實時時鍾是一組用於測量時間的計數器,如果使用電池供電,在系統掉電以后它也可以正常運行以記錄系統的時間。LPC1788時鍾采用內部的32K振盪器輸出1HZ的時鍾信號做為RTC的時鍾源。
RTC的寄存器比較簡單,主要有時鍾計數器寄存器包括秒SEC 分MIN 小時HOUR 日期(月)DOM 星期DOW 日期(年)DOY 月MONTH 年YEAR, 這些寄存器為R/W 可以從中讀出具體的時間信息。其中的秒計數由1HZ時鍾驅動。報警寄存器組中的值將和時間計數器寄存器中的值比較,如果所有為屏蔽的報警寄存器都與他們對應的時間計數器相匹配,那么將產生一次中斷。報警屏蔽在報警屏蔽寄存器AMR中設置。中斷設置在中斷位置寄存器ILR中設置。RTC中斷不僅可以在報警寄存器和時間計數器匹配時產生,我們也可以配置計數器增量中斷寄存器CIIR,使計數器每增加1就產生一次中斷。RTC的控制在時鍾控制寄存器CCR中,我們可以使能或禁止時鍾,以及復位等。
在下面的程序中,首先PC端使用串口軟件發送一串固定格式的時間信息給開發板,開發板收到字符‘a’表示后面跟着的是時間信息,設置了初始時間后,我們配置CCIR使1秒產生一次中斷,配置報警寄存器組合報價屏蔽寄存器,使秒計數為30的時候產生中斷。在RTC的中斷函數中,如果是計數中斷,就讓接LED的GPIO輸出反向電平,根據設置LED燈將1S閃爍。 如果是報警中斷,就通過串口在PC打印時間信息。
注意:為了程序的簡潔,省去了之前介紹了的系統時鍾配置和串口的配置。具體的信息可查詢之前的文章。
- #include "LPC1788_REG.h"
- #include "uart.h"
- #define rILR (*(volatile unsigned*)0x40024000)
- #define rCCR (*(volatile unsigned*)0x40024008)
- #define rCIIR (*(volatile unsigned*)0x4002400C)
- #define rAMR (*(volatile unsigned*)0x40024010)
- #define rCALIBRATION (*(volatile unsigned*)0x40024040)
- #define rYEAR (*(volatile unsigned*)0x4002403C)
- #define rMONTH (*(volatile unsigned*)0x40024038)
- #define rDOM (*(volatile unsigned*)0x4002402C)
- #define rHOUR (*(volatile unsigned*)0x40024028)
- #define rMIN (*(volatile unsigned*)0x40024024)
- #define rSEC (*(volatile unsigned*)0x40024020)
- #define rALSEC (*(volatile unsigned*)0x40024060)
- #define rCTIME0 (*(volatile unsigned*)0x40024014)
- #define rCTIME1 (*(volatile unsigned*)0x40024018)
- #define rCTIME2 (*(volatile unsigned*)0x4002401C)
- unsigned char flag_setTime=1;
- unsigned char flag_receiveStatus=0;
- unsigned char timeData[14],cnt;
- void Set_Data()
- {
- rCCR &= ~(0x1<<0);
- rYEAR = (timeData[0]-'0')*1000 + (timeData[1]-'0')*100 + (timeData[2]-'0')*10 + (timeData[3]-'0');
- rMONTH = (timeData[4]-'0')*10 + (timeData[5]-'0');
- rDOM = (timeData[6]-'0')*10 + (timeData[7]-'0');
- rHOUR = (timeData[8]-'0')*10 + (timeData[9]-'0');
- rMIN = (timeData[10]-'0')*10 + (timeData[11]-'0');
- rSEC = (timeData[12]-'0')*10 + (timeData[13]-'0');
- }
- void Display_Data()
- {
- Uart2SendC('\n');
- Uart2SendC(rYEAR/1000+'0');
- Uart2SendC(rYEAR%1000/100+'0');
- Uart2SendC(rYEAR%100/10+'0');
- Uart2SendC(rYEAR%10+'0');
- Uart2SendC('-');
- Uart2SendC(rMONTH/10+'0');
- Uart2SendC(rMONTH%10+'0');
- Uart2SendC('-');
- Uart2SendC(rDOM/10+'0');
- Uart2SendC(rDOM%10+'0');
- Uart2SendC('\n');
