CUER / CUER_DS1820

CUER version of the DS1820 library

Dependents:   BMS_BMUCore_Max

Fork of DS1820 by HM Yoong

DS1820.cpp@2:4c7277e9f267, 2017-08-18 (annotated)

Committer:
DasSidG
Date:
Fri Aug 18 08:48:40 2017 +0000
Revision:
2:4c7277e9f267
Parent:
1:91aa74f0cb0e 
Commented out wait in the read-temperature function for the benefit of the  temperature measurement board (to speed up temperature meaurement).

Who changed what in which revision?

UserRevisionLine numberNew contents of line
yoonghm 0:245af9360f0d 1 #include "DS1820.h"
yoonghm 0:245af9360f0d 2 #include "mbed.h"
DasSidG 1:91aa74f0cb0e 3
yoonghm 0:245af9360f0d 4 // Global variables shared between all DS1820 objects
yoonghm 0:245af9360f0d 5 bool DS1820_done_flag;
yoonghm 0:245af9360f0d 6 int DS1820_last_descrepancy;
yoonghm 0:245af9360f0d 7 char DS1820_search_ROM[8];
DasSidG 1:91aa74f0cb0e 8
DasSidG 1:91aa74f0cb0e 9
yoonghm 0:245af9360f0d 10 DS1820::DS1820 (PinName data_pin, PinName power_pin) : _datapin(data_pin), _parasitepin(power_pin) {
yoonghm 0:245af9360f0d 11 int byte_counter;
yoonghm 0:245af9360f0d 12 _parasite_power = true;
DasSidG 1:91aa74f0cb0e 13 _parasitepin = 1; //Initial value set high, P-channel mosfet is off so data can transmit
yoonghm 0:245af9360f0d 14 for(byte_counter=0;byte_counter<8;byte_counter++)
yoonghm 0:245af9360f0d 15 ROM[byte_counter] = 0xFF;
yoonghm 0:245af9360f0d 16 for(byte_counter=0;byte_counter<9;byte_counter++)
yoonghm 0:245af9360f0d 17 RAM[byte_counter] = 0x00;
yoonghm 0:245af9360f0d 18 }
yoonghm 0:245af9360f0d 19 DS1820::DS1820 (PinName data_pin) : _datapin(data_pin), _parasitepin(NC) {
yoonghm 0:245af9360f0d 20 int byte_counter;
yoonghm 0:245af9360f0d 21 _parasite_power = false;
yoonghm 0:245af9360f0d 22 for(byte_counter=0;byte_counter<8;byte_counter++)
yoonghm 0:245af9360f0d 23 ROM[byte_counter] = 0xFF;
yoonghm 0:245af9360f0d 24 for(byte_counter=0;byte_counter<9;byte_counter++)
yoonghm 0:245af9360f0d 25 RAM[byte_counter] = 0x00;
yoonghm 0:245af9360f0d 26 }
DasSidG 1:91aa74f0cb0e 27
yoonghm 0:245af9360f0d 28 bool DS1820::onewire_reset() {
yoonghm 0:245af9360f0d 29 // This will return false if no devices are present on the data bus
yoonghm 0:245af9360f0d 30 bool presence=false;
yoonghm 0:245af9360f0d 31 _datapin.output();
yoonghm 0:245af9360f0d 32 _datapin = 0; // bring low for 500 us
yoonghm 0:245af9360f0d 33 wait_us(500);
yoonghm 0:245af9360f0d 34 _datapin.input(); // let the data line float high
yoonghm 0:245af9360f0d 35 wait_us(90); // wait 90us
yoonghm 0:245af9360f0d 36 if (_datapin.read()==0) // see if any devices are pulling the data line low
yoonghm 0:245af9360f0d 37 presence=true;
yoonghm 0:245af9360f0d 38 wait_us(410);
yoonghm 0:245af9360f0d 39 return presence;
yoonghm 0:245af9360f0d 40 }
DasSidG 1:91aa74f0cb0e 41
yoonghm 0:245af9360f0d 42 void DS1820::onewire_bit_out (bool bit_data) {
yoonghm 0:245af9360f0d 43 _datapin.output();
yoonghm 0:245af9360f0d 44 _datapin = 0;
yoonghm 0:245af9360f0d 45 wait_us(5);
yoonghm 0:245af9360f0d 46 if (bit_data) {
yoonghm 0:245af9360f0d 47 _datapin.input(); // bring data line high
yoonghm 0:245af9360f0d 48 wait_us(55);
yoonghm 0:245af9360f0d 49 } else {
yoonghm 0:245af9360f0d 50 wait_us(55); // keep data line low
yoonghm 0:245af9360f0d 51 _datapin.input();
yoonghm 0:245af9360f0d 52 }
yoonghm 0:245af9360f0d 53 }
DasSidG 1:91aa74f0cb0e 54
yoonghm 0:245af9360f0d 55 void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first).
