DS1302 RTC test.
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// DS1302: RST pin -> Arduino Digital 4
// DATA pin -> Arduino Digital 3
// CLK pin -> Arduino Digital 2
#include <DS1302.h>
#include <Wire.h>
DS1302 rtc(4, 3, 2);
void setup()
{
Serial.begin(9600);
Serial.println("DS1302 RTC test.");
// Set the clock to run-mode, and disable the write protection
rtc.halt(false);
rtc.writeProtect(false);
// The following lines can be commented out to use the values already stored in the DS1302
rtc.setDOW(WEDNESDAY); // Set Day-of-Week to FRIDAY
rtc.setTime(16, 7, 0); // Set the time to 12:00:00 (24hr format)
rtc.setDate(27, 1, 2016); // Set the date to August 6th, 2010
rtc.writeProtect(true);
}
void loop()
{
Serial.println(rtc.getTimeStr());
// Serial.println(rtc.getDOWStr(FORMAT_SHORT));
// Serial.println(rtc.getDateStr());
delay (1000);
}
There any couple of ds1302 libraries, which did you use?
#include <DS1302.h>
#include <Wire.h>
// Set your own pins with these defines !
#define DS1302_SCLK_PIN 4 // Arduino pin for the Serial Clock
#define DS1302_IO_PIN 3 // Arduino pin for the Data I/O
#define DS1302_CE_PIN 2u // Arduino pin for the Chip Enable
// Macros to convert the bcd values of the registers to normal
// integer variables.
// The code uses separate variables for the high byte and the low byte
// of the bcd, so these macros handle both bytes separately.
#define bcd2bin(h,l) (((h)*10) + (l))
#define bin2bcd_h(x) ((x)/10)
#define bin2bcd_l(x) ((x)%10)
// Register names.
// Since the highest bit is always '1',
// the registers start at 0x80
// If the register is read, the lowest bit should be '1'.
#define DS1302_SECONDS 0x80
#define DS1302_MINUTES 0x82
#define DS1302_HOURS 0x84
#define DS1302_DATE 0x86
#define DS1302_MONTH 0x88
#define DS1302_DAY 0x8A
#define DS1302_YEAR 0x8C
#define DS1302_ENABLE 0x8E
#define DS1302_TRICKLE 0x90
#define DS1302_CLOCK_BURST 0xBE
#define DS1302_CLOCK_BURST_WRITE 0xBE
#define DS1302_CLOCK_BURST_READ 0xBF
#define DS1302_RAMSTART 0xC0
#define DS1302_RAMEND 0xFC
#define DS1302_RAM_BURST 0xFE
#define DS1302_RAM_BURST_WRITE 0xFE
#define DS1302_RAM_BURST_READ 0xFF
// Defines for the bits, to be able to change
// between bit number and binary definition.
// By using the bit number, using the DS1302
// is like programming an AVR microcontroller.
// But instead of using "(1<<X)", or "_BV(X)",
// the Arduino "bit(X)" is used.
#define DS1302_D0 0
#define DS1302_D1 1
#define DS1302_D2 2
#define DS1302_D3 3
#define DS1302_D4 4
#define DS1302_D5 5
#define DS1302_D6 6
#define DS1302_D7 7
// Bit for reading (bit in address)
#define DS1302_READBIT DS1302_D0 // READBIT=1: read instruction
// Bit for clock (0) or ram (1) area,
// called R/C-bit (bit in address)
#define DS1302_RC DS1302_D6
// Seconds Register
#define DS1302_CH DS1302_D7 // 1 = Clock Halt, 0 = start
// Hour Register
#define DS1302_AM_PM DS1302_D5 // 0 = AM, 1 = PM
#define DS1302_12_24 DS1302_D7 // 0 = 24 hour, 1 = 12 hour
// Enable Register
#define DS1302_WP DS1302_D7 // 1 = Write Protect, 0 = enabled
// Trickle Register
#define DS1302_ROUT0 DS1302_D0
#define DS1302_ROUT1 DS1302_D1
#define DS1302_DS0 DS1302_D2
#define DS1302_DS1 DS1302_D2
#define DS1302_TCS0 DS1302_D4
#define DS1302_TCS1 DS1302_D5
#define DS1302_TCS2 DS1302_D6
#define DS1302_TCS3 DS1302_D7
// Structure for the first 8 registers.
// These 8 bytes can be read at once with
// the 'clock burst' command.
// Note that this structure contains an anonymous union.
// It might cause a problem on other compilers.
typedef struct ds1302_struct
{
uint8_t Seconds:4; // low decimal digit 0-9
uint8_t Seconds10:3; // high decimal digit 0-5
uint8_t CH:1; // CH = Clock Halt
uint8_t Minutes:4;
uint8_t Minutes10:3;
uint8_t reserved1:1;
union
{
struct
{
uint8_t Hour:4;
uint8_t Hour10:2;
uint8_t reserved2:1;
uint8_t hour_12_24:1; // 0 for 24 hour format
} h24;
struct
{
uint8_t Hour:4;
uint8_t Hour10:1;
uint8_t AM_PM:1; // 0 for AM, 1 for PM
uint8_t reserved2:1;
uint8_t hour_12_24:1; // 1 for 12 hour format
} h12;
};
uint8_t Date:4; // Day of month, 1 = first day
uint8_t Date10:2;
uint8_t reserved3:2;
uint8_t Month:4; // Month, 1 = January
uint8_t Month10:1;
uint8_t reserved4:3;
uint8_t Day:3; // Day of week, 1 = first day (any day)
uint8_t reserved5:5;
uint8_t Year:4; // Year, 0 = year 2000
uint8_t Year10:4;
uint8_t reserved6:7;
uint8_t WP:1; // WP = Write Protect
};
void setup()
{
ds1302_struct rtc;
Serial.begin(9600);
Serial.println(F("DS1302 Real Time Clock"));
Serial.println(F("Version 2, March 2013"));
// Start by clearing the Write Protect bit
// Otherwise the clock data cannot be written
// The whole register is written,
// but the WP-bit is the only bit in that register.
DS1302_write (DS1302_ENABLE, 0);
// Disable Trickle Charger.
DS1302_write (DS1302_TRICKLE, 0x00);
// Remove the next define,
// after the right date and time are set.
#define SET_DATE_TIME_JUST_ONCE
#ifdef SET_DATE_TIME_JUST_ONCE
// Fill these variables with the date and time.
int seconds, minutes, hours, dayofweek, dayofmonth, month, year;
// Example for april 15, 2013, 10:08, monday is 2nd day of Week.
// Set your own time and date in these variables.
seconds = 0;
minutes = 8;
hours = 10;
dayofweek = 2; // Day of week, any day can be first, counts 1...7
dayofmonth = 15; // Day of month, 1...31
month = 4; // month 1...12
year = 2013;
// Set a time and date
// This also clears the CH (Clock Halt) bit,
// to start the clock.
