Paul Staron / DS1820

Fork of Erik's DS1820 library working on OS6

Dependencies:   LinkedList2

Dependents:   DS1820-example DS1820mitWebserver DS1820ohneWebserver

DS1820.cpp@1:ce70453af3db, 2020-12-29 (annotated)

Committer:
star297
Date:
Tue Dec 29 13:11:12 2020 +0000
Revision:
1:ce70453af3db
Parent:
0:a43dcf6ca539 
Initial commit.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
star297 0:a43dcf6ca539 1 #include "DS1820.h"
star297 0:a43dcf6ca539 2
star297 0:a43dcf6ca539 3 #ifdef TARGET_STM
star297 0:a43dcf6ca539 4 //STM targets use opendrain mode since their switching between input and output is slow
star297 0:a43dcf6ca539 5 #define ONEWIRE_INPUT(pin) pin->write(1)
star297 0:a43dcf6ca539 6 #define ONEWIRE_OUTPUT(pin)
star297 0:a43dcf6ca539 7 #define ONEWIRE_INIT(pin) pin->output(); pin->mode(OpenDrain)
star297 0:a43dcf6ca539 8 #else
star297 0:a43dcf6ca539 9 #define ONEWIRE_INPUT(pin) pin->input()
star297 0:a43dcf6ca539 10 #define ONEWIRE_OUTPUT(pin) pin->output()
star297 0:a43dcf6ca539 11 #define ONEWIRE_INIT(pin)
star297 0:a43dcf6ca539 12 #endif
star297 0:a43dcf6ca539 13
star297 0:a43dcf6ca539 14 #ifdef TARGET_NORDIC
star297 0:a43dcf6ca539 15 //NORDIC targets (NRF) use software delays since their ticker uses a 32kHz clock
star297 0:a43dcf6ca539 16 static uint32_t loops_per_us = 0;
star297 0:a43dcf6ca539 17
star297 0:a43dcf6ca539 18 #define INIT_DELAY init_soft_delay()
star297 0:a43dcf6ca539 19 #define ONEWIRE_DELAY_US(value) for(int cnt = 0; cnt < (value * loops_per_us) >> 5; cnt++) {__NOP(); __NOP(); __NOP();}
star297 0:a43dcf6ca539 20
star297 0:a43dcf6ca539 21 void init_soft_delay( void ) {
star297 0:a43dcf6ca539 22 if (loops_per_us == 0) {
star297 0:a43dcf6ca539 23 loops_per_us = 1;
star297 0:a43dcf6ca539 24 Timer timey;
star297 0:a43dcf6ca539 25 timey.start();
star297 0:a43dcf6ca539 26 ONEWIRE_DELAY_US(320000);
star297 0:a43dcf6ca539 27 timey.stop();
star297 0:a43dcf6ca539 28 loops_per_us = (320000 + timey.read_us() / 2) / timey.read_us();
star297 0:a43dcf6ca539 29 }
star297 0:a43dcf6ca539 30 }
star297 0:a43dcf6ca539 31 #else
star297 0:a43dcf6ca539 32 #define INIT_DELAY
star297 0:a43dcf6ca539 33 #define ONEWIRE_DELAY_US(value) wait_us(value)
star297 0:a43dcf6ca539 34 #endif
star297 0:a43dcf6ca539 35
star297 0:a43dcf6ca539 36 LinkedList2<node> DS1820::probes;
star297 0:a43dcf6ca539 37
star297 0:a43dcf6ca539 38
star297 0:a43dcf6ca539 39 DS1820::DS1820 (PinName data_pin, PinName power_pin, bool power_polarity) : _datapin(data_pin), _parasitepin(power_pin) {
star297 0:a43dcf6ca539 40 int byte_counter;
star297 0:a43dcf6ca539 41 _power_polarity = power_polarity;
star297 0:a43dcf6ca539 42
star297 0:a43dcf6ca539 43 _power_mosfet = power_pin != NC;
star297 0:a43dcf6ca539 44
