PCF8563 with NXP Cortex-M3, LPC1343 Keil

main.c

#include <LPC13xx.h>
#include <stdbool.h>
#include "i2c.h"
#include <time.h>
#include "pcf8563.h"

tm_t timestamp;

int main(void) {
	SystemCoreClockUpdate(); /* Initialize CPU and CMSIS */
	
	I2CInit(I2CMASTER);	/* initialize the I2C for sensor modules */
	pcf8563Init();			/* initialize RTC provider, PCF8563 */
	pcf8563Get(&timestamp);		/* read time */
	while (1); /* endless loop */
}

pcf8563.c

#include <LPC13xx.h>
#include <stdbool.h>
#include <time.h>
#include "i2c.h"
#include "pcf8563.h"


extern volatile uint8_t   I2CMasterBuffer[I2C_BUFSIZE];
extern volatile uint8_t   I2CSlaveBuffer[I2C_BUFSIZE];
extern volatile uint32_t  I2CReadLength, I2CWriteLength;

static bool _pcf8563Initialised = false;

int bcd_to_byte(uint8_t bcd) { return (((bcd >> 4) * 10) + (bcd & 0x0F)); }
uint8_t int_to_bcd(int in) { return ((in / 10) << 4) + (in % 10); }

void pcf8563Init(void) {	
	// assuming you have initialized I2C before

  // Set initialisation flag
  _pcf8563Initialised = true;
}
void pcf8563Set(tm_t *timestamp) {	
	if (!_pcf8563Initialised) pcf8563Init();
	
	//stop counting
	I2CWriteLength = 3;
	I2CReadLength = 0;
	I2CMasterBuffer[0] = PCF8563_ADDR_WRITE;
	I2CMasterBuffer[1] = 0x00;//control register
	I2CMasterBuffer[2] = (1 << 5);//set stop bit
	I2CEngine();
	
	//set date
	I2CWriteLength = 9;
	I2CReadLength = 0;
	I2CMasterBuffer[0] = PCF8563_ADDR_WRITE;
	I2CMasterBuffer[1] = 0x02;// Start from address 2(VL_seconds)
	I2CMasterBuffer[2] = int_to_bcd(timestamp->tm_sec);//register address 2
	I2CMasterBuffer[3] = int_to_bcd(timestamp->tm_min);//register address 3
	I2CMasterBuffer[4] = int_to_bcd(timestamp->tm_hour);//register address 4
	I2CMasterBuffer[5] = int_to_bcd(timestamp->tm_mday);//register address 5
	I2CMasterBuffer[6] = int_to_bcd(timestamp->tm_wday);//register address 6
	I2CMasterBuffer[7] = int_to_bcd(timestamp->tm_mon);//register address 7
	I2CMasterBuffer[8] = int_to_bcd(timestamp->tm_year);//register address 8
	I2CEngine();
	
	//continue counting
	I2CWriteLength = 3;
	I2CReadLength = 0;
	I2CMasterBuffer[0] = PCF8563_ADDR_WRITE;
	I2CMasterBuffer[1] = 0x00;//control register
	I2CMasterBuffer[2] = 0;//release stop bit
	I2CEngine();
}
void pcf8563Get(tm_t *timestamp) {
	if (!_pcf8563Initialised) pcf8563Init();
	
	I2CWriteLength = 2;
	I2CReadLength = 0;
	I2CMasterBuffer[0] = PCF8563_ADDR_WRITE;
	I2CMasterBuffer[1] = 2;// Start from address 2(VL_seconds)
	I2CEngine();
	
	I2CWriteLength = 1;
	I2CReadLength = 7;
	I2CMasterBuffer[0] = PCF8563_ADDR_READ;
	I2CEngine();
	
	timestamp->tm_sec = bcd_to_byte(I2CSlaveBuffer[0] & 0x7F);//register address 2
	timestamp->tm_min = bcd_to_byte(I2CSlaveBuffer[1] & 0x7F);//register address 3
	timestamp->tm_hour = bcd_to_byte(I2CSlaveBuffer[2] & 0x3F);//register address 4
	timestamp->tm_mday = bcd_to_byte(I2CSlaveBuffer[3] & 0x3F);//register address 5
	timestamp->tm_wday = bcd_to_byte(I2CSlaveBuffer[4] & 0x07);//register address 6
	timestamp->tm_mon = bcd_to_byte(I2CSlaveBuffer[5] & 0x1F);//register address 7
	timestamp->tm_year = bcd_to_byte(I2CSlaveBuffer[6]);//register address 8
}

pcf8563.h

#ifndef PCF8563_H_
#define PCF8563_H_

#ifdef __cplusplus
 extern "C" {
#endif
	 
typedef struct tm tm_t;
	 
#define PCF8563_ADDR_READ			0xA3
#define PCF8563_ADDR_WRITE		0xA2

extern void pcf8563Init(void);
extern void pcf8563Set(tm_t *timestamp);
extern void pcf8563Get(tm_t *timestamp);


#ifdef __cplusplus
 }
#endif

#endif /* PCF8563_H_ */