// Fill the structure with zeros to make
// any unused bits zero
memset ((char *) &rtc, 0, sizeof(rtc));
rtc.Seconds = bin2bcd_l( seconds);
rtc.Seconds10 = bin2bcd_h( seconds);
rtc.CH = 0; // 1 for Clock Halt, 0 to run;
rtc.Minutes = bin2bcd_l( minutes);
rtc.Minutes10 = bin2bcd_h( minutes);
// To use the 12 hour format,
// use it like these four lines:
// rtc.h12.Hour = bin2bcd_l( hours);
// rtc.h12.Hour10 = bin2bcd_h( hours);
// rtc.h12.AM_PM = 0; // AM = 0
// rtc.h12.hour_12_24 = 1; // 1 for 24 hour format
rtc.h24.Hour = bin2bcd_l( hours);
rtc.h24.Hour10 = bin2bcd_h( hours);
rtc.h24.hour_12_24 = 0; // 0 for 24 hour format
rtc.Date = bin2bcd_l( dayofmonth);
rtc.Date10 = bin2bcd_h( dayofmonth);
rtc.Month = bin2bcd_l( month);
rtc.Month10 = bin2bcd_h( month);
rtc.Day = dayofweek;
rtc.Year = bin2bcd_l( year - 2000);
rtc.Year10 = bin2bcd_h( year - 2000);
rtc.WP = 0;
// Write all clock data at once (burst mode).
DS1302_clock_burst_write( (uint8_t *) &rtc);
#endif
}
void loop()
{
ds1302_struct rtc;
char buffer[80]; // the code uses 70 characters.
// Read all clock data at once (burst mode).
DS1302_clock_burst_read( (uint8_t *) &rtc);
sprintf( buffer, "Time = %02d:%02d:%02d, ", \
bcd2bin( rtc.h24.Hour10, rtc.h24.Hour), \
bcd2bin( rtc.Minutes10, rtc.Minutes), \
bcd2bin( rtc.Seconds10, rtc.Seconds));
Serial.print(buffer);
sprintf(buffer, "Date(day of month) = %d, Month = %d, " \
"Day(day of week) = %d, Year = %d", \
bcd2bin( rtc.Date10, rtc.Date), \
bcd2bin( rtc.Month10, rtc.Month), \
rtc.Day, \
2000 + bcd2bin( rtc.Year10, rtc.Year));
Serial.println( buffer);
delay( 5000);
}
// --------------------------------------------------------
// DS1302_clock_burst_read
//
// This function reads 8 bytes clock data in burst mode
// from the DS1302.
//
// This function may be called as the first function,
// also the pinMode is set.
//
void DS1302_clock_burst_read( uint8_t *p)
{
int i;
_DS1302_start();
// Instead of the address,
// the CLOCK_BURST_READ command is issued
// the I/O-line is released for the data
_DS1302_togglewrite( DS1302_CLOCK_BURST_READ, true);
for( i=0; i<8; i++)
{
*p++ = _DS1302_toggleread();
}
_DS1302_stop();
}
// --------------------------------------------------------
// DS1302_clock_burst_write
//
// This function writes 8 bytes clock data in burst mode
// to the DS1302.
//
// This function may be called as the first function,
// also the pinMode is set.
//
void DS1302_clock_burst_write( uint8_t *p)
{
int i;
_DS1302_start();
// Instead of the address,
// the CLOCK_BURST_WRITE command is issued.
// the I/O-line is not released
_DS1302_togglewrite( DS1302_CLOCK_BURST_WRITE, false);
for( i=0; i<8; i++)
{
// the I/O-line is not released
_DS1302_togglewrite( *p++, false);
}
_DS1302_stop();
}
// --------------------------------------------------------
// DS1302_read
//
// This function reads a byte from the DS1302
// (clock or ram).
//
// The address could be like "0x80" or "0x81",
// the lowest bit is set anyway.
//
// This function may be called as the first function,
// also the pinMode is set.
//
uint8_t DS1302_read(int address)
{
uint8_t data;
// set lowest bit (read bit) in address
bitSet( address, DS1302_READBIT);
_DS1302_start();
// the I/O-line is released for the data
_DS1302_togglewrite( address, true);
data = _DS1302_toggleread();
_DS1302_stop();
return (data);
}
// --------------------------------------------------------
// DS1302_write
//
// This function writes a byte to the DS1302 (clock or ram).
//
// The address could be like "0x80" or "0x81",
// the lowest bit is cleared anyway.
//
// This function may be called as the first function,
// also the pinMode is set.
//
void DS1302_write( int address, uint8_t data)
{
// clear lowest bit (read bit) in address
bitClear( address, DS1302_READBIT);
_DS1302_start();
// don't release the I/O-line
_DS1302_togglewrite( address, false);
// don't release the I/O-line
_DS1302_togglewrite( data, false);
_DS1302_stop();
}
// --------------------------------------------------------
// _DS1302_start
//
// A helper function to setup the start condition.
//
// An 'init' function is not used.
// But now the pinMode is set every time.
// That's not a big deal, and it's valid.
// At startup, the pins of the Arduino are high impedance.
// Since the DS1302 has pull-down resistors,
// the signals are low (inactive) until the DS1302 is used.
void _DS1302_start( void)
{
digitalWrite( DS1302_CE_PIN, LOW); // default, not enabled
pinMode( DS1302_CE_PIN, OUTPUT);
digitalWrite( DS1302_SCLK_PIN, LOW); // default, clock low
pinMode( DS1302_SCLK_PIN, OUTPUT);
pinMode( DS1302_IO_PIN, OUTPUT);
digitalWrite( DS1302_CE_PIN, HIGH); // start the session
delayMicroseconds( 4); // tCC = 4us
}
// --------------------------------------------------------
// _DS1302_stop
//
// A helper function to finish the communication.
//
void _DS1302_stop(void)
{
// Set CE low
digitalWrite( DS1302_CE_PIN, LOW);
delayMicroseconds( 4); // tCWH = 4us
}
// --------------------------------------------------------
// _DS1302_toggleread
//
// A helper function for reading a byte with bit toggle
//
// This function assumes that the SCLK is still high.
//
uint8_t _DS1302_toggleread( void)
{
uint8_t i, data;
data = 0;
for( i = 0; i <= 7; i++)
{
// Issue a clock pulse for the next databit.
// If the 'togglewrite' function was used before
// this function, the SCLK is already high.
digitalWrite( DS1302_SCLK_PIN, HIGH);
delayMicroseconds( 1);
// Clock down, data is ready after some time.
digitalWrite( DS1302_SCLK_PIN, LOW);
delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns
// read bit, and set it in place in 'data' variable
bitWrite( data, i, digitalRead( DS1302_IO_PIN));
}
return( data);
}
// --------------------------------------------------------
// _DS1302_togglewrite
//
// A helper function for writing a byte with bit toggle
//
// The 'release' parameter is for a read after this write.