star297 0:a43dcf6ca539 45 for(byte_counter=0;byte_counter<9;byte_counter++)
star297 0:a43dcf6ca539 46 RAM[byte_counter] = 0x00;
star297 0:a43dcf6ca539 47
star297 0:a43dcf6ca539 48 ONEWIRE_INIT((&_datapin));
star297 0:a43dcf6ca539 49 INIT_DELAY;
star297 0:a43dcf6ca539 50
star297 0:a43dcf6ca539 51 if (!unassignedProbe(&_datapin, _ROM))
star297 0:a43dcf6ca539 52 error("No unassigned DS1820 found!\n");
star297 0:a43dcf6ca539 53 else {
star297 0:a43dcf6ca539 54 _datapin.input();
star297 0:a43dcf6ca539 55 probes.append(this);
star297 0:a43dcf6ca539 56 _parasite_power = !read_power_supply();
star297 0:a43dcf6ca539 57 }
star297 0:a43dcf6ca539 58 }
star297 0:a43dcf6ca539 59
star297 0:a43dcf6ca539 60 DS1820::~DS1820 (void) {
star297 0:a43dcf6ca539 61 node *tmp;
star297 0:a43dcf6ca539 62 for(int i=1; i<=probes.length(); i++)
star297 0:a43dcf6ca539 63 {
star297 0:a43dcf6ca539 64 tmp = probes.pop(i);
star297 0:a43dcf6ca539 65 if (tmp->data == this)
star297 0:a43dcf6ca539 66 probes.remove(i);
star297 0:a43dcf6ca539 67 }
star297 0:a43dcf6ca539 68 }
star297 0:a43dcf6ca539 69
star297 0:a43dcf6ca539 70 bool DS1820::onewire_reset(DigitalInOut *pin) {
star297 0:a43dcf6ca539 71 // This will return false if no devices are present on the data bus
star297 0:a43dcf6ca539 72 bool presence=false;
star297 0:a43dcf6ca539 73 ONEWIRE_OUTPUT(pin);
star297 0:a43dcf6ca539 74 pin->write(0); // bring low for 500 us
star297 0:a43dcf6ca539 75 ONEWIRE_DELAY_US(500);
star297 0:a43dcf6ca539 76 ONEWIRE_INPUT(pin); // let the data line float high
star297 0:a43dcf6ca539 77 ONEWIRE_DELAY_US(90); // wait 90us
star297 0:a43dcf6ca539 78 if (pin->read()==0) // see if any devices are pulling the data line low
star297 0:a43dcf6ca539 79 presence=true;
star297 0:a43dcf6ca539 80 ONEWIRE_DELAY_US(410);
star297 0:a43dcf6ca539 81 return presence;
star297 0:a43dcf6ca539 82 }
star297 0:a43dcf6ca539 83
star297 0:a43dcf6ca539 84 void DS1820::onewire_bit_out (DigitalInOut *pin, bool bit_data) {
star297 0:a43dcf6ca539 85 ONEWIRE_OUTPUT(pin);
star297 0:a43dcf6ca539 86 pin->write(0);
star297 0:a43dcf6ca539 87 ONEWIRE_DELAY_US(3); // DXP modified from 5
star297 0:a43dcf6ca539 88 if (bit_data) {
star297 0:a43dcf6ca539 89 pin->write(1); // bring data line high
star297 0:a43dcf6ca539 90 ONEWIRE_DELAY_US(55);
star297 0:a43dcf6ca539 91 } else {
star297 0:a43dcf6ca539 92 ONEWIRE_DELAY_US(55); // keep data line low
star297 0:a43dcf6ca539 93 pin->write(1);
star297 0:a43dcf6ca539 94 ONEWIRE_DELAY_US(10); // DXP added to allow bus to float high before next bit_out
star297 0:a43dcf6ca539 95 }
star297 0:a43dcf6ca539 96 }
star297 0:a43dcf6ca539 97
star297 0:a43dcf6ca539 98 void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first).
