PCF2127 and PCF2129 are high accuracy real-time-clock (RTC) module. This library provides simple interface to accessing clock information.
Dependents: PCF2127_Demo PCF2127_Hello
PCF2127 and PCF2129
PCF2127T is in SO16 package
The PCF2127 and the PCF2129 are a CMOS Real Time Clock (RTC) and calendar with an integrated Temperature Compensated Crystal (Xtal) Oscillator (TCXO) and a 32.768 kHz quartz crystal optimized for very high accuracy and very low power consumption.
Both of PCF2127 and PCF2129 have a selectable I2C-bus or SPI-bus, a backup battery switch-over circuit, a programmable watchdog function, a timestamp function, and many other features.
On addition to this, the PCF2127 has 512 bytes of general-purpose static RAM.
These 4 types of RTC modules are software compatible. So this library "PCF2127" can be used all of those.
This library only supports I2C to communicate with the PCF2127/PCF2129.
Type variations
Main feature difference
type | +/-3ppm accuracy range | 512 bytes RAM | package |
---|---|---|---|
PCF2127T | -30℃ to +80℃ | yes | SO16 |
PCF2127AT | -30℃ to +60℃ | yes | SO20 |
PCF2129T | -30℃ to +80℃ | not available | SO16 |
PCF2129AT | -15℃ to +60℃ | not available | SO20 |
Pin assign
PCF2127T
Connection between MCU and PCF2127/PCF2129
These examples show how the RTC module can be connected via I2C bus.
References
- Datasheet
- User manual
- Other information PCF2127
Revision 0:1377bcf1455e, committed 2014-12-04
- Comitter:
- nxp_ip
- Date:
- Thu Dec 04 04:58:24 2014 +0000
- Child:
- 1:700e0285cfd8
- Commit message:
- initial version
Changed in this revision
PCF2127.cpp | Show annotated file Show diff for this revision Revisions of this file |
PCF2127.h | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/PCF2127.cpp Thu Dec 04 04:58:24 2014 +0000 @@ -0,0 +1,148 @@ +/* + * PCF2127 library + * + * @author Akifumi (Tedd) OKANO, NXP Semiconductors + * @version 1.5 + * @date 04-Dec-2014 + * + * PCF2127 is a "real time clock (RTC)" module which is including a Xtal and TCXO + * http://www.nxp.com/products/interface_and_connectivity/real_time_clocks/rtcs_with_temp_compensation/series/PCF2127.html + * + * RTC initializing part is ported from.. + * http://mbed.org/users/roen/notebook/real-time/ + * + * This code is refined version of.. + * http://developer.mbed.org/users/okano/code/NXP_PCF2127A/ + */ + +#include "mbed.h" +#include "PCF2127.h" + +#define PCF2127_I2C_SLAVE_ADDRESS 0xA2 + +PCF2127::PCF2127( PinName sda, PinName sdl, char vControl_1, char vControl_2, char vControl_3 ) + : i2c( sda, sdl ), device_address( PCF2127_I2C_SLAVE_ADDRESS ) +{ + set_register( Control_1, vControl_1 ); + set_register( Control_2, vControl_2 ); + set_register( Control_3, vControl_3 ); +} + +PCF2127::~PCF2127() +{ +} + +int PCF2127::is_init_required( void ) +{ + return ( read_register( Seconds ) & 0x80 ? true : false ); +} + +void PCF2127::set_time( struct tm *dtp ) +{ + char buf[ 8 ]; + char c; + + buf[ 0 ] = Seconds; + buf[ 1 ] = i2bcd( dtp->tm_sec ); + buf[ 2 ] = i2bcd( dtp->tm_min ); + buf[ 3 ] = i2bcd( dtp->tm_hour ); + buf[ 4 ] = i2bcd( dtp->tm_mday ); + buf[ 5 ] = i2bcd( dtp->tm_wday ); + buf[ 6 ] = i2bcd( dtp->tm_mon + 1 ); + buf[ 7 ] = i2bcd( dtp->tm_year - 100 ); + + c = read_register( Seconds ); + while ( c == read_register( Seconds ) ) + ; + + i2c.write( device_address, buf, 8 ); +} + +void PCF2127::set_time( char *s ) +{ + // The time information should be given in format of "YYYY MM DD HH MM SS" + + struct tm dt, *dtp; + + dtp = &dt; + + sscanf( s, "%d %d %d %d %d %d", &(dtp->tm_year), &(dtp->tm_mon), &(dtp->tm_mday), &(dtp->tm_hour), &(dtp->tm_min), &(dtp->tm_sec) ); + printf( "%d/%d/%d - %d:%d:%d\r\n", (dtp->tm_year), (dtp->tm_mon), (dtp->tm_mday), (dtp->tm_hour), (dtp->tm_min), (dtp->tm_sec) ); + + // adjust for tm structure required values + dtp->tm_year = dtp->tm_year - 1900; + dtp->tm_mon = dtp->tm_mon - 1; + + set_time( dtp ); +} + +time_t PCF2127::time( time_t *tp ) +{ + struct tm dt, *dtp; + time_t