// It will release the I/O-line and will keep the SCLK high.
//
void _DS1302_togglewrite( uint8_t data, uint8_t release)
{
int i;
for( i = 0; i <= 7; i++)
{
// set a bit of the data on the I/O-line
digitalWrite( DS1302_IO_PIN, bitRead(data, i));
delayMicroseconds( 1); // tDC = 200ns
// clock up, data is read by DS1302
digitalWrite( DS1302_SCLK_PIN, HIGH);
delayMicroseconds( 1); // tCH = 1000ns, tCDH = 800ns
if( release && i == 7)
{
// If this write is followed by a read,
// the I/O-line should be released after
// the last bit, before the clock line is made low.
// This is according the datasheet.
// I have seen other programs that don't release
// the I/O-line at this moment,
// and that could cause a shortcut spike
// on the I/O-line.
pinMode( DS1302_IO_PIN, INPUT);
// For Arduino 1.0.3, removing the pull-up is no longer needed.
// Setting the pin as 'INPUT' will already remove the pull-up.
// digitalWrite (DS1302_IO, LOW); // remove any pull-up
}
else
{
digitalWrite( DS1302_SCLK_PIN, LOW);
delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns
}
}
}
// Set your own pins with these defines !
#define DS1302_SCLK_PIN 4 // Arduino pin for the Serial Clock
#define DS1302_IO_PIN 3 // Arduino pin for the Data I/O
#define DS1302_CE_PIN 2u // Arduino pin for the Chip Enable
// Macros to convert the bcd values of the registers to normal
// integer variables.
// The code uses separate variables for the high byte and the low byte
// of the bcd, so these macros handle both bytes separately.
#define bcd2bin(h,l) (((h)*10) + (l))
#define bin2bcd_h(x) ((x)/10)
#define bin2bcd_l(x) ((x)%10)
// Register names.
// Since the highest bit is always '1',
// the registers start at 0x80
// If the register is read, the lowest bit should be '1'.
#define DS1302_SECONDS 0x80
#define DS1302_MINUTES 0x82
#define DS1302_HOURS 0x84
#define DS1302_DATE 0x86
#define DS1302_MONTH 0x88
#define DS1302_DAY 0x8A
#define DS1302_YEAR 0x8C
#define DS1302_ENABLE 0x8E
#define DS1302_TRICKLE 0x90
#define DS1302_CLOCK_BURST 0xBE
#define DS1302_CLOCK_BURST_WRITE 0xBE
#define DS1302_CLOCK_BURST_READ 0xBF
#define DS1302_RAMSTART 0xC0
#define DS1302_RAMEND 0xFC
#define DS1302_RAM_BURST 0xFE
#define DS1302_RAM_BURST_WRITE 0xFE
#define DS1302_RAM_BURST_READ 0xFF
// Defines for the bits, to be able to change
// between bit number and binary definition.
// By using the bit number, using the DS1302
// is like programming an AVR microcontroller.
// But instead of using "(1<<X)", or "_BV(X)",
// the Arduino "bit(X)" is used.
#define DS1302_D0 0
#define DS1302_D1 1
#define DS1302_D2 2
#define DS1302_D3 3
#define DS1302_D4 4
#define DS1302_D5 5
#define DS1302_D6 6
#define DS1302_D7 7
// Bit for reading (bit in address)
#define DS1302_READBIT DS1302_D0 // READBIT=1: read instruction
// Bit for clock (0) or ram (1) area,
// called R/C-bit (bit in address)
#define DS1302_RC DS1302_D6
// Seconds Register
#define DS1302_CH DS1302_D7 // 1 = Clock Halt, 0 = start
// Hour Register
#define DS1302_AM_PM DS1302_D5 // 0 = AM, 1 = PM
#define DS1302_12_24 DS1302_D7 // 0 = 24 hour, 1 = 12 hour
// Enable Register
#define DS1302_WP DS1302_D7 // 1 = Write Protect, 0 = enabled
// Trickle Register
#define DS1302_ROUT0 DS1302_D0
#define DS1302_ROUT1 DS1302_D1
#define DS1302_DS0 DS1302_D2
#define DS1302_DS1 DS1302_D2
#define DS1302_TCS0 DS1302_D4
#define DS1302_TCS1 DS1302_D5
#define DS1302_TCS2 DS1302_D6
#define DS1302_TCS3 DS1302_D7
// Structure for the first 8 registers.
// These 8 bytes can be read at once with
// the 'clock burst' command.
// Note that this structure contains an anonymous union.
// It might cause a problem on other compilers.
typedef struct ds1302_struct
{
uint8_t Seconds:4; // low decimal digit 0-9
uint8_t Seconds10:3; // high decimal digit 0-5
uint8_t CH:1; // CH = Clock Halt
uint8_t Minutes:4;
uint8_t Minutes10:3;
uint8_t reserved1:1;
union
{
struct
{
uint8_t Hour:4;
uint8_t Hour10:2;
uint8_t reserved2:1;
uint8_t hour_12_24:1; // 0 for 24 hour format
} h24;
struct
{
uint8_t Hour:4;
uint8_t Hour10:1;
uint8_t AM_PM:1; // 0 for AM, 1 for PM
uint8_t reserved2:1;
uint8_t hour_12_24:1; // 1 for 12 hour format
} h12;
};
uint8_t Date:4; // Day of month, 1 = first day
uint8_t Date10:2;
uint8_t reserved3:2;
uint8_t Month:4; // Month, 1 = January
uint8_t Month10:1;
uint8_t reserved4:3;
uint8_t Day:3; // Day of week, 1 = first day (any day)
uint8_t reserved5:5;
uint8_t Year:4; // Year, 0 = year 2000
uint8_t Year10:4;
uint8_t reserved6:7;
uint8_t WP:1; // WP = Write Protect
};
void setup()
{
ds1302_struct rtc;
Serial.begin(9600);
Serial.println(F("DS1302 Real Time Clock"));
Serial.println(F("Version 2, March 2013"));
// Start by clearing the Write Protect bit
// Otherwise the clock data cannot be written
// The whole register is written,
// but the WP-bit is the only bit in that register.
DS1302_write (DS1302_ENABLE, 0);
// Disable Trickle Charger.
DS1302_write (DS1302_TRICKLE, 0x00);
// Remove the next define,
// after the right date and time are set.
#define SET_DATE_TIME_JUST_ONCE
#ifdef SET_DATE_TIME_JUST_ONCE
// Fill these variables with the date and time.
int seconds, minutes, hours, dayofweek, dayofmonth, month, year;
// Example for april 15, 2013, 10:08, monday is 2nd day of Week.
// Set your own time and date in these variables.
seconds = 0;
minutes = 8;
hours = 10;
dayofweek = 2; // Day of week, any day can be first, counts 1...7
dayofmonth = 15; // Day of month, 1...31
month = 4; // month 1...12
year = 2013;
// Set a time and date
// This also clears the CH (Clock Halt) bit,
// to start the clock.
