Library for reading temperature from DS1820, DS18B20 and DS1822
Dependents: heatmap BLE_Temperature BLE_Temperature_Exercise F334andDS18B20 ... more
Fork of DS1820 by
HelloWorld: http://mbed.org/users/Sissors/code/DS1820_HelloWorld/
Library should currently work on all mbed targets, let me know if there is an issue. First however make sure you have latest version of mbed library and this library.
DS1820.cpp
- Committer:
- Sissors
- Date:
- 2017-01-08
- Revision:
- 14:c591209285e9
- Parent:
- 12:196e9e54b033
- Child:
- 15:236eb8f8e73a
File content as of revision 14:c591209285e9:
#include "DS1820.h" #ifdef TARGET_STM //STM targets use opendrain mode since their GPIO code is too bad to be used like the others #define ONEWIRE_INPUT(pin) pin->write(1) #define ONEWIRE_OUTPUT(pin) #define ONEWIRE_INIT(pin) pin->output(); pin->mode(OpenDrain) // TEMP, remove once STM fixed their stuff // Enable GPIO clock and return GPIO base address static uint32_t Set_GPIO_Clock(uint32_t port_idx) { uint32_t gpio_add = 0; switch (port_idx) { case PortA: gpio_add = GPIOA_BASE; __GPIOA_CLK_ENABLE(); break; case PortB: gpio_add = GPIOB_BASE; __GPIOB_CLK_ENABLE(); break; #if defined(GPIOC_BASE) case PortC: gpio_add = GPIOC_BASE; __GPIOC_CLK_ENABLE(); break; #endif #if defined(GPIOD_BASE) case PortD: gpio_add = GPIOD_BASE; __GPIOD_CLK_ENABLE(); break; #endif #if defined(GPIOF_BASE) case PortF: gpio_add = GPIOF_BASE; __GPIOF_CLK_ENABLE(); break; #endif default: error("Pinmap error: wrong port number."); break; } return gpio_add; } #else #define ONEWIRE_INPUT(pin) pin->input() #define ONEWIRE_OUTPUT(pin) pin->output() #define ONEWIRE_INIT(pin) #endif LinkedList<node> DS1820::probes; DS1820::DS1820 (PinName data_pin, PinName power_pin, bool power_polarity) : _datapin(data_pin), _parasitepin(power_pin) { int byte_counter; _power_polarity = power_polarity; _power_mosfet = power_pin != NC; for(byte_counter=0;byte_counter<9;byte_counter++) RAM[byte_counter] = 0x00; ONEWIRE_INIT((&_datapin)); // Temp code since the above doesn't actually do anything in mbed revisions up to 133 #ifdef TARGET_STM uint32_t port_index = STM_PORT(data_pin); uint32_t pin_index = STM_PIN(data_pin); // Enable GPIO clock uint32_t gpio_add = Set_GPIO_Clock(port_index); GPIO_TypeDef *gpio = (GPIO_TypeDef *)gpio_add; gpio->OTYPER |= (uint32_t)(1 << pin_index); #endif if (!unassignedProbe(&_datapin, _ROM)) error("No unassigned DS1820 found!\n"); else { _datapin.input(); probes.append(this); _parasite_power = !read_power_supply(); } } DS1820::~DS1820 (void) { node *tmp; for(int i=1; i<=probes.length(); i++) { tmp = probes.pop(i); if (tmp->data == this) probes.remove(i); } } bool DS1820::onewire_reset(DigitalInOut *pin) { // This will return false if no devices are present on the data bus bool presence=false; ONEWIRE_OUTPUT(pin); pin->write(0); // bring low for 500 us wait_us(500); ONEWIRE_INPUT(pin); // let the data line float high wait_us(90); // wait 90us if (pin->read()==0) // see if any devices are pulling the data line low presence=true; wait_us(410); return presence; } void DS1820::onewire_bit_out (DigitalInOut *pin, bool bit_data) { ONEWIRE_OUTPUT(pin); pin->write(0); wait_us(3); // DXP modified from 5 if (bit_data) { pin->write(1); // bring data line high wait_us(55); } else { wait_us(55); // keep data line low pin->write(1); wait_us(10); // DXP added to allow bus to float high before next bit_out } } void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first). int n; for (n=0; n<8; n++) { onewire_bit_out(&this->_datapin, data & 0x01); data = data >> 1; // now the next bit is in the least sig bit position. } } bool DS1820::onewire_bit_in(DigitalInOut *pin) { bool answer; ONEWIRE_OUTPUT(pin); pin->write(0); wait_us(3); // DXP modofied from 5 ONEWIRE_INPUT(pin); wait_us(10); // DXP modified from 5 answer = pin->read(); wait_us(45); // DXP modified from 50 return answer; } char DS1820::onewire_byte_in() { // read byte, least sig byte first char answer = 0x00; int i; for (i=0; i<8; i++) { answer = answer >> 1; // shift over to make room for the next bit if (onewire_bit_in(&this->_datapin)) answer = answer | 0x80; // if the data port is high, make this