yoonghm 0:245af9360f0d 56 int n;
yoonghm 0:245af9360f0d 57 for (n=0; n<8; n++) {
yoonghm 0:245af9360f0d 58 onewire_bit_out(data & 0x01);
yoonghm 0:245af9360f0d 59 data = data >> 1; // now the next bit is in the least sig bit position.
yoonghm 0:245af9360f0d 60 }
yoonghm 0:245af9360f0d 61 }
DasSidG 1:91aa74f0cb0e 62
yoonghm 0:245af9360f0d 63 bool DS1820::onewire_bit_in() {
yoonghm 0:245af9360f0d 64 bool answer;
yoonghm 0:245af9360f0d 65 _datapin.output();
yoonghm 0:245af9360f0d 66 _datapin = 0;
yoonghm 0:245af9360f0d 67 wait_us(5);
yoonghm 0:245af9360f0d 68 _datapin.input();
yoonghm 0:245af9360f0d 69 wait_us(5);
yoonghm 0:245af9360f0d 70 answer = _datapin.read();
yoonghm 0:245af9360f0d 71 wait_us(50);
yoonghm 0:245af9360f0d 72 return answer;
yoonghm 0:245af9360f0d 73 }
DasSidG 1:91aa74f0cb0e 74
yoonghm 0:245af9360f0d 75 char DS1820::onewire_byte_in() { // read byte, least sig byte first
yoonghm 0:245af9360f0d 76 char answer = 0x00;
yoonghm 0:245af9360f0d 77 int i;
yoonghm 0:245af9360f0d 78 for (i=0; i<8; i++) {
yoonghm 0:245af9360f0d 79 answer = answer >> 1; // shift over to make room for the next bit
yoonghm 0:245af9360f0d 80 if (onewire_bit_in())
yoonghm 0:245af9360f0d 81 answer = answer | 0x80; // if the data port is high, make this bit a 1
yoonghm 0:245af9360f0d 82 }
yoonghm 0:245af9360f0d 83 return answer;
yoonghm 0:245af9360f0d 84 }
DasSidG 1:91aa74f0cb0e 85
yoonghm 0:245af9360f0d 86 bool DS1820::search_ROM() {
yoonghm 0:245af9360f0d 87 return search_ROM_routine(0xF0); // Search ROM command
yoonghm 0:245af9360f0d 88 }
DasSidG 1:91aa74f0cb0e 89
yoonghm 0:245af9360f0d 90 bool DS1820::search_alarm() {
yoonghm 0:245af9360f0d 91 return search_ROM_routine(0xEC); // Search Alarm command
yoonghm 0:245af9360f0d 92 }
DasSidG 1:91aa74f0cb0e 93
yoonghm 0:245af9360f0d 94 bool DS1820::search_ROM_routine(char command) {
yoonghm 0:245af9360f0d 95 extern bool DS1820_done_flag;
yoonghm 0:245af9360f0d 96 extern int DS1820_last_descrepancy;
yoonghm 0:245af9360f0d 97 extern char DS1820_search_ROM[8];
yoonghm 0:245af9360f0d 98 int descrepancy_marker, ROM_bit_index;
yoonghm 0:245af9360f0d 99 bool return_value, Bit_A, Bit_B;
yoonghm 0:245af9360f0d 100 char byte_counter, bit_mask;
DasSidG 1:91aa74f0cb0e 101
yoonghm 0:245af9360f0d 102 return_value=false;
yoonghm 0:245af9360f0d 103 if (!DS1820_done_flag) {
yoonghm 0:245af9360f0d 104 if (!onewire_reset()) {
