InetrfaceProducts NXP / PCF2127

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 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 range512 bytes RAMpackage
PCF2127T-30℃ to +80℃yesSO16
PCF2127AT-30℃ to +60℃yesSO20
PCF2129T-30℃ to +80℃not availableSO16
PCF2129AT-15℃ to +60℃not availableSO20

Pin assign

/media/uploads/nxp_ip/pcf2127_pcf2129_pin_assign.png

PCF2127T
PCF2127T

Connection between MCU and PCF2127/PCF2129

These examples show how the RTC module can be connected via I2C bus.

http://developer.mbed.org/media/components/pinouts/both_types_connection3.png

References

PCF2127.h@3:e2a6ac61fcbd, 2014-12-10 (annotated)

Committer:
nxp_ip
Date:
Wed Dec 10 02:07:35 2014 +0000
Revision:
3:e2a6ac61fcbd
Parent:
2:db76c68f998f 
online document (class description) updated

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nxp_ip 0:1377bcf1455e 1 /*
nxp_ip 0:1377bcf1455e 2 * PCF2127 library
nxp_ip 0:1377bcf1455e 3 *
nxp_ip 0:1377bcf1455e 4 * @author Akifumi (Tedd) OKANO, NXP Semiconductors
nxp_ip 3:e2a6ac61fcbd 5 * @version 1.8
nxp_ip 2:db76c68f998f 6 * @date 10-Dec-2014
nxp_ip 0:1377bcf1455e 7 *
nxp_ip 0:1377bcf1455e 8 * PCF2127 is a "real time clock (RTC)" module which is including a Xtal and TCXO
nxp_ip 0:1377bcf1455e 9 * http://www.nxp.com/products/interface_and_connectivity/real_time_clocks/rtcs_with_temp_compensation/series/PCF2127.html
nxp_ip 0:1377bcf1455e 10 *
nxp_ip 0:1377bcf1455e 11 * RTC initializing part is ported from..
nxp_ip 0:1377bcf1455e 12 * http://mbed.org/users/roen/notebook/real-time/
nxp_ip 0:1377bcf1455e 13 *
nxp_ip 0:1377bcf1455e 14 * This code is refined version of..
nxp_ip 0:1377bcf1455e 15 * http://developer.mbed.org/users/okano/code/NXP_PCF2127A/
nxp_ip 0:1377bcf1455e 16 */
nxp_ip 0:1377bcf1455e 17
nxp_ip 0:1377bcf1455e 18 #ifndef MBED_PCF2127
nxp_ip 0:1377bcf1455e 19 #define MBED_PCF2127
nxp_ip 0:1377bcf1455e 20
nxp_ip 0:1377bcf1455e 21 #include "mbed.h"
nxp_ip 0:1377bcf1455e 22
nxp_ip 3:e2a6ac61fcbd 23 /** PCF2127 class
nxp_ip 3:e2a6ac61fcbd 24 *
nxp_ip 3:e2a6ac61fcbd 25 * This is a driver code for the PPCF2127: "real time clock (RTC)" module which is including a Xtal and TCXO
nxp_ip 3:e2a6ac61fcbd 26 * This class provides interface for PCF2127 operation and accessing its registers.
nxp_ip 3:e2a6ac61fcbd 27 * Detail information is available on next URL.
nxp_ip 3:e2a6ac61fcbd 28 * http://www.nxp.com/products/interface_and_connectivity/real_time_clocks/rtcs_with_temp_compensation/series/PCF2127.html
nxp_ip 3:e2a6ac61fcbd 29 *
nxp_ip 3:e2a6ac61fcbd 30 * Example:
nxp_ip 3:e2a6ac61fcbd 31 * @code
nxp_ip 3:e2a6ac61fcbd 32 * #include "mbed.h"
nxp_ip 3:e2a6ac61fcbd 33 * #include "PCF2127.h"
nxp_ip 3:e2a6ac61fcbd 34 *
nxp_ip 3:e2a6ac61fcbd 35 * PCF2127 rtc( p28, p27 );
nxp_ip 3:e2a6ac61fcbd 36 *
nxp_ip 3:e2a6ac61fcbd 37 * int main()
nxp_ip 3:e2a6ac61fcbd 38 * {
nxp_ip 3:e2a6ac61fcbd 39 * time_t t;
nxp_ip 3:e2a6ac61fcbd 40 *
nxp_ip 3:e2a6ac61fcbd 41 * printf( "PCF2127 demo started.\r\n" );
nxp_ip 3:e2a6ac61fcbd 42 *
