Dallas' DS1820 family temperature sensor. For more details see [https://developer.mbed.org/users/hudakz/code/DS1820/wiki/Homepage]
Dependencies: OneWire
Diff: DS1820.cpp
- Revision:
- 20:98c261bcb399
- Parent:
- 17:9ff584b9809f
- Child:
- 22:16537aa25bd9
--- a/DS1820.cpp Sun Jan 27 18:02:01 2019 +0000 +++ b/DS1820.cpp Sun Mar 10 13:19:03 2019 +0000 @@ -5,34 +5,114 @@ * * Example of use: * - * #include "DS1820.h" + * Single sensor. * - * Serial serial(USBTX, USBRX); + * #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 + * wait(1.0); // 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() { - * DS1820 ds1820(PA_9); // substitute PA_9 with actual mbed pin name connected to the DS1820 data pin - * - * if(ds1820.begin()) { - * ds1820.startConversion(); - * wait(1.0); - * while(1) { - * printf("temp = %3.1f\r\n", ds1820.read()); // read temperature - * ds1820.startConversion(); // start temperature conversion - * wait(1.0); // let DS1820 complete the temperature conversion - * } - * } else - * printf("No DS1820 sensor found!\r\n"); + * 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 + * wait(1.0); // 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 + * } + * } * } - * * - * Note: Don't forget to connect a 4.7k Ohm resistor - * between the DS1820's data pin and the +3.3V pin - * */ #include "DS1820.h" -//#define DEBUG 1 +#define DEBUG 0 + +//* 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 pin: Name of data pin + * @retval + */ +DS1820::DS1820(PinName pin) { + oneWire = new OneWire(pin); + present = false; + model_s = false; +} /** * @brief Constructs a generic DS1820 sensor @@ -40,34 +120,13 @@ * @param pin: Name of data pin * @retval */ -DS1820::DS1820(PinName pin) : - oneWire(pin) { +DS1820::DS1820(OneWire* wire) : + oneWire(wire) { present = false; model_s = false; } /** - * @brief Constructs a specific model - * @note No need to call begin() to detect and initialize the model - * @param model: One character model name: 'S', 's', 'B' or 'b' - * pin: Name of data pin - * @retval - */ -DS1820::DS1820(char model, PinName pin) : - oneWire(pin) { - if((model == 'S') or (model == 's')) { - present = true; - model_s = true; - } - else if((model == 'B') or (model == 'b')) { - present = true; - model_s = false; - } - else - present = false; -} - -/** * @brief Detects and initializes the actual DS1820 model * @note * @param @@ -75,16 +134,24 @@ false: otherwise */ bool DS1820::begin(void) { - oneWire.reset_search(); - wait_ms(250); - if(!oneWire.search(addr)) { +#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(); + oneWire->reset_search(); wait_ms(250); return false; } + + for (int i = 0; i < 8; i++) + addr[i] = lastAddr[i]; #if DEBUG printf("ROM ="); @@ -168,18 +235,18 @@ if(model_s) res = 9; - oneWire.reset(); - oneWire.skip(); - oneWire.write_byte(0xBE); // to read Scratchpad + 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[i] = oneWire->read_byte(); data[4] |= (res - 9) << 5; // update configuration byte (set resolution) - oneWire.reset(); - oneWire.skip(); - oneWire.write_byte(0x4E); // to write into Scratchpad + 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]); + oneWire->write_byte(data[i]); } /** @@ -194,9 +261,9 @@ */ void DS1820::startConversion(void) { if(present) { - oneWire.reset(); - oneWire.skip(); - oneWire.write_byte(0x44); //start temperature conversion + oneWire->reset(); + oneWire->select(addr); + oneWire->write_byte(0x44); //start temperature conversion } } @@ -208,11 +275,11 @@ */ float DS1820::read(void) { if(present) { - oneWire.reset(); - oneWire.skip(); - oneWire.write_byte(0xBE); // to read Scratchpad + 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(); + 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]); @@ -270,13 +337,13 @@ */ uint8_t DS1820::read(float& temp) { if(present) { - oneWire.reset(); - oneWire.skip(); - oneWire.write_byte(0xBE); // to read Scratchpad + 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(); + data[i] = oneWire->read_byte(); - if(oneWire.crc8(data, 8) != data[8]) // if calculated CRC does not match the stored one + 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++)