yoonghm 0:245af9360f0d 105 DS1820_last_descrepancy = 0; // no devices present
yoonghm 0:245af9360f0d 106 } else {
yoonghm 0:245af9360f0d 107 ROM_bit_index=1;
yoonghm 0:245af9360f0d 108 descrepancy_marker=0;
yoonghm 0:245af9360f0d 109 onewire_byte_out(command); // Search ROM command or Search Alarm command
yoonghm 0:245af9360f0d 110 byte_counter = 0;
yoonghm 0:245af9360f0d 111 bit_mask = 0x01;
yoonghm 0:245af9360f0d 112 while (ROM_bit_index<=64) {
yoonghm 0:245af9360f0d 113 Bit_A = onewire_bit_in();
yoonghm 0:245af9360f0d 114 Bit_B = onewire_bit_in();
yoonghm 0:245af9360f0d 115 if (Bit_A & Bit_B) {
yoonghm 0:245af9360f0d 116 descrepancy_marker = 0; // data read error, this should never happen
yoonghm 0:245af9360f0d 117 ROM_bit_index = 0xFF;
yoonghm 0:245af9360f0d 118 } else {
yoonghm 0:245af9360f0d 119 if (Bit_A | Bit_B) {
yoonghm 0:245af9360f0d 120 // Set ROM bit to Bit_A
yoonghm 0:245af9360f0d 121 if (Bit_A) {
yoonghm 0:245af9360f0d 122 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
yoonghm 0:245af9360f0d 123 } else {
yoonghm 0:245af9360f0d 124 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
yoonghm 0:245af9360f0d 125 }
yoonghm 0:245af9360f0d 126 } else {
yoonghm 0:245af9360f0d 127 // both bits A and B are low, so there are two or more devices present
yoonghm 0:245af9360f0d 128 if ( ROM_bit_index == DS1820_last_descrepancy ) {
yoonghm 0:245af9360f0d 129 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
yoonghm 0:245af9360f0d 130 } else {
yoonghm 0:245af9360f0d 131 if ( ROM_bit_index > DS1820_last_descrepancy ) {
yoonghm 0:245af9360f0d 132 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
yoonghm 0:245af9360f0d 133 descrepancy_marker = ROM_bit_index;
yoonghm 0:245af9360f0d 134 } else {
yoonghm 0:245af9360f0d 135 if (( DS1820_search_ROM[byte_counter] & bit_mask) == 0x00 )
yoonghm 0:245af9360f0d 136 descrepancy_marker = ROM_bit_index;
yoonghm 0:245af9360f0d 137 }
yoonghm 0:245af9360f0d 138 }
yoonghm 0:245af9360f0d 139 }
yoonghm 0:245af9360f0d 140 onewire_bit_out (DS1820_search_ROM[byte_counter] & bit_mask);
yoonghm 0:245af9360f0d 141 ROM_bit_index++;
yoonghm 0:245af9360f0d 142 if (bit_mask & 0x80) {
yoonghm 0:245af9360f0d 143 byte_counter++;
yoonghm 0:245af9360f0d 144 bit_mask = 0x01;
yoonghm 0:245af9360f0d 145 } else {
yoonghm 0:245af9360f0d 146 bit_mask = bit_mask << 1;
yoonghm 0:245af9360f0d 147 }
