COUNT is not counting again

[jellis00]

Bruce, I moved the TMR0 = 0 clear statement after the WRITE statement. However, that is not the problem. I can see while running the code that the TMR0 value is never exceeding the value of K so it never enters the ELSE block and therefore never gets to the WRITE statement which leaves the EEPROM address at inital value of FF continuously.
All this is telling me that my approach to simulating the input pulses by momentarily grounding the RA2 port with my switch closure is not triggering the TMR0 count, but not quite sure what to do about that...I don't yet have access to the meter so I can use real pulse inputs from the sensor.
I understand what you are saying about the threshold value for Vih. However, my 16F690 is running off 5.0 volts, so I would have expected the voltage at RA2 to be near 5.0 volts when the switch is open (not grounded). Yet what I see is 1.8 volts, which is obviously not enough for Vih. This doesn't make sense to me, but explains why the TMR0 value is not incrementing. Any ideas why the RA2 port voltage would be at 1.8 vdc rather than 5.0 vdc when it is unloaded?
I also didn't quite understnd your comments about RA5. My code is a close modification of the Non-interrupt version code you posted above and doesn't even mention RA5 (see current code posting below). Are you saying I have to use RA5 somehow in generating the "clock" input to RA2??

@ __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF
  K CON 15     ' Calibration factor for flow meter = # pulses per gal
  
' Setup Timer0 as an 8-bit counter with the clock input on RA2.
' 1:1 TMR0 prescaler
' TMR0 counts on high-to-low transitions
  OPTION_REG = %00111000
  
' A/D & Comparators disabled
  ANSEL=0           ' all digital
  ANSELH=0          ' analog module disabled
  CM1CON0=0
  CM2CON0=0
  
' Port setup
  PORTC = 0         ' LEDs off, PULSOUT RC3 provides a high-going pulse
  PORTA = 0
  TRISC = %11110000 ' lower 4 pins outputs
  TRISA = %11111111 ' RA2 = 2TMR0 clock input for simulated meter pulse inputs
  TMR0 = 0          ' clear TMR0 count       
  
Main:
  IF TMR0 < K  THEN
    ' Keep the valve open...do nothing..let water flow
    HIGH PORTC.0    ' Light LED continuously while water is flowing
  ELSE
    WRITE 7, TMR0   ' write before TMR0 cleared
    TMR0 = 0        ' clear TMR0 count
    Low PORTC.0     ' Blink LED on each clear after TMR0 >= K
    PAUSE 500
    HIGH PORTC.0    
    PAUSE 500
    LOW PORTC.0
    PULSOUT PORTC.3,1000  ' Generate required 10 msec pulse to RC3 
  ENDIF
  GOTO Main
  END

[jellis00]

Bruce, I may have stumbled onto part of my problem. I checked the switch interface more closely and discovered that the wire I was inserting into a female header that was connected to RA2 from the switch was not making good contact. Now when I check the voltage on RA2 pin when it is open output it reads 3.2 vdc. Still a long ways from VDD or Vih, but yet when I now depress the switch I am getting TMR0 count values. However, I notice that only 3-4 depressions of the switch causes TMR0 to obviously exceed the K value and trigger the ELSE block where it is written to memory and then cleared. I presume that this means there is a lot of switch bounce on the momentary switch depressions, each bounce being counted as a pulse by TMR0. Yet I can't figure out why it even works when the RA2 voltage transitions are only from 3.2 volts to ground. Any ideas?
Maybe Interrupts would still be the better approach to do the counting, where the interrupt would trigger on the first switch closure and should ignore the switch bounces while further interrupts are disabled during the Int-handler. What do you think?

[Archangel]

However, my 16F690 is running off 5.0 volts, so I would have expected the voltage at RA2 to be near 5.0 volts when the switch is open (not grounded). Yet what I see is 1.8 volts, which is obviously not enough for Vih. This doesn't make sense to me, but explains why the TMR0 value is not incrementing. Any ideas why the RA2 port voltage would be at 1.8 vdc rather than 5.0 vdc when it is unloaded?

