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LeranCCS
Joined: 13 Jan 2004
Posts: 5
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| question about constant string and an array of characters |
 Posted: Tue Jan 13, 2004 8:47 pm |
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Thank you for your attention, and I am sorry for my poor English. I am a beginner of CCS and PIC MCU.
I have an funtion as below, whitch is used to drive the LCD. I can't use it to printf constant string. would you help me to solve the problem?
void LCD_Display ( char address_X, char address_Y, char *content )
{
LCD_write_command ( address_X );
LCD_write_command ( address_Y );
while ( *content )
{
LCD_write_data ( *content );
++content;
}
}
It can be used to printf an array of characters, but not to printf constant string. The error message is " Bad expression syntax "
void main ( void )
{
char String[16];
...
LCD_Display ( 0x01, 0x02, String ); //this sentence is OK
LCD_Display ( 0x01, 0x02, "Hello" ); //this can't be compiled
...
}
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Jan 14, 2004 12:30 am |
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| Quote: | I have a function as below, which is used to drive the LCD.
I can't use it to printf constant string. Would you help me to
solve the problem? |
With the CCS compiler you can't pass a pointer to a constant string.
You have to copy the string into a ram buffer first, by using the
special CCS function: strcpy()
In the code below, I have given some examples of other methods
of sending a constant string to the LCD. I have used the functions
in the CCS lcd driver (in LCD.C).
In the first method, I have written a macro, and tried to make it
look like your LCD_Display() function. In the main code I have
two examples of how to call it.
For the 2nd method, I have used a special CCS extension of the
printf() function, to send the output of printf to the lcd_putc function.
| Code: | #include <16F877.h>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock = 4000000)
//#use rs232(baud = 9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#include <lcd.c>
#define LCD_Display(x, y, string) \
lcd_gotoxy(x, y); \
lcd_putc(string)
//==========================================
void main()
{
char value;
LCD_Display(1, 1, "ABC");
LCD_Display(1, 2, "This is line 2");
value = 0x55;
printf(lcd_putc, "Value = %u \n", value);
while(1);
} |
(I'm not at the company right now, so I can't test this code, but
I believe it should work). |
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LeranCCS
Joined: 13 Jan 2004
Posts: 5
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| Thank you, your methods are OK |
| Posted: Wed Jan 14, 2004 9:19 pm |
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