yoonghm 0:245af9360f0d 148 }
yoonghm 0:245af9360f0d 149 }
yoonghm 0:245af9360f0d 150 DS1820_last_descrepancy = descrepancy_marker;
yoonghm 0:245af9360f0d 151 if (ROM_bit_index != 0xFF) {
yoonghm 0:245af9360f0d 152 for(byte_counter=0;byte_counter<8;byte_counter++)
yoonghm 0:245af9360f0d 153 ROM[byte_counter] = DS1820_search_ROM[byte_counter];
yoonghm 0:245af9360f0d 154 return_value = true;
yoonghm 0:245af9360f0d 155 }
yoonghm 0:245af9360f0d 156 }
yoonghm 0:245af9360f0d 157 if (DS1820_last_descrepancy == 0)
yoonghm 0:245af9360f0d 158 DS1820_done_flag = true;
yoonghm 0:245af9360f0d 159 }
yoonghm 0:245af9360f0d 160 return return_value;
yoonghm 0:245af9360f0d 161 }
DasSidG 1:91aa74f0cb0e 162
yoonghm 0:245af9360f0d 163 void DS1820::search_ROM_setup() {
yoonghm 0:245af9360f0d 164 extern bool DS1820_done_flag;
yoonghm 0:245af9360f0d 165 extern int DS1820_last_descrepancy;
yoonghm 0:245af9360f0d 166 extern char DS1820_search_ROM[8];
yoonghm 0:245af9360f0d 167 DS1820_done_flag = false;
yoonghm 0:245af9360f0d 168 DS1820_last_descrepancy = 0;
yoonghm 0:245af9360f0d 169 int i;
yoonghm 0:245af9360f0d 170 for (i=0; i<8; i++)
yoonghm 0:245af9360f0d 171 DS1820_search_ROM[i]=0x00;
yoonghm 0:245af9360f0d 172 }
DasSidG 1:91aa74f0cb0e 173
yoonghm 0:245af9360f0d 174 void DS1820::read_ROM() {
yoonghm 0:245af9360f0d 175 // NOTE: This command can only be used when there is one DS1820 on the bus. If this command
yoonghm 0:245af9360f0d 176 // is used when there is more than one slave present on the bus, a data collision will occur
yoonghm 0:245af9360f0d 177 // when all the DS1820s attempt to respond at the same time.
yoonghm 0:245af9360f0d 178 int i;
yoonghm 0:245af9360f0d 179 onewire_reset();
yoonghm 0:245af9360f0d 180 onewire_byte_out(0x33); // Read ROM id
yoonghm 0:245af9360f0d 181 for (i=0; i<8; i++)
yoonghm 0:245af9360f0d 182 ROM[i]=onewire_byte_in();
yoonghm 0:245af9360f0d 183 }
DasSidG 1:91aa74f0cb0e 184
yoonghm 0:245af9360f0d 185 void DS1820::match_ROM() {
yoonghm 0:245af9360f0d 186 // Used to select a specific device
yoonghm 0:245af9360f0d 187 int i;
yoonghm 0:245af9360f0d 188 onewire_reset();
yoonghm 0:245af9360f0d 189 onewire_byte_out( 0x55); //Match ROM command
yoonghm 0:245af9360f0d 190 for (i=0;i<8;i++)
yoonghm 0:245af9360f0d 191 onewire_byte_out(ROM[i]);
yoonghm 0:245af9360f0d 192 }
DasSidG 1:91aa74f0cb0e 193
yoonghm 0:245af9360f0d 194 void DS1820::skip_ROM() {