bit a 1 } return answer; } bool DS1820::unassignedProbe(PinName pin) { DigitalInOut _pin(pin); ONEWIRE_INIT((&_pin)); // Temp code since the above doesn't actually do anything in mbed revisions up to 133 #ifdef TARGET_STM uint32_t port_index = STM_PORT(pin); uint32_t pin_index = STM_PIN(pin); // Enable GPIO clock uint32_t gpio_add = Set_GPIO_Clock(port_index); GPIO_TypeDef *gpio = (GPIO_TypeDef *)gpio_add; gpio->OTYPER |= (uint32_t)(1 << pin_index); #endif char ROM_address[8]; return search_ROM_routine(&_pin, 0xF0, ROM_address); } bool DS1820::unassignedProbe(DigitalInOut *pin, char *ROM_address) { return search_ROM_routine(pin, 0xF0, ROM_address); } bool DS1820::search_ROM_routine(DigitalInOut *pin, char command, char *ROM_address) { bool DS1820_done_flag = false; int DS1820_last_descrepancy = 0; char DS1820_search_ROM[8] = {0, 0, 0, 0, 0, 0, 0, 0}; int descrepancy_marker, ROM_bit_index; bool return_value, Bit_A, Bit_B; char byte_counter, bit_mask; return_value=false; while (!DS1820_done_flag) { if (!onewire_reset(pin)) { return false; } else { ROM_bit_index=1; descrepancy_marker=0; char command_shift = command; for (int n=0; n<8; n++) { // Search ROM command or Search Alarm command onewire_bit_out(pin, command_shift & 0x01); command_shift = command_shift >> 1; // now the next bit is in the least sig bit position. } byte_counter = 0; bit_mask = 0x01; while (ROM_bit_index<=64) { Bit_A = onewire_bit_in(pin); Bit_B = onewire_bit_in(pin); if (Bit_A & Bit_B) { descrepancy_marker = 0; // data read error, this should never happen ROM_bit_index = 0xFF; } else { if (Bit_A | Bit_B) { // Set ROM bit to Bit_A if (Bit_A) { DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one } else { DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero } } else { // both bits A and B are low, so there are two or more devices present if ( ROM_bit_index == DS1820_last_descrepancy ) { DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one } else { if ( ROM_bit_index > DS1820_last_descrepancy ) { DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero descrepancy_marker = ROM_bit_index; } else { if (( DS1820_search_ROM[byte_counter] & bit_mask) == 0x00 ) descrepancy_marker = ROM_bit_index; } } } onewire_bit_out (pin, DS1820_search_ROM[byte_counter] & bit_mask); ROM_bit_index++; if (bit_mask & 0x80) { byte_counter++; bit_mask = 0x01; } else { bit_mask = bit_mask << 1; } } } DS1820_last_descrepancy = descrepancy_marker; if (ROM_bit_index != 0xFF) { int i = 1; node *list_container; while(1) { list_container = probes.pop(i); if (list_container == NULL) { //End of list, or empty list if (ROM_checksum_error(DS1820_search_ROM)) { // Check the CRC return false; } for(byte_counter=0;byte_counter<8;byte_counter++) ROM_address[byte_counter] = DS1820_search_ROM[byte_counter]; return true; } else { //Otherwise, check if ROM is already known bool equal = true; DS1820 *pointer = (DS1820*) list_container->data; char *ROM_compare = pointer->_ROM; for(byte_counter=0;byte_counter<8;byte_counter++) { if ( ROM_compare[byte_counter] != DS1820_search_ROM[byte_counter]) equal = false; } if (equal) break; else i++; } } } } if (DS1820_last_descrepancy == 0) DS1820_done_flag = true; } return return_value; } void DS1820::match_ROM() { // Used to select a specific device int i; onewire_reset(&this->_datapin); onewire_byte_out( 0x55); //Match ROM command for (i=0;i<8;i++) { onewire_byte_out(_ROM[i]); } } void DS1820::skip_ROM() { onewire_reset(&this->_datapin); onewire_byte_out(0xCC); // Skip ROM command } bool DS1820::ROM_checksum_error(char *_ROM_address) { char _CRC=0x00; int i; for(i=0;i<7;i++) // Only going to shift the lower 7 bytes _CRC = CRC_byte(_CRC, _ROM_address[i]); // After 7 bytes CRC should equal the 8th byte (ROM CRC) return (_CRC!=_ROM_address[7]); // will return true if there is a CRC checksum mis-match } bool DS1820::RAM_checksum_error() { char _CRC=0x00; int i; for(i=0;i<8;i++) // Only going to shift the lower 8 bytes _CRC = CRC_byte(_CRC, RAM[i]); // After 8 bytes CRC should equal the 9th byte (RAM CRC) return (_CRC!