star297 0:a43dcf6ca539 99 int n;
star297 0:a43dcf6ca539 100 for (n=0; n<8; n++) {
star297 0:a43dcf6ca539 101 onewire_bit_out(&this->_datapin, data & 0x01);
star297 0:a43dcf6ca539 102 data = data >> 1; // now the next bit is in the least sig bit position.
star297 0:a43dcf6ca539 103 }
star297 0:a43dcf6ca539 104 }
star297 0:a43dcf6ca539 105
star297 0:a43dcf6ca539 106 bool DS1820::onewire_bit_in(DigitalInOut *pin) {
star297 0:a43dcf6ca539 107 bool answer;
star297 0:a43dcf6ca539 108 ONEWIRE_OUTPUT(pin);
star297 0:a43dcf6ca539 109 pin->write(0);
star297 0:a43dcf6ca539 110 ONEWIRE_DELAY_US(3); // DXP modofied from 5
star297 0:a43dcf6ca539 111 ONEWIRE_INPUT(pin);
star297 0:a43dcf6ca539 112 ONEWIRE_DELAY_US(6); // DXP modified from 5
star297 0:a43dcf6ca539 113 answer = pin->read();
star297 0:a43dcf6ca539 114 ONEWIRE_DELAY_US(45); // DXP modified from 50
star297 0:a43dcf6ca539 115 return answer;
star297 0:a43dcf6ca539 116 }
star297 0:a43dcf6ca539 117
star297 0:a43dcf6ca539 118 char DS1820::onewire_byte_in() { // read byte, least sig byte first
star297 0:a43dcf6ca539 119 char answer = 0x00;
star297 0:a43dcf6ca539 120 int i;
star297 0:a43dcf6ca539 121 for (i=0; i<8; i++) {
star297 0:a43dcf6ca539 122 answer = answer >> 1; // shift over to make room for the next bit
star297 0:a43dcf6ca539 123 if (onewire_bit_in(&this->_datapin))
star297 0:a43dcf6ca539 124 answer = answer | 0x80; // if the data port is high, make this bit a 1
star297 0:a43dcf6ca539 125 }
star297 0:a43dcf6ca539 126 return answer;
star297 0:a43dcf6ca539 127 }
star297 0:a43dcf6ca539 128
star297 0:a43dcf6ca539 129 bool DS1820::unassignedProbe(PinName pin) {
star297 0:a43dcf6ca539 130 DigitalInOut _pin(pin);
star297 0:a43dcf6ca539 131 ONEWIRE_INIT((&_pin));
star297 0:a43dcf6ca539 132 INIT_DELAY;
star297 0:a43dcf6ca539 133 char ROM_address[8];
star297 0:a43dcf6ca539 134 return search_ROM_routine(&_pin, 0xF0, ROM_address);
star297 0:a43dcf6ca539 135 }
star297 0:a43dcf6ca539 136
star297 0:a43dcf6ca539 137 bool DS1820::unassignedProbe(DigitalInOut *pin, char *ROM_address) {
star297 0:a43dcf6ca539 138 return search_ROM_routine(pin, 0xF0, ROM_address);
star297 0:a43dcf6ca539 139 }
star297 0:a43dcf6ca539 140
star297 0:a43dcf6ca539 141 bool DS1820::search_ROM_routine(DigitalInOut *pin, char command, char *ROM_address) {
star297 0:a43dcf6ca539 142 bool DS1820_done_flag = false;
star297 0:a43dcf6ca539 143 int DS1820_last_descrepancy = 0;
star297 0:a43dcf6ca539 144 char DS1820_search_ROM[8] = {0, 0, 0, 0, 0, 0, 0, 0};
star297 0:a43dcf6ca539 145
star297 0:a43dcf6ca539 146 int descrepancy_marker, ROM_bit_index;
star297 0:a43dcf6ca539 147 bool return_value, Bit_A, Bit_B;
star297 0:a43dcf6ca539 148 char byte_counter, bit_mask;
star297 0:a43dcf6ca539 149
star297 0:a43dcf6ca539 150 return_value=false;
star297 0:a43dcf6ca539 151 while (!DS1820_done_flag) {
star297 0:a43dcf6ca539 152 if (!onewire_reset(pin)) {
star297 0:a43dcf6ca539 153 return false;
star297 0:a43dcf6ca539 154 } else {
star297 0:a43dcf6ca539 155 ROM_bit_index=1;
star297 0:a43dcf6ca539 156 descrepancy_marker=0;
star297 0:a43dcf6ca539 157 char command_shift = command;
star297 0:a43dcf6ca539 158 for (int n=0; n<8; n++) { // Search ROM command or Search Alarm command
star297 0:a43dcf6ca539 159 onewire_bit_out(pin, command_shift & 0x01);
star297 0:a43dcf6ca539 160 command_shift = command_shift >> 1; // now the next bit is in the least sig bit position.
