RTC PCF8583 -iscitavanje utice na tacnost!?
PCF8583 i2c +PIC16F877A
Koristio sam kod sa Mikroelektronikinog sajta da ispisem datum i vreme na LCD.PCF8583 je spojen na port C RC3 i RC4.
Sve radi vise manje kako treba,iskljucim napajanje mikrokontroleru i nakon nekog vremena kad ga ukljucim on iscita korektno vreme.
Evo kod:
char seconds, minutes, hours, day, month, year; // Global date/time variables
// Software I2C connections
sbit Soft_I2C_Scl at RC3_bit;
sbit Soft_I2C_Sda at RC4_bit;
sbit Soft_I2C_Scl_Direction at TRISC3_bit;
sbit Soft_I2C_Sda_Direction at TRISC4_bit;
// End Software I2C connections
// LCD module connections
sbit LCD_RS at RB4_bit;
sbit LCD_EN at RB5_bit;
sbit LCD_D4 at RB0_bit;
sbit LCD_D5 at RB1_bit;
sbit LCD_D6 at RB2_bit;
sbit LCD_D7 at RB3_bit;
sbit LCD_RS_Direction at TRISB4_bit;
sbit LCD_EN_Direction at TRISB5_bit;
sbit LCD_D4_Direction at TRISB0_bit;
sbit LCD_D5_Direction at TRISB1_bit;
sbit LCD_D6_Direction at TRISB2_bit;
sbit LCD_D7_Direction at TRISB3_bit;
// End LCD module connections
//--------------------- Reads time and date information from RTC (PCF8583)
void Read_Time() {
Soft_I2C_Start(); // Issue start signal
Soft_I2C_Write(0xA0); // Address PCF8583, see PCF8583 datasheet
Soft_I2C_Write(2); // Start from address 2
Soft_I2C_Start(); // Issue repeated start signal
Soft_I2C_Write(0xA1); // Address PCF8583 for reading R/W=1
seconds = Soft_I2C_Read(1); // Read seconds byte
minutes = Soft_I2C_Read(1); // Read minutes byte
hours = Soft_I2C_Read(1); // Read hours byte
day = Soft_I2C_Read(1); // Read year/day byte
month = Soft_I2C_Read(0); // Read weekday/month byte
Soft_I2C_Stop(); // Issue stop signal
}
//-------------------- Formats date and time
void Transform_Time() {
seconds = ((seconds & 0xF0) >> 4)*10 + (seconds & 0x0F); // Transform seconds
minutes = ((minutes & 0xF0) >> 4)*10 + (minutes & 0x0F); // Transform months
hours = ((hours & 0xF0) >> 4)*10 + (hours & 0x0F); // Transform hours
year = (day & 0xC0) >> 6; // Transform year
day = ((day & 0x30) >> 4)*10 + (day & 0x0F); // Transform day
month = ((month & 0x10) >> 4)*10 + (month & 0x0F); // Transform month
}
//-------------------- Output values to LCD
void Display_Time() {
Lcd_Chr(1, 6, (day / 10) + 48); // Print tens digit of day variable
Lcd_Chr(1, 7, (day % 10) + 48); // Print oness digit of day variable
Lcd_Chr(1, 9, (month / 10) + 48);
Lcd_Chr(1,10, (month % 10) + 48);
Lcd_Chr(1,15, year + 48); // Print year vaiable + 8 (start from year 2008)
Lcd_Chr(2, 6, (hours / 10) + 48);
Lcd_Chr(2, 7, (hours % 10) + 48);
Lcd_Chr(2, 9, (minutes / 10) + 48);
Lcd_Chr(2,10, (minutes % 10) + 48);
Lcd_Chr(2,12, (seconds / 10) + 48);
Lcd_Chr(2,13, (seconds % 10) + 48);
}
//------------------ Performs project-wide init
void Init_Main() {
TRISB = 0;
PORTB = 0xFF;
TRISB = 0xff;
//ANSEL = 0; // Configure AN pins as digital I/O
//ANSELH = 0;
//C1ON_bit = 0; // Disable comparators
//C2ON_bit = 0;
Soft_I2C_Init(); // Initialize Soft I2C communication
Lcd_Init(); // Initialize LCD
Lcd_Cmd(_LCD_CLEAR); // Clear LCD display
Lcd_Cmd(_LCD_CURSOR_OFF); // Turn cursor off
Lcd_Out(1,1,"Date:"); // Prepare and output static text on LCD
Lcd_Chr(1,8,':');
Lcd_Chr(1,11,':');
Lcd_Out(2,1,"Time:");
Lcd_Chr(2,8,':');
Lcd_Chr(2,11,':');
Lcd_Out(1,12,"201");
}
//----------------- Main procedure
void main() {
Delay_ms(2000);
Init_Main(); // Perform initialization
while (1) { // Endless loop
Read_Time(); // Read time from RTC(PCF8583)
Transform_Time(); // Format date and time
Display_Time(); // Prepare and display on LCD
Delay_ms(1000); // Wait 1 second
}
}
E sad,kad promenim zadnju naredbu u kodu sa Delay_ms(1000) sa Delay_ms(500) sat radi duplo brze!??
Koliko ja zakljucujem iscitavanjem uticemo na tacnost vremena u RTC?!
Kako iscitati PCF8583P bez da uticemo na njega,odnosno na njegovu tacnost???
Hvala unapred na pomoci.
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