sad
Dependencies: OneWire
DS1820.cpp
- Committer:
- brose
- Date:
- 2022-09-12
- Revision:
- 25:b78d40247b97
- Parent:
- 24:d683d826dccd
- Child:
- 26:ab2080dd9e46
File content as of revision 25:b78d40247b97:
/* * Dallas' DS1820 family temperature sensor. * This library depends on the OneWire library (Dallas' 1-Wire bus protocol implementation) * available at <http://developer.mbed.org/users/hudakz/code/OneWire/> * * Example of use: * * Single sensor. * * #include "mbed.h" * #include "DS1820.h" * * Serial pc(USBTX, USBRX); * DigitalOut led(LED1); * OneWire oneWire(D8); // substitute D8 with actual mbed pin name connected 1-wire bus * float temp = 0; * int result = 0; * * int main() * { * pc.printf("\r\n--Starting--\r\n"); * if (ds1820.begin()) { * while (1) { * ds1820.startConversion(); // start temperature conversion from analog to digital * ThisThread::sleep_for(1000ms);// let DS1820 complete the temperature conversion * result = ds1820.read(temp); // read temperature from DS1820 and perform cyclic redundancy check (CRC) * switch (result) { * case 0: // no errors -> 'temp' contains the value of measured temperature * pc.printf("temp = %3.1f%cC\r\n", temp, 176); * break; * * case 1: // no sensor present -> 'temp' is not updated * pc.printf("no sensor present\n\r"); * break; * * case 2: // CRC error -> 'temp' is not updated * pc.printf("CRC error\r\n"); * } * * led = !led; * } * } * else * pc.printf("No DS1820 sensor found!\r\n"); * } * * * More sensors connected to the same 1-wire bus. * * #include "mbed.h" * #include "DS1820.h" * * #define SENSORS_COUNT 64 // number of DS1820 sensors to be connected to the 1-wire bus (max 256) * * Serial pc(USBTX, USBRX); * DigitalOut led(LED1); * OneWire oneWire(D8); // substitute D8 with actual mbed pin name connected to the DS1820 data pin * DS1820* ds1820[SENSORS_COUNT]; * int sensors_found = 0; // counts the actually found DS1820 sensors * float temp = 0; * int result = 0; * * int main() { * int i = 0; * * pc.printf("\r\n Starting \r\n"); * //Enumerate (i.e. detect) DS1820 sensors on the 1-wire bus * for(i = 0; i < SENSORS_COUNT; i++) { * ds1820[i] = new DS1820(&oneWire); * if(!ds1820[i]->begin()) { * delete ds1820[i]; * break; * } * } * * sensors_found = i; * * if (sensors_found == 0) { * pc.printf("No DS1820 sensor found!\r\n"); * return -1; * } * else * pc.printf("Found %d sensors.\r\n", sensors_found); * * while(1) { * pc.printf("-------------------\r\n"); * for(i = 0; i < sensors_found; i++) * ds1820[i]->startConversion(); // start temperature conversion from analog to digital * ThisThread::sleep_for(1000ms); // let DS1820s complete the temperature conversion * for(int i = 0; i < sensors_found; i++) { * if(ds1820[i]->isPresent()) * pc.printf("temp[%d] = %3.1f%cC\r\n", i, ds1820[i]->read(), 176); // read temperature * } * } * } * */ #include "DS1820.h" //u#define DEBUG 1 //* Initializing static members uint8_t DS1820:: _lastAddr[8] = { 0, 0, 0, 0, 0, 0, 0, 0 }; /** * @brief Constructs a generic DS1820 sensor * @note begin() must be called to detect and initialize the actual model * @param gpioPin: Name of the GPIO pin * @retval */ DS1820::DS1820(PinName gpioPin, int samplePoint_us /*=13*/ ) { _oneWire = new OneWire(gpioPin, samplePoint_us); _present = false; _model_s = false; } /** * @brief Constructs a generic DS1820 sensor * @note begin() must be called to detect and initialize the actual model * @param txPin: UART's Tx pin * @param rxPin: UART's Rx pin * @retval */ DS1820::DS1820(PinName txPin, PinName rxPin) { _oneWire = new OneWire(txPin, rxPin); _present = false; _model_s = false; } /** * @brief Constructs a generic DS1820 sensor * @note begin() must be called to detect and initialize the actual model * @param pin: Name of data pin * @retval */ DS1820::DS1820(OneWire* oneWire) : _oneWire(oneWire) { _present = false; _model_s = false; } /** * @brief Detects and initializes the actual DS1820 model * @note * @param * @retval true: if a DS1820 family sensor was detected and initialized false: otherwise */ bool DS1820::begin(void) { #if DEBUG printf("lastAddr ="); for (uint8_t i = 0; i < 8; i++) { printf(" %x", _lastAddr[i]); } printf("\r\n"); #endif if (!