star297 0:a43dcf6ca539 161 }
star297 0:a43dcf6ca539 162 byte_counter = 0;
star297 0:a43dcf6ca539 163 bit_mask = 0x01;
star297 0:a43dcf6ca539 164 while (ROM_bit_index<=64) {
star297 0:a43dcf6ca539 165 Bit_A = onewire_bit_in(pin);
star297 0:a43dcf6ca539 166 Bit_B = onewire_bit_in(pin);
star297 0:a43dcf6ca539 167 if (Bit_A & Bit_B) {
star297 0:a43dcf6ca539 168 descrepancy_marker = 0; // data read error, this should never happen
star297 0:a43dcf6ca539 169 ROM_bit_index = 0xFF;
star297 0:a43dcf6ca539 170 } else {
star297 0:a43dcf6ca539 171 if (Bit_A | Bit_B) {
star297 0:a43dcf6ca539 172 // Set ROM bit to Bit_A
star297 0:a43dcf6ca539 173 if (Bit_A) {
star297 0:a43dcf6ca539 174 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
star297 0:a43dcf6ca539 175 } else {
star297 0:a43dcf6ca539 176 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
star297 0:a43dcf6ca539 177 }
star297 0:a43dcf6ca539 178 } else {
star297 0:a43dcf6ca539 179 // both bits A and B are low, so there are two or more devices present
star297 0:a43dcf6ca539 180 if ( ROM_bit_index == DS1820_last_descrepancy ) {
star297 0:a43dcf6ca539 181 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
star297 0:a43dcf6ca539 182 } else {
star297 0:a43dcf6ca539 183 if ( ROM_bit_index > DS1820_last_descrepancy ) {
star297 0:a43dcf6ca539 184 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
star297 0:a43dcf6ca539 185 descrepancy_marker = ROM_bit_index;
star297 0:a43dcf6ca539 186 } else {
star297 0:a43dcf6ca539 187 if (( DS1820_search_ROM[byte_counter] & bit_mask) == 0x00 )
star297 0:a43dcf6ca539 188 descrepancy_marker = ROM_bit_index;
star297 0:a43dcf6ca539 189 }
star297 0:a43dcf6ca539 190 }
star297 0:a43dcf6ca539 191 }
star297 0:a43dcf6ca539 192 onewire_bit_out (pin, DS1820_search_ROM[byte_counter] & bit_mask);
star297 0:a43dcf6ca539 193 ROM_bit_index++;
star297 0:a43dcf6ca539 194 if (bit_mask & 0x80) {
star297 0:a43dcf6ca539 195 byte_counter++;
star297 0:a43dcf6ca539 196 bit_mask = 0x01;
star297 0:a43dcf6ca539 197 } else {
star297 0:a43dcf6ca539 198 bit_mask = bit_mask << 1;
star297 0:a43dcf6ca539 199 }
star297 0:a43dcf6ca539 200 }
star297 0:a43dcf6ca539 201 }
star297 0:a43dcf6ca539 202 DS1820_last_descrepancy = descrepancy_marker;
star297 0:a43dcf6ca539 203 if (ROM_bit_index != 0xFF) {
star297 0:a43dcf6ca539 204 int i = 1;
star297 0:a43dcf6ca539 205 node *list_container;
star297 0:a43dcf6ca539 206 while(1) {
star297 0:a43dcf6ca539 207 list_container = probes.pop(i);
star297 0:a43dcf6ca539 208 if (list_container == NULL) { //End of list, or empty list
star297 0:a43dcf6ca539 209 if (ROM_checksum_error(DS1820_search_ROM)) { // Check the CRC
star297 0:a43dcf6ca539 210 return false;
star297 0:a43dcf6ca539 211 }
star297 0:a43dcf6ca539 212 for(byte_counter=0;byte_counter<8;byte_counter++)
star297 0:a43dcf6ca539 213 ROM_address[byte_counter] = DS1820_search_ROM[byte_counter];
