Michael Ohayon / Mbed 2 deprecated RUCHE2-CODES

ruches 2

Dependencies:   mbed Ruche-2 Temps HX711 DHT22 Sigfox GPS

DS1820/DS1820.cpp@3:fe4b3bfd2237, 2019-02-03 (annotated)

Committer:
mohayonor
Date:
Sun Feb 03 20:27:56 2019 +0000
Revision:
3:fe4b3bfd2237
Parent:
0:126a8e290bd5 
all;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sidibe 0:126a8e290bd5 1 #include "DS1820.h"
Sidibe 0:126a8e290bd5 2 #include "mbed.h"
Sidibe 0:126a8e290bd5 3
Sidibe 0:126a8e290bd5 4 // Global variables shared between all DS1820 objects
Sidibe 0:126a8e290bd5 5 bool DS1820_done_flag;
Sidibe 0:126a8e290bd5 6 int DS1820_last_descrepancy;
Sidibe 0:126a8e290bd5 7 char DS1820_search_ROM[8];
Sidibe 0:126a8e290bd5 8
Sidibe 0:126a8e290bd5 9
Sidibe 0:126a8e290bd5 10 DS1820::DS1820 (PinName data_pin, PinName power_pin) : _datapin(data_pin), _parasitepin(power_pin) {
Sidibe 0:126a8e290bd5 11 int byte_counter;
Sidibe 0:126a8e290bd5 12
Sidibe 0:126a8e290bd5 13 _parasite_power = true;
Sidibe 0:126a8e290bd5 14 for(byte_counter=0;byte_counter<8;byte_counter++)
Sidibe 0:126a8e290bd5 15 ROM[byte_counter] = 0xFF;
Sidibe 0:126a8e290bd5 16 for(byte_counter=0;byte_counter<9;byte_counter++)
Sidibe 0:126a8e290bd5 17 RAM[byte_counter] = 0x00;
Sidibe 0:126a8e290bd5 18 }
Sidibe 0:126a8e290bd5 19 DS1820::DS1820 (PinName data_pin) : _datapin(data_pin), _parasitepin(NC) {
Sidibe 0:126a8e290bd5 20 int byte_counter;
Sidibe 0:126a8e290bd5 21 _parasite_power = false;
Sidibe 0:126a8e290bd5 22 for(byte_counter=0;byte_counter<8;byte_counter++)
Sidibe 0:126a8e290bd5 23 ROM[byte_counter] = 0xFF;
Sidibe 0:126a8e290bd5 24 for(byte_counter=0;byte_counter<9;byte_counter++)
Sidibe 0:126a8e290bd5 25 RAM[byte_counter] = 0x00;
Sidibe 0:126a8e290bd5 26 }
Sidibe 0:126a8e290bd5 27
Sidibe 0:126a8e290bd5 28 bool DS1820::onewire_reset() {
Sidibe 0:126a8e290bd5 29 // This will return false if no devices are present on the data bus
Sidibe 0:126a8e290bd5 30 bool presence=false;
Sidibe 0:126a8e290bd5 31 _datapin.output();
Sidibe 0:126a8e290bd5 32 _datapin.mode(PullUp);
Sidibe 0:126a8e290bd5 33 _datapin = 0; // bring low for 500 us
Sidibe 0:126a8e290bd5 34 wait_us(500);
Sidibe 0:126a8e290bd5 35 _datapin.input(); // let the data line float high
Sidibe 0:126a8e290bd5 36 _datapin.mode(PullUp);
Sidibe 0:126a8e290bd5 37 wait_us(90); // wait 90us
Sidibe 0:126a8e290bd5 38 if (_datapin.read()==0) // see if any devices are pulling the data line low
