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MPLAB + CCS + LCD code

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Chantry

Joined: 18 Jan 2011
Posts: 13

MPLAB + CCS + LCD code

Posted: Wed Jan 26, 2011 4:30 pm

Hi,

I'm trying to program a PIC 16F88 with my PICKIT3. This is the CCS C code I'm using:

CCS :: View topic - Flexible LCD driver

My code is as such:

main.c

Code:

#include <16F88.H>
#fuses NOMCLR, INTRC_IO, NOBROWNOUT, NOWDT, NOPROTECT, PUT, NOLVP
#use delay(clock=8M)

#include "flex_lcd.c"

//==========================
void main()
{
lcd_init(); // Always call this first.

lcd_putc("\fHello World\n");
lcd_putc("Line Number 2");

while(1);
}

flex_lcd.c

Code:

// flex_lcd.c

// These pins are for the Microchip PicDem2-Plus board,
// which is what I used to test the driver. Change these
// pins to fit your own board.

#define LCD_DB4 PIN_A6
#define LCD_DB5 PIN_A7
#define LCD_DB6 PIN_A0
#define LCD_DB7 PIN_A1

#define LCD_E PIN_A2
#define LCD_RS PIN_A3
#define LCD_RW PIN_A4

// If you only want a 6-pin interface to your LCD, then
// connect the R/W pin on the LCD to ground, and comment
// out the following line.

#define USE_LCD_RW 1

//========================================

#define lcd_type 2 // 0=5x7, 1=5x10, 2=2 lines
#define lcd_line_two 0x40 // LCD RAM address for the 2nd line

int8 const LCD_INIT_STRING[4] =
{
0x20 | (lcd_type << 2), // Func set: 4-bit, 2 lines, 5x8 dots
0xc, // Display on
1, // Clear display
6 // Increment cursor
};

//-------------------------------------
void lcd_send_nibble(int8 nibble)
{
// Note: !! converts an integer expression
// to a boolean (1 or 0).
output_bit(LCD_DB4, !!(nibble & 1));
output_bit(LCD_DB5, !!(nibble & 2));
output_bit(LCD_DB6, !!(nibble & 4));
output_bit(LCD_DB7, !!(nibble & 8));

delay_cycles(1);
output_high(LCD_E);
delay_us(2);
output_low(LCD_E);
}

//-----------------------------------
// This sub-routine is only called by lcd_read_byte().
// It's not a stand-alone routine. For example, the
// R/W signal is set high by lcd_read_byte() before
// this routine is called.

#ifdef USE_LCD_RW
int8 lcd_read_nibble(void)
{
int8 retval;
// Create bit variables so that we can easily set
// individual bits in the retval variable.
#bit retval_0 = retval.0
#bit retval_1 = retval.1
#bit retval_2 = retval.2
#bit retval_3 = retval.3

retval = 0;

output_high(LCD_E);
delay_cycles(1);

retval_0 = input(LCD_DB4);
retval_1 = input(LCD_DB5);
retval_2 = input(LCD_DB6);
retval_3 = input(LCD_DB7);

output_low(LCD_E);

return(retval);
}
#endif

//---------------------------------------
// Read a byte from the LCD and return it.

#ifdef USE_LCD_RW
int8 lcd_read_byte(void)
{
int8 low;
int8 high;

output_high(LCD_RW);
delay_cycles(1);

high = lcd_read_nibble();

low = lcd_read_nibble();

return( (high<<4) | low);
}
#endif

//----------------------------------------
// Send a byte to the LCD.
void lcd_send_byte(int8 address, int8 n)
{
output_low(LCD_RS);

#ifdef USE_LCD_RW
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60);
#endif

if(address)
output_high(LCD_RS);
else
output_low(LCD_RS);

delay_cycles(1);

#ifdef USE_LCD_RW
output_low(LCD_RW);
delay_cycles(1);
#endif

output_low(LCD_E);

lcd_send_nibble(n >> 4);
lcd_send_nibble(n & 0xf);
}

//----------------------------
void lcd_init(void)
{
int8 i;

output_low(LCD_RS);

#ifdef USE_LCD_RW
output_low(LCD_RW);
#endif

output_low(LCD_E);

delay_ms(15);

for(i=0 ;i < 3; i++)
{
lcd_send_nibble(0x03);
delay_ms(5);
}

lcd_send_nibble(0x02);

for(i=0; i < sizeof(LCD_INIT_STRING); i++)
{
lcd_send_byte(0, LCD_INIT_STRING[i]);

// If the R/W signal is not used, then
// the busy bit can't be polled. One of
// the init commands takes longer than
// the hard-coded delay of 60 us, so in
// that case, lets just do a 5 ms delay
// after all four of them.
#ifndef USE_LCD_RW
delay_ms(5);
#endif
}

}

//----------------------------

void lcd_gotoxy(int8 x, int8 y)
{
int8 address;

if(y != 1)
address = lcd_line_two;
else
address=0;

address += x-1;
lcd_send_byte(0, 0x80 | address);
}

//-----------------------------
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;
}
}

//------------------------------
#ifdef USE_LCD_RW
char lcd_getc(int8 x, int8 y)
{
char value;

lcd_gotoxy(x,y);

// Wait until busy flag is low.
while(bit_test(lcd_read_byte(),7));

output_high(LCD_RS);
value = lcd_read_byte();
output_low(lcd_RS);

return(value);
}
#endif

All I've done on either code is modify it for 16F88 and adjust the pin numbers. When I try to program I get what you see in the attachment.

I said "ok" to this and it said it programmed ok, and it also verified ok, but the screen doesn't work, it has 16 solid black box's across the top.

Any suggestions on how I can move forward with this?

James

PCM programmer

Joined: 06 Sep 2003
Posts: 21708

Posted: Wed Jan 26, 2011 4:49 pm

Quote:

#include <16F88.H>
#fuses NOMCLR, INTRC_IO, NOBROWNOUT, NOWDT, NOPROTECT, PUT, NOLVP

This is really a Microchip/Pickit 3 issue. But to fix it, give it what it wants.
Remove the "NOMCLR" fuse and put a 10K pullup resistor to Vdd (+5v) on
the MCLR pin of the 16F88 (pin 4). Then you won't get that message.

temtronic

Joined: 01 Jul 2010
Posts: 9243
Location: Greensville,Ontario


Posted: Wed Jan 26, 2011 7:25 pm

Any chance you have the project>build option> set to 'debug' and not 'release'?

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