star297 0:a43dcf6ca539 214 return true;
star297 0:a43dcf6ca539 215 } else { //Otherwise, check if ROM is already known
star297 0:a43dcf6ca539 216 bool equal = true;
star297 0:a43dcf6ca539 217 DS1820 *pointer = (DS1820*) list_container->data;
star297 0:a43dcf6ca539 218 char *ROM_compare = pointer->_ROM;
star297 0:a43dcf6ca539 219
star297 0:a43dcf6ca539 220 for(byte_counter=0;byte_counter<8;byte_counter++) {
star297 0:a43dcf6ca539 221 if ( ROM_compare[byte_counter] != DS1820_search_ROM[byte_counter])
star297 0:a43dcf6ca539 222 equal = false;
star297 0:a43dcf6ca539 223 }
star297 0:a43dcf6ca539 224 if (equal)
star297 0:a43dcf6ca539 225 break;
star297 0:a43dcf6ca539 226 else
star297 0:a43dcf6ca539 227 i++;
star297 0:a43dcf6ca539 228 }
star297 0:a43dcf6ca539 229 }
star297 0:a43dcf6ca539 230 }
star297 0:a43dcf6ca539 231 }
star297 0:a43dcf6ca539 232 if (DS1820_last_descrepancy == 0)
star297 0:a43dcf6ca539 233 DS1820_done_flag = true;
star297 0:a43dcf6ca539 234 }
star297 0:a43dcf6ca539 235 return return_value;
star297 0:a43dcf6ca539 236 }
star297 0:a43dcf6ca539 237
star297 0:a43dcf6ca539 238 void DS1820::match_ROM() {
star297 0:a43dcf6ca539 239 // Used to select a specific device
star297 0:a43dcf6ca539 240 int i;
star297 0:a43dcf6ca539 241 onewire_reset(&this->_datapin);
star297 0:a43dcf6ca539 242 onewire_byte_out( 0x55); //Match ROM command
star297 0:a43dcf6ca539 243 for (i=0;i<8;i++) {
star297 0:a43dcf6ca539 244 onewire_byte_out(_ROM[i]);
star297 0:a43dcf6ca539 245 }
star297 0:a43dcf6ca539 246 }
star297 0:a43dcf6ca539 247
star297 0:a43dcf6ca539 248 void DS1820::skip_ROM() {
star297 0:a43dcf6ca539 249 onewire_reset(&this->_datapin);
star297 0:a43dcf6ca539 250 onewire_byte_out(0xCC); // Skip ROM command
star297 0:a43dcf6ca539 251 }
star297 0:a43dcf6ca539 252
star297 0:a43dcf6ca539 253 bool DS1820::ROM_checksum_error(char *_ROM_address) {
star297 0:a43dcf6ca539 254 char _CRC=0x00;
star297 0:a43dcf6ca539 255 int i;
star297 0:a43dcf6ca539 256 for(i=0;i<7;i++) // Only going to shift the lower 7 bytes
star297 0:a43dcf6ca539 257 _CRC = CRC_byte(_CRC, _ROM_address[i]);
star297 0:a43dcf6ca539 258 // After 7 bytes CRC should equal the 8th byte (ROM CRC)
star297 0:a43dcf6ca539 259 return (_CRC!=_ROM_address[7]); // will return true if there is a CRC checksum mis-match
star297 0:a43dcf6ca539 260 }
star297 0:a43dcf6ca539 261
star297 0:a43dcf6ca539 262 bool DS1820::RAM_checksum_error() {
star297 0:a43dcf6ca539 263 char _CRC=0x00;
star297 0:a43dcf6ca539 264 int i;
star297 0:a43dcf6ca539 265 for(i=0;i<8;i++) // Only going to shift the lower 8 bytes
star297 0:a43dcf6ca539 266 _CRC = CRC_byte(_CRC, RAM[i]);
star297 0:a43dcf6ca539 267 // After 8 bytes CRC should equal the 9th byte (RAM CRC)
star297 0:a43dcf6ca539 268 return (_CRC!=RAM[8]); // will return true if there is a CRC checksum mis-match
