Mukodik tobb DS18B20 de nem lehet updatolni az mbedet mert azutan nem mukodik mar
Fork of DS1820 by
DS1820.cpp
- Committer:
- Sissors
- Date:
- 2014-07-08
- Revision:
- 8:d87e11e8d012
- Parent:
- 7:58b61681818f
- Child:
- 9:3821ca0b7f14
File content as of revision 8:d87e11e8d012:
#include "DS1820.h" 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; if (power_pin != NC) _power_mosfet = true; for(byte_counter=0;byte_counter<9;byte_counter++) RAM[byte_counter] = 0x00; 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; pin->output(); pin->write(0); // bring low for 500 us wait_us(500); pin->input(); // 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) { pin->output(); 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; pin->output(); pin->write(0); wait_us(3); // DXP modofied from 5 pin->input(); 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); 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; for (int n=0; n<8; n++) { // Search ROM command or Search Alarm command onewire_bit_out(pin, command & 0x01); command = command >> 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 / 8.0; } else { remaining_count = RAM[6]; count_per_degree = RAM[7]; answer = answer - 0.25 + (count_per_degree - remaining_count) / count_per_degree; } if (scale=='C' or scale=='c') answer = answer / 2.0; else // Convert to deg F answer = answer * 9.0 / 10.0 + 32.0; } 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); }