Timing Measurement

HI
I am wanting to measure time between a switch closing and a programmed Pulsewidth. The code executes fine. When I push the button, the display reads out correctly. When I get the output of my pulse generator to the desired stop pulsewidth, an Elapsed time is displayed on the LED.

The elapsed time sees a bit off, yet I am not sure if its really a measurement problem or my perception. I don't have anyway of measuring it with an instrument at the moment.

Also is this the best route to take? I am trying to learn about TM0 and TM1 by looking through threads here. So I do have some TM config info in the code from playing around. Any links to TM0 info would be greatly appreciated. Or are there any books available that talk about Timers and CCP's that use PBP? It looks like I could use a CCP to get the pulsewidth too.

Thanks for the input
Toby

Code:

Include "modedefs.bas" ' Mode definitions for Serout DEFINE OSC 20 OPTION_REG.7 = 0 'Pull Ups enabled OPTION_REG.6 = 1 'PB0 interrupt on falling edge OPTION_REG.5 = 0 'TMR0 Clock source CLK0 OPTION_REG.4 = 1 'TMR0 high to low OPTION_REG.3 = 0 'Prescaler to timer0 OPTION_REG.2 = 0 'Timer prescaler 1:2 OPTION_REG.1 = 0 OPTION_REG.0 = 0 T1CON.5=0 'Prescaler 1:1 T1CON.4=0 T1CON.1=0 'Interal clock T1CON.0=1 'Enable Timer INTCON.4=0 ADCON1 = 6 'A2D Off LCD VAR PortC.0 Start var PortB.0 Finish var PortB.1 DSRPM Var PortC.3 LDSRPM var word HDSRPM Var Word Time1 var word Time2 VAr word PB var PortB.2 Checker var byte Seconds var byte Remainder var word RPM1000 var byte RPM100 var byte Display1000 var byte Display100 var byte Timer1000 var byte Timer100 var byte TriggerRPM var word Serout LCD, N9600, [$1b, $30] Serout LCD,N9600,["Ryan Timer",10,13,10,13] Pause 1000 ' Wait .5 second Repeat 'Sets up backlighting iF pb = 0 tHEN IF Checker = 0 then Serout LCD,N9600,[$1b ,$2a,123 ] Checker = Checker + 1 else 'pause 200 if Checker = 1 then Serout LCD,N9600,[$1b ,$2a,225 ] Checker = Checker + 1 else 'pause 200 if Checker = 2 then Serout LCD,N9600,[$1b ,$2a,0 ] Checker = 0 endif endif endif pause 200 endif Serout LCD, N9600, [$1b, $30] Serout LCD,N9600,[" Waiting",10,13] TriggerRPM = 528 Until Start = 0 'B.0 goes low and starts timer Serout LCD, N9600, [$1b, $30] Serout LCD,N9600,[" Timer Activated",10,13] INTCON.5=1 'Enable Timer0 Interrupt on Interrupt goto Increment 'Measures RPM Repeat Pulsin DSRPM, 0, LDSRPM PULSIN DSRPM, 1, HDSRPM HDSRPM = HDSRPM + LDSRPM Until HDSRPM <= TriggerRPM High Finish 'Turns on light Serout LCD, N9600, [$1b, $30] Serout LCD, N9600, ["E/T ", # Time2,".", # Time1/10,10,13] End disable Increment: Time1= Time1 +1 If Time1 = 1000 then Time1 = 0 Time2 = Time2 + 1 endif INTCON.2 = 0 resume