star297 0:a43dcf6ca539 269 }
star297 0:a43dcf6ca539 270
star297 0:a43dcf6ca539 271 char DS1820::CRC_byte (char _CRC, char byte ) {
star297 0:a43dcf6ca539 272 int j;
star297 0:a43dcf6ca539 273 for(j=0;j<8;j++) {
star297 0:a43dcf6ca539 274 if ((byte & 0x01 ) ^ (_CRC & 0x01)) {
star297 0:a43dcf6ca539 275 // DATA ^ LSB CRC = 1
star297 0:a43dcf6ca539 276 _CRC = _CRC>>1;
star297 0:a43dcf6ca539 277 // Set the MSB to 1
star297 0:a43dcf6ca539 278 _CRC = _CRC | 0x80;
star297 0:a43dcf6ca539 279 // Check bit 3
star297 0:a43dcf6ca539 280 if (_CRC & 0x04) {
star297 0:a43dcf6ca539 281 _CRC = _CRC & 0xFB; // Bit 3 is set, so clear it
star297 0:a43dcf6ca539 282 } else {
star297 0:a43dcf6ca539 283 _CRC = _CRC | 0x04; // Bit 3 is clear, so set it
star297 0:a43dcf6ca539 284 }
star297 0:a43dcf6ca539 285 // Check bit 4
star297 0:a43dcf6ca539 286 if (_CRC & 0x08) {
star297 0:a43dcf6ca539 287 _CRC = _CRC & 0xF7; // Bit 4 is set, so clear it
star297 0:a43dcf6ca539 288 } else {
star297 0:a43dcf6ca539 289 _CRC = _CRC | 0x08; // Bit 4 is clear, so set it
star297 0:a43dcf6ca539 290 }
star297 0:a43dcf6ca539 291 } else {
star297 0:a43dcf6ca539 292 // DATA ^ LSB CRC = 0
star297 0:a43dcf6ca539 293 _CRC = _CRC>>1;
star297 0:a43dcf6ca539 294 // clear MSB
star297 0:a43dcf6ca539 295 _CRC = _CRC & 0x7F;
star297 0:a43dcf6ca539 296 // No need to check bits, with DATA ^ LSB CRC = 0, they will remain unchanged
star297 0:a43dcf6ca539 297 }
star297 0:a43dcf6ca539 298 byte = byte>>1;
star297 0:a43dcf6ca539 299 }
star297 0:a43dcf6ca539 300 return _CRC;
star297 0:a43dcf6ca539 301 }
star297 0:a43dcf6ca539 302
star297 0:a43dcf6ca539 303 int DS1820::convertTemperature(bool wait, devices device) {
star297 0:a43dcf6ca539 304 // Convert temperature into scratchpad RAM for all devices at once
star297 0:a43dcf6ca539 305 int delay_time = 750000; // Default delay time
star297 0:a43dcf6ca539 306 char resolution;
star297 0:a43dcf6ca539 307 if (device==all_devices)
star297 0:a43dcf6ca539 308 skip_ROM(); // Skip ROM command, will convert for ALL devices
star297 0:a43dcf6ca539 309 else {
star297 0:a43dcf6ca539 310 match_ROM();
star297 0:a43dcf6ca539 311 if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) {
star297 0:a43dcf6ca539 312 resolution = RAM[4] & 0x60;
star297 0:a43dcf6ca539 313 if (resolution == 0x00) // 9 bits
star297 0:a43dcf6ca539 314 delay_time = 94000;
star297 0:a43dcf6ca539 315 if (resolution == 0x20) // 10 bits
star297 0:a43dcf6ca539 316 delay_time = 188000;
star297 0:a43dcf6ca539 317 if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default
star297 0:a43dcf6ca539 318 delay_time = 375000;
star297 0:a43dcf6ca539 319 }
star297 0:a43dcf6ca539 320 }
star297 0:a43dcf6ca539 321
star297 0:a43dcf6ca539 322 onewire_byte_out( 0x44); // perform temperature conversion
star297 0:a43dcf6ca539 323 if (_parasite_power) {