- Uart2SendC(rHOUR/10+'0');
- Uart2SendC(rHOUR%10+'0');
- Uart2SendC(':');
- Uart2SendC(rMIN/10+'0');
- Uart2SendC(rMIN%10+'0');
- Uart2SendC(':');
- Uart2SendC(rSEC/10+'0');
- Uart2SendC(rSEC%10+'0');
- }
- void UART2_IRQHandler()
- {
- unsigned int intId;
- char tmp_char;
- intId = rU2IIR&0xf;
- if(intId == 0xc || intId == 0x4) //RDA或者CTI中斷
- {
- rU2LCR &= ~(0x1<<7); //DLAB=0
- tmp_char = rU2RBR&0xff;
- rU2THR = tmp_char;
- }
- if(tmp_char == 'a' && flag_receiveStatus == 0)
- {
- flag_receiveStatus = 1;
- cnt = 0;
- }
- elseif(flag_receiveStatus == 1)
- {
- timeData[cnt]=tmp_char;
- cnt++;
- if(cnt == 14)
- {
- Set_Data();
- cnt = 0;
- flag_receiveStatus = 0;
- flag_setTime=0;
- }
- }
- }
- void RTC_IRQHandler()
- {
- unsigned char IntStatus;
- IntStatus = rILR;
- if(IntStatus & 0x1) //計數中斷
- {
- rFIO1PIN = ~rFIO1PIN;
- rILR = IntStatus;
- }
- elseif (IntStatus & (0x1<<1)) //報警中斷
- {
- Display_Data();
- rILR = IntStatus;
- }
- }
- void Init_RTC()
- {
- rILR = 0;
- rCCR = 0;
- rCIIR = 0;
- rAMR = 0xff;
- rCALIBRATION = 0;
- rCCR |= 0x1<<1; //CTC Reset
- rCCR &= ~(0x1<<1);
- }
- int main(void)
- {
- char menu[] = {"\n\r===> Send a frame with 6 Byte data to set RTC \n['a']+[year]+[month]+[day]+[hour]+[minute]+[second]\n"};
- char str[]={"\r\nTime set ok! \r\nCurrent time set to:\r\n"};
- rFIO1DIR |= (1<<18); //GPIO1.18 -> OUTPUT
- Init_Uart2();
- Uart2SendS(menu);
- while(flag_setTime);
- Uart2SendS(str);
- Display_Data();
- rCCR |= 0x1;
- rCCR |= 0x1<<4;
- rCIIR |= 0x1; //秒值增加產生一次中斷
- rAMR &= ~(0x1<<0); //秒值與報警寄存器比較
- rALSEC = 30; //秒值為30的時候產生一個報警
- rISER0 |= 0x1<<17; //使能RTC中斷
- while(1);
- }
#include "LPC1788_REG.h"
#include "uart.h"
#define rILR (*(volatile unsigned*)0x40024000)
#define rCCR (*(volatile unsigned*)0x40024008)
#define rCIIR (*(volatile unsigned*)0x4002400C)
#define rAMR (*(volatile unsigned*)0x40024010)
#define rCALIBRATION (*(volatile unsigned*)0x40024040)
#define rYEAR (*(volatile unsigned*)0x4002403C)
#define rMONTH (*(volatile unsigned*)0x40024038)
#define rDOM (*(volatile unsigned*)0x4002402C)
#define rHOUR (*(volatile unsigned*)0x40024028)
#define rMIN (*(volatile unsigned*)0x40024024)
#define rSEC (*(volatile unsigned*)0x40024020)
#define rALSEC (*(volatile unsigned*)0x40024060)
#define rCTIME0 (*(volatile unsigned*)0x40024014)
#define rCTIME1 (*(volatile unsigned*)0x40024018)