RA2 is set as an input by the tris register, so the impeadence is relativly high, your meter MAY be enough load to reduce the voltage read, install a pull up resistor from RA2 to VDD to bring it up to the 5v level or enable WPUA (sect 4.3) data sheet.

[jellis00]

Joe, I enabled a WPUA.2 = 1 on RA2. However, with this change the voltage on RA2 when open circuit output is still at 3.2 vdc rather than Vih or close to Vdd. My code now looks like below. Interestingly the WRITE 7, TMR0 in the IF block never shows a value other than zero. However, just a couple of momentary switch activations will enter into the ELSE block where the WRITE 9, TRM0 statement shows a value of greater than K each time. So it looks like a lot of switch bounce going on, but the thing I don't understand is why the WRITE 7, TMR0 statement isn't showing any TMR0 values< K.
I also notice that if I comment out the LED blink statements in the IF block, the WRITE 7 statement doesn't write anything because the memory address shows a continuous FF value. Strange things that I don't understand. But at least it looks like the TMR0 is counting whether the value shows up correctly or not.
Tomorrow I am going to try to generate another method of simulating the external sensor input pulses to eliminate the switch bounce problem. I thought this might be possible by using one of the I/O pin outputs in a similar blink sequence loop as I am using for the LED, and then route that output into RA2. Do you think this would work? I will try to use one of the I/O pins that has a CMOS output.

[jellis00]

This time with the code:

@ __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF
  K CON 15    ' Calibration factor for flow meter = # pulses per gal
  
' Setup Timer0 as an 8-bit counter with the clock input on RA2.
' 1:1 TMR0 prescaler
' TMR0 counts on high-to-low transitions
  OPTION_REG = %00111000
  
' A/D & Comparators disabled
  ANSEL=0           ' all digital
  ANSELH=0          ' analog module disabled
  CM1CON0=0
  CM2CON0=0
  
' Port setup
  PORTC = 0         ' LEDs off, PULSOUT RC3 provides a high-going pulse
  PORTA = 0
  TRISC = %11110000 ' lower 4 pins outputs
  TRISA = %11111111 ' RA2 = 2TMR0 clock input for simulated meter pulse inputs
  TMR0 = 0          ' clear TMR0 count
  WPUA.2 = 1        ' enable weak pull-up on RA2       
  
Main:
  IF TMR0 < K  THEN
    WRITE 7, TMR0   ' write count during testing
    ' Keep the valve open...do nothing..let water flow
    HIGH PORTC.0    ' Blink Light LED while water is flowing
    Pause 500
    LOW PORTC.0
    PAUSE 500
  ELSE
    WRITE 9, TMR0   ' write count during testing before clearing
    TMR0 = 0        ' clear TMR0 count
    PULSOUT PORTC.3,1000  ' Generate required 10 msec pulse to RC3 
  ENDIF
  GOTO Main
  END

[Archangel]

This time with the code:

@ __config _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF
  K CON 15    ' Calibration factor for flow meter = # pulses per gal
  
' Setup Timer0 as an 8-bit counter with the clock input on RA2.
' 1:1 TMR0 prescaler
' TMR0 counts on high-to-low transitions
  OPTION_REG = %00111000
  
' A/D & Comparators disabled
  ANSEL=0           ' all digital
  ANSELH=0          ' analog module disabled
  CM1CON0=0
  CM2CON0=0
  
' Port setup
  PORTC = 0         ' LEDs off, PULSOUT RC3 provides a high-going pulse
  PORTA = 0
  TRISC = %11110000 ' lower 4 pins outputs
  TRISA = %11111111 ' RA2 = 2TMR0 clock input for simulated meter pulse inputs
  TMR0 = 0          ' clear TMR0 count
  WPUA.2 = 1        ' enable weak pull-up on RA2       
  
