S3C2440 Real-time Clock RTC-EEWORLD

Collect

The Real Time Clock (RTC) unit can be operated by a backup battery when the system power is off. The RTC can be

The RTC unit operates on an
external 32.768kHz crystal oscillator and can perform alarm functions.

RTC operation is relatively simple, and the register settings are described in detail in the data sheet, so I will not write about them here. I will post an RTC code. This program refers to Tianxiang's RTC program code, mainly because his code is better and modularized. I modified his code to have an alarm (using a buzzer) and it can run on the TQ2440 board. Program functions: The serial port displays the time once per second and LED1 flashes once. In the alarm setting, when the second is 20, the alarm time is displayed and the buzzer sounds for a few seconds.

#include "2440addr.h"
#include "Option.h"
#include "2440lib.h"
#include "def.h"
#define LED1_ON (rGPBDAT &=~(1<<5))
#define LED1_OFF (rGPBDAT |=(1<<5) )
void __irq RTC_tickHandler(void);
void __irq RTC_alarmHandler(void);
U8 alarmflag=0;
typedef struct Date //Define a structure representing date and time
{ U16 year;
U8 month;
U8 day;
U8 week_day;
U8 hour;
U8 minute;
U8 second;
}date;
date C_date;
char *week_num[7]={ "SUN","MON","TUES","WED","THURS","FRI","SAT" }; //define a pointer array
void Beep_Freq_Set( U32 freq )
{
rGPBCON &=~3;
rGPBCON |= 2; //Set GPB0 to OUT0
rGPBUP=0x0; //Enable pull-up
rTCFG0 &=~0xff;
rTCFG0 |=15; //Prescaler value is 15
rTCFG1 &=~0x0f;
rTCFG1 |=0x02; //Division value is 8
rTCNTB0 = (PCLK>>7)/freq; //Set the value of timer 0 count buffer
rTCMPB0 = rTCNTB0>>1; // Timer 0 compares the buffer value, PWM output duty cycle 50%
rTCON &= ~0x1f;
rTCON |= 0xb; //Auto reload, turn off phase shift, manually update, turn on timer 0
rTCON &= ~2; // Clear the manual update bit
}
void Beep_Stop( void )
{
rGPBCON &= ~3; //set GPB0 as output
rGPBCON |= 1;
rGPBDAT &= ~1; //output low level
}
void delay(int x)
{
int i,j;
for(i=0;i
for(j=0;j<1000000;j++);
}
/**********************************
*
* Set the real-time clock date and time
*
*********************************/
void RTC_setdate(date *p_date)
{
rRTCCON=0x01; //RTC read and write enable, BCD clock, counter, no reset
rBCDYEAR = p_date->year;
rBCDMON = p_date->month;
rBCDDATE = p_date->day;
rBCDDAY = p_date->week_day; //Set date and time
rBCDHOUR = p_date->hour;
rBCDMIN = p_date->minute;
rBCDSEC = p_date->second;
rRTCCON=0x00; //RTC read and write disabled, BCD clock, counter, no reset
}
/**********************************
*
* Read real-time clock date and time
*
*********************************/
void RTC_getdate(date *p_date)
{
rRTCCON=0x01; //RTC read and write enable, BCD clock, counter, no reset
p_date->year = rBCDYEAR+0x2000;
p_date->month = rBCDMON;
p_date->day = rBCDDATE;
p_date->week_day = rBCDDAY; //Read date and time
p_date->hour = rBCDHOUR;
p_date->minute = rBCDMIN;
p_date->second = rBCDSEC;
rRTCCON=0x00; //RTC read and write disabled, BCD clock, counter, no reset
}
/**********************************
*
* TICK interrupt initialization
*
*********************************/
void RTC_tickIRQ_Init(U8 tick)
{
ClearPending(BIT_TICK); // Clear the flag
EnableIrq(BIT_TICK); //Enable interrupt source
pISR_TICK=(unsigned)RTC_tickHandler; //interrupt function entry address
rRTCCON=0x00;
rTICNT=(tick&0x7f)|0x80; //Enable interrupt
}
/**********************************
*
* Set alarm date, time and alarm wake-up mode
*
*********************************/
void RTC_alarm_setdate(date *p_date,U8 mode)
{
rRTCCON = 0x01;
rALMYEAR = p_date->year;
rALMMON = p_date->month;
rALMDATE = p_date->day;
rALMHOUR = p_date->hour;
rALMMIN = p_date->minute;
rALMSEC = p_date->second;
rRTCALM = mode; //RTC alarm control register
rRTCCON = 0x00;
ClearPending(BIT_RTC); //Clear flag
EnableIrq(BIT_RTC); //open RTC alarm INTERRUPT
pISR_RTC = (unsigned)RTC_alarmHandler;
}
void Main(void)
{
SelectFclk(2); //Set the system clock to 400M
ChangeClockDivider(2, 1); //Set the frequency division to 1:4:8
CalcBusClk(); //Calculate bus frequency
rGPHCON &=~((3<<4)|(3<<6));
rGPHCON |=(2<<4)|(2<<6); //GPH2--TXD[0];GPH3--RXD[0]
rGPHUP=0x00; //Enable pull-up function
Uart_Init(0,115200);
Uart_Select(0);
rGPBCON &=~((3<<10)|(3<<12)|(3<<14)|(3<<16)); // Clear GPBCON[10:17]
rGPBCON |=((1<<10)|(1<<12)|(1<<14)|(1<<16)); //Set GPB5~8 to output
rGPBUP &=~((1<<5)|(1<<6)|(1<<7)|(1<<8)); //Set the pull-up function of GPB5~8
rGPBDAT |=(1<<5)|(1<<6)|(1<<7)|(1<<8); //Turn off LED
Beep_Stop(); //The buzzer stops sounding and is used as an alarm
C_date.year = 0x12;
C_date.month = 0x05;
C_date.day = 0x09;
C_date.week_day = 0x03; //Set the current date and time
C_date.hour = 0x12;
C_date.minute = 0x00;
C_date.second = 0x10;
RTC_setdate(&C_date);
C_date.second=0x20;
RTC_alarm_setdate(&C_date,0x41); //0x41 means enabling the RTC alarm and the second clock alarm
RTC_tickIRQ_Init(127); // Set the tick to occur once per second
Uart_Printf("\n ---Real-time clock test program---\n");
while(Uart_GetKey()!= ESC_KEY)
{
LED1_OFF;
RTC_getdate(&C_date);
if(alarmflag)
{
alarmflag=0;
Uart_Printf("\nRTC ALARM %02x:%02x:%02x \n",C_date.hour,C_date.minute,C_date.second);
Beep_Freq_Set(1000);
delay(5);
Beep_Stop();
}
}
}
/**********************************
*
* TICK interrupt
*
*********************************/
void __irq RTC_tickHandler(void)
{
ClearPending(BIT_TICK);
LED1_ON; //Refresh LED1
Delay(500);
RTC_getdate(&C_date);
Uart_Printf("RTC TIME: %04x-%02x-%02x %s %02x:%02x:%02x\n", C_date.year,C_date.month,C_date.day,week_num[C_date.week_day], C_date.hour , C_date.minute, C_date.second );
}
/**********************************
*
* TICK interrupt
*
*********************************/
void __irq RTC_alarmHandler(void)
{
alarmflag = 1;
ClearPending(BIT_RTC);
}

Keywords：S3C2440 Reference address：S3C2440 Real-time Clock RTC

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