internetuser2k12
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No when you define DATA_PORT PORTA you are actually setting the whole port and if you write 0xff to DATA_PORT then RA6 and RA7 i.e., RS and E becomes 1.
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When i change this
#define RS_PIN LATAbits.RA6
#define E_PIN LATAbits.RA7#define RS_PIN LATAbits.LATA6
#define E_PIN LATAbits.LATA7Thank you for the datasheet.
Then why you don't increase the delays? Insert big delays whether this is the problem or not, and when you find the solution restore proper delay values.
void main (void)
{
//SET UP
// OSCCON defaults to 31kHz. So no need to alter it.
ADCON1 = 0x0F;
CMCON = 0x07;
CVRCONbits.CVROE = 0;
TRISA = 0b00100000;; //sets PORTA
PORTA = 0b00000000; //turns off PORTA outputs
// this code configures the display
WriteCmd ( 0x02 ); // sets 4bit operation
WriteCmd ( FOUR_BIT & LINES_5X7 ); // sets 5x7 font and multiline operation.
WriteCmd ( CURSOR_BLINK ); // blinks cursor
WriteCmd ( CURSOR_RIGHT ); // moves cursor right
// Start of user program.
SetAddr (0x80);
WriteString("Hello World");
Delay1KTCYx(8); //delay 1s
WriteCmd(CLEAR_SCREEN);
SetAddr (0xC0);
WriteString("Hello again");
while(1);
}#include <p18f2520.h>
#pragma config WDT=OFF , OSC=INTIO67 , PWRT = ON, LVP=OFF, MCLRE = OFF
#include <delays.h>
#define CLEAR_SCREEN 0b00000001
#define FOUR_BIT 0b00101100
#define LINES_5X7 0b00111000
#define CURSOR_BLINK 0b00001111
#define CURSOR_RIGHT 0b00000110
#define DATA_PORT LATA
#define RS_PIN LATCbits.LATC1
#define E_PIN LATCbits.LATC2
void Delay20TCY() //20 clock cycles, 2.5mS
{
Delay10TCYx(2);
}
void SetAddr(unsigned char DDaddr)
{
DATA_PORT &= 0xf0; // Write upper nibble
DATA_PORT |= (((DDaddr | 0b10000000)>>4) & 0x0f);
RS_PIN = 0; // Set control bit
Delay20TCY();
E_PIN = 1; // Clock the cmd and address in
Delay20TCY();
E_PIN = 0;
DATA_PORT &= 0xf0; // Write lower nibble
DATA_PORT |= (DDaddr&0x0f);
Delay20TCY();
E_PIN = 1; // Clock the cmd and address in
Delay20TCY();
E_PIN = 0;
}
void WriteCmd(unsigned char cmd)
{
DATA_PORT &= 0xf0;
DATA_PORT |= (cmd>>4)&0x0f;
RS_PIN = 0; // Set control signals for command
Delay20TCY();
E_PIN = 1; // Clock command in
Delay20TCY();
E_PIN = 0;
// Lower nibble interface
DATA_PORT &= 0xf0;
DATA_PORT |= cmd&0x0f;
Delay20TCY();
E_PIN = 1; // Clock command in
Delay20TCY();
E_PIN = 0;
}
void WriteChar(char data)
{
DATA_PORT &= 0xf0;
DATA_PORT |= ((data>>4)&0x0f);
RS_PIN = 1; // Set control bits
Delay20TCY();
E_PIN = 1; // Clock nibble into LCD
Delay20TCY();
E_PIN = 0;
DATA_PORT &= 0xf0; // Lower nibble interface
DATA_PORT |= (data&0x0f);
Delay20TCY();
E_PIN = 1; // Clock nibble into LCD
Delay20TCY();
E_PIN = 0;
}
void WriteString(const rom char *buffer)
{
while(*buffer) // Write data to LCD up to null
{
Delay20TCY();
WriteChar( *buffer); // Write character to LCD
buffer++; // Increment buffer
}
return;
}
void main (void)
{
//SET UP
// OSCCON defaults to 31kHz. So no need to alter it.
ADCON1 = 0x0F;
CMCON = 0x07;
CVRCONbits.CVROE = 0;
TRISA =0b00000000; //sets PORTA
LATA = 0b00000000; //turns off PORTA outputs
TRISC =0b00000000; //sets PORTA 3
LATC = 0b00000000; //turns off PORTA outputs
// this code configures the display
WriteCmd ( 0x02 ); // sets 4bit operation
WriteCmd ( FOUR_BIT & LINES_5X7 ); // sets 5x7 font and multiline operation.
WriteCmd ( CURSOR_BLINK ); // blinks cursor
WriteCmd ( CURSOR_RIGHT ); // moves cursor right
// Start of user program.
SetAddr (0x80);
WriteString("Hello World");
Delay10KTCYx(100);
WriteCmd(CLEAR_SCREEN);
SetAddr (0xC0);
WriteString("Hello again");
while(1);
}The clock frequency is 40 MHz
Yes i added delay before and after screen command and its working but alexx said that "This will not fix the problem, but it will help you understand what is going on, before the second print."
The initialize is it this one?:
This is the initialization algorithm, 4 bit mode:
40MHz means 25ns. 25*20 = 500ns. This doesn't meet the requirement of 1.64ms. I'm not aware of PIC or the compiler you are using, but I believe that it is time you gave a second look into your delay functions.
void Delay20TCY() //20 clock cycles, 2.5mS
{
Delay10TCYx(2);
}void Delay20TCY()
{
Delay10TCYx(50);
}
