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gs
Joined: 22 Aug 2005
Posts: 30
Location: Ioannina - Greece
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| DS1340 RTC driver |
 Posted: Sun Dec 17, 2006 9:32 am |
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Hello, I finally got a DS1340 and played with it the last few days, I post here the results.
The driver checks for the OSF (Oscillator Stop Flag) to check data validity so if you are reading all zeros, you have to re-adjust the time.
Please post any comments for improvements.
| Code: |
///////////////////////////////////////////////////////////////////////////////////
/// DS1340.C ///
/// Driver for Real Time Clock ///
/// For Dallas/Maxim DS1340 RTC (I2C, trickle charge, etc) ///
/// Based on DS1307 driver. ///
/// ///
/// rtc_init() -Call once at start-up. To Set trickle charge state ///
/// uncomment the line you want below. No Calibration ///
/// used here Control byte is set to all 0's ///
/// ///
/// ///
/// rtc_set_date_time(day,mth,year,dow,hour,min,sec) Set the date/time ///
/// ///
/// rtc_get_date(day,mth,year,dow) Get the date* ///
/// ///
/// rtc_get_time(hr,min,sec) Get the time* ///
/// ///
/// *(if returned value's are all zeros this means that the clock ///
/// stopped for some reason and the time is invalid) ///
/// ///
///////////////////////////////////////////////////////////////////////////////////
//#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 rtc_check_valid();
void rtc_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 DS1340
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); // goto Control reg
i2c_write(0); // Set control byte to zer0s
i2c_start();
i2c_write(0xD0); // WR to RTC
i2c_write(0x08); // goto trickle address
// Set Trickle Charger byte (uncomment ONLY one of the following)*****************
// i2c_write(0b00100101); // disabled
// i2c_write(0b10100101); // No diode, 250Ω resistor
// i2c_write(0b10101001); // One diode, 250Ω resistor
// i2c_write(0b10100110); // No diode, 2kΩ resistor
// i2c_write(0b10101010); // One diode, 2kΩ resistor
i2c_write(0b10100111); // No diode, 4kΩ resistor
// i2c_write(0b10101011); // One diode, 4kΩ resistor
// Set Trickle Charger byte
i2c_stop();
}
void rtc_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_start();
i2c_write(0xD0); // WR to RTC
i2c_write(0x09); // Set OSF address
i2c_write(0); // Clear OSF
i2c_stop();
}
void rtc_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();
rtc_check_valid();
}
void rtc_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();
rtc_check_valid();
}
void rtc_check_valid()
{
int validity;
i2c_start(); //read OSF bit to check data validity
i2c_write(0xD0);
i2c_write(0x09);
i2c_start();
i2c_write(0xD1);
validity=i2c_read(0);
i2c_stop();
if (validity!=0) //if data not valid make them zeros
{
sec=0;
min=0;
hour=0;
dow=0;
year=0;
mth=0;
day=0;
}
}
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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_________________
www.hlektronika.gr |
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YARGICH
Joined: 19 Jan 2007
Posts: 8
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| Posted: Wed Mar 18, 2009 7:56 pm |
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Hi,
I tried to use your ds1340 driver. But when I read hour, minute and second, I always read hour=0x2D, minute=0x55, and second=0x55. what do you think about my problem ?
I am using ds1340c model. You know that, ds1340 have internal xtal in its ds1340c model. Should I define to use this xtal to my ds1340c?
best regards. |
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gs
Joined: 22 Aug 2005
Posts: 30
Location: Ioannina - Greece
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| Posted: Thu Mar 19, 2009 4:26 pm |
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I don't see any settings on the datasheet specifically for the C version, but I noticed this:
| Quote: | All N.C. (no connect) pins must be connected
to ground. |
I did not read thorougly the datasheet and the last time I used this chip is some years ago.
_________________
www.hlektronika.gr |
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YARGICH
Joined: 19 Jan 2007
Posts: 8
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| Posted: Thu Mar 19, 2009 6:16 pm |
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Thx for your research. I solved this problem. When I read hour, minute, and second data serially, It gave me wrong datas. after that I wrote separate routines to read these datas. Now, It gives me true datas. But in this wise, I must call different routines to take all datas.
Actually it is not important for me. Thanks a lot for DS1340 CCS driver.
Best Regards. |
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sajjadonline
Joined: 07 Sep 2011
Posts: 5
Location: Banned - spammer
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| tnx for ds1307 library |
| Posted: Wed Feb 27, 2013 3:22 am |
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| very nice this library gs |
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