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arduino学习笔记27 - DS1307 RTC时钟芯片与DS18B20数字温度传感器...

2014-10-24 10:38:35 4087 Arduino

0 本次实验我使用的是购买的一个DS1307 RTC模块，上面集成了一个DS18B20温度传感器，还集成了另外一个存储芯片~~ 先上图再看下硬件连接图，DS1307是I2C接口SCL接模拟5号口，SDA接模拟4号口。DS18B20是单总线模式，他的DS接口接数字2号口。 DS18B20： DS18x20系列数字温度传感器主要有DS18S20和DS18B20(DS18S20只有9位一种工作模式，分辨率只到0.5摄氏度，DS18B20有9、10、11、12位四种工作可编程控制的模式，分辨率最高为0.0625摄氏度。)，都是由美国Dallas半导体公司(现在改名叫Maxim)生产的。这个系列最大的特点就是采用了Maxim的专利威廉希尔官方网站 1-Wire。顾名思义，1-Wire就是采用单一信号线，但可像I2C，SPI一样，同时传输时钟（clock）又传输数据（data），而且数据传输是双向的。1-Wire 使用较低的数据传输速率，通常是用来沟通小型device，如数位温度计。通过1-Wire威廉希尔官方网站可以在单一信号线的基础上构成传感器网络，Maxim起名”MicroLan”。 DS18x20的供电主要有两种模式： Parasite power mode/寄生供电所谓的寄生供电是指DS18x20只需要两根接线，一根数据线，一根接地线，数据线上还要接一个4.7k上拉电阻连电源，数据线同时也提供了电能。DS18x20内置了电容，高电平期时把电能储存在内部电容里，低电平期内消耗内部电容里的能量工作，直到下次高电平期内再次电容充电。虽然这样的模式简化了线路同时也带来了一些缺陷： 1. 电路的电流一般很小，只有当DS18x20进行温度转化或者写EEPROM时会高达1.5mA，当DS18x20进行上述操作时，数据线必须保持电平拉高状态直到操作结束，期间master端的Arduino不能做任何操作，DS18x20温度转化时这个时间间隔大概是750ms。 2.如果要求DS18x20有精确的转化，数据线在温度转化期间必须保证足够的能量，但当你使用多个DS18x20构成MicroLan进行多点测温时，单靠4.7k的上拉电阻无法提供足够的能量，会导致较大的测温误差。 Normal (external supply) mode/标准(外部供电) 标准外部供电模式，相比寄生供电模式，每个DS18x20需要多一条独立的电源线接独立电源。虽然多用些线，但由于外部供电，保证了每个设备的进精确度和稳定性。而且没有了上述温度转换期间Arduino不能做任何事的问题。 DS18B20的详细介绍就不多讲了，具体可以查看论坛的另一篇帖子http://www.geek-workshop.com/for ... =198&extra=page%3D1 直接进入实战，调用DS18B20，需要使用OneWire库。把下面代码下载进入arduino控制板。ARDUINO 代码复制打印 #include h> // DS18S20 Temperature chip i/o OneWire ds(2); // on pin 2 void setup(void) { // initialize inputs/outputs // start serial port Serial.begin(9600); } void loop(void) { byte i; byte present = 0; byte data[12; byte addr[8; if ( !ds.search(addr)) { Serial.print("No more addresses.n"); ds.reset_search(); return; } Serial.print("R="); for( i = 0; i < 8; i++) { Serial.print(addr[i, HEX); Serial.print(" "); } if ( OneWire::crc8( addr, 7) != addr[7) { Serial.print("CRC is not valid!n"); return; } if ( addr[0 == 0x10) { Serial.print("Device is a DS18S20 family device.n"); } else if ( addr[0 == 0x28) { Serial.print("Device is a DS18B20 family device.n"); } else { Serial.print("Device family is not recognized: 0x"); Serial.println(addr[0,HEX); return; } ds.reset(); ds.select(addr); ds.write(0x44,1); // start conversion, with parasite power on at the end delay(1000); // maybe 750ms is enough, maybe not // we might do a ds.depower() here, but the reset will take care of it. present = ds.reset(); ds.select(addr); ds.write(0xBE); // Read Scratchpad Serial.print("P="); Serial.print(present,HEX); Serial.print(" "); for ( i = 0; i < 9; i++) { // we need 9 bytes data[i = ds.read(); Serial.print(data[i, HEX); Serial.print(" "); } Serial.print(" CRC="); Serial.print( OneWire::crc8( data, 8), HEX); Serial.println(); } 代码下载好以后打开串口编辑器，然后就会出现下面这样子的画面。虽然我们读到了Scratchpad的数据，但是显示的是HEX16进制代码，我们还需要转化成我们能读的温度格式。这里推荐一个叫Dallas Temperature Control的Library,大大简化了这个过程。官方地址：http://www.mile*urton.com/?titl ... ure_Control_LibraryARDUINO 代码复制打印 #include h> #include h> // Data wire is plugged into port 2 on the Arduino #define ONE_WIRE_BUS 2 // Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs) OneWire oneWire(ONE_WIRE_BUS); // Pass our oneWire reference to Dallas Temperature. DallasTemperature sensors(&oneWire); void setup(void) { // start serial port Serial.begin(9600); Serial.println("Dallas Temperature IC Control Library Demo"); // Start up the library sensors.begin(); } void loop(void) { // call sensors.requestTemperatures() to issue a global temperature // request to all devices on the bus Serial.print("Requesting temperatures..."); sensors.requestTemperatures(); // Send the command to get temperatures Serial.println("DONE"); Serial.print("Temperature for the device 1 (index 0) is: "); Serial.println(sensors.getTemPCByIndex(0)); } 代码下载好以后，打开串口监视器，就可以看到当前室温了。