star297 0:a43dcf6ca539 324 if (_power_mosfet) {
star297 0:a43dcf6ca539 325 _parasitepin = _power_polarity; // Parasite power strong pullup
star297 0:a43dcf6ca539 326 wait_us(delay_time);
star297 0:a43dcf6ca539 327 _parasitepin = !_power_polarity;
star297 0:a43dcf6ca539 328 delay_time = 0;
star297 0:a43dcf6ca539 329 } else {
star297 0:a43dcf6ca539 330 _datapin.output();
star297 0:a43dcf6ca539 331 _datapin.write(1);
star297 0:a43dcf6ca539 332 wait_us(delay_time);
star297 0:a43dcf6ca539 333 _datapin.input();
star297 0:a43dcf6ca539 334 }
star297 0:a43dcf6ca539 335 } else {
star297 0:a43dcf6ca539 336 if (wait) {
star297 0:a43dcf6ca539 337 wait_us(delay_time);
star297 0:a43dcf6ca539 338 delay_time = 0;
star297 0:a43dcf6ca539 339 }
star297 0:a43dcf6ca539 340 }
star297 0:a43dcf6ca539 341 return delay_time;
star297 0:a43dcf6ca539 342 }
star297 0:a43dcf6ca539 343
star297 0:a43dcf6ca539 344 void DS1820::read_RAM() {
star297 0:a43dcf6ca539 345 // This will copy the DS1820's 9 bytes of RAM data
star297 0:a43dcf6ca539 346 // into the objects RAM array. Functions that use
star297 0:a43dcf6ca539 347 // RAM values will automaticly call this procedure.
star297 0:a43dcf6ca539 348 int i;
star297 0:a43dcf6ca539 349 match_ROM(); // Select this device
star297 0:a43dcf6ca539 350 onewire_byte_out( 0xBE); //Read Scratchpad command
star297 0:a43dcf6ca539 351 for(i=0;i<9;i++) {
star297 0:a43dcf6ca539 352 RAM[i] = onewire_byte_in();
star297 0:a43dcf6ca539 353 }
star297 0:a43dcf6ca539 354 // if (!RAM_checksum_error())
star297 0:a43dcf6ca539 355 // crcerr = 1;
star297 0:a43dcf6ca539 356 }
star297 0:a43dcf6ca539 357
star297 0:a43dcf6ca539 358 bool DS1820::setResolution(unsigned int resolution) {
star297 0:a43dcf6ca539 359 bool answer = false;
star297 0:a43dcf6ca539 360 resolution = resolution - 9;
star297 0:a43dcf6ca539 361 if (resolution < 4) {
star297 0:a43dcf6ca539 362 resolution = resolution<<5; // align the bits
star297 0:a43dcf6ca539 363 RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new
star297 0:a43dcf6ca539 364 write_scratchpad ((RAM[2]<<8) + RAM[3]);
star297 0:a43dcf6ca539 365 write_scratchpad (DS1820::this_device); // Need to test if this is required
star297 0:a43dcf6ca539 366 answer = true;
star297 0:a43dcf6ca539 367 }
star297 0:a43dcf6ca539 368 return answer;
star297 0:a43dcf6ca539 369 }
star297 0:a43dcf6ca539 370
star297 0:a43dcf6ca539 371 void DS1820::write_scratchpad(int data) {
star297 0:a43dcf6ca539 372 RAM[3] = data;
star297 0:a43dcf6ca539 373 RAM[2] = data>>8;
star297 0:a43dcf6ca539 374 match_ROM();
star297 0:a43dcf6ca539 375 onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory
star297 0:a43dcf6ca539 376 onewire_byte_out(RAM[2]); // T(H)
star297 0:a43dcf6ca539 377 onewire_byte_out(RAM[3]); // T(L)
star297 0:a43dcf6ca539 378 if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) {
