Colin D Barnard shares this code:
These file were compiled by the Wiz C compiler from FORED. www.fored.co.uk
lcd_shiftout.h
extern shiftport;
extern clockport;
extern latchport;
void lcd_init(void);
void out_74595(unsigned char shift_data);
void lcd_out(unsigned char lcd_data,unsigned char rs_bit);
void lcd_packet(unsigned char raw_data,unsigned char rs_bit);
void lcd_clear();
void lcd_st(unsigned char *string);
void lcd_num(unsigned int conv);
void lcd_hex(unsigned char dec);
void lcd_pos(unsigned char line,unsigned char column);
unsigned char num2hex(unsigned char decimal);
//extern unsigned char bit_no;
//extern unsigned char rs_state;
//extern unsigned char clockbit,latchbit;
lcd_shift. library file
//Routine using 74HC595 to shift out data to LCD in 4 bit mode.
//This only uses 3 pins from the PIC - Latch, Clock, Data.
// Pin outs
// 74_595 LCD
//Q7 7 DB4
//Q6 6 DB5
//Q5 5 DB6
//Q4 4 DB7
//Q2 3 RS
//Q1 2 EN
//
// port for clock and latch may be changed by appropriate port declaration
//
//**copyright C D Barnard 1/5/2002 Version 1.2
//#include
#include "lcd_shiftout.h"
#include
//These must be included because of the #ifdef declarations
#asmfunc lcd_num(conv)
#asmfunc num2hex(decimal)
#asmfunc lcd_hex(dec)
#asmfunc lcd_st(*string)
//****************************************************************
// 74HC595 to LCD routines
void lcd_packet(unsigned char raw_data,unsigned char rs_state)
{
lcd_out(raw_data>>4,rs_state);
lcd_out(raw_data&0x0F,rs_state);
Wait(10); //delay between data bytes
}
void lcd_out(unsigned char lcd_data,unsigned char inst)
{
inst<<=4; //shift RS state to bit 4 of data stream
out_74595(lcd_data|inst); //enable=0
out_74595(lcd_data|(0x20 | inst)); //enable=1
out_74595(lcd_data|inst); //enable=0
}
//This could be replaced with pClockOut(8,lcd_data|inst) etc
void out_74595(unsigned char shift_data)
{
unsigned char bitcount,bitmask;
bitmask=1<>=1; //Next data bit
}
latchport^=1<0x94 and 0xD0->0xD4 for 4*20 display
const unsigned char row[4]={0x80,0xC0,0x90,0xD0};
rs_state=0; //command mode
line-=1; //adjust for human maths
lcd_packet((row[line] + column),rs_state); //row + column required
rs_state=1;
Wait(1);
}
#endif
#ifdef _lcd_st
void lcd_st(unsigned char *string)
{
rs_state=1; //data mode
while(*string) //while not end of string
{
lcd_packet(*string,rs_state);
++string; //move to next character
}
}
#endif
#ifdef _lcd_hex
void lcd_hex(unsigned char dec)
{
unsigned char hexnum;
rs_state=1; //data mode
hexnum=num2hex(dec>>4); //convert decimal number
lcd_packet(hexnum,rs_state); // pump it out
hexnum=num2hex(dec&0x0F);
lcd_packet(hexnum,rs_state);
}
#endif
#ifdef _lcd_num
//Converts decimal numbers to 9999 to ASCII
void lcd_num(unsigned int conv)
{
unsigned int temp1,decnum;
unsigned char hexnum,suppress=0;
rs_state=1; //data mode
decnum=conv/1000 ; //get the thousands
if (decnum==0)
{ //if none then suppress leading zero
hexnum=0x20; //possibly change SPACE's to 0x00 NULL's
suppress=1;
}
else
{
hexnum=num2hex(decnum); //convert to ASCII hex
}
lcd_packet(hexnum,rs_state);
temp1=conv-(decnum*1000); //workout the remainder
decnum=temp1/100; //get the hundreds
if (decnum ==0 && suppress)
hexnum=0x20;
else
{
hexnum=num2hex(decnum);
suppress=0;
}
lcd_packet(hexnum,rs_state);
temp1=temp1-(decnum*100);
decnum=temp1/10; //get the tens
if (decnum < 1 && suppress)
hexnum=0x20;
else
hexnum=num2hex(decnum);
lcd_packet(hexnum,rs_state);
decnum=temp1-(decnum*10);
hexnum=num2hex(decnum); //the units
lcd_packet(hexnum,rs_state);
}
#endif
#ifdef _num2hex
unsigned char num2hex(unsigned char decimal)
{
unsigned char temp;
if (decimal < 10)
{
temp= decimal+'0'; //if number less than 10 add 30h for ASCII No.
}
else
{
temp=decimal-10; //Number greater than ten add 41h
temp+= 'A'; //to get number in hex
}
return (temp);
}
#endif
Demo.c putting it all together
#define shiftport PORTB
#define clockport PORTB
#define latchport PORTB
const char bit_no=7;
unsigned char rs_state;
const char clockbit=5;
const char latchbit=6;
#include
#include "lcd_shiftout_1.c"
//config info only included whilst testing
# __config 0x3F61
void main(void)
{
PORTA=PORTB=0;
TRISA=TRISB=0;
lcd_init();
lcd_packet('V',1);
lcd_hex(2);
lcd_packet('.',1);
lcd_hex(19);
lcd_st("Shift Demo");
Wait(6000);
lcd_clear();
//Wait(2000);
lcd_pos(1,3);
lcd_st("74HC595 End");
lcd_pos(2,6);
lcd_num(1024);
while(1);
}