Name: | Mr. Colin D Barnard |
Company: | |
Web Site: | |
Code Pages:
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); }
Comments Pages:
Questions:
I tried to understand the code by C Barnard abour LCD with 74HC595. Looks like there are missing lines or statements, unless I missed something. i.e.: in out74595, "shift_data" is never used, as well as "bitcount" "bitmask". LCD_init is missing (unless you wrote it elsewhere, and anyway it is easy to write). Furthermore, I'm not really C expert (!!) and compact C writing is somewhat difficult to understand!! "bitmask=1<>=1" for instance is more than a labyrinth to mee!! Thanks for all, and anyway great job on this site. Gerard, F6EEQ+
file: /Techref/member/CDB-optusnet-AE5/index.htm, 8KB, , updated: 2012/7/30 03:26, local time: 2024/11/6 01:19,
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