star297 0:a43dcf6ca539 379 onewire_byte_out(RAM[4]); // Configuration register
star297 0:a43dcf6ca539 380 }
star297 0:a43dcf6ca539 381 }
star297 0:a43dcf6ca539 382
star297 0:a43dcf6ca539 383 float DS1820::temperature(char scale) {
star297 0:a43dcf6ca539 384 // The data specs state that count_per_degree should be 0x10 (16), I found my devices
star297 0:a43dcf6ca539 385 // to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C
star297 0:a43dcf6ca539 386 // this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this
star297 0:a43dcf6ca539 387 // being super acurate, but it does allow for a smooth display in the 1/10ths of a
star297 0:a43dcf6ca539 388 // deg C or F scales.
star297 0:a43dcf6ca539 389 float answer, remaining_count, count_per_degree;
star297 0:a43dcf6ca539 390 int reading;
star297 0:a43dcf6ca539 391 read_RAM();
star297 0:a43dcf6ca539 392 if (RAM_checksum_error())
star297 0:a43dcf6ca539 393 // Indicate we got a CRC error
star297 0:a43dcf6ca539 394 answer = invalid_conversion;
star297 0:a43dcf6ca539 395 else {
star297 0:a43dcf6ca539 396 reading = (RAM[1] << 8) + RAM[0];
star297 0:a43dcf6ca539 397 if (reading & 0x8000) { // negative degrees C
star297 0:a43dcf6ca539 398 reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int
star297 0:a43dcf6ca539 399 }
star297 0:a43dcf6ca539 400 answer = reading +0.0; // convert to floating point
star297 0:a43dcf6ca539 401 if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) {
star297 0:a43dcf6ca539 402 answer = answer / 16.0f;
star297 0:a43dcf6ca539 403 }
star297 0:a43dcf6ca539 404 else {
star297 0:a43dcf6ca539 405 remaining_count = RAM[6];
star297 0:a43dcf6ca539 406 count_per_degree = RAM[7];
star297 0:a43dcf6ca539 407 answer = floor(answer/2.0f) - 0.25f + (count_per_degree - remaining_count) / count_per_degree;
star297 0:a43dcf6ca539 408 }
star297 0:a43dcf6ca539 409 if (scale=='F' or scale=='f')
star297 0:a43dcf6ca539 410 // Convert to deg F
star297 0:a43dcf6ca539 411 answer = answer * 9.0f / 5.0f + 32.0f;
star297 0:a43dcf6ca539 412 }
star297 0:a43dcf6ca539 413 return answer;
star297 0:a43dcf6ca539 414 }
star297 0:a43dcf6ca539 415
star297 0:a43dcf6ca539 416 bool DS1820::read_power_supply(devices device) {
star297 0:a43dcf6ca539 417 // This will return true if the device (or all devices) are Vcc powered
star297 0:a43dcf6ca539 418 // This will return false if the device (or ANY device) is parasite powered
star297 0:a43dcf6ca539 419 if (device==all_devices)
star297 0:a43dcf6ca539 420 skip_ROM(); // Skip ROM command, will poll for any device using parasite power
star297 0:a43dcf6ca539 421 else
star297 0:a43dcf6ca539 422 match_ROM();
star297 0:a43dcf6ca539 423 onewire_byte_out(0xB4); // Read power supply command
star297 0:a43dcf6ca539 424 return onewire_bit_in(&this->_datapin);
star297 0:a43dcf6ca539 425 }
star297 0:a43dcf6ca539 426