// Fill the structure with zeros to make
// any unused bits zero
memset ((char *) &rtc, 0, sizeof(rtc));
rtc.Seconds = bin2bcd_l( seconds);
rtc.Seconds10 = bin2bcd_h( seconds);
rtc.CH = 0; // 1 for Clock Halt, 0 to run;
rtc.Minutes = bin2bcd_l( minutes);
rtc.Minutes10 = bin2bcd_h( minutes);
// To use the 12 hour format,
// use it like these four lines:
// rtc.h12.Hour = bin2bcd_l( hours);
// rtc.h12.Hour10 = bin2bcd_h( hours);
// rtc.h12.AM_PM = 0; // AM = 0
// rtc.h12.hour_12_24 = 1; // 1 for 24 hour format
rtc.h24.Hour = bin2bcd_l( hours);
rtc.h24.Hour10 = bin2bcd_h( hours);
rtc.h24.hour_12_24 = 0; // 0 for 24 hour format
rtc.Date = bin2bcd_l( dayofmonth);
rtc.Date10 = bin2bcd_h( dayofmonth);
rtc.Month = bin2bcd_l( month);
rtc.Month10 = bin2bcd_h( month);
rtc.Day = dayofweek;
rtc.Year = bin2bcd_l( year - 2000);
rtc.Year10 = bin2bcd_h( year - 2000);
rtc.WP = 0;
// Write all clock data at once (burst mode).
DS1302_clock_burst_write( (uint8_t *) &rtc);
#endif
}
void loop()
{
ds1302_struct rtc;
char buffer[80]; // the code uses 70 characters.
// Read all clock data at once (burst mode).
DS1302_clock_burst_read( (uint8_t *) &rtc);
sprintf( buffer, "Time = %02d:%02d:%02d, ", \
bcd2bin( rtc.h24.Hour10, rtc.h24.Hour), \
bcd2bin( rtc.Minutes10, rtc.Minutes), \
bcd2bin( rtc.Seconds10, rtc.Seconds));
Serial.print(buffer);
sprintf(buffer, "Date(day of month) = %d, Month = %d, " \
"Day(day of week) = %d, Year = %d", \
bcd2bin( rtc.Date10, rtc.Date), \
bcd2bin( rtc.Month10, rtc.Month), \
rtc.Day, \
2000 + bcd2bin( rtc.Year10, rtc.Year));
Serial.println( buffer);
delay( 5000);
}
// --------------------------------------------------------
// DS1302_clock_burst_read
//
// This function reads 8 bytes clock data in burst mode
// from the DS1302.
//
// This function may be called as the first function,
// also the pinMode is set.
//
void DS1302_clock_burst_read( uint8_t *p)
{
int i;
_DS1302_start();
// Instead of the address,
// the CLOCK_BURST_READ command is issued
// the I/O-line is released for the data
_DS1302_togglewrite( DS1302_CLOCK_BURST_READ, true);
for( i=0; i<8; i++)
{
*p++ = _DS1302_toggleread();
}
_DS1302_stop();
}
// --------------------------------------------------------
// DS1302_clock_burst_write
//
// This function writes 8 bytes clock data in burst mode
// to the DS1302.
//
// This function may be called as the first function,
// also the pinMode is set.
//
void DS1302_clock_burst_write( uint8_t *p)
{
int i;
_DS1302_start();
// Instead of the address,
// the CLOCK_BURST_WRITE command is issued.
// the I/O-line is not released
_DS1302_togglewrite( DS1302_CLOCK_BURST_WRITE, false);
for( i=0; i<8; i++)
{
// the I/O-line is not released
_DS1302_togglewrite( *p++, false);
}
_DS1302_stop();
}
// --------------------------------------------------------
// DS1302_read
//
// This function reads a byte from the DS1302
// (clock or ram).
//
// The address could be like "0x80" or "0x81",
// the lowest bit is set anyway.
//
// This function may be called as the first function,
// also the pinMode is set.
//
uint8_t DS1302_read(int address)
{
uint8_t data;
// set lowest bit (read bit) in address
bitSet( address, DS1302_READBIT);
_DS1302_start();
// the I/O-line is released for the data
_DS1302_togglewrite( address, true);
data = _DS1302_toggleread();
_DS1302_stop();
return (data);
}
// --------------------------------------------------------
// DS1302_write
//
// This function writes a byte to the DS1302 (clock or ram).
//
// The address could be like "0x80" or "0x81",
// the lowest bit is cleared anyway.
//
// This function may be called as the first function,
// also the pinMode is set.
//
void DS1302_write( int address, uint8_t data)
{
// clear lowest bit (read bit) in address
bitClear( address, DS1302_READBIT);
_DS1302_start();
// don't release the I/O-line
_DS1302_togglewrite( address, false);
// don't release the I/O-line
_DS1302_togglewrite( data, false);
_DS1302_stop();
}
// --------------------------------------------------------
// _DS1302_start
//
// A helper function to setup the start condition.
//
// An 'init' function is not used.
// But now the pinMode is set every time.
// That's not a big deal, and it's valid.
// At startup, the pins of the Arduino are high impedance.
// Since the DS1302 has pull-down resistors,
// the signals are low (inactive) until the DS1302 is used.
void _DS1302_start( void)
{
digitalWrite( DS1302_CE_PIN, LOW); // default, not enabled
pinMode( DS1302_CE_PIN, OUTPUT);
digitalWrite( DS1302_SCLK_PIN, LOW); // default, clock low
pinMode( DS1302_SCLK_PIN, OUTPUT);
pinMode( DS1302_IO_PIN, OUTPUT);
digitalWrite( DS1302_CE_PIN, HIGH); // start the session
delayMicroseconds( 4); // tCC = 4us
}
// --------------------------------------------------------
// _DS1302_stop
//
// A helper function to finish the communication.
//
void _DS1302_stop(void)
{
// Set CE low
digitalWrite( DS1302_CE_PIN, LOW);
delayMicroseconds( 4); // tCWH = 4us
}
// --------------------------------------------------------
// _DS1302_toggleread
//
// A helper function for reading a byte with bit toggle
//
// This function assumes that the SCLK is still high.
//
uint8_t _DS1302_toggleread( void)
{
uint8_t i, data;
data = 0;
for( i = 0; i <= 7; i++)
{
// Issue a clock pulse for the next databit.
// If the 'togglewrite' function was used before
// this function, the SCLK is already high.
digitalWrite( DS1302_SCLK_PIN, HIGH);
delayMicroseconds( 1);
// Clock down, data is ready after some time.
digitalWrite( DS1302_SCLK_PIN, LOW);
delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns
// read bit, and set it in place in 'data' variable
bitWrite( data, i, digitalRead( DS1302_IO_PIN));
}
return( data);
}
// --------------------------------------------------------
// _DS1302_togglewrite
//
// A helper function for writing a byte with bit toggle
//
// The 'release' parameter is for a read after this write.