nxp_ip 3:e2a6ac61fcbd 43 * if ( rtc.is_init_required() ) {
nxp_ip 3:e2a6ac61fcbd 44 * rtc.set_time( "2014 12 10 12 00 00" );
nxp_ip 3:e2a6ac61fcbd 45 * }
nxp_ip 3:e2a6ac61fcbd 46 *
nxp_ip 3:e2a6ac61fcbd 47 * while ( 1 ) {
nxp_ip 3:e2a6ac61fcbd 48 * t = rtc.time( NULL );
nxp_ip 3:e2a6ac61fcbd 49 * printf( "%s\r", ctime( &t ) );
nxp_ip 3:e2a6ac61fcbd 50 * wait( 0.25 );
nxp_ip 3:e2a6ac61fcbd 51 * }
nxp_ip 3:e2a6ac61fcbd 52 * }
nxp_ip 3:e2a6ac61fcbd 53 * @endcode
nxp_ip 3:e2a6ac61fcbd 54 */
nxp_ip 3:e2a6ac61fcbd 55
nxp_ip 0:1377bcf1455e 56 class PCF2127
nxp_ip 0:1377bcf1455e 57 {
nxp_ip 0:1377bcf1455e 58 public:
nxp_ip 0:1377bcf1455e 59
nxp_ip 0:1377bcf1455e 60 /** name of the PCF2127 registers */
nxp_ip 0:1377bcf1455e 61 typedef enum {
nxp_ip 0:1377bcf1455e 62 Control_1,
nxp_ip 0:1377bcf1455e 63 Control_2,
nxp_ip 0:1377bcf1455e 64 Control_3,
nxp_ip 0:1377bcf1455e 65 Seconds,
nxp_ip 0:1377bcf1455e 66 Minutes,
nxp_ip 0:1377bcf1455e 67 Hours,
nxp_ip 0:1377bcf1455e 68 Days,
nxp_ip 0:1377bcf1455e 69 Weekdays,
nxp_ip 0:1377bcf1455e 70 Months,
nxp_ip 0:1377bcf1455e 71 Years,
nxp_ip 0:1377bcf1455e 72 Second_alarm,
nxp_ip 0:1377bcf1455e 73 Minute_alarm,
nxp_ip 0:1377bcf1455e 74 Hour_alarm,
nxp_ip 0:1377bcf1455e 75 Day_alarm,
nxp_ip 0:1377bcf1455e 76 Weekday_alarm,
nxp_ip 0:1377bcf1455e 77 CLKOUT_ctl,
nxp_ip 0:1377bcf1455e 78 Watchdg_tim_ctl,
nxp_ip 0:1377bcf1455e 79 Watchdg_tim_val,
nxp_ip 0:1377bcf1455e 80 Timestp_ctl,
nxp_ip 0:1377bcf1455e 81 Sec_timestp,
nxp_ip 0:1377bcf1455e 82 Min_timestp,
nxp_ip 0:1377bcf1455e 83 Hour_timestp,
nxp_ip 0:1377bcf1455e 84 Day_timestp,
nxp_ip 0:1377bcf1455e 85 Mon_timestp,
nxp_ip 0:1377bcf1455e 86 Year_timestp,
nxp_ip 2:db76c68f998f 87 Aging_offset,
nxp_ip 2:db76c68f998f 88 RAM_addr_MSB,
nxp_ip 2:db76c68f998f 89 RAM_addr_LSB,
nxp_ip 2:db76c68f998f 90 RAM_wrt_cmd,
nxp_ip 2:db76c68f998f 91 RAM_rd_cmd
nxp_ip 0:1377bcf1455e 92 }
nxp_ip 0:1377bcf1455e 93 RegisterName;
nxp_ip 2:db76c68f998f 94
nxp_ip 1:700e0285cfd8 95 /** Error code */
nxp_ip 1:700e0285cfd8 96 typedef enum {
nxp_ip 1:700e0285cfd8 97 NO_ERROR = 0,
nxp_ip 1:700e0285cfd8 98 CLOCK_INTEGRITY_FAIL = 1,
nxp_ip 1:700e0285cfd8 99 I2C_ACCESS_FAIL = 2,
nxp_ip 1:700e0285cfd8 100 TIME_FUNC_ERROR = ((time_t)-1)
nxp_ip 1:700e0285cfd8 101 }
nxp_ip 1:700e0285cfd8 102 ErrorNum;
nxp_ip 2:db76c68f998f 103
nxp_ip 0:1377bcf1455e 104 /** Create a PCF2127 instance connected to specified I2C pins with specified address
nxp_ip 0:1377bcf1455e 105 *
nxp_ip 2:db76c68f998f 106 * @param I2C_sda I2C-bus SDA pin
nxp_ip 2:db76c68f998f 107 * @param I2C_scl I2C-bus SCL pin
nxp_ip 2:db76c68f998f 108 * @param vControl_1 (option) data for Control_1 register (default setting generates interrupts by second and minute)
nxp_ip 2:db76c68f998f 109 * @param vControl_2 (option) data for Control_2 register
nxp_ip 2:db76c68f998f 110 * @param vControl_3 (option) data for Control_3 register (default setting of battery switch-over function as standard mode)
nxp_ip 2:db76c68f998f 111 * @param vCLKOUT_ctl (option) data for CLKOUT_ctl register (default setting 1Hz output on CLKOUT pin)
