DEVICE 		SX28,TURBO,BANKS8,OSCHS3,SYNC,OPTIONX
FREQ            50_000_000
ID		"FUNCTEST"

' -----[ I/O Definitions ]-------------------------------------------------

Sensor        PIN RB.0 INPUT SCHMITT 
                                       
' -----[ Variables ]-------------------------------------------------------

' tach vars
rpm           VAR WORD
dividendMSW   VAR WORD
dividendLSW   VAR WORD

pWidth0       VAR word               
pWidth1       VAR word                  

'wanna be local variables
tmpW1		VAR	Word
tmpW2		VAR	Word
tmpB1		VAR	Byte
tmpB2		VAR 	Byte

flags  VAR Byte
isrFlag VAR flags.0 


INTERRUPT 100_000

ISR_Start:
 GOTO Int_Start 
' -------------------------------------------------------------------------
' Subroutine Declarations
' -------------------------------------------------------------------------

HIGHTIME	   FUNC    1
LOWTIME		   FUNC	   1

  
' =========================================================================
PROGRAM Start
' =========================================================================

Int_Start:
  \ SETB  isrFlag
RETURNINT


' -------------------------------------------------------------------------
' Program Code
' -------------------------------------------------------------------------
Start:
  
  DO
    ' Measure pulse low time
    pWidth0 = LOWTIME

    ' Measure pulse high time
    pWidth1 = HIGHTIME


' Watch statements for debuging
WATCH pWidth0, 8, SDEC
WATCH pWidth1, 8, SDEC
BREAK

END

FUNC LOWTIME
  tmpW1 = 0
\ JNB Sensor, @$                              ' let old low clear 
\ JB  Sensor, @$                              ' let high clear  
  DO
    \ CLRB isrFlag                              ' clear old ISR marker
    \ JNB  isrFlag, @$                          ' wait for new marker
    INC tmpW1
    IF tmpW1 = 0 THEN EXIT 
  LOOP UNTIL Sensor = 1
  RETURN tmpW1
ENDFUNC

FUNC HIGHTIME
  tmpW1 = 0
  \ JB  Sensor, @$                              ' let old high clear
  \ JNB Sensor, @$                              ' let low clear  
  DO
    \ CLRB isrFlag                              ' clear old ISR marker
    \ JNB  isrFlag, @$                          ' wait for new marker
    INC tmpW1
    IF tmpW1 = 0 THEN EXIT 
  LOOP UNTIL Sensor = 0
  RETURN tmpW1
ENDFUNC