Sidibe 0:126a8e290bd5 39 presence=true;
Sidibe 0:126a8e290bd5 40 wait_us(410);
Sidibe 0:126a8e290bd5 41 return presence;
Sidibe 0:126a8e290bd5 42 }
Sidibe 0:126a8e290bd5 43
Sidibe 0:126a8e290bd5 44 void DS1820::onewire_bit_out (bool bit_data) {
Sidibe 0:126a8e290bd5 45 _datapin.output();
Sidibe 0:126a8e290bd5 46 _datapin = 0;
Sidibe 0:126a8e290bd5 47 wait_us(5);
Sidibe 0:126a8e290bd5 48 if (bit_data) {
Sidibe 0:126a8e290bd5 49 _datapin.input(); // bring data line high
Sidibe 0:126a8e290bd5 50 _datapin.mode(PullUp);
Sidibe 0:126a8e290bd5 51 wait_us(55);
Sidibe 0:126a8e290bd5 52 } else {
Sidibe 0:126a8e290bd5 53 wait_us(55); // keep data line low
Sidibe 0:126a8e290bd5 54 _datapin.input();
Sidibe 0:126a8e290bd5 55 _datapin.mode(PullUp);
Sidibe 0:126a8e290bd5 56 }
Sidibe 0:126a8e290bd5 57 }
Sidibe 0:126a8e290bd5 58
Sidibe 0:126a8e290bd5 59 void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first).
Sidibe 0:126a8e290bd5 60 int n;
Sidibe 0:126a8e290bd5 61 for (n=0; n<8; n++) {
Sidibe 0:126a8e290bd5 62 onewire_bit_out(data & 0x01);
Sidibe 0:126a8e290bd5 63 data = data >> 1; // now the next bit is in the least sig bit position.
Sidibe 0:126a8e290bd5 64 }
Sidibe 0:126a8e290bd5 65 }
Sidibe 0:126a8e290bd5 66
Sidibe 0:126a8e290bd5 67 bool DS1820::onewire_bit_in() {
Sidibe 0:126a8e290bd5 68 bool answer;
Sidibe 0:126a8e290bd5 69 _datapin.output();
Sidibe 0:126a8e290bd5 70 _datapin = 0;
Sidibe 0:126a8e290bd5 71 wait_us(5);
Sidibe 0:126a8e290bd5 72 _datapin.input();
Sidibe 0:126a8e290bd5 73 _datapin.mode(PullUp);
Sidibe 0:126a8e290bd5 74 wait_us(5);
Sidibe 0:126a8e290bd5 75 answer = _datapin.read();
Sidibe 0:126a8e290bd5 76 wait_us(50);
Sidibe 0:126a8e290bd5 77 return answer;
Sidibe 0:126a8e290bd5 78 }
Sidibe 0:126a8e290bd5 79
Sidibe 0:126a8e290bd5 80 char DS1820::onewire_byte_in() { // read byte, least sig byte first
Sidibe 0:126a8e290bd5 81 char answer = 0x00;
Sidibe 0:126a8e290bd5 82 int i;
Sidibe 0:126a8e290bd5 83 for (i=0; i<8; i++) {
Sidibe 0:126a8e290bd5 84 answer = answer >> 1; // shift over to make room for the next bit
Sidibe 0:126a8e290bd5 85 if (onewire_bit_in())
Sidibe 0:126a8e290bd5 86 answer = answer | 0x80; // if the data port is high, make this bit a 1
Sidibe 0:126a8e290bd5 87 }
Sidibe 0:126a8e290bd5 88 return answer;
Sidibe 0:126a8e290bd5 89 }
Sidibe 0:126a8e290bd5 90
Sidibe 0:126a8e290bd5 91 bool DS1820::search_ROM() {
