Problem with WHILE - WEND

[Acetronics2]

Try ( to understand ) this ...

'device: 16F627A master clear is on pin#4 (RA5)
TRISA = %00010000 ' port A all outputs, except MCLR is input
TRISB = %00111111 'PORT B ALL INPUT, EXCEPT 6 & 7 OUTPUT
option_REG = %01111111 'enable weak pullups on port B
FOOTSW var portb.5 'Foot switch OR CCREADY must be high
READY var portb.4 'at start

T var word
J VAR WORD


RENCA var portb.7 'FREQUENCY OUTPUT TO J1 PIN 13
EJECT var portb.6 '100 mS PULSE TO J1 PIN 21
on interrupt goto poo


START:
LOW RENCA : LOW EJECT

WHILE READY = 0

'zzzzzzzzzzzzzzzzzzzz ... waiting !!!
WEND

GOTO what to do if not ready ???


DISABLE INTERRUPT
poo:
T = 1 '1mS AT 4 mHZ

freq:

TOGGLE RENCA
PAUSE T 'frequency should be 500 Hz (2mS period)

GOTO freq

RESUME
ENABLE INTERRUPT

end

NOTE : RESUME and ENABLE INTERRUPT are not compulsory here as program enters an endless loop ...

Alain

[Acetronics2]

and now we're here :


'device: 16F627A master clear is on pin#4 (RA5)
TRISA = %00010000 ' port A all outputs, except MCLR is input
PORTB = 0
TRISB = %00111111 'PORT B ALL INPUT, EXCEPT 6 & 7 OUTPUT
option_REG = %01111111 'enable weak pullups on port B

INTCON = %10001000 ' Define the interrupt origin ....YESSSS

FOOTSW var portb.5 'Foot switch OR CCREADY must be high
READY var portb.4 'at start

T var word
J VAR WORD


RENCA var portb.7 'FREQUENCY OUTPUT TO J1 PIN 13
EJECT var portb.6 '100 mS PULSE TO J1 PIN 21

on interrupt goto poo


START:
LOW RENCA : LOW EJECT

WHILE READY = 0

'zzzzzzzzzzzzzzzzzzzz ... waiting !!!
WEND

GOTO Start 'GOTO what to do if not ready ???




DISABLE INTERRUPT

poo:

IF NOT FOOTSW THEN false 'we are looking for a Portb.5 interrupt ... not PortB.4 or else

T = 1000 '1mS AT 4 mHZ ...........Note: 1000 for MPSIM, 1 for real

freq:

TOGGLE RENCA
PAUSE T 'frequency should be 500 Hz (2mS period)

GOTO freq

false:

RESUME
ENABLE INTERRUPT

end

[Russ Kincaid]

I really appreciate your help, I hope you are not tired of my dumb questions!
I tried your program; the clock starts when power is applied but nothing happens when footsw is low. When footsw goes high, the clock stops and reset will not start it. I have to turn power off and on or if I put footsw low, the clock will start again, as long as footsw is low. I put the nap statement in to see if it was seeing that part of the program; it isn't.

I don't understand the WHILE - WEND, what is that doing?

TRISB = %00111111 'PORT B ALL INPUT, EXCEPT 6 & 7 OUTPUT
option_REG = %01111111 'enable weak pullups on port B
FOOTSW var portb.5 'Foot switch OR CCREADY must be high
READY var portb.4 'at start

T var word
J VAR WORD


RENCA var portb.7 'FREQUENCY OUTPUT TO J1 PIN 13
EJECT var portb.6 '100 mS PULSE TO J1 PIN 21
on interrupt goto poo
START:
LOW RENCA : LOW EJECT

WHILE READY = 0
WEND
GOTO START
DISABLE INTERRUPT
poo:
IF NOT FOOTSW THEN FALSE
nap 6
T = 100

freq:

toggle renca 'frequency should be 500 Hz (2mS period)
PAUSEus T*7 ' 1 mS at 4 mHz

GOTO freq
false:
RESUME
ENABLE INTERRUPT

end

[Russ Kincaid]

I had a thought and used this code:
IF footsw = 0 THEN LOW portb.5
IF footsw =1 THEN poo

I figgured that since portb.5 was changed to an output, it could not generate an interupt; but the clock does not run so nothing happens.

I think I will take a break and go do something physical.

[Acetronics2]

I really appreciate your help, I hope you are not tired of my dumb questions!
I tried your program; the clock starts when power is applied but nothing happens when footsw is low.

> YOU must define what the pic does if ready is low !!! I Wrote something the program to run ... ( GOTO start ) ... so program just loops !!!

When footsw goes high, the clock stops and reset will not start it.

> No reason the clock stops ... except ...

> mmmhhh, I do not see PORTA settings anymore ...and is Reset tied to Vcc ???
> Got it ... we must add CMCON = 7 at the program top !!! to turn comparators OFF

I have to turn power off and on or if I put footsw low, the clock will start again, as long as footsw is low. I put the nap statement in to see if it was seeing that part of the program; it isn't.

I don't understand the WHILE - WEND, what is that doing?

> As long as READY = 0 does the following lines ... here, as there is nothing to do, it just verfies READY state ... and also allows interrupts !!!



TRISB = %00111111 'PORT B ALL INPUT, EXCEPT 6 & 7 OUTPUT
option_REG = %01111111 'enable weak pullups on port B
FOOTSW var portb.5 'Foot switch OR CCREADY must be high
READY var portb.4 'at start

T var word
J VAR WORD


RENCA var portb.7 'FREQUENCY OUTPUT TO J1 PIN 13
EJECT var portb.6 '100 mS PULSE TO J1 PIN 21
on interrupt goto poo
START:
LOW RENCA : LOW EJECT

WHILE READY = 0
WEND
GOTO START
DISABLE INTERRUPT
poo:
IF NOT FOOTSW THEN FALSE
nap 6
T = 100

freq:

toggle renca 'frequency should be 500 Hz (2mS period)
PAUSEus T*7 ' 1 mS at 4 mHz

GOTO freq
false:
RESUME
ENABLE INTERRUPT

end

> Pauseus 700 won't give 500 Hz ...

Alain

[Acetronics2]

Hi, Russ

For those who follow the thread ...

Here is the MPLAB Project.

The .BAS file is dirctly usable ... the .Hex too !!!

Alain

[Russ Kincaid]

I copied your program, my hex file is different: it starts with 020000002C28AA but your hex file starts with 020000040000FA and then has 020000002C28AA. The last two lines of the hex files agree, but everything in between is different. I double-checked and did not make an error in copying the program. Do you suppose my assembler is corrupted?

Russ

[Russ Kincaid]

I compared the .ASM files: If it is true that lines starting with semicolon are comments, and if lines starting at the far left edge are wraparound from the previous comment, then there are no differences in the files. Otherwise, there are significant differences. So, if the .ASM files are the same, why would the .HEX files be different?