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 2:db76c68f998f, committed 2014-12-10
- Comitter:
- nxp_ip
- Date:
- Wed Dec 10 01:43:30 2014 +0000
- Parent:
- 1:700e0285cfd8
- Child:
- 3:e2a6ac61fcbd
- Commit message:
- internal RAM access API has been added (for PCF2127 only)
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 |
--- a/PCF2127.cpp Tue Dec 09 07:21:13 2014 +0000 +++ b/PCF2127.cpp Wed Dec 10 01:43:30 2014 +0000 @@ -2,8 +2,8 @@ * PCF2127 library * * @author Akifumi (Tedd) OKANO, NXP Semiconductors - * @version 1.6 - * @date 09-Dec-2014 + * @version 1.7 + * @date 10-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 @@ -42,12 +42,12 @@ { char data[ 4 ]; int err; - + data[ 0 ] = Control_1; // access start register address data[ 1 ] = vControl_1; data[ 2 ] = vControl_2; data[ 3 ] = vControl_3; - + err = i2c.write( device_address, data, sizeof( data ) ); err |= set_register( CLKOUT_ctl, vCLKOUT_ctl ); @@ -74,7 +74,7 @@ buf[ 7 ] = i2bcd( dtp->tm_year - 100 ); err = i2c.write( device_address, buf, 8 ); - + return ( err ? I2C_ACCESS_FAIL : NO_ERROR ); } @@ -138,7 +138,7 @@ char v; v = i2bcd( s ); - + return ( set_register( addr, v ) ); } @@ -147,6 +147,46 @@ return ( set_register( Control_2, 0x00 ) ); } +int PCF2127::RAM_write( int address, char *p, int size ) +{ + char b[ size + 1 ]; + + b[ 0 ] = RAM_wrt_cmd; + + for ( int i = 1; i <= size; i++ ) + b[ i ] = *p++; + + if ( set_RAM_address( address ) ) + return ( I2C_ACCESS_FAIL ); + + return ( i2c.write( device_address, b, sizeof( b ) ) ? I2C_ACCESS_FAIL : NO_ERROR ); +} + +int PCF2127::RAM_read( int address, char *p, int size ) +{ + char b = RAM_rd_cmd; + + if ( set_RAM_address( address ) ) + return ( I2C_ACCESS_FAIL ); + + if ( i2c.write( device_address, &b, 1 ) ) + return ( I2C_ACCESS_FAIL ); + + return ( i2c.read( device_address, p, size ) ? I2C_ACCESS_FAIL : NO_ERROR ); +} + + +int PCF2127::set_RAM_address( char address ) +{ + char b[ 3 ]; + + b[ 0 ] = RAM_addr_MSB; + b[ 1 ] = (address >> 8) & 0x1; + b[ 2 ] = address & 0xFF; + + return ( i2c.write( device_address, b, sizeof( b ) ) ); +} + int PCF2127::set_register( char addr, char data ) { char b[ 2 ]; @@ -154,7 +194,7 @@ b[ 0 ] = addr; b[ 1 ] = data; - return ( i2c.write( device_address, b, 2 ) ); + return ( i2c.write( device_address, b, sizeof( b ) ) ); } int PCF2127::read_register( char addr )
--- a/PCF2127.h Tue Dec 09 07:21:13 2014 +0000 +++ b/PCF2127.h Wed Dec 10 01:43:30 2014 +0000 @@ -2,8 +2,8 @@ * PCF2127 library * * @author Akifumi (Tedd) OKANO, NXP Semiconductors - * @version 1.6 - * @date 09-Dec-2014 + * @version 1.7 + * @date 10-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 @@ -51,10 +51,14 @@ Day_timestp, Mon_timestp, Year_timestp, - Aging_offset + Aging_offset, + RAM_addr_MSB, + RAM_addr_LSB, + RAM_wrt_cmd, + RAM_rd_cmd } RegisterName; - + /** Error code */ typedef enum { NO_ERROR = 0, @@ -63,53 +67,57 @@ TIME_FUNC_ERROR = ((time_t)-1) } ErrorNum; - + /** 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 (default setting generates interrupts by second and minute) - * @param vControl_2 (option) data for Control_2 register - * @param vControl_3 (option) data for Control_3 register (default setting of battery switch-over function as standard mode) - * @param vCLKOUT_ctl (option) data for CLKOUT_ctl register (default setting 1Hz output on CLKOUT pin) + * @param I2C_sda I2C-bus SDA pin + * @param I2C_scl I2C-bus SCL pin + * @param vControl_1 (option) data for Control_1 register (default setting generates interrupts by second and minute) + * @param vControl_2 (option) data for Control_2 register + * @param vControl_3 (option) data for Control_3 register (default setting of battery switch-over