=RAM[8]); // will return true if there is a CRC checksum mis-match } char DS1820::CRC_byte (char _CRC, char byte ) { int j; for(j=0;j<8;j++) { if ((byte & 0x01 ) ^ (_CRC & 0x01)) { // DATA ^ LSB CRC = 1 _CRC = _CRC>>1; // Set the MSB to 1 _CRC = _CRC | 0x80; // Check bit 3 if (_CRC & 0x04) { _CRC = _CRC & 0xFB; // Bit 3 is set, so clear it } else { _CRC = _CRC | 0x04; // Bit 3 is clear, so set it } // Check bit 4 if (_CRC & 0x08) { _CRC = _CRC & 0xF7; // Bit 4 is set, so clear it } else { _CRC = _CRC | 0x08; // Bit 4 is clear, so set it } } else { // DATA ^ LSB CRC = 0 _CRC = _CRC>>1; // clear MSB _CRC = _CRC & 0x7F; // No need to check bits, with DATA ^ LSB CRC = 0, they will remain unchanged } byte = byte>>1; } return _CRC; } int DS1820::convertTemperature(bool wait, devices device) { // Convert temperature into scratchpad RAM for all devices at once int delay_time = 750; // Default delay time char resolution; if (device==all_devices) skip_ROM(); // Skip ROM command, will convert for ALL devices else { match_ROM(); if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) { resolution = RAM[4] & 0x60; if (resolution == 0x00) // 9 bits delay_time = 94; if (resolution == 0x20) // 10 bits delay_time = 188; if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default delay_time = 375; } } onewire_byte_out( 0x44); // perform temperature conversion if (_parasite_power) { if (_power_mosfet) { _parasitepin = _power_polarity; // Parasite power strong pullup wait_ms(delay_time); _parasitepin = !_power_polarity; delay_time = 0; } else { _datapin.output(); _datapin.write(1); wait_ms(delay_time); _datapin.input(); } } else { if (wait) { wait_ms(delay_time); delay_time = 0; } } return delay_time; } void DS1820::read_RAM() { // This will copy the DS1820's 9 bytes of RAM data // into the objects RAM array. Functions that use // RAM values will automaticly call this procedure. int i; match_ROM(); // Select this device onewire_byte_out( 0xBE); //Read Scratchpad command for(i=0;i<9;i++) { RAM[i] = onewire_byte_in(); } // if (!RAM_checksum_error()) // crcerr = 1; } bool DS1820::setResolution(unsigned int resolution) { bool answer = false; resolution = resolution - 9; if (resolution < 4) { resolution = resolution<<5; // align the bits RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new write_scratchpad ((RAM[2]<<8) + RAM[3]); // store_scratchpad (DS1820::this_device); // Need to test if this is required answer = true; } return answer; } void DS1820::write_scratchpad(int data) { RAM[3] = data; RAM[2] = data>>8; match_ROM(); onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory onewire_byte_out(RAM[2]); // T(H) onewire_byte_out(RAM[3]); // T(L) if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) { onewire_byte_out(RAM[4]); // Configuration register } } float DS1820::temperature(char scale) { // The data specs state that count_per_degree should be 0x10 (16), I found my devices // to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C // this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this // being super acurate, but it does allow for a smooth display in the 1/10ths of a // deg C or F scales. float answer, remaining_count, count_per_degree; int reading; read_RAM(); if (RAM_checksum_error()) // Indicate we got a CRC error answer = invalid_conversion; else { reading = (RAM[1] << 8) + RAM[0]; if (reading & 0x8000) { // negative degrees C reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int } answer = reading +0.0; // convert to floating point if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) { answer = answer / 16.0f; } else { remaining_count = RAM[6]; count_per_degree = RAM[7]; answer = floor(answer/2.0f) - 0.25f + (count_per_degree - remaining_count) / count_per_degree; } if (scale=='F' or scale=='f') // Convert to deg F answer = answer * 9.0f / 5.0f + 32.0f; } return answer; } bool DS1820::read_power_supply(devices device) { // This will return true if the device (or all devices) are Vcc powered // This will return false if the device (or ANY device) is parasite powered if (device==all_devices) skip_ROM(); // Skip ROM command, will poll for any device using parasite power else match_ROM(); onewire_byte_out(0xB4); // Read power supply command return onewire_bit_in(&this->_datapin); }