// It will release the I/O-line and will keep the SCLK high.
//
void _DS1302_togglewrite( uint8_t data, uint8_t release)
{
int i;
for( i = 0; i <= 7; i++)
{
// set a bit of the data on the I/O-line
digitalWrite( DS1302_IO_PIN, bitRead(data, i));
delayMicroseconds( 1); // tDC = 200ns
// clock up, data is read by DS1302
digitalWrite( DS1302_SCLK_PIN, HIGH);
delayMicroseconds( 1); // tCH = 1000ns, tCDH = 800ns
if( release && i == 7)
{
// If this write is followed by a read,
// the I/O-line should be released after
// the last bit, before the clock line is made low.
// This is according the datasheet.
// I have seen other programs that don't release
// the I/O-line at this moment,
// and that could cause a shortcut spike
// on the I/O-line.
pinMode( DS1302_IO_PIN, INPUT);
// For Arduino 1.0.3, removing the pull-up is no longer needed.
// Setting the pin as 'INPUT' will already remove the pull-up.
// digitalWrite (DS1302_IO, LOW); // remove any pull-up
}
else
{
digitalWrite( DS1302_SCLK_PIN, LOW);
delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns
}
}
}
This worked well (even it doesn't use libraries!) This sketch sets the time, fill in values in code
After then, this code can be used to actually SEE the time. Cycle power to make sure RTC keeps time with battery backup.C:// Set your own pins with these defines ! #define DS1302_SCLK_PIN 4 // Arduino pin for the Serial Clock #define DS1302_IO_PIN 3 // Arduino pin for the Data I/O #define DS1302_CE_PIN 2u // Arduino pin for the Chip Enable // Macros to convert the bcd values of the registers to normal // integer variables. // The code uses separate variables for the high byte and the low byte // of the bcd, so these macros handle both bytes separately. #define bcd2bin(h,l) (((h)*10) + (l)) #define bin2bcd_h(x) ((x)/10) #define bin2bcd_l(x) ((x)%10) // Register names. // Since the highest bit is always '1', // the registers start at 0x80 // If the register is read, the lowest bit should be '1'. #define DS1302_SECONDS 0x80 #define DS1302_MINUTES 0x82 #define DS1302_HOURS 0x84 #define DS1302_DATE 0x86 #define DS1302_MONTH 0x88 #define DS1302_DAY 0x8A #define DS1302_YEAR 0x8C #define DS1302_ENABLE 0x8E #define DS1302_TRICKLE 0x90 #define DS1302_CLOCK_BURST 0xBE #define DS1302_CLOCK_BURST_WRITE 0xBE #define DS1302_CLOCK_BURST_READ 0xBF #define DS1302_RAMSTART 0xC0 #define DS1302_RAMEND 0xFC #define DS1302_RAM_BURST 0xFE #define DS1302_RAM_BURST_WRITE 0xFE #define DS1302_RAM_BURST_READ 0xFF // Defines for the bits, to be able to change // between bit number and binary definition. // By using the bit number, using the DS1302 // is like programming an AVR microcontroller. // But instead of using "(1<<X)", or "_BV(X)", // the Arduino "bit(X)" is used. #define DS1302_D0 0 #define DS1302_D1 1 #define DS1302_D2 2 #define DS1302_D3 3 #define DS1302_D4 4 #define DS1302_D5 5 #define DS1302_D6 6 #define DS1302_D7 7 // Bit for reading (bit in address) #define DS1302_READBIT DS1302_D0 // READBIT=1: read instruction // Bit for clock (0) or ram (1) area, // called R/C-bit (bit in address) #define DS1302_RC DS1302_D6 // Seconds Register #define DS1302_CH DS1302_D7 // 1 = Clock Halt, 0 = start // Hour Register #define DS1302_AM_PM DS1302_D5 // 0 = AM, 1 = PM #define DS1302_12_24 DS1302_D7 // 0 = 24 hour, 1 = 12 hour // Enable Register #define DS1302_WP DS1302_D7 // 1 = Write Protect, 0 = enabled // Trickle Register #define DS1302_ROUT0 DS1302_D0 #define DS1302_ROUT1 DS1302_D1 #define DS1302_DS0 DS1302_D2 #define DS1302_DS1 DS1302_D2 #define DS1302_TCS0 DS1302_D4 #define DS1302_TCS1 DS1302_D5 #define DS1302_TCS2 DS1302_D6 #define DS1302_TCS3 DS1302_D7 // Structure for the first 8 registers. // These 8 bytes can be read at once with // the 'clock burst' command. // Note that this structure contains an anonymous union. // It might cause a problem on other compilers. typedef struct ds1302_struct { uint8_t Seconds:4; // low decimal digit 0-9 uint8_t Seconds10:3; // high decimal digit 0-5 uint8_t CH:1; // CH = Clock Halt uint8_t Minutes:4; uint8_t Minutes10:3; uint8_t reserved1:1; union { struct { uint8_t Hour:4; uint8_t Hour10:2; uint8_t reserved2:1; uint8_t hour_12_24:1; // 0 for 24 hour format } h24; struct { uint8_t Hour:4; uint8_t Hour10:1; uint8_t AM_PM:1; // 0 for AM, 1 for PM uint8_t reserved2:1; uint8_t hour_12_24:1; // 1 for 12 hour format } h12; }; uint8_t Date:4; // Day of month, 1 = first day uint8_t Date10:2; uint8_t reserved3:2; uint8_t Month:4; // Month, 1 = January uint8_t Month10:1; uint8_t reserved4:3; uint8_t Day:3; // Day of week, 1 = first day (any day) uint8_t reserved5:5; uint8_t Year:4; // Year, 0 = year 2000 uint8_t Year10:4; uint8_t reserved6:7; uint8_t WP:1; // WP = Write Protect }; void setup() { ds1302_struct rtc; Serial.begin(9600); Serial.println(F("DS1302 Real Time Clock")); Serial.println(F("Version 2, March 2013")); // Start by clearing the Write Protect bit // Otherwise the clock data cannot be written // The whole register is written, // but the WP-bit is the only bit in that register. DS1302_write (DS1302_ENABLE, 0); // Disable Trickle Charger. DS1302_write (DS1302_TRICKLE, 0x00); // Remove the next define, // after the right date and time are set. #define SET_DATE_TIME_JUST_ONCE #ifdef SET_DATE_TIME_JUST_ONCE // Fill these variables with the date and time. int seconds, minutes, hours, dayofweek, dayofmonth, month, year; // Example for april 15, 2013, 10:08, monday is 2nd day of Week. // Set your own time and date in these variables. seconds = 0; minutes = 8; hours = 10; dayofweek = 2; // Day of week, any day can be first, counts 1...7 dayofmonth = 15; // Day of month, 1...31 month = 4; // month 1...12 year = 2013; // Set a time and date // This also clears the CH (Clock Halt) bit, // to start the clock. // Fill the structure with zeros to make // any unused bits zero memset ((char *) &rtc, 0, sizeof(rtc)); rtc.Seconds = bin2bcd_l( seconds); rtc.Seconds10 = bin2bcd_h( seconds); rtc.CH = 0; // 1 for Clock Halt, 0 to run; rtc.Minutes = bin2bcd_l( minutes); rtc.Minutes10 = bin2bcd_h( minutes); // To