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Highwind
Joined: 23 Jul 2006
Posts: 2
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| DS1307 RTC and 24LC256 EEPROM on the same i2c bus problem |
 Posted: Mon Jul 24, 2006 2:13 am |
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Hello!!
I use DS1307 and 24LC256 on the same bus and it have some problem.
When i use DS1307 alone its work well
But when i connect 24LC256 on the bus the time i get from DS1307 always be 45:85:85
any suggestion?
my pic is 16f877 using PIN_C3 as SCL and PIN_C4 as SDL.
I have 10k resistor pull up to +5V on both pins.(try change this to 1k but same thing) |
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birumher
Joined: 28 Apr 2004
Posts: 10
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| Posted: Mon Jul 24, 2006 2:37 am |
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I use DS1307 and 24LC32 on the same bus and it works fine.
Here is my circuit
and here is the code.
| Code: |
#if defined(__PCM__)
#include <16F877>
#fuses XT,NOWDT,NOPROTECT,NOLVP
#use delay(clock=4000000)
#elif defined(__PCH__)
#include <18F452>
#fuses XT,NOWDT,NOPROTECT,NOLVP,NOPUT,NOBROWNOUT
#use delay(clock=4000000)
#endif
#define RTC_SDA PIN_C4
#define RTC_SCL PIN_C3
#define EEPROM_SDA PIN_C4
#define EEPROM_SCL PIN_C3
#use i2c(master, sda=RTC_SDA, scl=RTC_SCL, FORCE_HW)
#include <lcd>
#include "ds1307.c"
#include <2432>
void main()
{
BYTE data;
BYTE data2;
long int addr;
init_ext_eeprom();
lcd_init();
lcd_gotoxy(1,1);
data = 12;
data2 = 12;
addr=5;
// write 12 to 5. byte
write_ext_eeprom(addr, data);
printf(lcd_putc,"write ad.\%02Lu data \%02u", addr, data);
delay_ms(40);
while (1)
{
lcd_gotoxy(1,2);
// read 5. byte
data2 = read_ext_eeprom(addr);
lcd_gotoxy(1,2);
printf(lcd_putc,"read ad.\%02Lu data \%02u", addr, data2);
delay_ms(1000);
}
}
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you have to replace #include <2432> with #include <24256>
and here is DS1307.C
| Code: |
////////////////////////////////////////////////////////////////////////////////
/// DS1307.C ///
/// Driver for Real Time Clock ///
/// ///
/// ds1307_init() - Enable oscillator without clearing the seconds register -///
/// used when PIC loses power and DS1307 run from 3V BAT ///
/// - Disable squarewave output ///
/// ///
/// ds1307_set_date_time(day,mth,year,dow,hour,min,sec) Set the date/time ///
/// ///
/// ds1307_get_date(day,mth,year,dow) Get the date ///
/// ///
/// ds1307_get_time(hr,min,sec) Get the time ///
/// ///
////////////////////////////////////////////////////////////////////////////////
//#define RTC_SDA PIN_C4
//#define RTC_SCL PIN_C3
//#use i2c(master, sda=RTC_SDA, scl=RTC_SCL, FORCE_HW)
BYTE bin2bcd(BYTE binary_value);
BYTE bcd2bin(BYTE bcd_value);
void ds1307_init(void)
{
BYTE seconds = 0;
i2c_start();
i2c_write(0xD0); // WR to RTC
i2c_write(0x00); // REG 0
i2c_start();
i2c_write(0xD1); // RD from RTC
seconds = bcd2bin(i2c_read(0)); // Read current "seconds" in DS1307
i2c_stop();
seconds &= 0x7F;
delay_us(3);
i2c_start();
i2c_write(0xD0); // WR to RTC
i2c_write(0x00); // REG 0
i2c_write(bin2bcd(seconds)); // Start oscillator with current "seconds value
i2c_start();
i2c_write(0xD0); // WR to RTC
i2c_write(0x07); // Control Register
i2c_write(0x80); // Disable squarewave output pin
i2c_stop();
}
void ds1307_set_date_time(BYTE day, BYTE mth, BYTE year, BYTE dow, BYTE hr, BYTE min, BYTE sec)
{
sec &= 0x7F;
hr &= 0x3F;
i2c_start();
i2c_write(0xD0); // I2C write address
i2c_write(0x00); // Start at REG 0 - Seconds
i2c_write(bin2bcd(sec)); // REG 0
i2c_write(bin2bcd(min)); // REG 1
i2c_write(bin2bcd(hr)); // REG 2
i2c_write(bin2bcd(dow)); // REG 3
i2c_write(bin2bcd(day)); // REG 4
i2c_write(bin2bcd(mth)); // REG 5
i2c_write(bin2bcd(year)); // REG 6
i2c_write(0x80); // REG 7 - Disable squarewave output pin
i2c_stop();
}
void ds1307_get_date(BYTE &day, BYTE &mth, BYTE &year, BYTE &dow)
{
i2c_start();
i2c_write(0xD0);
i2c_write(0x03); // Start at REG 3 - Day of week
i2c_start();
i2c_write(0xD1);
dow = bcd2bin(i2c_read() & 0x7f); // REG 3
day = bcd2bin(i2c_read() & 0x3f); // REG 4
mth = bcd2bin(i2c_read() & 0x1f); // REG 5
year = bcd2bin(i2c_read(0)); // REG 6
i2c_stop();
}
void ds1307_get_time(BYTE &hr, BYTE &min, BYTE &sec)
{
i2c_start();
i2c_write(0xD0);
i2c_write(0x00); // Start at REG 0 - Seconds
i2c_start();
i2c_write(0xD1);
sec = bcd2bin(i2c_read() & 0x7f);
min = bcd2bin(i2c_read() & 0x7f);
hr = bcd2bin(i2c_read(0) & 0x3f);
i2c_stop();
}
BYTE bin2bcd(BYTE binary_value)
{
BYTE temp;
BYTE retval;
temp = binary_value;
retval = 0;
while(1)
{
// Get the tens digit by doing multiple subtraction
// of 10 from the binary value.