function as standard mode) + * @param vCLKOUT_ctl (option) data for CLKOUT_ctl register (default setting 1Hz output on CLKOUT pin) CLKOUT_ctl */ PCF2127( PinName sda, PinName sdl, char vControl_1 = Cntl1, char vControl_2 = Cntl2, char vControl_3 = Cntl1, char vCLKOUT_ctl = ClkOut ); /** Create a PCF2127 instance connected to specified I2C pins with specified address * - * @param i2c I2C object (instance) - * @param vControl_1 (option) data for Control_1 register (default setting generates interrupts by second and minute) - * @param vControl_2 (option) data for Control_2 register - * @param vControl_3 (option) data for Control_3 register (default setting of battery switch-over function as standard mode) - * @param vCLKOUT_ctl (option) data for CLKOUT_ctl register (default setting 1Hz output on CLKOUT pin) + * @param i2c I2C object (instance) + * @param vControl_1 (option) data for Control_1 register (default setting generates interrupts by second and minute) + * @param vControl_2 (option) data for Control_2 register + * @param vControl_3 (option) data for Control_3 register (default setting of battery switch-over function as standard mode) + * @param vCLKOUT_ctl (option) data for CLKOUT_ctl register (default setting 1Hz output on CLKOUT pin) */ PCF2127( I2C &i2c, char vControl_1 = Cntl1, char vControl_2 = Cntl2, char vControl_3 = Cntl1, char vCLKOUT_ctl = ClkOut ); - + /** Destractor */ ~PCF2127(); /** Clock integrity check * - * @return non-zero value if the clock was stopped (means need to set the time) + * @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 + * @param dtp Pointer to struct tm + * @return Error code (NO_ERROR==0) */ int set_time( struct tm *dtp ); - + /** Set the time * - * @param tp pointer to time_t + * @param tp pointer to time_t + * @return Error code (NO_ERROR==0) */ int set_time( time_t *tp ); /** Set the time - * @param s String data: The time information should be given in format of "YYYY MM DD HH MM SS" + * + * @param s String data: The time information should be given in format of "YYYY MM DD HH MM SS" + * @return Error code (NO_ERROR==0) */ int set_time( char *s ); @@ -117,14 +125,16 @@ * * This function works similar to "time()" in standard-C-library * - * @param tp Pointer to time_t + * @param tp Pointer to time_t + * @return Error code (NO_ERROR==0) */ 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. + * @param s Integer data. Converted to BCD before writing inot the register. + * @return Error code (NO_ERROR==0) */ int set_alarm( char addr, char s ); @@ -132,9 +142,32 @@ * * Clears interrupt flags by writing 0x00 into Control_2 register * + * @return Error code (NO_ERROR==0) */ int clear_intr( void ); + /** Writing data into RAM (for PCF2127 only) + * + * Write data into PCF2127 internal RAM + * + * @param address target address of internal RAM + * @param *p pointer to write data buffer + * @param size size of writing data + * @return Error code (NO_ERROR==0) + */ + int RAM_write( int address, char *p, int size ); + + /** Reading data from RAM (for PCF2127 only) + * + * Read data from PCF2127 internal RAM + * + * @param address target address of internal RAM + * @param *p pointer to read data buffer + * @param size size of writing data + * @return Error code (NO_ERROR==0) + */ + int RAM_read( int address, char *p, int size ); + private: typedef enum { @@ -144,13 +177,14 @@ ClkOut = 0x46 } DefaultRegParam; - + int init( char vControl_1, char vControl_2, char vControl_3, char vCLKOUT_ctl ); int set_register( char addr, char data ); int read_register( char addr ); char i2bcd( char n ); char bcd2i( char bcd ); - + int set_RAM_address( char address ); + I2C *i2c_p; I2C &i2c; char device_address;