#define rCTIME2 (*(volatile unsigned*)0x4002401C)
unsigned char flag_setTime=1;
unsigned char flag_receiveStatus=0;
unsigned char timeData[14],cnt;
void Set_Data()
{
rCCR &= ~(0x1<<0);
rYEAR = (timeData[0]-'0')*1000 + (timeData[1]-'0')*100 + (timeData[2]-'0')*10 + (timeData[3]-'0');
rMONTH = (timeData[4]-'0')*10 + (timeData[5]-'0');
rDOM = (timeData[6]-'0')*10 + (timeData[7]-'0');
rHOUR = (timeData[8]-'0')*10 + (timeData[9]-'0');
rMIN = (timeData[10]-'0')*10 + (timeData[11]-'0');
rSEC = (timeData[12]-'0')*10 + (timeData[13]-'0');
}
void Display_Data()
{
Uart2SendC('\n');
Uart2SendC(rYEAR/1000+'0');
Uart2SendC(rYEAR%1000/100+'0');
Uart2SendC(rYEAR%100/10+'0');
Uart2SendC(rYEAR%10+'0');
Uart2SendC('-');
Uart2SendC(rMONTH/10+'0');
Uart2SendC(rMONTH%10+'0');
Uart2SendC('-');
Uart2SendC(rDOM/10+'0');
Uart2SendC(rDOM%10+'0');
Uart2SendC('\n');
Uart2SendC(rHOUR/10+'0');
Uart2SendC(rHOUR%10+'0');
Uart2SendC(':');
Uart2SendC(rMIN/10+'0');
Uart2SendC(rMIN%10+'0');
Uart2SendC(':');
Uart2SendC(rSEC/10+'0');
Uart2SendC(rSEC%10+'0');
}
void UART2_IRQHandler()
{
unsigned int intId;
char tmp_char;
intId = rU2IIR&0xf;
if(intId == 0xc || intId == 0x4) //RDA或者CTI中斷
{
rU2LCR &= ~(0x1<<7); //DLAB=0
tmp_char = rU2RBR&0xff;
rU2THR = tmp_char;
}
if(tmp_char == 'a' && flag_receiveStatus == 0)
{
flag_receiveStatus = 1;
cnt = 0;
}
else if(flag_receiveStatus == 1)
{
timeData[cnt]=tmp_char;
cnt++;
if(cnt == 14)
{
Set_Data();
cnt = 0;
flag_receiveStatus = 0;
flag_setTime=0;
}
}
}
void RTC_IRQHandler()
{
unsigned char IntStatus;
IntStatus = rILR;
if(IntStatus & 0x1) //計數中斷
{
rFIO1PIN = ~rFIO1PIN;
rILR = IntStatus;
}
else if (IntStatus & (0x1<<1)) //報警中斷
{
Display_Data();
rILR = IntStatus;
}
}
void Init_RTC()
{
rILR = 0;
rCCR = 0;
rCIIR = 0;
rAMR = 0xff;
rCALIBRATION = 0;
rCCR |= 0x1<<1; //CTC Reset
rCCR &= ~(0x1<<1);
}
int main(void)
{
char menu[] = {"\n\r===> Send a frame with 6 Byte data to set RTC \n['a']+[year]+[month]+[day]+[hour]+[minute]+[second]\n"};
char str[]={"\r\nTime set ok! \r\nCurrent time set to:\r\n"};
rFIO1DIR |= (1<<18); //GPIO1.18 -> OUTPUT
Init_Uart2();
Uart2SendS(menu);
while(flag_setTime);
Uart2SendS(str);
Display_Data();
rCCR |= 0x1;
rCCR |= 0x1<<4;
rCIIR |= 0x1; //秒值增加產生一次中斷
rAMR &= ~(0x1<<0); //秒值與報警寄存器比較
rALSEC = 30; //秒值為30的時候產生一個報警
rISER0 |= 0x1<<17; //使能RTC中斷
while(1);
}
程序運行串口打印信息如下圖:

