Triggering 5 TTL clocks simultaneously

[mister_e]

By polling INT0 flag bit... no interrupt handler

    ' INT0 polling with PWM
    ' =====================
    '
    ' File name :  INT0_poll_PWM.bas
    ' Company : Mister E 
    ' Programmer : Steve Monfette
    ' Date : 02/03/2005
    ' Device : PIC18F2320
    '
    '
    ' This program generate 3.6Khz @ 25% duty PWM on CCP1 pin.
    '
    ' CCP1 pin is connected to RB0 pin via 1k resistor.
    '
    ' Program blink a led on PORTB.6 while generating PWM.
    ' Each rising edge of PWM, PORTB.7 is toggle.  This will 
    ' generate 1.8Khz 50% duty on this PORTB.7 pin.
    '
    ' We will check INTCON.1 (Interrupt on RB0(INT0) flag bit) pin to 
    ' detect rising edge
    

    ' Hardware Definition
    ' ===================
    '
    DEFINE LOADER_USED 1
    DEFINE OSC 20
    
    TRISB=%00000001   ' PORTB.0 as input
    TRISC.2=0         ' PORTC as output
    ADCON1=$0F        ' disable A/D converter
    
    ' Interrupt definition
    ' ====================
    '
    INTCON=%00010000  ' Disable global interrupts
                      ' Enable INT0 interrupt (RB0)
    
    INTCON2.6=1       ' Enable INT0 on rising edge
    
   
    ' Variable definition
    ' ===================
    '
    Tmr2dutyvar VAR WORD
    DelayLoop   var word

    ' PWM signal generation
    ' =====================
    '
    
    Tmr2dutyvar=86 ' load duty time duration
    PR2=$57        ' load frequency period (PWM freq=3.6 KHZ)

        ' set Duty cycle
        ' --------------
        '
        CCP1CON.5=Tmr2dutyvar.1
        CCP1CON.4=Tmr2dutyvar.0
        CCPR1L =(tmr2dutyvar>>2)
        
        T2CON=%00000110 ' start timer 2
                        ' set prescaler = 16
    
        CCP1CON = %00001100 ' pwm mode for CCP1
    

    ' Main Loop
    ' =========
    '
    ' Stupid led blink on PORTB.6 while testing INT0 flag bit 
    '
Start:
      toggle PORTB.6
      for delayloop = 1 to 50000
          pauseus 5 
          if INTCON.1 then
             INTCON.1=0
             toggle PORTB.7
          endif
             
      next
      goto start

[TurboLS]

Is there any reason why I can't get the process to start when PORTA.2 goes high?? I haven't rewired the HPWM/RB0 yet, but that should not matter. The PIC should at least shift the vertical clocks before even checking the reset (interrupt flag). Are my registers set correctly for analog input to PORTA.0 and digital input to PORTA.2??

[mister_e]

to have analog on PORTA.0

ADCON1=%00001110

[TurboLS]

OK, well I think I got it working so that it waits for the push button to start, but then it seems like it keeps going even after the loops have completed. I will put in an LED command to signal when clocking is in progress and see what happens. It may just be that my calculations for transfer times are just off. I figured that at 3.6Khz sampling (which is how fast we would be sampling the real data), we could sample the data, do the A/D, and send the data off chip in about 2 minutes at 19200 inverted baud. Am I off in my estimations?

[TurboLS]

Again, I have about 350,000 samples to take and transfer off the PIC serially.

[TurboLS]

OK, I think I finally have everything working. I have an LED on bit 5 of portb the is low when the clocks are not running and hig when they are. I had had a problem with the switch on PORTA.2 floating high, so I put a 2 position switch between 5v and ground and that seemed to solve the problems. My next move is to hook up a logic analyzer to make sure all the clocks are synched up. Thanks guys for all your help and I'll let you know how it goes.

[mister_e]

you don't really need that kind of switch.... place a pull-up or pull down resistor will do the job as well.

For the logic analyser stuff... great idea if you have one. Case not, if you still have an analog scope, it's easy to build one with few CMOS components.