jellis00
- 24th March 2009, 04:17
I feel rather stupid asking about this very basic Basic problem, but have wasted a full day trying to troubleshoot it.
I have a block in my current coding project that defies my understanding of how PICBasic Pro works. I have been programming in Visual Basic for years and thought that indexing inside of a While...Wend loop in PICBasic Pro would work the same as in Visual Basic. Evidently it doesn't. I have posted the relevent code below and would appreciate someone explaining to me why the indexing I am trying to do isn't working. Here is an explanation of what I thought the code was doing.
Basically what I am trying to do is count the received pulses on a pin during each 10 sec epoch, add the result of each epoch to previous epochs, and when the total accumulation reaches a predefined pulse count that is used as the condition of the While...Wend, to jump out of the loop. Because the indexing is not happening, the loop is continuous And the indexing isn't happening because the count variable is not being added to the index variable in the indexing statement.
As you can see from the code, I initialize a count variable, C1, and a count index, i, to zero before entering the While...End loop.
I then use a COUNT statement to count the incoming pulses on the RA1 pin in PORTA.1 over a period of 10 seconds.
I then write the value in the count variable C1 to EEProm locations 5 & 6 so I can read it as a test after the program runs. My testing shows by this method that the COUNT statement is collecting the pulse count during each 10 second epoch. The total number of pulses is low enough to be contained in only Byte0 of the C1 variable.
I blink a LED one time after each epoch that executes the COUNT statement so I can see the result at end of each epoch if I want to during testing and see what is going on.
Now the next statement is where the PICBasic isn't working as I expected it to.....the statement i = i + C1 is intended to index the variable i for use in the WHILE condition check. What is happening is that the value in C1 is not being added to i in this indexing statement. I know that because I see by reading EEPROM memory after the program is run that the value that is written by the WRITE 8,i statement never stores a value other than zero, which was the original initialization of the index.
My problem is I don't know why the value in C1 is not being added to i in the indexing statement. Is there something I am misunderstanding about PICBasic versus Visual Basic?? I am using this code with a PICkit2 and PIC16F690 chip. Any other suggestions as to how to do this??
'Registers Settings
TRISA = 0 ' Set PORTA pins to outputs
TRISB = 0 ' Set all PORTB and PORTC pins to outputs
TRISC = 0
ANSEL = 0 ' Set all pins to digital
ANSELH = 0
PORTC = 0 ' Preset LEDs off
TRISA.1 =1 ' Set RA1 as input port for meter pulse inputs
'Variables Initialization
k CON 30 ' Calibration factor for flow meter...# pulses per gal
i VAR WORD ' Index used in Gallon counter While loop
C1 VAR WORD ' Storage variable for count from COUNTER
'Start...normal code here
MAIN:
'Send PWM pulse to latching solenoid to open valve
Generates 10 millisec pulse on RC3 output pin
LOW PORTC.3 ' Initialize output pulse polarity
PULSOUT PORTC.3,1000 ' Generate 10 msec pulse to RC3
' Valve should be open at this point and water flowing
' Start measuring output of flow meter at RA1 input pin
C1 = 0 ' Initialize pulse count variable to zero
i = 0 ' Initialize total pulse count index to zero
WRITE 7,i
WHILE i <= 20 ' Assume it takes 20 accumulated pulses for required gallons
' Count the number of pulses from Hall Effect Magnetic Sensor in 10 sec
' epochs and add count from each epoch to total accumulation and then
' shutoff the valve when index reaches While...Wend i <=20 criteria.
Count PORTA.1,10000,C1
WRITE 5,C1.Byte0 ' Write count into EEPROM location 5,6 for post-run count test
WRITE 6,C1.Byte1
'Slowly blink LED during water flow
HIGH PORTC.0 ' If we get here, Blink the LED once
PAUSE 200
LOW PORTC.0
' THIS NEXT STATEMENT IS WHERE THE PROBLEM LIES...i doesn't get
' indexed by value of C1!!
i = i + C1 ' Add count to total accumulation to index loop
WRITE 8,i 'Store result for post-run test
WEND 'When C1 = 20, required gallons have flowed by the meter
ShutValve: 'Send PWM pulse to latching solenoid to close valve
PULSOUT PORTC.3,1000 ' Generate required 10 msec pulse to RC3
END
I have a block in my current coding project that defies my understanding of how PICBasic Pro works. I have been programming in Visual Basic for years and thought that indexing inside of a While...Wend loop in PICBasic Pro would work the same as in Visual Basic. Evidently it doesn't. I have posted the relevent code below and would appreciate someone explaining to me why the indexing I am trying to do isn't working. Here is an explanation of what I thought the code was doing.