Sidibe 0:126a8e290bd5 92 return search_ROM_routine(0xF0); // Search ROM command
Sidibe 0:126a8e290bd5 93 }
Sidibe 0:126a8e290bd5 94
Sidibe 0:126a8e290bd5 95 bool DS1820::search_alarm() {
Sidibe 0:126a8e290bd5 96 return search_ROM_routine(0xEC); // Search Alarm command
Sidibe 0:126a8e290bd5 97 }
Sidibe 0:126a8e290bd5 98
Sidibe 0:126a8e290bd5 99 bool DS1820::search_ROM_routine(char command) {
Sidibe 0:126a8e290bd5 100 extern bool DS1820_done_flag;
Sidibe 0:126a8e290bd5 101 extern int DS1820_last_descrepancy;
Sidibe 0:126a8e290bd5 102 extern char DS1820_search_ROM[8];
Sidibe 0:126a8e290bd5 103 int descrepancy_marker, ROM_bit_index;
Sidibe 0:126a8e290bd5 104 bool return_value, Bit_A, Bit_B;
Sidibe 0:126a8e290bd5 105 char byte_counter, bit_mask;
Sidibe 0:126a8e290bd5 106
Sidibe 0:126a8e290bd5 107 return_value=false;
Sidibe 0:126a8e290bd5 108 if (!DS1820_done_flag) {
Sidibe 0:126a8e290bd5 109 if (!onewire_reset()) {
Sidibe 0:126a8e290bd5 110 DS1820_last_descrepancy = 0; // no devices present
Sidibe 0:126a8e290bd5 111 } else {
Sidibe 0:126a8e290bd5 112 ROM_bit_index=1;
Sidibe 0:126a8e290bd5 113 descrepancy_marker=0;
Sidibe 0:126a8e290bd5 114 onewire_byte_out(command); // Search ROM command or Search Alarm command
Sidibe 0:126a8e290bd5 115 byte_counter = 0;
Sidibe 0:126a8e290bd5 116 bit_mask = 0x01;
Sidibe 0:126a8e290bd5 117 while (ROM_bit_index<=64) {
Sidibe 0:126a8e290bd5 118 Bit_A = onewire_bit_in();
Sidibe 0:126a8e290bd5 119 Bit_B = onewire_bit_in();
Sidibe 0:126a8e290bd5 120 if (Bit_A & Bit_B) {
Sidibe 0:126a8e290bd5 121 descrepancy_marker = 0; // data read error, this should never happen
Sidibe 0:126a8e290bd5 122 ROM_bit_index = 0xFF;
Sidibe 0:126a8e290bd5 123 } else {
Sidibe 0:126a8e290bd5 124 if (Bit_A | Bit_B) {
Sidibe 0:126a8e290bd5 125 // Set ROM bit to Bit_A
Sidibe 0:126a8e290bd5 126 if (Bit_A) {
Sidibe 0:126a8e290bd5 127 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
Sidibe 0:126a8e290bd5 128 } else {
Sidibe 0:126a8e290bd5 129 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
Sidibe 0:126a8e290bd5 130 }
Sidibe 0:126a8e290bd5 131 } else {
Sidibe 0:126a8e290bd5 132 // both bits A and B are low, so there are two or more devices present
Sidibe 0:126a8e290bd5 133 if ( ROM_bit_index == DS1820_last_descrepancy ) {
Sidibe 0:126a8e290bd5 134 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
Sidibe 0:126a8e290bd5 135 } else {
Sidibe 0:126a8e290bd5 136 if ( ROM_bit_index > DS1820_last_descrepancy ) {