下面我们试用一下DS1307时钟芯片功能。先把下面库自带测试代码下载进入arduino控制板ARDUINO 代码复制打印 #include h> #include h> #include h> int rtc[7; int ledPin = 13; void setup() { DDRC\|=_BV(2) \|_BV(3); // POWER:Vcc Gnd PORTC \|=_BV(3); // VCC PINC3 pinMode(ledPin, OUTPUT); Serial.begin(9600); RTC.stop(); RTC.set(DS1307_SEC,1); RTC.set(DS1307_MIN,57); RTC.set(DS1307_HR,17); RTC.set(DS1307_DOW,2); RTC.set(DS1307_DATE,18); RTC.set(DS1307_MTH,1); RTC.set(DS1307_YR,10); RTC.start(); } void loop() { RTC.get(rtc,true); for(int i=0; i<7; i++) { Serial.print(rtc[i); Serial.print(" "); } Serial.println(); digitalWrite(ledPin, HIGH); delay(500); digitalWrite(ledPin, LOW); delay(500); } 然后打开串口监视器，就能看到类似下图的样子。这个模块上还有一个T24C32A EEPROM存储器。。。下面上一个全面一点的代码，对各个期间进行测试。其中刚开始会对I2C器件进行扫描。。。代码不错，大家可以参考下。ARDUINO 代码复制打印 / * I2CScanner.pde -- I2C bus scanner for Arduino * * 2009, Tod E. Kurt, http://todbot.com/blog/ * / #include h> #include "Wire.h" #include h> #include h> #include h> extern "C" { #include "utility/twi.h" // from Wire library, so we can do bus scanning } byte* start_address = 1; byte end_address = 127; OneWire ds(2); // on pin 2 byte Tdata[12; int sensorValue = 0; // value read from the pot int rtc[7; float TT=0.0; // Scan the I2C bus between addresses from_addr and to_addr. // On each address, call the callback function with the address and result. // If result==0, address was found, otherwise, address wasn't found // (can use result to potentially get other status on the I2C bus, see twi.c) // Assumes Wire.begin() has already been called void scanI2CBus(byte from_addr, byte to_addr, void(callback)(byte* address, byte result) ) { byte rc; byte data = 0; // not used, just an address to feed to twi_writeTo() for( byte addr = from_addr; addr <= to_addr; addr++ ) { rc = twi_writeTo(addr, &data, 0, 1); if(rc==0) callback( addr, rc ); } } // Called when address is found in scanI2CBus() // Feel free to change this as needed // (like adding I2C comm code to figure out what kind of I2C device is there) void scanFunc( byte addr, byte result ) { Serial.print("addr: "); Serial.print(addr,DEC); addr = addr<<1; Serial.print("t HEX: 0x"); Serial.print(addr,HEX); Serial.println( (result==0) ? "t found!":" "); // Serial.print( (addr%4) ? "t":"n"); } void i2c_eeprom_write_byte( int deviceaddress, unsigned int eeaddress, byte data ) { int rdata = data; Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddress >> 8)); // MSB Wire.send((int)(eeaddress & 0xFF)); // LSB Wire.send(rdata); Wire.endTransmission(); } // WARNING: address is a page address, 6-bit end will wrap around // also, data can be maximum of about 30 bytes, because the Wire library has a buffer of 32 bytes void i2c_eeprom_write_page( int deviceaddress, unsigned int eeaddresspage, byte* data, byte length ) { Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddresspage >> 8)); // MSB Wire.send((int)(eeaddresspage & 0xFF)); // LSB byte c; for ( c = 0; c < length; c++) Wire.send(data[c); Wire.endTransmission(); } byte i2c_eeprom_read_byte( int deviceaddress, unsigned int eeaddress ) { byte rdata = 0xFF; Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddress >> 8)); // MSB Wire.send((int)(eeaddress & 0xFF)); // LSB Wire.endTransmission(); Wire.requestFrom(deviceaddress,1); if (Wire.available()) rdata = Wire.receive(); return rdata; } // maybe let's not read more than 30 or 32 bytes at a time! void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte buffer, int* length ) { Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddress >> 8)); // MSB