标签：
DS1307是Maxim的串行、I2C实时时钟芯片。主要特性有：
采用I2C接口与Arduino连接。SQW/OUT脚亦为开漏（open-drain）设计，需要接上拉电阻。
DS1307的VCC脚接Arduino UNO的5V；GND脚接Arduino UNO的GND；SDA脚接Arduino UNO的A4(SDA)；SCL脚接Arduino UNO的A5(SCL)。
1. 写寄存器时，先写入寄存器指针（Register pointer），之后依次写入寄存器内容。每写入一个字节，Register pointer都自动加一。
2. 读寄存器时，也是先写入Register pointer，之后发Sr（Repeated start），依次读出寄存器内容。同样的，每读出一个字节，Register pinter都自动加一。
1. 首先设置DS1307时间。代码中timeDec数组保存的是当前时间，根据实际调整。
1 /* 2 real time clock using DS1307 3 function: set the time 4 */ 5 6 #include <Wire.h> 7 8 #define ADDRESS_DS1307 0x68 9 10 byte timeDec[] = {15, 1, 15, 5, 19, 20, 0}; 11 byte timeBcd[] = {0, 0, 0, 0, 0, 0, 0}; 12 //time = {year, month, date, day, hours, minutes, seconds}; 13 14 void setup() 15 { 16 Wire.begin(); 17 Serial.begin(9600); 18 19 //convert decimal to BCD code 20 int i; 21 for (i = 0; i < 7; i++) 22 { 23 timeBcd[i] = DecToBcd(timeDec[i]); 24 } 25 26 //set the time 27 Wire.beginTransmission(ADDRESS_DS1307); 28 Wire.write(0x00); 29 for (i = 0; i < 7; i++) 30 { 31 Wire.write(timeBcd[6-i]); 32 } 33 Wire.endTransmission(); 34 35 Serial.println("Time has been set."); 36 37 } 38 39 void loop() 40 { 41 delay(4000); 42 } 43 44 // Convert normal decimal numbers to binary coded decimal 45 byte DecToBcd(byte val) 46 { 47 byte res; 48 if ((val <= 99) && (val >= 0)) 49 { 50 res = ((val/10)<<4) | (val%10); 51 } 52 else 53 { 54 res = 0; 55 Serial.println("Error"); 56 } 57 return res; 58 } 59 // Convert binary coded decimal to normal decimal numbers 60 byte BcdToDec(byte val) 61 { 62 byte res; 63 if (val <= 0x99) 64 { 65 res = (val >> 4)*10 + (val & 0x0F); 66 } 67 else 68 { 69 res = 0; 70 Serial.println("Error"); 71 } 72 return res; 73 }
2. 之后可以向DS1307获取实时时间。
1 /* 2 real time clock using DS1307 3 function: read the time 4 */ 5 6 #include <Wire.h> 7 8 #define ADDRESS_DS1307 0x68 9 10 byte timeBcd[] = {0, 0, 0, 0, 0, 0, 0}; 11 //time = {year, month, date, day, hours, minutes, seconds}; 12 13 void setup() 14 { 15 Wire.begin(); 16 Serial.begin(9600); 17 } 18 19 void loop() 20 { 21 //read the time 22 Wire.beginTransmission(ADDRESS_DS1307); 23 Wire.write(0x00); 24 Wire.endTransmission(); 25 Wire.requestFrom(ADDRESS_DS1307, 7); 26 if (Wire.available() >= 7) 27 { 28 for (int i = 0; i < 7; i++) 29 { 30 timeBcd[6-i] = Wire.read(); 31 } 32 } 33 34 //print 35 Serial.print("20"); Serial.print(timeBcd[0], HEX); Serial.print("/"); 36 Serial.print(timeBcd[1], HEX); Serial.print("/"); Serial.print(timeBcd[2], HEX); 37 Serial.print(" "); Serial.print(BcdToDay(timeBcd[3])); Serial.print(" "); 38 Serial.print(timeBcd[4], HEX); Serial.print(":"); 39 Serial.print(timeBcd[5], HEX); Serial.print(":"); 40 Serial.print(timeBcd[6], HEX); Serial.println(); 41 42 delay(1000); 43 } 44 45 46 // Convert binary coded decimal to day 47 String BcdToDay(byte val) 48 { 49 String res; 50 switch(val) 51 { 52 case 1: res = "Sunday"; break; 53 case 2: res = "Monday"; break; 54 case 3: res = "Tuesday"; break; 55 case 4: res = "Wednesday"; break; 56 case 5: res = "Thursday"; break; 57 case 6: res = "Friday"; break; 58 case 7: res = "Saturday"; break; 59 default: res = "Error!"; 60 } 61 return res; 62 }
程序运行后，通过串口打印当前时间如下图。
3. 通过设置控制寄存器，可以设置SQW/OUT管脚输出高电平、低电平或某个频率的方波。方波支持的频率有1Hz、4.096kHz、8.192kHz、32.768kHz。以下代码设置的频率为32.768kHz。
1 /* 2 real time clock using DS1307 3 function: output the square-wave 4 */ 5 6 #include <Wire.h> 7 8 #define ADDRESS_DS1307 0x68 9 #define CONTROL_REGISTER 0x07 10 11 void setup() 12 { 13 Wire.begin(); 14 Serial.begin(9600); 15 16 //set the time 17 Wire.beginTransmission(ADDRESS_DS1307); 18 Wire.write(CONTROL_REGISTER); 19 Wire.write(0b00010011); //frequency = 32.768kHz 20 Wire.endTransmission(); 21 22 Serial.println("Square-wave output is enabled."); 23 } 24 25 void loop() 26 { 27 delay(4000); 28 }
与示波器测试的信号图形相符。
Maxim - DS1307 64x8、串行、I²C实时时钟
Tutorial – Using DS1307 and DS3231 Real-time Clock Modules with Arduino
Digital Clock with Arduino and DS1307
Assemble an Adafruit DS1307 Real Time Clock Kit
标签：
原文地址：http://www.cnblogs.com/zlbg/p/4227428.html