Sidibe 0:126a8e290bd5 137 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
Sidibe 0:126a8e290bd5 138 descrepancy_marker = ROM_bit_index;
Sidibe 0:126a8e290bd5 139 } else {
Sidibe 0:126a8e290bd5 140 if (( DS1820_search_ROM[byte_counter] & bit_mask) == 0x00 )
Sidibe 0:126a8e290bd5 141 descrepancy_marker = ROM_bit_index;
Sidibe 0:126a8e290bd5 142 }
Sidibe 0:126a8e290bd5 143 }
Sidibe 0:126a8e290bd5 144 }
Sidibe 0:126a8e290bd5 145 onewire_bit_out (DS1820_search_ROM[byte_counter] & bit_mask);
Sidibe 0:126a8e290bd5 146 ROM_bit_index++;
Sidibe 0:126a8e290bd5 147 if (bit_mask & 0x80) {
Sidibe 0:126a8e290bd5 148 byte_counter++;
Sidibe 0:126a8e290bd5 149 bit_mask = 0x01;
Sidibe 0:126a8e290bd5 150 } else {
Sidibe 0:126a8e290bd5 151 bit_mask = bit_mask << 1;
Sidibe 0:126a8e290bd5 152 }
Sidibe 0:126a8e290bd5 153 }
Sidibe 0:126a8e290bd5 154 }
Sidibe 0:126a8e290bd5 155 DS1820_last_descrepancy = descrepancy_marker;
Sidibe 0:126a8e290bd5 156 if (ROM_bit_index != 0xFF) {
Sidibe 0:126a8e290bd5 157 for(byte_counter=0;byte_counter<8;byte_counter++)
Sidibe 0:126a8e290bd5 158 ROM[byte_counter] = DS1820_search_ROM[byte_counter];
Sidibe 0:126a8e290bd5 159 return_value = true;
Sidibe 0:126a8e290bd5 160 }
Sidibe 0:126a8e290bd5 161 }
Sidibe 0:126a8e290bd5 162 if (DS1820_last_descrepancy == 0)
Sidibe 0:126a8e290bd5 163 DS1820_done_flag = true;
Sidibe 0:126a8e290bd5 164 }
Sidibe 0:126a8e290bd5 165 return return_value;
Sidibe 0:126a8e290bd5 166 }
Sidibe 0:126a8e290bd5 167
Sidibe 0:126a8e290bd5 168 void DS1820::search_ROM_setup() {
Sidibe 0:126a8e290bd5 169 extern bool DS1820_done_flag;
Sidibe 0:126a8e290bd5 170 extern int DS1820_last_descrepancy;
Sidibe 0:126a8e290bd5 171 extern char DS1820_search_ROM[8];
Sidibe 0:126a8e290bd5 172 DS1820_done_flag = false;
Sidibe 0:126a8e290bd5 173 DS1820_last_descrepancy = 0;
Sidibe 0:126a8e290bd5 174 int i;
Sidibe 0:126a8e290bd5 175 for (i=0; i<8; i++)
Sidibe 0:126a8e290bd5 176 DS1820_search_ROM[i]=0x00;
Sidibe 0:126a8e290bd5 177 }
Sidibe 0:126a8e290bd5 178
Sidibe 0:126a8e290bd5 179 void DS1820::read_ROM() {
Sidibe 0:126a8e290bd5 180 // NOTE: This command can only be used when there is one DS1820 on the bus. If this command
Sidibe 0:126a8e290bd5 181 // is used when there is more than one slave present on the bus, a data collision will occur
Sidibe 0:126a8e290bd5 182 // when all the DS1820s attempt to respond at the same time.
