function call problem

[Joseph88]

Hi guys,

I'm having a small problem with function calls. Please see the code and explaination below:

This code works
----------------------------
void main(void){
...
lcd_putc("lcd1");
}

void lcd_putc(char c)
{
switch(c)
{
case '\f':
lcd_send_byte(0,1);
delay_ms(2);
break;

case '\n':
lcd_gotoxy(1,2);
break;

case '\b':
lcd_send_byte(0,0x10);
break;

default:
lcd_send_byte(1,c);
break;
}
}
--------------------------

The code below gives me a "Attempt to create a pointer to a constant
" error, please help. The only difference being the extra variable in the function call.

void main(void){
...
lcd_putc("lcd1", 1); <-- error here
}

void lcd_putc(char c, int lcdNum)
{
switch(c)
{
case '\f':
lcd_send_byte(0,1, lcdNum);
delay_ms(2);
break;

case '\n':
lcd_gotoxy(1,2, lcdNum);
break;

case '\b':
lcd_send_byte(0,0x10, lcdNum);
break;

default:
lcd_send_byte(1,c, lcdNum);
break;
}
}

[PCM programmer]

You're trying to re-write the lcd_putc() function to allow use with
multiple LCDs.

CCS has a special feature in which you can pass a constant string
to a function and it will do multiple calls of the function, one for each
byte in the string. That feature only works if the function has only
one parameter, and the parameter is a byte. That's why your code
fails to compile.

One solution for your problem is just to use a global variable to
set the LCD number.
Then you can keep the lcd_putc() function in the single parameter
form, and you can give it a constant string.

[Joseph88]

Will the global variable work if the putc function is in a different file?

[PCM programmer]

Yes, it would.

[Joseph88]

From the CCS Manual, to create a global variable, you use the #MODULE command. Everything before the #MODULE is considered global correct?

This is what i've done below. Should the lcdNum variable be global? I'm getting an "Undefined identifier lcdNum" in my FlexLCD.c file in lcd_putc.

#include <18f4525.h>
#use delay(clock=8000000, int)
#fuses NOWDT, NOLVP
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, PARITY=N)

#include < FlexLCD.c >
int lcdNum;
#MODULE

void main(void)
{
lcdNum=1;
lcd_init(lcdNum);
lcd_putc("lcd1");
}

void lcd_putc(char c)
{
switch(c)
{
case '\f':
lcd_send_byte(0,1, lcdNum);
delay_ms(2);
break;

case '\n':
lcd_gotoxy(1,2, lcdNum);
break;

case '\b':
lcd_send_byte(0,0x10, lcdNum);
break;

default:
lcd_send_byte(1,c, lcdNum);
break;
}
}

[PCM programmer]

Forget the #module directive. Just stick the global immediately above
your #include statement for the LCD driver.