Basically what I am trying to do is count the received pulses on a pin during each 10 sec epoch, add the result of each epoch to previous epochs, and when the total accumulation reaches a predefined pulse count that is used as the condition of the While...Wend, to jump out of the loop. Because the indexing is not happening, the loop is continuous And the indexing isn't happening because the count variable is not being added to the index variable in the indexing statement.
As you can see from the code, I initialize a count variable, C1, and a count index, i, to zero before entering the While...End loop.
I then use a COUNT statement to count the incoming pulses on the RA1 pin in PORTA.1 over a period of 10 seconds.
I then write the value in the count variable C1 to EEProm locations 5 & 6 so I can read it as a test after the program runs. My testing shows by this method that the COUNT statement is collecting the pulse count during each 10 second epoch. The total number of pulses is low enough to be contained in only Byte0 of the C1 variable.
I blink a LED one time after each epoch that executes the COUNT statement so I can see the result at end of each epoch if I want to during testing and see what is going on.
Now the next statement is where the PICBasic isn't working as I expected it to.....the statement i = i + C1 is intended to index the variable i for use in the WHILE condition check. What is happening is that the value in C1 is not being added to i in this indexing statement. I know that because I see by reading EEPROM memory after the program is run that the value that is written by the WRITE 8,i statement never stores a value other than zero, which was the original initialization of the index.
My problem is I don't know why the value in C1 is not being added to i in the indexing statement. Is there something I am misunderstanding about PICBasic versus Visual Basic?? I am using this code with a PICkit2 and PIC16F690 chip. Any other suggestions as to how to do this??
'Registers Settings
TRISA = 0 ' Set PORTA pins to outputs
TRISB = 0 ' Set all PORTB and PORTC pins to outputs
TRISC = 0
ANSEL = 0 ' Set all pins to digital
ANSELH = 0
PORTC = 0 ' Preset LEDs off
TRISA.1 =1 ' Set RA1 as input port for meter pulse inputs
'Variables Initialization
k CON 30 ' Calibration factor for flow meter...# pulses per gal
i VAR WORD ' Index used in Gallon counter While loop
C1 VAR WORD ' Storage variable for count from COUNTER
'Start...normal code here
MAIN:
'Send PWM pulse to latching solenoid to open valve
Generates 10 millisec pulse on RC3 output pin
LOW PORTC.3 ' Initialize output pulse polarity
PULSOUT PORTC.3,1000 ' Generate 10 msec pulse to RC3
' Valve should be open at this point and water flowing
' Start measuring output of flow meter at RA1 input pin
C1 = 0 ' Initialize pulse count variable to zero
i = 0 ' Initialize total pulse count index to zero
WRITE 7,i
WHILE i <= 20 ' Assume it takes 20 accumulated pulses for required gallons
' Count the number of pulses from Hall Effect Magnetic Sensor in 10 sec
' epochs and add count from each epoch to total accumulation and then
' shutoff the valve when index reaches While...Wend i <=20 criteria.
Count PORTA.1,10000,C1
WRITE 5,C1.Byte0 ' Write count into EEPROM location 5,6 for post-run count test
WRITE 6,C1.Byte1
'Slowly blink LED during water flow
HIGH PORTC.0 ' If we get here, Blink the LED once
PAUSE 200
LOW PORTC.0
' THIS NEXT STATEMENT IS WHERE THE PROBLEM LIES...i doesn't get
' indexed by value of C1!!
i = i + C1 ' Add count to total accumulation to index loop
WRITE 8,i 'Store result for post-run test
WEND 'When C1 = 20, required gallons have flowed by the meter
ShutValve: 'Send PWM pulse to latching solenoid to close valve
PULSOUT PORTC.3,1000 ' Generate required 10 msec pulse to RC3
END