Sidibe 0:126a8e290bd5 183 int i;
Sidibe 0:126a8e290bd5 184 onewire_reset();
Sidibe 0:126a8e290bd5 185 onewire_byte_out(0x33); // Read ROM id
Sidibe 0:126a8e290bd5 186 for (i=0; i<8; i++)
Sidibe 0:126a8e290bd5 187 ROM[i]=onewire_byte_in();
Sidibe 0:126a8e290bd5 188 }
Sidibe 0:126a8e290bd5 189
Sidibe 0:126a8e290bd5 190 void DS1820::match_ROM() {
Sidibe 0:126a8e290bd5 191 // Used to select a specific device
Sidibe 0:126a8e290bd5 192 int i;
Sidibe 0:126a8e290bd5 193 onewire_reset();
Sidibe 0:126a8e290bd5 194 onewire_byte_out( 0x55); //Match ROM command
Sidibe 0:126a8e290bd5 195 for (i=0;i<8;i++)
Sidibe 0:126a8e290bd5 196 onewire_byte_out(ROM[i]);
Sidibe 0:126a8e290bd5 197 }
Sidibe 0:126a8e290bd5 198
Sidibe 0:126a8e290bd5 199 void DS1820::skip_ROM() {
Sidibe 0:126a8e290bd5 200 onewire_reset();
Sidibe 0:126a8e290bd5 201 onewire_byte_out(0xCC); // Skip ROM command
Sidibe 0:126a8e290bd5 202 }
Sidibe 0:126a8e290bd5 203
Sidibe 0:126a8e290bd5 204 bool DS1820::ROM_checksum_error() {
Sidibe 0:126a8e290bd5 205 char xCRC=0x00;
Sidibe 0:126a8e290bd5 206 int i;
Sidibe 0:126a8e290bd5 207 for(i=0;i<7;i++) // Only going to shift the lower 7 bytes
Sidibe 0:126a8e290bd5 208 xCRC = CRC_byte(xCRC, ROM[i]);
Sidibe 0:126a8e290bd5 209 // After 7 bytes CRC should equal the 8th byte (ROM CRC)
Sidibe 0:126a8e290bd5 210 return (xCRC!=ROM[7]); // will return true if there is a CRC checksum error
Sidibe 0:126a8e290bd5 211 }
Sidibe 0:126a8e290bd5 212
Sidibe 0:126a8e290bd5 213 bool DS1820::RAM_checksum_error() {
Sidibe 0:126a8e290bd5 214 char xCRC=0x00;
Sidibe 0:126a8e290bd5 215 int i;
Sidibe 0:126a8e290bd5 216 read_RAM();
Sidibe 0:126a8e290bd5 217 for(i=0;i<8;i++) // Only going to shift the lower 8 bytes
Sidibe 0:126a8e290bd5 218 xCRC = CRC_byte(xCRC, RAM[i]);
Sidibe 0:126a8e290bd5 219 // After 8 bytes CRC should equal the 9th byte (RAM CRC)
Sidibe 0:126a8e290bd5 220 return (xCRC!=RAM[8]); // will return true if there is a CRC checksum error
Sidibe 0:126a8e290bd5 221 }
Sidibe 0:126a8e290bd5 222
Sidibe 0:126a8e290bd5 223 char DS1820::CRC_byte (char xCRC, char byte ) {
Sidibe 0:126a8e290bd5 224 int j;
Sidibe 0:126a8e290bd5 225 for(j=0;j<8;j++) {
Sidibe 0:126a8e290bd5 226 if ((byte & 0x01 ) ^ (xCRC & 0x01)) {
Sidibe 0:126a8e290bd5 227 // DATA ^ LSB CRC = 1
Sidibe 0:126a8e290bd5 228 xCRC = xCRC>>1;
Sidibe 0:126a8e290bd5 229 // Set the MSB to 1
Sidibe 0:126a8e290bd5 230 xCRC = xCRC | 0x80;
Sidibe 0:126a8e290bd5 231 // Check bit 3
Sidibe 0:126a8e290bd5 232 if (xCRC & 0x04) {
Sidibe 0:126a8e290bd5 233 xCRC = xCRC & 0xFB; // Bit 3 is set, so clear it
Sidibe 0:126a8e290bd5 234 } else {