Main:
  IF TMR0 < K  THEN
    WRITE 7, TMR0   ' write count during testing
    ' Keep the valve open...do nothing..let water flow
    HIGH PORTC.0    ' Blink Light LED while water is flowing
    Pause 500
    LOW PORTC.0
    PAUSE 500
  ELSE
    WRITE 9, TMR0   ' write count during testing before clearing
    TMR0 = 0        ' clear TMR0 count
    PULSOUT PORTC.3,1000  ' Generate required 10 msec pulse to RC3 
  ENDIF
  GOTO Main
  END

try masking the interrupt just before write and reenable right after.

eecon1 = 6 ' enables eeprom write
intcon.7 = 1 
write  address, data
intcon.7 =0

[mister_e]

FYI, there's a new DEFINE for that

DEFINE WRITE_INT 1

[Bruce]

This code;

 @ device  pic16F690, intrc_osc_noclkout, wdt_off, mclr_off, protect_off 
  K CON 15     ' Calibration factor for flow meter = # pulses per gal
  
' Setup Timer0 as an 8-bit counter with the clock input on RA2.
' 1:1 TMR0 prescaler
' TMR0 counts on high-to-low transitions
  OPTION_REG = %00111000
  
' A/D & Comparators disabled
  ANSEL=0           ' all digital
  ANSELH=0          ' analog module disabled
  CM1CON0=0
  CM2CON0=0
  
' Port setup
  PORTC = 0         ' LEDs off, PULSOUT RC3 provides a high-going pulse
  PORTA = 0
  TRISC = %11110000 ' lower 4 pins outputs
  TRISA = %11111111 ' RA2 = TMR0 clock input for simulated meter pulse inputs
  TMR0 = 0          ' clear TMR0 count       
  
Main:
  IF TMR0 < K  THEN
                    ' Keep the valve open...do nothing..let water flow
  ELSE
    PULSOUT PORTC.3,1000  ' Generate required 10 msec pulse to RC3
    WRITE 7, TMR0   ' write count if you need to?
    TMR0 = 0        ' clear TMR0 count
    HIGH PORTC.0    ' LED toggle stuff
    PAUSE 500
    LOW PORTC.0 
  ENDIF
  GOTO Main
  
  END

With the schematic attached - works. It writes 15 to EEPROM after precisely
15 press/release actions on the switch.

Tested on the PICkit 2 low pin count demo board.

The cap on RA3 is 0.01uF, which helps eliminate contact bounce from the switch.

The switch on the PICkit 2 demo board connects to RA3, so a wire runs directly from
RA3 to RA2. Remove the cap, and switch bounce causes problems. It's a really simple
fix.

If your circuit is powered from 5V, and you measure 5V between the PIC VDD/VSS pins,
and you only see 3.2V on RA2 with a pull-up to VDD, then check your circuit. There's a
problem somewhere with your wiring or connections.

[jellis00]

FYI, there's a new DEFINE for that

DEFINE WRITE_INT 1

I don't see this DEFINE listed in Appendix B of the PICBASIC PRO manual, which supposedly lists all DEFINEs.
Can you explain how you would use this to replace the code statements Joe lists to mask interrupts while writing? Do you just precede the WRITE statement with DEFINE WRITE_INT1? After the WRITE, do you still have to re-enable the interrupt? I guess if you have to do all this, I don't see how it is any more efficient than using Joe's 4 statements.

[Archangel]

FYI, there's a new DEFINE for that

DEFINE WRITE_INT 1

That should save someone some brain damage. Where did you learn that? Das Book ?

Joe S., the 0.01 uF capacitor definitely solved my switch bounce problem. The code now works perfectly and always counts exactly 15 pulses when it activates the external pulse to the valve solenoid.

Credit to where credit is due . . . BRUCE . . . always on target.

After the WRITE, do you still have to re-enable the interrupt? I guess if you have to do all this, I don't see how it is any more efficient than using Joe's 4 statements.

Maybe not more efficient, but way easier.