Wire.send((int)(eeaddress & 0xFF)); // LSB Wire.endTransmission(); Wire.requestFrom(deviceaddress,length); int c = 0; for ( c = 0; c < length; c++ ) if (Wire.available()) buffer[c = Wire.receive(); } void DS1302_SetOut(byte data ) { Wire.beginTransmission(B1101000); Wire.send(7); // LSB Wire.send(data); Wire.endTransmission(); } byte DS1302_GetOut(void) { byte rdata = 0xFF; Wire.beginTransmission(B1101000); Wire.send(7); // LSB Wire.endTransmission(); Wire.requestFrom(B1101000,1); if (Wire.available()) { rdata = Wire.receive(); Serial.println(rdata,HEX); } return rdata; } void showtime(void){ byte i; Serial.print("Time="); DS1302_SetOut(0x00); RTC.get(rtc,true); for(int i=0; i<7; i++) { Serial.print(rtc[i); Serial.print(" "); } } void readBatVcc(void){ sensorValue = analogRead(A1); TT = sensorValue0.0047; Serial.print("Battery: "); Serial.print(TT); Serial.print("V"); } // standard Arduino setup() void* setup() { DDRC\|=_BV(2) \|_BV(3); PORTC \|=_BV(3); Wire.begin(); Serial.begin(19200); Serial.println("--- I2C Bus Scanner Test---"); Serial.print("starting scanning of I2C bus from "); Serial.print(start_address,DEC); Serial.print(" to "); Serial.print(end_address,DEC); Serial.println("..."); // start the scan, will call "scanFunc()" on result from each address scanI2CBus( start_address, end_address, scanFunc ); Serial.println("n"); Serial.println("--- EEPROM Test---"); char somedata[ = "this is data from the eeprom"; // data to write i2c_eeprom_write_page(0x50, 0, (byte )somedata, sizeof(somedata)); // write to EEPROM delay(100); //add a small delay Serial.println("Written Done"); delay(10); Serial.print("Read EERPOM:"); byte* b = i2c_eeprom_read_byte(0x50, 0); // access the first address from the memory int addr=0; //first address while (b!=0) { Serial.print((char)b); //print content to serial port addr++; //increase address b = i2c_eeprom_read_byte(0x50, addr); //access an address from the memory } Serial.println("n"); Serial.println(""); Serial.println("--- DS11307 RTC Test---"); showtime(); if(rtc[6<2011){ RTC.stop(); RTC.set(DS1307_SEC,1); RTC.set(DS1307_MIN,52); RTC.set(DS1307_HR,16); RTC.set(DS1307_DOW,2); RTC.set(DS1307_DATE,25); RTC.set(DS1307_MTH,1); RTC.set(DS1307_YR,11); RTC.start(); Serial.println("SetTime:"); showtime(); } Serial.println("nn"); Serial.println("--- Reserve Power Test---"); Serial.println(" Close POWER!:"); PORTC &=~_BV(3); byte time; for(time=0;time<5;time++){ digitalWrite(13,HIGH); delay(500); digitalWrite(13,LOW); delay(500); readBatVcc(); Serial.println(""); } PORTC \|=_BV(3); Serial.println("n POWER On!"); delay(500); showtime(); Serial.println("n"); Serial.println("=== Done ==="); Serial.println("n"); } // standard Arduino loop() void loop() { byte i; byte present = 0; unsigned int Temper=0; readBatVcc(); ds.reset(); ds.write(0xCC,1); ds.write(0x44,1); // start conversion, with parasite power on at the end digitalWrite(13,HIGH); delay(450); digitalWrite(13,LOW); delay(450); present = ds.reset(); ds.write(0xCC,1); ds.write(0xBE); // Read Scratchpad for ( i = 0; i < 9; i++) { // we need 9 bytes Tdata[i = ds.read(); } Temper = (Tdata[1<<8 \| Tdata[0); TT =Temper0.0625; if(TT>200){ Serial.println("t DS18B20 Not installed!"); }else{ Serial.print("t Temperature="); Serial.println(TT); } Serial*.println(""); } 然后打开串口监视器，波特率要调节为19200. 附件是这次需要用到的库（适用于0022与0023 IDE）： OneWire.rar (8.59 KB, 下载次数: 430) DS1307.rar (2.59 KB, 下载次数: 645) DallasTemperature_371Beta.zip (22.44 KB, 下载次数: 392) 补充1.0.1下可用的DS180B20库 OneWire_1.0.1.zip (14.38 KB, 下载次数: 691) DallasTemperature_372Beta_1.0.1.zip (22.87 KB, 下载次数: 648) 4
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