16F1827 - Timer1 and ADC Conflict?

[Ioannis]

It seems that using the ADC Timer1 stops counting (No serial data output).

Can anyone see any conflict between ADC and Timer 1?

Timer stops when any of the ADCIN commands is un-commended.

ASM
  __config _CONFIG1, _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_ON & _CLKOUTEN_OFF & _IESO_OFF & _FCMEN_OFF
  __config _CONFIG2, _WRT_OFF & _PLLEN_OFF & _LVP_OFF & _STVREN_OFF & _BORV_25
ENDASM

DEFINE OSC 8
DEFINE INTHAND Tmr1Int
 
DEFINE HSER_RCSTA 90h
DEFINE HSER_TXSTA 20h				'9600 baud rate, BRGH=1
DEFINE HSER_BAUD 9600
'DEFINE HSER_SPBRG 12
DEFINE HSER_CLROERR 1

DEFINE ADC_BITS 8 ' Set number of bits in result (8, 10 or 12)
DEFINE ADC_CLOCK 3 ' Set clock source (rc = 3)
DEFINE ADC_SAMPLEUS 50 ' Set sampling time in microseconds

OSCCON= %01110000
 
flag1    var byte' bank0
t_flag  var flag1.0
t_counter   var byte
over        var word
an_1        var byte
an_2        var byte
an_3        var byte

clear

GOTO Init  ' jump over interrupt routine
 
  ASM
Tmr1Int
  ; retfie auto-restores w, status, bsr, fsr and pclath
  bcf   T1CON,TMR1ON ; stop timer 1
  bcf   PIR1,TMR1IF  ; clear over flow flag
  movlw 0xBF         ; load timer for 16,535 * 8 prescaler interrupt on 16 bit timer
  movwf TMR1H        ; load high byte
  movlw 0x69         
  movwf TMR1L        ; load low byte
  bsf   T1CON,TMR1ON ; re-enable timer 1
  movlw 0x01
  bsf   _flag1,0    ;xorwf PORTB,f      ; toggle RB0
  retfie             ; Return from interrupt
ENDASM
 
Init:
  APFCON0=%00100000
  APFCON1=%00000001
  WPUB=%11000000
  
  BAUDCON=%00010000
  PORTB = 0
  TRISB = %110001000
  trisa = %11111100
  adcon0 = %00001001
  adcon1 = %11110000
  CM1CON0.7=0
  CM2CON0.7=0
  CPSCON0=0
  CPSCON1=0
  daccon0=0
  
  ANSELA = %00011100           ' all digital. A/D disabled
  ANSELB = %01000000
  PIR1 = 0             ' clear TMR1 int flag                     
  PIE1 = %00000001     ' TMR1 int enabled
  INTCON = %11000000   ' global & peripheral ints enabled
  T1CON = %00110001    ' TMR1 1:8 prescale, timer1 on
 
Main:
  if t_flag then
    t_counter=t_counter+1
    t_flag=0
  endif
  
'    HSEROUT ["Timer overflowed ",#over," times",13,10," ",#an_1,"  ",#an_2,"  ",#an_3,13,10]
  
  
  if t_counter=20 then
    t_counter=0
    over=over+1
    HSEROUT ["Timer overflowed ",#over," times",13,10," ",#an_1,"  ",#an_2,"  ",#an_3,13,10]
  endif
  
'  ADCIN 2,AN_1
'  ADCIN 3,AN_2
'  ADCIN 4,AN_3
    
  GOTO Main
 
  END

Ioannis

[Bruce]

Insert BANKSEL T1CON in the top of your interrupt handler. If the interrupt happens during ADCIN, it's in bank1, so your writes to Timer1 registers go to the wrong registers.

[Ioannis]

Why didn't I think that??

Thanks Bruce. I was sure it had to be something that simple...

Works fine now. It is an impressive chip at a very good price. But a pain to setup.

Ioannis