PIC 16f84A and PowerTip Alphanumeric display

[27]

Hello people,
I'm trying to get a PIC 16f84A to output it's PORT A to a PowerTip PC1602-ARS-F-EB Alphanumeric Display.

I've got the code to do this with PORT B but would rather use PORT A with 5 wires. This will involve using the LCD in four wire mode.

Can someone please tell me how to do this?

----------------------------------------------------------


/* connects 2 line LCD panel */
/* using Hitachi 44780 controller */

/* assigments as follows: */

/* PORTB:0 -----> LCD bit 4 */
/* PORTB:1 -----> LCD bit 5 */
/* PORTB:2 -----> LCD bit 6 */
/* PORTB:3 -----> LCD bit 7 */
/* PORTB:4 -----> LCD RS */
/* PORTB:5 -----> LCD E */



/* function prototypes */

char lcd_start ( void ) ;

char lcd_clear ( void ) ;

char lcd_print_ch ( char ch ) ;

char lcd_print ( const char * message ) ;

char lcd_cursor ( char x, char y ) ;

/* You will have to change these bits */
/* if the hardware changes */

/* You will also need to change: */
/* setup_lcd and lcd_raw_send */

/* masks for control bits */

#define RSMASK 0x10
#define EBIT 0x05

/* defined values for delays */
/* tested up to 20Mhz PIC */

/* standard write delay */

#define PUTCH_DELAY 250

/* clear and cursor home take longer */
/* special delay for them */

#define CLEAR_DELAY 5000

/* power up delay to let the LCD settle */

#define POWER_UP_DELAY 10000

/* bit delay to let the ports settle */

#define BIT_DELAY 2

void lcd_delay ( int size )
{
int i ;

for ( i = 0 ; i < size ; i++ ) ;
}

/* sends a byte out to the LCD */
/* the byte is given by in, the */
/* mask is used to allow the */
/* state of RS to be set as well */

void lcd_raw_send ( unsigned char in,
unsigned char mask )
{
unsigned char pb ;

/* use a PIC assembler */
/* to swap the nibbles in the */
/* input */
/* puts high nibble at the */
/* bottom of the byte */

asm swapf param00_lcd_raw_send,F

/* OR in the mask */

pb = (in & 0x0f ) | mask ;

/* OR in the other bits */
/* PORTB */

pb = pb | (PORTB & 0xc0) ;

/* send the data */

/* send the data */
/* don't disturb the other */
/* bits in PORTB */

PORTB = pb ;

/* let the bits settle */
lcd_delay ( BIT_DELAY ) ;

/* now clock the bit out */
/* by raising and lowering E */

set_bit ( PORTB, EBIT ) ;

/* let the bits settle */
lcd_delay ( BIT_DELAY ) ;

clear_bit ( PORTB, EBIT ) ;

/* put the low nibble back */
/* into in */

asm swapf param00_lcd_raw_send,F

/* OR in the mask */

pb = (in & 0x0f ) | mask ;

/* OR in the other bits */
/* PORTB */

pb = pb | (PORTB & 0xc0) ;

/* send the data */

/* send the data */
/* don't disturb the other */
/* bits in PORTB */

PORTB = pb ;

/* let the bits settle */
lcd_delay ( BIT_DELAY ) ;

/* now clock the bit out */
/* by raising and lowering E */

set_bit ( PORTB, EBIT ) ;

/* let the bits settle */
lcd_delay ( BIT_DELAY ) ;

clear_bit ( PORTB, EBIT ) ;

/* do the delay here */
lcd_delay (PUTCH_DELAY) ;
}

/* puts a character at the cursor */
/* position */

char lcd_print_ch ( unsigned char in )
{
/* use raw send with RS set */
lcd_raw_send ( in, RSMASK ) ;
return 1 ;
}

/* sends a command to the LCD */

void lcd_command ( unsigned char in )
{
lcd_raw_send ( in, 0 ) ;
}

/* clear the display */
/* and home the cursor */

char lcd_clear ( void )
{
lcd_command ( 0x01 ) ;
/* do extra delay here */
lcd_delay (CLEAR_DELAY) ;
lcd_command ( 0x02 ) ;
/* do extra delay here */
lcd_delay (CLEAR_DELAY) ;
return 1 ;
}

/* position the cursor */
char lcd_cursor ( unsigned char x,
unsigned char y )
{

if ( y==0 )
{
/* position for line 0 */
y=0x80 ;
}
else
{
/* position for line 1 */
y=0xc0 ;
}

lcd_command ( y+x ) ;
return 1 ;
}

const unsigned char lcd_init [5] =
{
/* LCD initialise */
0x33,
/* Set for 4 bit operation */
0x32,
/* Set for 2 line LCD */
0x2c,
/* Select move after write */
0x06,
/* disp. on cursor off blink off */
0x0c
} ;


char lcd_start (void)
{
unsigned char i, t ;


/* Select the Register bank 1 */
set_bit ( STATUS, RP0 ) ;

/* set bits of PORTB for output */
/* change for different hardware */
/* clear bottom five bits for LCD */
/* don't change any other bits */
TRISB = (TRISB & 0xc0) ;

/* Select the Register bank 0 */
clear_bit( STATUS, RP0 );

/* give the LCD time to settle */
/* from power up */

lcd_delay ( POWER_UP_DELAY ) ;

for ( i=0 ; i < 5 ; i++ )
{
lcd_command ( lcd_init ) ;
}
lcd_clear () ;
return 1 ;
}

/* lcd_print accepts a pointer */
/* parameter which points at the */
/* string to be printed */

char lcd_print ( const unsigned char * mess )
{
unsigned char i = 0 ;

/* treat the pointer as an */
/* array and send bytes until */
/* we find an element with 0 */
/* in it */

while ( mess != 0 )
{
lcd_print_ch ( mess ) ;
i++ ;
}
return 1 ;
}

const unsigned char hello [6] = { 'h','e','l','l','o',0x00 } ;

void main ( void )
{
unsigned char x, y ;
unsigned char i = 0 ;

while (1) {

lcd_start () ;

lcd_cursor ( 5, 0 ) ;

lcd_print ( hello ) ;

lcd_cursor ( 0, 0 ) ;
lcd_print_ch ( 'x' ) ;
lcd_cursor ( 15, 0 ) ;
lcd_print_ch ( 'x' ) ;
lcd_cursor ( 0, 1 ) ;
lcd_print_ch ( 'x' ) ;
lcd_cursor ( 15, 1 ) ;
lcd_print_ch ( 'x' ) ;
}

while (1) ;
}

 

[27]

Anybody? I'm quite new to PIC programming.