t; + char buf[ 8 ] = { Seconds }; + + dtp = &dt; + + i2c.write( device_address, buf, 1 ); + i2c.read( device_address, buf, 7 ); + + dtp->tm_sec = bcd2i( buf[ 0 ] ); + dtp->tm_min = bcd2i( buf[ 1 ] ); + dtp->tm_hour = bcd2i( buf[ 2 ] ); + dtp->tm_mday = bcd2i( buf[ 3 ] ); + dtp->tm_wday = bcd2i( buf[ 4 ] ); + dtp->tm_mon = bcd2i( buf[ 5 ] ) - 1; + dtp->tm_year = bcd2i( buf[ 6 ] ) + 100; + + t = mktime( dtp ); + + if ( tp ) + *tp = t; + + return( t ); +} + +void PCF2127::set_alarm( char addr, char s ) +{ + char v; + + v = i2bcd( s ); + set_register( addr, v ); +} + +void PCF2127::clear_intr( void ) +{ + set_register( Control_2, 0x00 ); +} + +void PCF2127::set_register( char addr, char data ) +{ + char b[ 2 ]; + + b[ 0 ] = addr; + b[ 1 ] = data; + + i2c.write( device_address, b, 2 ); +} + +char PCF2127::read_register( char addr ) +{ + char data; + + data = addr; + i2c.write( device_address, &data, 1 ); + i2c.read( device_address, &data, 1 ); + + return ( data ); +} + +char PCF2127::i2bcd( char n ) +{ + return ( ((n / 10) << 4) | (n % 10) ); +} + +char PCF2127::bcd2i( char bcd ) +{ + return ( ((bcd >> 4) * 10) + (bcd & 0x0F) ); +}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/PCF2127.h Thu Dec 04 04:58:24 2014 +0000 @@ -0,0 +1,121 @@ +/* + * PCF2127 library + * + * @author Akifumi (Tedd) OKANO, NXP Semiconductors + * @version 1.5 + * @date 04-Dec-2014 + * + * PCF2127 is a "real time clock (RTC)" module which is including a Xtal and TCXO + * http://www.nxp.com/products/interface_and_connectivity/real_time_clocks/rtcs_with_temp_compensation/series/PCF2127.html + * + * RTC initializing part is ported from.. + * http://mbed.org/users/roen/notebook/real-time/ + * + * This code is refined version of.. + * http://developer.mbed.org/users/okano/code/NXP_PCF2127A/ + */ + +#ifndef MBED_PCF2127 +#define MBED_PCF2127 + +#include "mbed.h" + +class PCF2127 +{ +public: + + /** name of the PCF2127 registers */ + typedef enum { + Control_1, + Control_2, + Control_3, + Seconds, + Minutes, + Hours, + Days, + Weekdays, + Months, + Years, + Second_alarm, + Minute_alarm, + Hour_alarm, + Day_alarm, + Weekday_alarm, + CLKOUT_ctl, + Watchdg_tim_ctl, + Watchdg_tim_val, + Timestp_ctl, + Sec_timestp, + Min_timestp, + Hour_timestp, + Day_timestp, + Mon_timestp, + Year_timestp, + Aging_offset + } + RegisterName; + + /** Create a PCF2127 instance connected to specified I2C pins with specified address + * + * @param I2C_sda I2C-bus SDA pin + * @param I2C_scl I2C-bus SCL pin + * @param vControl_1 (option) data for Control_1 register + * @param vControl_2 (option) data for Control_2 register + * @param vControl_3 (option) data for Control_3 register + */ + PCF2127( PinName sda, PinName sdl, char vControl_1 = 0x03, char vControl_2 = 0x00, char vControl_3 = 0x60 ); + + /** Destractor + */ + ~PCF2127(); + + /** Clock integrity check + * + * @return non-zero value if the clock was stopped (means need to set the time) + */ + int is_init_required( void ); + + /** Set the time + * + * @param dtp Pointer to struct tm + */ + void set_time( struct tm *dtp ); + + /** Set the time + * @param s String data: The time information should be given in format of "YYYY MM DD HH MM SS" + */ + void set_time( char *s ); + + /** Get time of day + * + * This function works similar to "time()" in standard-C-library + * + * @param tp Pointer to time_t + */ + time_t time( time_t *tp ); + + /** Register access interface with integer to BCD conversion + * + * @param addr Register address + * @param Integer data. Converted to BCD before writing inot the register. + */ + void set_alarm( char addr, char s ); + + /** Clear interrupt flag + * + * Clears interrupt flags by writing 0x00 into Control_2 register + * + */ + void clear_intr( void ); + +private: + void set_register( char addr, char data ); + char read_register( char addr ); + char i2bcd( char n ); + char bcd2i( char bcd ); + + I2C i2c; + char device_address; +} +; +#endif // end of "#ifndef MBED_PCF2127"