yoonghm 0:245af9360f0d 195 onewire_reset();
yoonghm 0:245af9360f0d 196 onewire_byte_out(0xCC); // Skip ROM command
yoonghm 0:245af9360f0d 197 }
DasSidG 1:91aa74f0cb0e 198
yoonghm 0:245af9360f0d 199 bool DS1820::ROM_checksum_error() {
DasSidG 1:91aa74f0cb0e 200 char crc=0x00;
yoonghm 0:245af9360f0d 201 int i;
yoonghm 0:245af9360f0d 202 for(i=0;i<7;i++) // Only going to shift the lower 7 bytes
DasSidG 1:91aa74f0cb0e 203 crc = CRC_byte(crc, ROM[i]);
DasSidG 1:91aa74f0cb0e 204 // After 7 bytes crc should equal the 8th byte (ROM crc)
DasSidG 1:91aa74f0cb0e 205 return (crc!=ROM[7]); // will return true if there is a crc checksum error
yoonghm 0:245af9360f0d 206 }
DasSidG 1:91aa74f0cb0e 207
yoonghm 0:245af9360f0d 208 bool DS1820::RAM_checksum_error() {
DasSidG 1:91aa74f0cb0e 209 char crc=0x00;
yoonghm 0:245af9360f0d 210 int i;
yoonghm 0:245af9360f0d 211 read_RAM();
yoonghm 0:245af9360f0d 212 for(i=0;i<8;i++) // Only going to shift the lower 8 bytes
DasSidG 1:91aa74f0cb0e 213 crc = CRC_byte(crc, RAM[i]);
DasSidG 1:91aa74f0cb0e 214 // After 8 bytes crc should equal the 9th byte (RAM crc)
DasSidG 1:91aa74f0cb0e 215 return (crc!=RAM[8]); // will return true if there is a crc checksum error
yoonghm 0:245af9360f0d 216 }
DasSidG 1:91aa74f0cb0e 217
DasSidG 1:91aa74f0cb0e 218 char DS1820::CRC_byte (char crc, char byte ) {
yoonghm 0:245af9360f0d 219 int j;
yoonghm 0:245af9360f0d 220 for(j=0;j<8;j++) {
DasSidG 1:91aa74f0cb0e 221 if ((byte & 0x01 ) ^ (crc & 0x01)) {
DasSidG 1:91aa74f0cb0e 222 // DATA ^ LSB crc = 1
DasSidG 1:91aa74f0cb0e 223 crc = crc>>1;
yoonghm 0:245af9360f0d 224 // Set the MSB to 1
DasSidG 1:91aa74f0cb0e 225 crc = crc | 0x80;
yoonghm 0:245af9360f0d 226 // Check bit 3
DasSidG 1:91aa74f0cb0e 227 if (crc & 0x04) {
DasSidG 1:91aa74f0cb0e 228 crc = crc & 0xFB; // Bit 3 is set, so clear it
yoonghm 0:245af9360f0d 229 } else {
DasSidG 1:91aa74f0cb0e 230 crc = crc | 0x04; // Bit 3 is clear, so set it
yoonghm 0:245af9360f0d 231 }
yoonghm 0:245af9360f0d 232 // Check bit 4
DasSidG 1:91aa74f0cb0e 233 if (crc & 0x08) {
DasSidG 1:91aa74f0cb0e 234 crc = crc & 0xF7; // Bit 4 is set, so clear it
yoonghm 0:245af9360f0d 235 } else {
DasSidG 1:91aa74f0cb0e 236 crc = crc | 0x08; // Bit 4 is clear, so set it
yoonghm 0:245af9360f0d 237 }
yoonghm 0:245af9360f0d 238 } else {
DasSidG 1:91aa74f0cb0e 239 // DATA ^ LSB crc = 0
DasSidG 1:91aa74f0cb0e 240 crc = crc>>1;