_oneWire->search(_lastAddr)) { #if DEBUG printf("No addresses.\r\n"); #endif _oneWire->reset_search(); #if MBED_MAJOR_VERSION == 2 wait_ms(250); #else ThisThread::sleep_for(250ms); #endif return false; } for (int i = 0; i < 8; i++) _addr[i] = _lastAddr[i]; #if DEBUG printf("ROM ="); for (uint8_t i = 0; i < 8; i++) { printf(" %x", _addr[i]); } printf("\r\n"); #endif if (OneWire::crc8(_addr, 7) == _addr[7]) { _present = true; // the first ROM byte indicates which chip switch (_addr[0]) { case 0x10: _model_s = true; #if DEBUG printf("DS18S20 or old DS1820\r\n"); #endif break; case 0x28: _model_s = false; #if DEBUG printf("DS18B20\r\n"); #endif break; case 0x22: _model_s = false; #if DEBUG printf("DS1822\r\n"); #endif break; default: _present = false; #if DEBUG printf("Device doesn't belong to the DS1820 family\r\n"); #endif return false; } return true; } else { #if DEBUG printf("Invalid CRC!\r\n"); #endif return false; } } /** * @brief Informs about presence of a DS1820 sensor. * @note begin() shall be called before using this function * if a generic DS1820 instance was created by the user. * No need to call begin() for a specific DS1820 instance. * @param * @retval true: when a DS1820 sensor is present * false: otherwise */ bool DS1820::isPresent(void) { return _present; } /** * @brief Sets temperature-to-digital conversion resolution. * @note The configuration register allows the user to set the resolution * of the temperature-to-digital conversion to 9, 10, 11, or 12 bits. * Defaults to 12-bit resolution for DS18B20. * DS18S20 allows only 9-bit resolution. * @param res: Resolution of the temperature-to-digital conversion in bits. * @retval */ void DS1820::setResolution(uint8_t res) { // keep resolution within limits if (res > 12) res = 12; if (res < 9) res = 9; if (_model_s) res = 9; _oneWire->reset(); _oneWire->select(_addr); _oneWire->write_byte(0xBE); // to read Scratchpad for (uint8_t i = 0; i < 9; i++) // read Scratchpad bytes _data[i] = _oneWire->read_byte(); _data[4] |= (res - 9) << 5; // update configuration byte (set resolution) _oneWire->reset(); _oneWire->select(_addr); _oneWire->write_byte(0x4E); // to write into Scratchpad for (uint8_t i = 2; i < 5; i++) // write three bytes (2nd, 3rd, 4th) into Scratchpad _oneWire->write_byte(_data[i]); } /** * @brief Starts temperature conversion * @note The time to complete the converion depends on the selected resolution: * 9-bit resolution -> max conversion time = 93.75ms * 10-bit resolution -> max conversion time = 187.5ms * 11-bit resolution -> max conversion time = 375ms * 12-bit resolution -> max conversion time = 750ms * @param * @retval */ void DS1820::startConversion(void) { if (_present) { _oneWire->reset(); _oneWire->select(_addr); _oneWire->write_byte(0x44); //start temperature conversion } } /** * @brief Reads temperature from the chip's Scratchpad * @note * @param * @retval Floating point temperature value */ float DS1820::read(void) { if (_present) { _oneWire->reset(); _oneWire->select(_addr); _oneWire->write_byte(0xBE); // to read Scratchpad for (uint8_t i = 0; i < 9; i++) // reading scratchpad registers _data[i] = _oneWire->read_byte(); // Convert the raw bytes to a 16-bit unsigned value uint16_t* p_word = reinterpret_cast < uint16_t * > (&_data[0]); #if DEBUG printf("raw = %#x\r\n", *p_word); #endif if (_model_s) { *p_word = *p_word << 3; // 9-bit resolution if (_data[7] == 0x10) { // "count remain" gives full 12-bit resolution *p_word = (*p_word & 0xFFF0) + 12 - _data[6]; } } else { uint8_t cfg = (_data[4] & 0x60); // default 12-bit resolution // at lower resolution, the low bits are undefined, so let's clear them if (cfg == 0x00) *p_word = *p_word &~7; // 9-bit resolution else if (cfg == 0x20) *p_word = *p_word &~3; // 10-bit resolution else if (cfg == 0x40) *p_word = *p_word &~1; // 11-bit resolution } // Convert the raw bytes to a 16-bit signed fixed point value : // 1 sign bit, 7 integer bits, 8 fractional bits (two’s compliment // and the LSB of the 16-bit binary number represents 1/256th of a unit). *p_word = *p_word << 4; // Convert to floating point value return(toFloat(*p_word)); } else return 0; } /** * @brief Reads temperature from chip's scratchpad. * @note Verifies data integrity by calculating cyclic redundancy check (CRC). * If the calculated CRC dosn't match the one stored in chip's scratchpad register * the temperature variable is not updated and CRC error code is returned. * @param temp: The temperature variable to be updated by this routine. * (It's passed as reference to floating point.) * @retval error code: * 0 - no errors ('temp' contains the temperature measured) * 1 - sensor not present ('temp' is not updated) * 2 - CRC error ('temp' is not updated) */ uint8_t DS1820::read(float& temp) { if (_present) { _oneWire->reset(); _oneWire->select(_addr); _oneWire->write_byte(0xBE); // to read Scratchpad for (uint8_t i = 0; i < 9; i++) // reading scratchpad registers _data[i] = _oneWire->read_byte(); if (_oneWire->crc8(_data, 8) != _data[8]) // if calculated CRC does not match the stored one { #if DEBUG for (uint8_t i = 0; i < 9; i++) printf("data[%d]=0x%.2x\r\n", i, _data[i]); #endif return 2; // return with CRC error } // Convert the raw bytes to a 16bit unsigned value uint16_t* p_word = reinterpret_cast < uint16_t * > (&_data[0]); #if DEBUG printf("raw = %#x\r\n", *p_word); #endif if (_model_s) { *p_word = *p_word << 3; // 9 bit resolution, max conversion time = 750ms if (_data[7] == 0x10) { // "count remain" gives full 12 bit resolution *p_word = (*p_word & 0xFFF0) + 12 - _data[6]; } // Convert the raw bytes to a 16bit signed fixed point value : // 1 sign bit, 7 integer bits, 8 fractional bits (two's compliment // and the LSB of the 16bit binary number represents 1/256th of a unit). *p_word = *p_word << 4; // Convert to floating point value temp = toFloat(*p_word); return 0; // return with no errors } else { uint8_t cfg = (_data[4] & 0x60); // default 12bit resolution, max conversion time = 750ms // at lower resolution, the low bits are undefined, so let's clear them if (cfg == 0x00) *p_word = *p_word &~7; // 9bit resolution, max conversion time = 93.75ms else if (cfg == 0x20) *p_word = *p_word &~3; // 10bit resolution, max conversion time = 187.5ms else if (cfg == 0x40) *p_word = *p_word &~1; // 11bit resolution, max conversion time = 375ms // Convert the raw bytes to a 16bit signed fixed point value : // 1 sign bit, 7 integer bits, 8 fractional bits (two's complement // and the LSB of the 16bit binary number represents 1/256th of a unit). *p_word = *p_word << 4; // Convert to floating point value temp = toFloat(*p_word); return 0; // return with no errors } } else return 1; // error, sensor is not present } /** * @brief Converts a 16-bit signed fixed point value to floating point value * @note The 16-bit unsigned integer represnts actually * a 16-bit signed fixed point value: * 1 sign bit, 7 integer bits, 8 fractional bits (two’s complement * and the LSB of the 16-bit binary number represents 1/256th of a unit). * @param 16-bit unsigned integer * @retval Floating point value */ float DS1820::toFloat(uint16_t word) { if (word & 0x8000) return(-float(uint16_t(~word + 1)) / 256.0f); else return(float(word) / 256.0f); } // new from brose void DS1820::getAddress(char * b) { //char b[20]= {}; sprintf (b, "%hhx%hhx%hhx%hhx%hhx%hhx%hhx%hhx", _addr[0],_addr[1],_addr[2],_addr[3],_addr[4],_addr[5],_addr[6],_addr[7]); //printf(b); }