to 5v, and AN2 to GND. An A/D conversion on any of these
channels yields ~420, plus or minus a couple. This is the result I'd expect
on AN0 but not the other pins. I have double and triple checked that I am
setting the channel correctly before acquisition of each channel. Below is
the problem area of the code, with the AdcGet routine straight out of a
hobbyist magazine. Please help, this is my first pic project and a couple of
my friends need it working next week to faciliate the completion of a school
project.

The project should ultimately collect data and store it to a palm os device
via the usart. Currently most everything works, including storing collected
data into the palm, but AN0 is repeatedely sent to the palm rather than
AN0..5.

Lindsay




ReadAnalogData

;----------- Read Read and store Acceleromter X Axis
 movlw d'0'
 movwf CHAN
 call AdcGet  ; Read Analog Input

 movf MEMLO,W
 movwf ACCEL_X_AXIS_LO

 movf MEMHI,W
 movwf ACCEL_X_AXIS_HI

;----------- Read and store Acceleromter Y Axis
 movlw d'1'
 movwf CHAN
 call AdcGet  ; Read Analog Input

 movf MEMLO,W
 movwf ACCEL_Y_AXIS_LO
 movwf PORTB            ; even if I connect AN1 to GND PORTB
                        ; remains the value of the LSBs of AN0
 movf MEMHI,W
 movwf ACCEL_Y_AXIS_HI

;----------- Read and store Acceleromter Z Axis
 movlw d'2'
 movwf CHAN
 call AdcGet  ; Read Analog Input

 movf MEMLO,W
 movwf ACCEL_Z_AXIS_LO

 movf MEMHI,W
 movwf ACCEL_Z_AXIS_HI

;----------- Read and store Gyro X Axis
 movlw d'3'
 movwf CHAN
 call AdcGet  ; Read Analog Input

 movf MEMLO,W
 movwf GYRO_X_AXIS_LO

 movf MEMHI,W
 movwf GYRO_X_AXIS_HI

;----------- Read and store Gyro Y Axis
 movlw d'4'
 movwf CHAN
 call AdcGet  ; Read Analog Input

 movf MEMLO,W
 movwf GYRO_Y_AXIS_LO

 movf MEMHI,W
 movwf GYRO_Y_AXIS_HI

;----------- Read and store Gyro Z Axis
 movlw d'5'
 movwf CHAN
 call AdcGet  ; Read Analog Input

 movf MEMLO,W
 movwf GYRO_Z_AXIS_LO

 movf MEMHI,W
 movwf GYRO_Z_AXIS_HI

 return


AdcGet
 bcf STATUS,C
 movf CHAN,W
 movwf STORE
 rlf STORE,F
 rlf STORE,F
 rlf STORE,F
 movlw B'10000001'
 iorwf STORE
 movwf ADCON0
 clrf DELAY
Wait1
 decfsz DELAY,F
 goto Wait1
Sample
 bcf PIR1, ADIF
 bsf ADCON0,GO
Wait2
 decfsz DELAY,F
 goto Wait2
Wait3
 btfsc ADCON0,GO
 goto Wait3
GetVal
 movf ADRESH,W
 movwf MEMHI
 bcf STATUS,RP1
 bsf STATUS,RP0
 movf ADRESL,W
 bcf STATUS,RP0
 movwf MEMLO
 call Delay64I    ; 64 Instruction 2*Tad delay

return

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