Very Simple Declaration Question

[honeytree]

I'm a beginner, and I keep getting this error 'A numeric expression must appear here' referring to the int declaration in the following code I found on the board:
---------------------------------------------
#include <16F877.h>
#include <button.c>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)

int option1=0; //B0
int option2=0; //A4

void main() {
printf("\n\rStart: ");

set_tris_a(0x10); // Set Pin A4 as input
set_tris_b(0x01); // Set Pin B0 as input
while(1)
{
if(button(PIN_B0, 0, 50, 10, option1, 1))
printf("B");

if(button(PIN_A4, 0, 50, 10, option2, 1))
printf("A");

delay_ms(10);
}

}
---------------------------

I don't understand why the error is occuring!! I have spent about an hour an a silly int declaration. Please help!!!

[PCM programmer]

[honeytree]

PCWH Complier

IDE 3.235
PCM 3.236d
PCH 3.236d

[PCM programmer]

You're using the demo, within the PCW IDE.
I installed the command line compiler, PCM vs. 3.236, and compiled
within MPLAB and didn't get any errors.

Can you try the following program and see if you get any errors ?
You said your problem is with the declaration of the variables, so this
little program will test just that issue.

[honeytree]

This code works fine.


#include <16F877.h>
#fuses XT,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)

int option1=0;
int option2=0;

void main()
{


while(1);
}
------------------------------------------------------------------
I tried again with the below code and still get the error. Do I need to reinstall the software?
---------------------------------------------------------------
#include <16F877.h>
#include <button.c>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)

// These are the "Bvar" variables.
//

int button1=0; //B0
int button2=0; //A4




// Function parameters:
//
// button(pin, DownState, Delay, Rate, BVar, Action)
//
// Returns: The value of the Action variable (normally
// set = 1) is returned when the button is
// pressed. When the button isn't pressed,
// the opposite value is returned (normally 0).
//======================================
void main() {
printf("\n\rStart: ");

set_tris_a(0x10); // Set Pin A4 as input
set_tris_b(0x01); // Set Pin B0 as input

// This shows how to do a button loop. The PicDem2-Plus
// board has buttons on pins RA4 and RB0. There is one
// button() function below for each button. When the
// button on RB0 is pressed, "B" is displayed on the
// terminal window. When the RA4 button is pressed, "A"
// is displayed. If you hold the buttons down for more
// than 1/2 second, they will auto-repeat 10 times per
// second.

while(1)
{
if(button(PIN_B0, 0, 50, 10, button1, 1))
printf("B");

if(button(PIN_A4, 0, 50, 10, button2, 1))
printf("A");

// You must use a delay statement in the loop.
// A good value to use is 10 ms.
delay_ms(10);
}

}
}

[honeytree]

It actually runs without error until the button.c is included (see below)


//=====================================
// The following macro is used by the Button function.
#define read_bit_var(x) bit_test(*(int *)(x >> 3), x & 7)


//=====================================
int button(int16 pin, int downstate, int delay,
int rate, int &BVar, int action)
{
int pin_value;

// Read the button pin.
pin_value = read_bit_var(pin);

// Check if the button is pressed. It's pressed if the
// pin value is the same as the "downstate". If it's not
// pressed, then zero the Bvar and return "Not pressed".
if(pin_value != downstate)
{
Bvar = 0;
return(!action);
}

// The button is pressed. Check to see if it's a new
// keypress. We can tell if it's a new keypress by
// checking if BVar = 0. If so, load the counter with
// the initial auto-repeat delay and return "Pressed".
// (If the delay has been set to 0, then load a non-zero
// value to allow the function to operate properly).
if(Bvar == 0)
{
if(delay == 0)
Bvar = 255;
else
Bvar = delay;

return(action);
}

// Decrement the auto-repeat counter.
Bvar--;

// Check if we just counted down to 0. If so, then load
// the counter with the auto-repeat interval and return
// "Pressed". If the delay is set to 0 or 255, it means
// that auto-repeat is disabled, so fall through and
// return "Not Pressed".
if(BVar == 0)
{
BVar = rate;

if((delay != 0) && (delay != 255))
return(action);
}

// If the counter is positive, then it means an auto-repeat
// is still pending, so return "Not Pressed".
return(!action);

[PCM programmer]

I'll download the demo and test it tomorrow morning.

[Ttelmah]

As posted, the 'button' function, has no terminating '}'. If this is what is actually being included,then it'll cause a syntax error latter in the code, as is being displayed.......

Best Wishes

[honeytree]

still receive the same error with button function correctly terminated. thanks,

[honeytree]

Nevermind!! I ran the code on another computer and it works fine. Strange.

Thanks.

[Ttelmah]

The normal reason for this, is that the compiler is finding a different 'button.c', to the once you think it is loading. Hint here. The '<' brackets, mean to search in the compilers 'system' paths. If instead you bracket with ", then the compiler searches the loal directory by default. Normally the '<' brackets should be reserved for 'system includes' (things like stdio.h etc.), to avoid this behaviour.

Best Wishes