nxp_ip 1:700e0285cfd8 112 CLKOUT_ctl
nxp_ip 0:1377bcf1455e 113 */
nxp_ip 1:700e0285cfd8 114 PCF2127( PinName sda, PinName sdl, char vControl_1 = Cntl1, char vControl_2 = Cntl2, char vControl_3 = Cntl1, char vCLKOUT_ctl = ClkOut );
nxp_ip 0:1377bcf1455e 115
nxp_ip 1:700e0285cfd8 116 /** Create a PCF2127 instance connected to specified I2C pins with specified address
nxp_ip 1:700e0285cfd8 117 *
nxp_ip 2:db76c68f998f 118 * @param i2c I2C object (instance)
nxp_ip 2:db76c68f998f 119 * @param vControl_1 (option) data for Control_1 register (default setting generates interrupts by second and minute)
nxp_ip 2:db76c68f998f 120 * @param vControl_2 (option) data for Control_2 register
nxp_ip 2:db76c68f998f 121 * @param vControl_3 (option) data for Control_3 register (default setting of battery switch-over function as standard mode)
nxp_ip 2:db76c68f998f 122 * @param vCLKOUT_ctl (option) data for CLKOUT_ctl register (default setting 1Hz output on CLKOUT pin)
nxp_ip 1:700e0285cfd8 123 */
nxp_ip 1:700e0285cfd8 124 PCF2127( I2C &i2c, char vControl_1 = Cntl1, char vControl_2 = Cntl2, char vControl_3 = Cntl1, char vCLKOUT_ctl = ClkOut );
nxp_ip 2:db76c68f998f 125
nxp_ip 0:1377bcf1455e 126 /** Destractor
nxp_ip 0:1377bcf1455e 127 */
nxp_ip 0:1377bcf1455e 128 ~PCF2127();
nxp_ip 0:1377bcf1455e 129
nxp_ip 0:1377bcf1455e 130 /** Clock integrity check
nxp_ip 0:1377bcf1455e 131 *
nxp_ip 2:db76c68f998f 132 * @return non-zero value if the clock was stopped (means need to set the time)
nxp_ip 0:1377bcf1455e 133 */
nxp_ip 0:1377bcf1455e 134 int is_init_required( void );
nxp_ip 0:1377bcf1455e 135
nxp_ip 0:1377bcf1455e 136 /** Set the time
nxp_ip 0:1377bcf1455e 137 *
nxp_ip 2:db76c68f998f 138 * @param dtp Pointer to struct tm
nxp_ip 2:db76c68f998f 139 * @return Error code (NO_ERROR==0)
nxp_ip 0:1377bcf1455e 140 */
nxp_ip 1:700e0285cfd8 141 int set_time( struct tm *dtp );
nxp_ip 2:db76c68f998f 142
nxp_ip 1:700e0285cfd8 143 /** Set the time
nxp_ip 1:700e0285cfd8 144 *
nxp_ip 2:db76c68f998f 145 * @param tp pointer to time_t
nxp_ip 2:db76c68f998f 146 * @return Error code (NO_ERROR==0)
nxp_ip 1:700e0285cfd8 147 */
nxp_ip 1:700e0285cfd8 148 int set_time( time_t *tp );
nxp_ip 0:1377bcf1455e 149
nxp_ip 0:1377bcf1455e 150 /** Set the time
nxp_ip 2:db76c68f998f 151 *
nxp_ip 2:db76c68f998f 152 * @param s String data: The time information should be given in format of "YYYY MM DD HH MM SS"
nxp_ip 2:db76c68f998f 153 * @return Error code (NO_ERROR==0)
nxp_ip 0:1377bcf1455e 154 */
nxp_ip 1:700e0285cfd8 155 int set_time( char *s );
nxp_ip 0:1377bcf1455e 156
nxp_ip 0:1377bcf1455e 157 /** Get time of day
nxp_ip 0:1377bcf1455e 158 *
nxp_ip 0:1377bcf1455e 159 * This function works similar to "time()" in standard-C-library
nxp_ip 0:1377bcf1455e 160 *
nxp_ip 2:db76c68f998f 161 * @param tp Pointer to time_t
nxp_ip 2:db76c68f998f 162 * @return Error code (NO_ERROR==0)
nxp_ip 0:1377bcf1455e 163 */
nxp_ip 0:1377bcf1455e 164 time_t time( time_t *tp );
nxp_ip 0:1377bcf1455e 165