use the 12 hour format, // use it like these four lines: // rtc.h12.Hour = bin2bcd_l( hours); // rtc.h12.Hour10 = bin2bcd_h( hours); // rtc.h12.AM_PM = 0; // AM = 0 // rtc.h12.hour_12_24 = 1; // 1 for 24 hour format rtc.h24.Hour = bin2bcd_l( hours); rtc.h24.Hour10 = bin2bcd_h( hours); rtc.h24.hour_12_24 = 0; // 0 for 24 hour format rtc.Date = bin2bcd_l( dayofmonth); rtc.Date10 = bin2bcd_h( dayofmonth); rtc.Month = bin2bcd_l( month); rtc.Month10 = bin2bcd_h( month); rtc.Day = dayofweek; rtc.Year = bin2bcd_l( year - 2000); rtc.Year10 = bin2bcd_h( year - 2000); rtc.WP = 0; // Write all clock data at once (burst mode). DS1302_clock_burst_write( (uint8_t *) &rtc); #endif } void loop() { ds1302_struct rtc; char buffer[80]; // the code uses 70 characters. // Read all clock data at once (burst mode). DS1302_clock_burst_read( (uint8_t *) &rtc); sprintf( buffer, "Time = %02d:%02d:%02d, ", \ bcd2bin( rtc.h24.Hour10, rtc.h24.Hour), \ bcd2bin( rtc.Minutes10, rtc.Minutes), \ bcd2bin( rtc.Seconds10, rtc.Seconds)); Serial.print(buffer); sprintf(buffer, "Date(day of month) = %d, Month = %d, " \ "Day(day of week) = %d, Year = %d", \ bcd2bin( rtc.Date10, rtc.Date), \ bcd2bin( rtc.Month10, rtc.Month), \ rtc.Day, \ 2000 + bcd2bin( rtc.Year10, rtc.Year)); Serial.println( buffer); delay( 5000); } // -------------------------------------------------------- // DS1302_clock_burst_read // // This function reads 8 bytes clock data in burst mode // from the DS1302. // // This function may be called as the first function, // also the pinMode is set. // void DS1302_clock_burst_read( uint8_t *p) { int i; _DS1302_start(); // Instead of the address, // the CLOCK_BURST_READ command is issued // the I/O-line is released for the data _DS1302_togglewrite( DS1302_CLOCK_BURST_READ, true); for( i=0; i<8; i++) { *p++ = _DS1302_toggleread(); } _DS1302_stop(); } // -------------------------------------------------------- // DS1302_clock_burst_write // // This function writes 8 bytes clock data in burst mode // to the DS1302. // // This function may be called as the first function, // also the pinMode is set. // void DS1302_clock_burst_write( uint8_t *p) { int i; _DS1302_start(); // Instead of the address, // the CLOCK_BURST_WRITE command is issued. // the I/O-line is not released _DS1302_togglewrite( DS1302_CLOCK_BURST_WRITE, false); for( i=0; i<8; i++) { // the I/O-line is not released _DS1302_togglewrite( *p++, false); } _DS1302_stop(); } // -------------------------------------------------------- // DS1302_read // // This function reads a byte from the DS1302 // (clock or ram). // // The address could be like "0x80" or "0x81", // the lowest bit is set anyway. // // This function may be called as the first function, // also the pinMode is set. // uint8_t DS1302_read(int address) { uint8_t data; // set lowest bit (read bit) in address bitSet( address, DS1302_READBIT); _DS1302_start(); // the I/O-line is released for the data _DS1302_togglewrite( address, true); data = _DS1302_toggleread(); _DS1302_stop(); return (data); } // -------------------------------------------------------- // DS1302_write // // This function writes a byte to the DS1302 (clock or ram). // // The address could be like "0x80" or "0x81", // the lowest bit is cleared anyway. // // This function may be called as the first function, // also the pinMode is set. // void DS1302_write( int address, uint8_t data) { // clear lowest bit (read bit) in address bitClear( address, DS1302_READBIT); _DS1302_start(); // don't release the I/O-line _DS1302_togglewrite( address, false); // don't release the I/O-line _DS1302_togglewrite( data, false); _DS1302_stop(); } // -------------------------------------------------------- // _DS1302_start // // A helper function to setup the start condition. // // An 'init' function is not used. // But now the pinMode is set every time. // That's not a big deal, and it's valid. // At startup, the pins of the Arduino are high impedance. // Since the DS1302 has pull-down resistors, // the signals are low (inactive) until the DS1302 is used. void _DS1302_start( void) { digitalWrite( DS1302_CE_PIN, LOW); // default, not enabled pinMode( DS1302_CE_PIN, OUTPUT); digitalWrite( DS1302_SCLK_PIN, LOW); // default, clock low pinMode( DS1302_SCLK_PIN, OUTPUT); pinMode( DS1302_IO_PIN, OUTPUT); digitalWrite( DS1302_CE_PIN, HIGH); // start the session delayMicroseconds( 4); // tCC = 4us } // -------------------------------------------------------- // _DS1302_stop // // A helper function to finish the communication. // void _DS1302_stop(void) { // Set CE low digitalWrite( DS1302_CE_PIN, LOW); delayMicroseconds( 4); // tCWH = 4us } // -------------------------------------------------------- // _DS1302_toggleread // // A helper function for reading a byte with bit toggle // // This function assumes that the SCLK is still high. // uint8_t _DS1302_toggleread( void) { uint8_t i, data; data = 0; for( i = 0; i <= 7; i++) { // Issue a clock pulse for the next databit. // If the 'togglewrite' function was used before // this function, the SCLK is already high. digitalWrite( DS1302_SCLK_PIN, HIGH); delayMicroseconds( 1); // Clock down, data is ready after some time. digitalWrite( DS1302_SCLK_PIN, LOW); delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns // read bit, and set it in place in 'data' variable bitWrite( data, i, digitalRead( DS1302_IO_PIN)); } return( data); } // -------------------------------------------------------- // _DS1302_togglewrite // // A helper function for writing a byte with bit toggle // // The 'release' parameter is for a read after this write. // It will release the I/O-line and will keep the SCLK high. // void _DS1302_togglewrite( uint8_t data, uint8_t release) { int i; for( i = 0; i <= 7; i++) { // set a bit of the data on the I/O-line digitalWrite( DS1302_IO_PIN, bitRead(data, i)); delayMicroseconds( 1); // tDC = 200ns // clock up, data is read by DS1302 digitalWrite( DS1302_SCLK_PIN, HIGH); delayMicroseconds( 1); // tCH = 1000ns, tCDH = 800ns if( release && i == 7) { // If this write is followed by a read, // the I/O-line should be released after // the last bit, before the clock line is made low. // This is according the datasheet. // I have seen other programs that don't release // the I/O-line at this moment, // and that could cause a shortcut spike // on the I/O-line. pinMode( DS1302_IO_PIN, INPUT); // For Arduino 1.0.3, removing the pull-up is no longer needed. // Setting the pin as 'INPUT' will already remove the pull-up. // digitalWrite (DS1302_IO, LOW); // remove any pull-up } else { digitalWrite( DS1302_SCLK_PIN, LOW); delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns } } }
