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

Revision:
2:db76c68f998f
Parent:
1:700e0285cfd8
Child:
3:e2a6ac61fcbd
diff -r 700e0285cfd8 -r db76c68f998f PCF2127.h
--- 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;