yoonghm 0:245af9360f0d 241 // clear MSB
DasSidG 1:91aa74f0cb0e 242 crc = crc & 0x7F;
DasSidG 1:91aa74f0cb0e 243 // No need to check bits, with DATA ^ LSB crc = 0, they will remain unchanged
yoonghm 0:245af9360f0d 244 }
yoonghm 0:245af9360f0d 245 byte = byte>>1;
yoonghm 0:245af9360f0d 246 }
DasSidG 1:91aa74f0cb0e 247 return crc;
yoonghm 0:245af9360f0d 248 }
DasSidG 1:91aa74f0cb0e 249
yoonghm 0:245af9360f0d 250 void DS1820::convert_temperature(devices device) {
yoonghm 0:245af9360f0d 251 // Convert temperature into scratchpad RAM for all devices at once
DasSidG 1:91aa74f0cb0e 252 int delay_time = 750; // Default delay time
DasSidG 1:91aa74f0cb0e 253 char resolution;
yoonghm 0:245af9360f0d 254 if (device==all_devices)
yoonghm 0:245af9360f0d 255 skip_ROM(); // Skip ROM command, will convert for ALL devices
DasSidG 1:91aa74f0cb0e 256 else {
yoonghm 0:245af9360f0d 257 match_ROM();
DasSidG 1:91aa74f0cb0e 258 if (FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
DasSidG 1:91aa74f0cb0e 259 resolution = RAM[4] & 0x60;
DasSidG 1:91aa74f0cb0e 260 if (resolution == 0x00) // 9 bits
DasSidG 1:91aa74f0cb0e 261 delay_time = 94;
DasSidG 1:91aa74f0cb0e 262 if (resolution == 0x20) // 10 bits
DasSidG 1:91aa74f0cb0e 263 delay_time = 188;
DasSidG 1:91aa74f0cb0e 264 if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default
DasSidG 1:91aa74f0cb0e 265 delay_time = 375;
DasSidG 1:91aa74f0cb0e 266 }
DasSidG 1:91aa74f0cb0e 267 }
yoonghm 0:245af9360f0d 268 onewire_byte_out( 0x44); // perform temperature conversion
yoonghm 0:245af9360f0d 269 if (_parasite_power)
DasSidG 1:91aa74f0cb0e 270 _parasitepin = 0; // Parasite power strong pullup
DasSidG 2:4c7277e9f267 271 /*wait_ms(delay_time);
yoonghm 0:245af9360f0d 272 if (_parasite_power)
DasSidG 1:91aa74f0cb0e 273 _parasitepin = 1;
DasSidG 2:4c7277e9f267 274 */ //TODO: UNCOMMENT THIS TO RESTORE NORMAL LIBRARY FUNCTIONALITY. This has been commented out so that the delay happens in the loop for all temperature buses at once, rather than one at a time
yoonghm 0:245af9360f0d 275 }
DasSidG 1:91aa74f0cb0e 276
yoonghm 0:245af9360f0d 277 void DS1820::read_RAM() {
yoonghm 0:245af9360f0d 278 // This will copy the DS1820's 9 bytes of RAM data
yoonghm 0:245af9360f0d 279 // into the objects RAM array. Functions that use
yoonghm 0:245af9360f0d 280 // RAM values will automaticly call this procedure.