Sidibe 0:126a8e290bd5 235 xCRC = xCRC | 0x04; // Bit 3 is clear, so set it
Sidibe 0:126a8e290bd5 236 }
Sidibe 0:126a8e290bd5 237 // Check bit 4
Sidibe 0:126a8e290bd5 238 if (xCRC & 0x08) {
Sidibe 0:126a8e290bd5 239 xCRC = xCRC & 0xF7; // Bit 4 is set, so clear it
Sidibe 0:126a8e290bd5 240 } else {
Sidibe 0:126a8e290bd5 241 xCRC = xCRC | 0x08; // Bit 4 is clear, so set it
Sidibe 0:126a8e290bd5 242 }
Sidibe 0:126a8e290bd5 243 } else {
Sidibe 0:126a8e290bd5 244 // DATA ^ LSB xCRC = 0
Sidibe 0:126a8e290bd5 245 xCRC = xCRC>>1;
Sidibe 0:126a8e290bd5 246 // clear MSB
Sidibe 0:126a8e290bd5 247 xCRC = xCRC & 0x7F;
Sidibe 0:126a8e290bd5 248 // No need to check bits, with DATA ^ LSB xCRC = 0, they will remain unchanged
Sidibe 0:126a8e290bd5 249 }
Sidibe 0:126a8e290bd5 250 byte = byte>>1;
Sidibe 0:126a8e290bd5 251 }
Sidibe 0:126a8e290bd5 252 return xCRC;
Sidibe 0:126a8e290bd5 253 }
Sidibe 0:126a8e290bd5 254
Sidibe 0:126a8e290bd5 255 void DS1820::convert_temperature(devices device) {
Sidibe 0:126a8e290bd5 256 // Convert temperature into scratchpad RAM for all devices at once
Sidibe 0:126a8e290bd5 257 int delay_time = 750; // Default delay time
Sidibe 0:126a8e290bd5 258 char resolution;
Sidibe 0:126a8e290bd5 259 if (device==all_devices)
Sidibe 0:126a8e290bd5 260 skip_ROM(); // Skip ROM command, will convert for ALL devices
Sidibe 0:126a8e290bd5 261 else {
Sidibe 0:126a8e290bd5 262 match_ROM();
Sidibe 0:126a8e290bd5 263 if (FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
Sidibe 0:126a8e290bd5 264 resolution = RAM[4] & 0x60;
Sidibe 0:126a8e290bd5 265 if (resolution == 0x00) // 9 bits
Sidibe 0:126a8e290bd5 266 delay_time = 94;
Sidibe 0:126a8e290bd5 267 if (resolution == 0x20) // 10 bits
Sidibe 0:126a8e290bd5 268 delay_time = 188;
Sidibe 0:126a8e290bd5 269 if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default
Sidibe 0:126a8e290bd5 270 delay_time = 375;
Sidibe 0:126a8e290bd5 271 }
Sidibe 0:126a8e290bd5 272 }
Sidibe 0:126a8e290bd5 273 onewire_byte_out( 0x44); // perform temperature conversion
Sidibe 0:126a8e290bd5 274 if (_parasite_power)
Sidibe 0:126a8e290bd5 275 _parasitepin = 1; // Parasite power strong pullup
Sidibe 0:126a8e290bd5 276 wait_ms(delay_time);
Sidibe 0:126a8e290bd5 277 if (_parasite_power)
Sidibe 0:126a8e290bd5 278 _parasitepin = 0;
Sidibe 0:126a8e290bd5 279 }
Sidibe 0:126a8e290bd5 280
Sidibe 0:126a8e290bd5 281 void DS1820::read_RAM() {
Sidibe 0:126a8e290bd5 282 // This will copy the DS1820's 9 bytes of RAM data
Sidibe 0:126a8e290bd5 283 // into the objects RAM array. Functions that use
Sidibe 0:126a8e290bd5 284 // RAM values will automaticly call this procedure.
