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:
1:700e0285cfd8
Parent:
0:1377bcf1455e
Child:
2:db76c68f998f
--- a/PCF2127.cpp	Thu Dec 04 04:58:24 2014 +0000
+++ b/PCF2127.cpp	Tue Dec 09 07:21:13 2014 +0000
@@ -2,8 +2,8 @@
  *  PCF2127 library
  *
  *  @author     Akifumi (Tedd) OKANO, NXP Semiconductors
- *  @version    1.5
- *  @date       04-Dec-2014
+ *  @version    1.6
+ *  @date       09-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
@@ -20,16 +20,38 @@
 
 #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 )
+PCF2127::PCF2127( PinName sda, PinName sdl, char vControl_1, char vControl_2, char vControl_3, char vCLKOUT_ctl )
+    : i2c_p( new I2C( sda, sdl ) ), i2c( *i2c_p ), device_address( PCF2127_I2C_SLAVE_ADDRESS )
 {
-    set_register( Control_1, vControl_1 );
-    set_register( Control_2, vControl_2 );
-    set_register( Control_3, vControl_3 );
+    init( vControl_1, vControl_2, vControl_3, vCLKOUT_ctl );
+}
+
+PCF2127::PCF2127( I2C &i2c_, char vControl_1, char vControl_2, char vControl_3, char vCLKOUT_ctl )
+    : i2c_p( NULL ), i2c( i2c_ ), device_address( PCF2127_I2C_SLAVE_ADDRESS )
+{
+    init( vControl_1, vControl_2, vControl_3, vCLKOUT_ctl );
 }
 
 PCF2127::~PCF2127()
 {
+    if ( NULL != i2c_p )
+        delete  i2c_p;
+}
+
+int PCF2127::init( char vControl_1, char vControl_2, char vControl_3, char vCLKOUT_ctl )
+{
+    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 );
+
+    return ( err ? I2C_ACCESS_FAIL : NO_ERROR );
 }
 
 int PCF2127::is_init_required( void )
@@ -37,10 +59,10 @@
     return ( read_register( Seconds ) & 0x80 ? true : false );
 }
 
-void PCF2127::set_time( struct tm *dtp )
+int PCF2127::set_time( struct tm *dtp )
 {
     char        buf[ 8 ];
-    char        c;
+    char        err;
 
     buf[ 0 ]    = Seconds;
     buf[ 1 ]    = i2bcd( dtp->tm_sec  );
@@ -51,14 +73,17 @@
     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 );
+    err = i2c.write( device_address, buf, 8 );
+    
+    return ( err ? I2C_ACCESS_FAIL : NO_ERROR );
 }
 
-void PCF2127::set_time( char *s )
+int PCF2127::set_time( time_t *tp )
+{
+    return ( set_time( localtime( tp ) ) );
+}
+
+int PCF2127::set_time( char *s )
 {
     //  The time information should be given in format of "YYYY MM DD HH MM SS"
 
@@ -67,25 +92,30 @@
     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) );
+    printf( "%02d/%02d/%02d - %02d:%02d:%02d\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 );
+    return ( set_time( dtp ) );
 }
 
 time_t PCF2127::time( time_t *tp )
 {
     struct tm   dt, *dtp;
     time_t      t;
-    char        buf[ 8 ]    = { Seconds };
+    char        buf[ 8 ];
 
     dtp = &dt;
 
-    i2c.write( device_address, buf, 1 );
-    i2c.read( device_address, buf, 7 );
+    buf[ 0 ]    = Seconds;  //  read start register address
+
+    if ( i2c.write( device_address, buf, 1 ) )
+        return ( TIME_FUNC_ERROR );
+
+    if ( i2c.read( device_address, buf, 7 ) )
+        return ( TIME_FUNC_ERROR );
 
     dtp->tm_sec     = bcd2i( buf[ 0 ] );
     dtp->tm_min     = bcd2i( buf[ 1 ] );
@@ -103,30 +133,31 @@
     return( t );
 }
 
-void PCF2127::set_alarm( char addr, char s )
+int PCF2127::set_alarm( char addr, char s )
 {
     char    v;
 
     v   = i2bcd( s );
-    set_register( addr, v );
+    
+    return ( set_register( addr, v ) );
 }
 
-void PCF2127::clear_intr( void )
+int PCF2127::clear_intr( void )
 {
-    set_register( Control_2, 0x00 );
+    return ( set_register( Control_2, 0x00 ) );
 }
 
-void PCF2127::set_register( char addr, char data )
+int PCF2127::set_register( char addr, char data )
 {
     char    b[ 2 ];
 
     b[ 0 ]    = addr;
     b[ 1 ]    = data;
 
-    i2c.write( device_address, b, 2 );
+    return ( i2c.write( device_address, b, 2 ) );
 }
 
-char PCF2127::read_register( char addr )
+int PCF2127::read_register( char addr )
 {
     char    data;