yoonghm 0:245af9360f0d 281 int i;
yoonghm 0:245af9360f0d 282 match_ROM(); // Select this device
yoonghm 0:245af9360f0d 283 onewire_byte_out( 0xBE); //Read Scratchpad command
yoonghm 0:245af9360f0d 284 for(i=0;i<9;i++) {
yoonghm 0:245af9360f0d 285 RAM[i] = onewire_byte_in();
yoonghm 0:245af9360f0d 286 }
yoonghm 0:245af9360f0d 287 }
DasSidG 1:91aa74f0cb0e 288
DasSidG 1:91aa74f0cb0e 289 bool DS1820::set_configuration_bits(unsigned int resolution) {
DasSidG 1:91aa74f0cb0e 290 bool answer = false;
DasSidG 1:91aa74f0cb0e 291 resolution = resolution - 9;
DasSidG 1:91aa74f0cb0e 292 if (resolution < 4) {
DasSidG 1:91aa74f0cb0e 293 resolution = resolution<<5; // align the bits
DasSidG 1:91aa74f0cb0e 294 RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new
DasSidG 1:91aa74f0cb0e 295 write_scratchpad ((RAM[2]<<8) + RAM[3]);
DasSidG 1:91aa74f0cb0e 296 // store_scratchpad (DS1820::this_device); // Need to test if this is required
DasSidG 1:91aa74f0cb0e 297 answer = true;
DasSidG 1:91aa74f0cb0e 298 }
DasSidG 1:91aa74f0cb0e 299 return answer;
DasSidG 1:91aa74f0cb0e 300 }
DasSidG 1:91aa74f0cb0e 301
yoonghm 0:245af9360f0d 302 int DS1820::read_scratchpad() {
yoonghm 0:245af9360f0d 303 int answer;
yoonghm 0:245af9360f0d 304 read_RAM();
yoonghm 0:245af9360f0d 305 answer = (RAM[2]<<8) + RAM[3];
yoonghm 0:245af9360f0d 306 return answer;
yoonghm 0:245af9360f0d 307 }
DasSidG 1:91aa74f0cb0e 308
yoonghm 0:245af9360f0d 309 void DS1820::write_scratchpad(int data) {
yoonghm 0:245af9360f0d 310 RAM[3] = data;
yoonghm 0:245af9360f0d 311 RAM[2] = data>>8;
yoonghm 0:245af9360f0d 312 match_ROM();
yoonghm 0:245af9360f0d 313 onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory
yoonghm 0:245af9360f0d 314 onewire_byte_out(RAM[2]); // T(H)
yoonghm 0:245af9360f0d 315 onewire_byte_out(RAM[3]); // T(L)
DasSidG 1:91aa74f0cb0e 316 if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
DasSidG 1:91aa74f0cb0e 317 onewire_byte_out(RAM[4]); // Configuration register
DasSidG 1:91aa74f0cb0e 318 }
yoonghm 0:245af9360f0d 319 }
DasSidG 1:91aa74f0cb0e 320
yoonghm 0:245af9360f0d 321 void DS1820::store_scratchpad(devices device) {
yoonghm 0:245af9360f0d 322 if (device==all_devices)
yoonghm 0:245af9360f0d 323 skip_ROM(); // Skip ROM command, will store for ALL devices
yoonghm 0:245af9360f0d 324 else
yoonghm 0:245af9360f0d 325 match_ROM();
yoonghm 0:245af9360f0d 326 onewire_byte_out(0x48); // Write scratchpad into E2 command
yoonghm 0:245af9360f0d 327 if (_parasite_power)
DasSidG 1:91aa74f0cb0e 328 _parasitepin=0;
yoonghm 0:245af9360f0d 329 wait_ms(10); // Parasite power strong pullup for 10ms
yoonghm 0:245af9360f0d 330 if (_parasite_power)
DasSidG 1:91aa74f0cb0e 331 _parasitepin=1;
yoonghm 0:245af9360f0d 332 }
DasSidG 1:91aa74f0cb0e 333
yoonghm 0:245af9360f0d 334 int DS1820::recall_scratchpad(devices device) {
yoonghm 0:245af9360f0d 335 // This copies the E2 values into the DS1820's memory.
yoonghm 0:245af9360f0d 336 // If you specify all_devices this will return zero, otherwise
yoonghm 0:245af9360f0d 337 // it will return the value of the scratchpad memory.