Could you test these?C:// Set your own pins with these defines ! #define DS1302_SCLK_PIN 4 // Arduino pin for the Serial Clock #define DS1302_IO_PIN 3 // Arduino pin for the Data I/O #define DS1302_CE_PIN 2u // Arduino pin for the Chip Enable // Macros to convert the bcd values of the registers to normal // integer variables. // The code uses separate variables for the high byte and the low byte // of the bcd, so these macros handle both bytes separately. #define bcd2bin(h,l) (((h)*10) + (l)) #define bin2bcd_h(x) ((x)/10) #define bin2bcd_l(x) ((x)%10) // Register names. // Since the highest bit is always '1', // the registers start at 0x80 // If the register is read, the lowest bit should be '1'. #define DS1302_SECONDS 0x80 #define DS1302_MINUTES 0x82 #define DS1302_HOURS 0x84 #define DS1302_DATE 0x86 #define DS1302_MONTH 0x88 #define DS1302_DAY 0x8A #define DS1302_YEAR 0x8C #define DS1302_ENABLE 0x8E #define DS1302_TRICKLE 0x90 #define DS1302_CLOCK_BURST 0xBE #define DS1302_CLOCK_BURST_WRITE 0xBE #define DS1302_CLOCK_BURST_READ 0xBF #define DS1302_RAMSTART 0xC0 #define DS1302_RAMEND 0xFC #define DS1302_RAM_BURST 0xFE #define DS1302_RAM_BURST_WRITE 0xFE #define DS1302_RAM_BURST_READ 0xFF // Defines for the bits, to be able to change // between bit number and binary definition. // By using the bit number, using the DS1302 // is like programming an AVR microcontroller. // But instead of using "(1<<X)", or "_BV(X)", // the Arduino "bit(X)" is used. #define DS1302_D0 0 #define DS1302_D1 1 #define DS1302_D2 2 #define DS1302_D3 3 #define DS1302_D4 4 #define DS1302_D5 5 #define DS1302_D6 6 #define DS1302_D7 7 // Bit for reading (bit in address) #define DS1302_READBIT DS1302_D0 // READBIT=1: read instruction // Bit for clock (0) or ram (1) area, // called R/C-bit (bit in address) #define DS1302_RC DS1302_D6 // Seconds Register #define DS1302_CH DS1302_D7 // 1 = Clock Halt, 0 = start // Hour Register #define DS1302_AM_PM DS1302_D5 // 0 = AM, 1 = PM #define DS1302_12_24 DS1302_D7 // 0 = 24 hour, 1 = 12 hour // Enable Register #define DS1302_WP DS1302_D7 // 1 = Write Protect, 0 = enabled // Trickle Register #define DS1302_ROUT0 DS1302_D0 #define DS1302_ROUT1 DS1302_D1 #define DS1302_DS0 DS1302_D2 #define DS1302_DS1 DS1302_D2 #define DS1302_TCS0 DS1302_D4 #define DS1302_TCS1 DS1302_D5 #define DS1302_TCS2 DS1302_D6 #define DS1302_TCS3 DS1302_D7 // Structure for the first 8 registers. // These 8 bytes can be read at once with // the 'clock burst' command. // Note that this structure contains an anonymous union. // It might cause a problem on other compilers. typedef struct ds1302_struct { uint8_t Seconds:4; // low decimal digit 0-9 uint8_t Seconds10:3; // high decimal digit 0-5 uint8_t CH:1; // CH = Clock Halt uint8_t Minutes:4; uint8_t Minutes10:3; uint8_t reserved1:1; union { struct { uint8_t Hour:4; uint8_t Hour10:2; uint8_t reserved2:1; uint8_t hour_12_24:1; // 0 for 24 hour format } h24; struct { uint8_t Hour:4; uint8_t Hour10:1; uint8_t AM_PM:1; // 0 for AM, 1 for PM uint8_t reserved2:1; uint8_t hour_12_24:1; // 1 for 12 hour format } h12; }; uint8_t Date:4; // Day of month, 1 = first day uint8_t Date10:2; uint8_t reserved3:2; uint8_t Month:4; // Month, 1 = January uint8_t Month10:1; uint8_t reserved4:3; uint8_t Day:3; // Day of week, 1 = first day (any day) uint8_t reserved5:5; uint8_t Year:4; // Year, 0 = year 2000 uint8_t Year10:4; uint8_t reserved6:7; uint8_t WP:1; // WP = Write Protect }; void setup() { ds1302_struct rtc; Serial.begin(9600); Serial.println(F("DS1302 Real Time Clock")); Serial.println(F("Version 2, March 2013")); // Start by clearing the Write Protect bit // Otherwise the clock data cannot be written // The whole register is written, // but the WP-bit is the only bit in that register. DS1302_write (DS1302_ENABLE, 0); // Disable Trickle Charger. DS1302_write (DS1302_TRICKLE, 0x00); // Remove the next define, // after the right date and time are set. #define SET_DATE_TIME_JUST_ONCE #ifdef SET_DATE_TIME_JUST_ONCE // Fill these variables with the date and time. int seconds, minutes, hours, dayofweek, dayofmonth, month, year; // Example for april 15, 2013, 10:08, monday is 2nd day of Week. // Set your own time and date in these variables. seconds = 0; minutes = 8; hours = 10; dayofweek = 2; // Day of week, any day can be first, counts 1...7 dayofmonth = 15; // Day of month, 1...31 month = 4; // month 1...12 year = 2013; // Set a time and date // This also clears the CH (Clock Halt) bit, // to start the clock. // Fill the structure with zeros to make // any unused bits zero memset ((char *) &rtc, 0, sizeof(rtc)); rtc.Seconds = bin2bcd_l( seconds); rtc.Seconds10 = bin2bcd_h( seconds); rtc.CH = 0; // 1 for Clock Halt, 0 to run; rtc.Minutes = bin2bcd_l( minutes); rtc.Minutes10 = bin2bcd_h( minutes); // To use the 12 hour format, // use it like these four lines: // rtc.h12.Hour = bin2bcd_l( hours); // rtc.h12.Hour10 = bin2bcd_h( hours); // rtc.h12.AM_PM = 0; // AM = 0 // rtc.h12.hour_12_24 = 1; // 1 for 24 hour format rtc.h24.Hour = bin2bcd_l( hours); rtc.h24.Hour10 = bin2bcd_h( hours); rtc.h24.hour_12_24 = 0; // 0 for 24 hour format rtc.Date = bin2bcd_l( dayofmonth); rtc.Date10 = bin2bcd_h( dayofmonth); rtc.Month = bin2bcd_l( month); rtc.Month10 = bin2bcd_h( month); rtc.Day = dayofweek; rtc.Year = bin2bcd_l( year - 2000); rtc.Year10 = bin2bcd_h( year - 2000); rtc.WP = 0; // Write all clock data at once (burst mode). DS1302_clock_burst_write( (uint8_t *) &rtc); #endif } void loop() { ds1302_struct rtc; char buffer[80]; // the code uses 70 characters. // Read all clock data at once (burst mode). DS1302_clock_burst_read( (uint8_t *) &rtc); sprintf( buffer, "Time = %02d:%02d:%02d, ", \ bcd2bin( rtc.h24.Hour10, rtc.h24.Hour), \ bcd2bin( rtc.Minutes10, rtc.Minutes), \ bcd2bin( rtc.Seconds10, rtc.Seconds)); Serial.print(buffer); sprintf(buffer, "Date(day of month) = %d, Month = %d, " \ "Day(day of week) = %d, Year = %d", \ bcd2bin( rtc.Date10, rtc.Date), \ bcd2bin( rtc.Month10, rtc.Month), \ rtc.Day, \ 2000 + bcd2bin( rtc.Year10, rtc.Year)); Serial.println( buffer); delay( 5000); } // -------------------------------------------------------- // DS1302_clock_burst_read // // This function reads 8 bytes clock data in burst mode // from the DS1302. // // This function may be called as the first function, // also the pinMode is set. // void DS1302_clock_burst_read( uint8_t *p) { int i; _DS1302_start(); // Instead of the address, // the CLOCK_BURST_READ command is issued // the I/O-line is released for the data _DS1302_togglewrite( DS1302_CLOCK_BURST_READ, true); for( i=0; i<8; i++) { *p++ = _DS1302_toggleread(); } _DS1302_stop(); } // -------------------------------------------------------- // DS1302_clock_burst_write // // This function writes 8 bytes clock data in burst mode // to the DS1302. // // This function may be called as the first function, // also the pinMode is set. // void DS1302_clock_burst_write( uint8_t *p) { int i; _DS1302_start(); // Instead of the address, // the CLOCK_BURST_WRITE command is issued. // the I/O-line is not released _DS1302_togglewrite( DS1302_CLOCK_BURST_WRITE, false); for( i=0; i<8; i++) { // the I/O-line is not released _DS1302_togglewrite( *p++, false); } _DS1302_stop(); } // -------------------------------------------------------- // DS1302_read // // This function reads a byte from the DS1302 // (clock or ram). // // The address could be like "0x80" or "0x81", // the lowest bit is set anyway. // // This function may be called as the first function, // also the pinMode is set. // uint8_t DS1302_read(int address) { uint8_t data; // set lowest bit (read bit) in address bitSet( address, DS1302_READBIT); _DS1302_start(); // the I/O-line is released for the data _DS1302_togglewrite( address, true); data = _DS1302_toggleread(); _DS1302_stop(); return (data); } // -------------------------------------------------------- // DS1302_write // // This function writes a byte to the DS1302 (clock or ram). // // The address could be like "0x80" or "0x81", // the lowest bit is cleared anyway. // // This function may be called as the first function, // also the pinMode is set. // void DS1302_write( int address, uint8_t data) { // clear lowest bit (read bit) in address bitClear( address, DS1302_READBIT); _DS1302_start(); // don't release the I/O-line _DS1302_togglewrite( address, false); // don't release the I/O-line _DS1302_togglewrite( data, false); _DS1302_stop(); } // -------------------------------------------------------- // _DS1302_start // // A helper function to setup the start condition. // // An 'init' function is not used. // But now the pinMode is set every time. // That's not a big deal, and it's valid. // At startup, the pins of the Arduino are high impedance. // Since the DS1302 has pull-down resistors, // the signals are low (inactive) until the DS1302 is used. void _DS1302_start( void) { digitalWrite( DS1302_CE_PIN, LOW); // default, not enabled pinMode( DS1302_CE_PIN, OUTPUT); digitalWrite( DS1302_SCLK_PIN, LOW); // default, clock low pinMode( DS1302_SCLK_PIN, OUTPUT); pinMode( DS1302_IO_PIN, OUTPUT); digitalWrite( DS1302_CE_PIN, HIGH); // start the session delayMicroseconds( 4); // tCC = 4us } // -------------------------------------------------------- // _DS1302_stop // // A helper function to finish the communication. // void _DS1302_stop(void) { // Set CE low digitalWrite( DS1302_CE_PIN, LOW); delayMicroseconds( 4); // tCWH = 4us } // -------------------------------------------------------- // _DS1302_toggleread // // A helper function for reading a byte with bit toggle // // This function assumes that the SCLK is still high. // uint8_t _DS1302_toggleread( void) { uint8_t i, data; data = 0; for( i = 0; i <= 7; i++) { // Issue a clock pulse for the next databit. // If the 'togglewrite' function was used before // this function, the SCLK is already high. digitalWrite( DS1302_SCLK_PIN, HIGH); delayMicroseconds( 1); // Clock down, data is ready after some time. digitalWrite( DS1302_SCLK_PIN, LOW); delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns // read bit, and set it in place in 'data' variable bitWrite( data, i, digitalRead( DS1302_IO_PIN)); } return( data); } // -------------------------------------------------------- // _DS1302_togglewrite // // A helper function for writing a byte with bit toggle // // The 'release' parameter is for a read after this write. // It will release the I/O-line and will keep the SCLK high. // void _DS1302_togglewrite( uint8_t data, uint8_t release) { int i; for( i = 0; i <= 7; i++) { // set a bit of the data on the I/O-line digitalWrite( DS1302_IO_PIN, bitRead(data, i)); delayMicroseconds( 1); // tDC = 200ns // clock up, data is read by DS1302 digitalWrite( DS1302_SCLK_PIN, HIGH); delayMicroseconds( 1); // tCH = 1000ns, tCDH = 800ns if( release && i == 7) { // If this write is followed by a read, // the I/O-line should be released after // the last bit, before the clock line is made low. // This is according the datasheet. // I have seen other programs that don't release // the I/O-line at this moment, // and that could cause a shortcut spike // on the I/O-line. pinMode( DS1302_IO_PIN, INPUT); // For Arduino 1.0.3, removing the pull-up is no longer needed. // Setting the pin as 'INPUT' will already remove the pull-up. // digitalWrite (DS1302_IO, LOW); // remove any pull-up } else { digitalWrite( DS1302_SCLK_PIN, LOW); delayMicroseconds( 1); // tCL=1000ns, tCDD=800ns } } }
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