Measuring audio phase shift through a circuit with a PIC

[HankMcSpank]

Ok, this seems to work (ie it allows a 'main body' of program to run, with an interrupt handler)....

Comp1Time       var  word    
Comp2Time       var  word
phase_shift     var  word
c               var  word
dummy           var word


T1CON.0= 1  'start timer

Comp1Time = 0 'clear down Comp1Time, prior to starting.
comp2Time = 0  'clear down Comp2Time, prior to starting

PIR2.5 = 0    'Clear the Comp1 interrupt flag

INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System  PO90OOO9
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   CMP1_INT,  _Comp1_Int,   PBP,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

T1CON.0= 1  'start timer

Comp1Time = 0 'clear down Comp1Time, prior to starting.
comp2Time = 0  'clear down Comp2Time, prior to starting

@ INT_ENABLE  CMP1_INT     ; enable Comparator 1 interrupts

Top:
        c = 3600
        dummy = comp2time * c  
        phase_shift  = DIV32 comp1time
        HSEROUT ["  C1=",dec Comp1Time,9,"  C2=", dec comp2time,9, "phase_shift=", dec phase_shift/10,".",dec phase_shift//10, 13, 10]
        goto top

Comp1_Int:
        PIR2.5 = 0
    Loop1:
        WHILE PIR2.5 = 0       
        GOTO Loop1
        WEND
        TMR1H = 0                    
        TMR1L = 0
        PIR2.5 = 0
        
        Comp1_count:
        WHILE PIR2.5 = 0
        goto Comp1_count
        wend 
        Comp1Time.Highbyte = TMR1H  
        Comp1Time.Lowbyte = TMR1L+2
        TMR1H = 0                    
        TMR1L = 0
        PIR2.6 = 0
        'HSEROUT [dec Comp1Time,13, 10]
            
        Comp2_count:
        WHILE PIR2.6 = 0
        goto Comp2_count
        wend
        Comp2Time.Highbyte = TMR1H  
        Comp2Time.Lowbyte = TMR1L+6
        TMR1H = 0                    
        TMR1L = 0
        if comp2time> comp1time-23 then comp2time = 0
        'HSEROUT ["C1=",dec Comp1Time,9,"C2=", dec comp2time, 13, 10]
        PIR2.5 = 0
@ INT_RETURN

The actual final phase calculation jitters about a bit (but I suspect that down to the somewhat jittery quality of my audio input signal into the PIC comparators)...



Now I'm sure there are more efficient ways of doing the above - but for now, it work s& I'm chuffed!

The actual final phase calculation jitters about a bit (but I suspect that down to the somewhat jittery quality of my audio input signal into the PIC comparators!)...




Listen guys - a great collaborative effort there - I can't thank you all enough....hopefully this gives a bit of closure to a long & painful saga!