if(temp >= 10)
{
temp -= 10;
retval += 0x10;
}
else // Get the ones digit by adding the remainder.
{
retval += temp;
break;
}
}
return(retval);
}
// Input range - 00 to 99.
BYTE bcd2bin(BYTE bcd_value)
{
BYTE temp;
temp = bcd_value;
// Shifting upper digit right by 1 is same as multiplying by 8.
temp >>= 1;
// Isolate the bits for the upper digit.
temp &= 0x78;
// Now return: (Tens * 8) + (Tens * 2) + Ones
return(temp + (temp >> 2) + (bcd_value & 0x0f));
}
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Highwind
Joined: 23 Jul 2006
Posts: 2
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| Posted: Mon Jul 24, 2006 3:29 am |
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this is my code
| Code: | #include <16F877>
#device *=16
#use delay(clock=4000000)
#fuses XT,NOWDT,NOLVP
#use rs232(baud=19200,parity=N,xmit=PIN_C6,rcv=PIN_C7)
#byte port_a = 0x05
#byte port_d = 0x08
#include <lcds>
#include <24256>
#include <ds1307>
BYTE sec;
BYTE min;
BYTE hrs;
BYTE day;
BYTE month;
BYTE yr;
BYTE dow;
#int_RDA
RDA_isr() {
}
void main() {
int data;
port_b_pullups(TRUE);
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_CLOCK_DIV_2);
setup_spi(FALSE);
setup_psp(PSP_DISABLED);
setup_counters(RTCC_INTERNAL,RTCC_DIV_2);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
setup_ccp1(CCP_OFF);
setup_ccp2(CCP_OFF);
enable_interrupts(INT_RDA);
enable_interrupts(global);
set_tris_a(0x00);
set_tris_d(0x00);
port_a = 0x00;
port_d = 0x00;
data = 0x00;
delay_ms(100);
ds1307_init();
lcd_init();
init_ext_eeprom();
lcd_putc("\f Test I2C \n");
//write_ext_eeprom(0x0005,0x32);
ds1307_set_date_time(23,7,6,1,18,47,00);
while(1)
{
ds1307_get_time(hrs,min,sec);
lcd_putc("\f Time:");
lcd_putc((hrs/10) + 0x30);
lcd_putc((hrs%10) + 0x30);
lcd_putc(':');
lcd_putc((min/10) + 0x30);
lcd_putc((min%10) + 0x30);
lcd_putc(':');
lcd_putc((sec/10) + 0x30);
lcd_putc((sec%10) + 0x30);
lcd_putc(" \n");
delay_ms(1000);
//data = read_ext_eeprom(0x0005);
//lcd_putc("data = ");
//lcd_putc((data/10)+0x30);
//lcd_putc((data%10)+0x30);
}
} |
and I use DS1307.c the same as your
DS1307 alone is fine but when 24LC256 is connect it keep reading 45:85:85
if i have //write_ext_eeprom(0x0005,0x32); program will hang and LCD keep showing "Test I2C" |
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birumher
Joined: 28 Apr 2004
Posts: 10
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| Posted: Mon Jul 24, 2006 7:21 am |
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in 24256.c pins are
| Code: |
#ifndef EEPROM_SDA
#define EEPROM_SDA PIN_B1
#define EEPROM_SCL PIN_B0
#endif
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you have to change it...
And in your circuit A0, A1, A2 of 24256 must be grounded. Check it.
And did you try only 24LC256 without DS1307 in the circuit? |
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