nxp_ip 0:1377bcf1455e 166 /** Register access interface with integer to BCD conversion
nxp_ip 0:1377bcf1455e 167 *
nxp_ip 0:1377bcf1455e 168 * @param addr Register address
nxp_ip 2:db76c68f998f 169 * @param s Integer data. Converted to BCD before writing inot the register.
nxp_ip 2:db76c68f998f 170 * @return Error code (NO_ERROR==0)
nxp_ip 0:1377bcf1455e 171 */
nxp_ip 1:700e0285cfd8 172 int set_alarm( char addr, char s );
nxp_ip 0:1377bcf1455e 173
nxp_ip 0:1377bcf1455e 174 /** Clear interrupt flag
nxp_ip 0:1377bcf1455e 175 *
nxp_ip 0:1377bcf1455e 176 * Clears interrupt flags by writing 0x00 into Control_2 register
nxp_ip 0:1377bcf1455e 177 *
nxp_ip 2:db76c68f998f 178 * @return Error code (NO_ERROR==0)
nxp_ip 0:1377bcf1455e 179 */
nxp_ip 1:700e0285cfd8 180 int clear_intr( void );
nxp_ip 0:1377bcf1455e 181
nxp_ip 2:db76c68f998f 182 /** Writing data into RAM (for PCF2127 only)
nxp_ip 2:db76c68f998f 183 *
nxp_ip 2:db76c68f998f 184 * Write data into PCF2127 internal RAM
nxp_ip 2:db76c68f998f 185 *
nxp_ip 2:db76c68f998f 186 * @param address target address of internal RAM
nxp_ip 2:db76c68f998f 187 * @param *p pointer to write data buffer
nxp_ip 2:db76c68f998f 188 * @param size size of writing data
nxp_ip 2:db76c68f998f 189 * @return Error code (NO_ERROR==0)
nxp_ip 2:db76c68f998f 190 */
nxp_ip 2:db76c68f998f 191 int RAM_write( int address, char *p, int size );
nxp_ip 2:db76c68f998f 192
nxp_ip 2:db76c68f998f 193 /** Reading data from RAM (for PCF2127 only)
nxp_ip 2:db76c68f998f 194 *
nxp_ip 2:db76c68f998f 195 * Read data from PCF2127 internal RAM
nxp_ip 2:db76c68f998f 196 *
nxp_ip 2:db76c68f998f 197 * @param address target address of internal RAM
nxp_ip 2:db76c68f998f 198 * @param *p pointer to read data buffer
nxp_ip 2:db76c68f998f 199 * @param size size of writing data
nxp_ip 2:db76c68f998f 200 * @return Error code (NO_ERROR==0)
nxp_ip 2:db76c68f998f 201 */
nxp_ip 2:db76c68f998f 202 int RAM_read( int address, char *p, int size );
nxp_ip 2:db76c68f998f 203
nxp_ip 0:1377bcf1455e 204 private:
nxp_ip 0:1377bcf1455e 205
nxp_ip 1:700e0285cfd8 206 typedef enum {
nxp_ip 1:700e0285cfd8 207 Cntl1 = 0x03,
nxp_ip 1:700e0285cfd8 208 Cntl2 = 0x00,
nxp_ip 1:700e0285cfd8 209 Cntl3 = 0x00,
nxp_ip 1:700e0285cfd8 210 ClkOut = 0x46
nxp_ip 1:700e0285cfd8 211 }
nxp_ip 1:700e0285cfd8 212 DefaultRegParam;
nxp_ip 2:db76c68f998f 213
nxp_ip 1:700e0285cfd8 214 int init( char vControl_1, char vControl_2, char vControl_3, char vCLKOUT_ctl );
nxp_ip 1:700e0285cfd8 215 int set_register( char addr, char data );
nxp_ip 1:700e0285cfd8 216 int read_register( char addr );
nxp_ip 1:700e0285cfd8 217 char i2bcd( char n );
nxp_ip 1:700e0285cfd8 218 char bcd2i( char bcd );
nxp_ip 2:db76c68f998f 219 int set_RAM_address( char address );
nxp_ip 2:db76c68f998f 220
nxp_ip 1:700e0285cfd8 221 I2C *i2c_p;
nxp_ip 1:700e0285cfd8 222 I2C &i2c;
nxp_ip 0:1377bcf1455e 223 char device_address;
nxp_ip 0:1377bcf1455e 224 }
nxp_ip 0:1377bcf1455e 225 ;
nxp_ip 0:1377bcf1455e 226 #endif // end of "#ifndef MBED_PCF2127"