Sidibe 0:126a8e290bd5 285 int i;
Sidibe 0:126a8e290bd5 286 match_ROM(); // Select this device
Sidibe 0:126a8e290bd5 287 onewire_byte_out( 0xBE); //Read Scratchpad command
Sidibe 0:126a8e290bd5 288 for(i=0;i<9;i++) {
Sidibe 0:126a8e290bd5 289 RAM[i] = onewire_byte_in();
Sidibe 0:126a8e290bd5 290 }
Sidibe 0:126a8e290bd5 291 }
Sidibe 0:126a8e290bd5 292
Sidibe 0:126a8e290bd5 293 bool DS1820::set_configuration_bits(unsigned int resolution) {
Sidibe 0:126a8e290bd5 294 bool answer = false;
Sidibe 0:126a8e290bd5 295 resolution = resolution - 9;
Sidibe 0:126a8e290bd5 296 if (resolution < 4) {
Sidibe 0:126a8e290bd5 297 resolution = resolution<<5; // align the bits
Sidibe 0:126a8e290bd5 298 RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new
Sidibe 0:126a8e290bd5 299 write_scratchpad ((RAM[2]<<8) + RAM[3]);
Sidibe 0:126a8e290bd5 300 // store_scratchpad (DS1820::this_device); // Need to test if this is required
Sidibe 0:126a8e290bd5 301 answer = true;
Sidibe 0:126a8e290bd5 302 }
Sidibe 0:126a8e290bd5 303 return answer;
Sidibe 0:126a8e290bd5 304 }
Sidibe 0:126a8e290bd5 305
Sidibe 0:126a8e290bd5 306 int DS1820::read_scratchpad() {
Sidibe 0:126a8e290bd5 307 int answer;
Sidibe 0:126a8e290bd5 308 read_RAM();
Sidibe 0:126a8e290bd5 309 answer = (RAM[2]<<8) + RAM[3];
Sidibe 0:126a8e290bd5 310 return answer;
Sidibe 0:126a8e290bd5 311 }
Sidibe 0:126a8e290bd5 312
Sidibe 0:126a8e290bd5 313 void DS1820::write_scratchpad(int data) {
Sidibe 0:126a8e290bd5 314 RAM[3] = data;
Sidibe 0:126a8e290bd5 315 RAM[2] = data>>8;
Sidibe 0:126a8e290bd5 316 match_ROM();
Sidibe 0:126a8e290bd5 317 onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory
Sidibe 0:126a8e290bd5 318 onewire_byte_out(RAM[2]); // T(H)
Sidibe 0:126a8e290bd5 319 onewire_byte_out(RAM[3]); // T(L)
Sidibe 0:126a8e290bd5 320 if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
Sidibe 0:126a8e290bd5 321 onewire_byte_out(RAM[4]); // Configuration register
Sidibe 0:126a8e290bd5 322 }
Sidibe 0:126a8e290bd5 323 }
Sidibe 0:126a8e290bd5 324
Sidibe 0:126a8e290bd5 325 void DS1820::store_scratchpad(devices device) {
Sidibe 0:126a8e290bd5 326 if (device==all_devices)
Sidibe 0:126a8e290bd5 327 skip_ROM(); // Skip ROM command, will store for ALL devices
Sidibe 0:126a8e290bd5 328 else
Sidibe 0:126a8e290bd5 329 match_ROM();
Sidibe 0:126a8e290bd5 330 onewire_byte_out(0x48); // Write scratchpad into E2 command
Sidibe 0:126a8e290bd5 331 if (_parasite_power)
Sidibe 0:126a8e290bd5 332 _parasitepin=1;
Sidibe 0:126a8e290bd5 333 wait_ms(10); // Parasite power strong pullup for 10ms
Sidibe 0:126a8e290bd5 334 if (_parasite_power)
Sidibe 0:126a8e290bd5 335 _parasitepin=0;
Sidibe 0:126a8e290bd5 336 }
Sidibe 0:126a8e290bd5 337
Sidibe 0:126a8e290bd5 338 int DS1820::recall_scratchpad(devices device) {
Sidibe 0:126a8e290bd5 339 // This copies the E2 values into the DS1820's memory.
Sidibe 0:126a8e290bd5 340 // If you specify all_devices this will return zero, otherwise
Sidibe 0:126a8e290bd5 341 // it will return the value of the scratchpad memory.