yoonghm 0:245af9360f0d 338 int answer=0;
yoonghm 0:245af9360f0d 339 if (device==all_devices)
yoonghm 0:245af9360f0d 340 skip_ROM(); // Skip ROM command, will recall for ALL devices
yoonghm 0:245af9360f0d 341 else
yoonghm 0:245af9360f0d 342 match_ROM();
yoonghm 0:245af9360f0d 343 onewire_byte_out(0xB8); // Recall E2 data to scratchpad command
yoonghm 0:245af9360f0d 344 wait_ms(10); // not sure I like polling for completion
yoonghm 0:245af9360f0d 345 // it could cause an infinite loop
yoonghm 0:245af9360f0d 346 if (device==DS1820::this_device) {
yoonghm 0:245af9360f0d 347 read_RAM();
yoonghm 0:245af9360f0d 348 answer = read_scratchpad();
yoonghm 0:245af9360f0d 349 }
yoonghm 0:245af9360f0d 350 return answer;
yoonghm 0:245af9360f0d 351 }
DasSidG 1:91aa74f0cb0e 352
yoonghm 0:245af9360f0d 353 float DS1820::temperature(char scale) {
yoonghm 0:245af9360f0d 354 // The data specs state that count_per_degree should be 0x10 (16), I found my devices
yoonghm 0:245af9360f0d 355 // to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C
yoonghm 0:245af9360f0d 356 // this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this
yoonghm 0:245af9360f0d 357 // being super acurate, but it does allow for a smooth display in the 1/10ths of a
yoonghm 0:245af9360f0d 358 // deg C or F scales.
yoonghm 0:245af9360f0d 359 float answer, remaining_count, count_per_degree;
yoonghm 0:245af9360f0d 360 int reading;
yoonghm 0:245af9360f0d 361 read_RAM();
yoonghm 0:245af9360f0d 362 reading = (RAM[1] << 8) + RAM[0];
yoonghm 0:245af9360f0d 363 if (reading & 0x8000) { // negative degrees C
yoonghm 0:245af9360f0d 364 reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int
yoonghm 0:245af9360f0d 365 }
DasSidG 1:91aa74f0cb0e 366 answer = reading +0.0; // convert to floating point
DasSidG 1:91aa74f0cb0e 367 if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
DasSidG 1:91aa74f0cb0e 368 answer = answer / 8.0;
DasSidG 1:91aa74f0cb0e 369 }
DasSidG 1:91aa74f0cb0e 370 else {
DasSidG 1:91aa74f0cb0e 371 remaining_count = RAM[6];
DasSidG 1:91aa74f0cb0e 372 count_per_degree = RAM[7];
DasSidG 1:91aa74f0cb0e 373 answer = answer - 0.25 + (count_per_degree - remaining_count) / count_per_degree;
DasSidG 1:91aa74f0cb0e 374 }
yoonghm 0:245af9360f0d 375 if (scale=='C' or scale=='c')
yoonghm 0:245af9360f0d 376 answer = answer / 2.0;
yoonghm 0:245af9360f0d 377 else
yoonghm 0:245af9360f0d 378 // Convert to deg F
yoonghm 0:245af9360f0d 379 answer = answer * 9.0 / 10.0 + 32.0;
yoonghm 0:245af9360f0d 380 return answer;
yoonghm 0:245af9360f0d 381 }
DasSidG 1:91aa74f0cb0e 382
yoonghm 0:245af9360f0d 383 bool DS1820::read_power_supply(devices device) {
yoonghm 0:245af9360f0d 384 // This will return true if the device (or all devices) are Vcc powered
yoonghm 0:245af9360f0d 385 // This will return false if the device (or ANY device) is parasite powered
yoonghm 0:245af9360f0d 386 if (device==all_devices)
yoonghm 0:245af9360f0d 387 skip_ROM(); // Skip ROM command, will poll for any device using parasite power
yoonghm 0:245af9360f0d 388 else
yoonghm 0:245af9360f0d 389 match_ROM();
yoonghm 0:245af9360f0d 390 onewire_byte_out(0xB4); // Read power supply command
yoonghm 0:245af9360f0d 391 return onewire_bit_in();
yoonghm 0:245af9360f0d 392 }
DasSidG 1:91aa74f0cb0e 393
DasSidG 1:91aa74f0cb0e 394