Sidibe 0:126a8e290bd5 342 int answer=0;
Sidibe 0:126a8e290bd5 343 if (device==all_devices)
Sidibe 0:126a8e290bd5 344 skip_ROM(); // Skip ROM command, will recall for ALL devices
Sidibe 0:126a8e290bd5 345 else
Sidibe 0:126a8e290bd5 346 match_ROM();
Sidibe 0:126a8e290bd5 347 onewire_byte_out(0xB8); // Recall E2 data to scratchpad command
Sidibe 0:126a8e290bd5 348 wait_ms(10); // not sure I like polling for completion
Sidibe 0:126a8e290bd5 349 // it could cause an infinite loop
Sidibe 0:126a8e290bd5 350 if (device==DS1820::this_device) {
Sidibe 0:126a8e290bd5 351 read_RAM();
Sidibe 0:126a8e290bd5 352 answer = read_scratchpad();
Sidibe 0:126a8e290bd5 353 }
Sidibe 0:126a8e290bd5 354 return answer;
Sidibe 0:126a8e290bd5 355 }
Sidibe 0:126a8e290bd5 356
Sidibe 0:126a8e290bd5 357 float DS1820::temperature(char scale) {
Sidibe 0:126a8e290bd5 358 // The data specs state that count_per_degree should be 0x10 (16), I found my devices
Sidibe 0:126a8e290bd5 359 // to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C
Sidibe 0:126a8e290bd5 360 // this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this
Sidibe 0:126a8e290bd5 361 // being super acurate, but it does allow for a smooth display in the 1/10ths of a
Sidibe 0:126a8e290bd5 362 // deg C or F scales.
Sidibe 0:126a8e290bd5 363 float answer, remaining_count, count_per_degree;
Sidibe 0:126a8e290bd5 364 int reading;
Sidibe 0:126a8e290bd5 365 read_RAM();
Sidibe 0:126a8e290bd5 366 reading = (RAM[1] << 8) + RAM[0];
Sidibe 0:126a8e290bd5 367 if (reading & 0x8000) { // negative degrees C
Sidibe 0:126a8e290bd5 368 reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int
Sidibe 0:126a8e290bd5 369 }
Sidibe 0:126a8e290bd5 370 answer = reading +0.0; // convert to floating point
Sidibe 0:126a8e290bd5 371 if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
Sidibe 0:126a8e290bd5 372 answer = answer / 8.0;
Sidibe 0:126a8e290bd5 373 }
Sidibe 0:126a8e290bd5 374 else {
Sidibe 0:126a8e290bd5 375 remaining_count = RAM[6];
Sidibe 0:126a8e290bd5 376 count_per_degree = RAM[7];
Sidibe 0:126a8e290bd5 377 answer = answer - 0.25 + (count_per_degree - remaining_count) / count_per_degree;
Sidibe 0:126a8e290bd5 378 }
Sidibe 0:126a8e290bd5 379 if (scale=='C' or scale=='c')
Sidibe 0:126a8e290bd5 380 answer = answer / 2.0;
Sidibe 0:126a8e290bd5 381 else
Sidibe 0:126a8e290bd5 382 // Convert to deg F
Sidibe 0:126a8e290bd5 383 answer = answer * 9.0 / 10.0 + 32.0;
Sidibe 0:126a8e290bd5 384 return answer;
Sidibe 0:126a8e290bd5 385 }
Sidibe 0:126a8e290bd5 386
Sidibe 0:126a8e290bd5 387 bool DS1820::read_power_supply(devices device) {
Sidibe 0:126a8e290bd5 388 // This will return true if the device (or all devices) are Vcc powered
Sidibe 0:126a8e290bd5 389 // This will return false if the device (or ANY device) is parasite powered
Sidibe 0:126a8e290bd5 390 if (device==all_devices)
Sidibe 0:126a8e290bd5 391 skip_ROM(); // Skip ROM command, will poll for any device using parasite power
Sidibe 0:126a8e290bd5 392 else
Sidibe 0:126a8e290bd5 393 match_ROM();
Sidibe 0:126a8e290bd5 394 onewire_byte_out(0xB4); // Read power supply command
Sidibe 0:126a8e290bd5 395 return onewire_bit_in();
Sidibe 0:126a8e290bd5 396 }