moha fehri / Mbed 2 deprecated TEMPHUMRUCHE2

RUCHE

Dependencies:   mbed DHT22

DS1820/DS1820.cpp@5:4510dda988cf, 2019-01-21 (annotated)

Committer:
moham
Date:
Mon Jan 21 11:35:50 2019 +0000
Revision:
5:4510dda988cf
Parent:
2:f760e8507750 
ruche

Who changed what in which revision?

UserRevisionLine numberNew contents of line
dahmani_belkacem 2:f760e8507750 1 #include "DS1820.h"
dahmani_belkacem 2:f760e8507750 2 #include "mbed.h"
dahmani_belkacem 2:f760e8507750 3
dahmani_belkacem 2:f760e8507750 4 // Global variables shared between all DS1820 objects
dahmani_belkacem 2:f760e8507750 5 bool DS1820_done_flag;
dahmani_belkacem 2:f760e8507750 6 int DS1820_last_descrepancy;
dahmani_belkacem 2:f760e8507750 7 char DS1820_search_ROM[8];
dahmani_belkacem 2:f760e8507750 8
dahmani_belkacem 2:f760e8507750 9
dahmani_belkacem 2:f760e8507750 10 DS1820::DS1820 (PinName data_pin, PinName power_pin) : _datapin(data_pin), _parasitepin(power_pin) {
dahmani_belkacem 2:f760e8507750 11 int byte_counter;
dahmani_belkacem 2:f760e8507750 12
dahmani_belkacem 2:f760e8507750 13 _parasite_power = true;
dahmani_belkacem 2:f760e8507750 14 for(byte_counter=0;byte_counter<8;byte_counter++)
dahmani_belkacem 2:f760e8507750 15 ROM[byte_counter] = 0xFF;
dahmani_belkacem 2:f760e8507750 16 for(byte_counter=0;byte_counter<9;byte_counter++)
dahmani_belkacem 2:f760e8507750 17 RAM[byte_counter] = 0x00;
dahmani_belkacem 2:f760e8507750 18 }
dahmani_belkacem 2:f760e8507750 19 DS1820::DS1820 (PinName data_pin) : _datapin(data_pin), _parasitepin(NC) {
dahmani_belkacem 2:f760e8507750 20 int byte_counter;
dahmani_belkacem 2:f760e8507750 21 _parasite_power = false;
dahmani_belkacem 2:f760e8507750 22 for(byte_counter=0;byte_counter<8;byte_counter++)
dahmani_belkacem 2:f760e8507750 23 ROM[byte_counter] = 0xFF;
dahmani_belkacem 2:f760e8507750 24 for(byte_counter=0;byte_counter<9;byte_counter++)
dahmani_belkacem 2:f760e8507750 25 RAM[byte_counter] = 0x00;
dahmani_belkacem 2:f760e8507750 26 }
dahmani_belkacem 2:f760e8507750 27
dahmani_belkacem 2:f760e8507750 28 bool DS1820::onewire_reset() {
dahmani_belkacem 2:f760e8507750 29 // This will return false if no devices are present on the data bus
dahmani_belkacem 2:f760e8507750 30 bool presence=false;
dahmani_belkacem 2:f760e8507750 31 _datapin.output();
dahmani_belkacem 2:f760e8507750 32 _datapin.mode(PullUp);
dahmani_belkacem 2:f760e8507750 33 _datapin = 0; // bring low for 500 us
dahmani_belkacem 2:f760e8507750 34 wait_us(500);
dahmani_belkacem 2:f760e8507750 35 _datapin.input(); // let the data line float high
dahmani_belkacem 2:f760e8507750 36 _datapin.mode(PullUp);
dahmani_belkacem 2:f760e8507750 37 wait_us(90); // wait 90us
dahmani_belkacem 2:f760e8507750 38 if (_datapin.read()==0) // see if any devices are pulling the data line low
dahmani_belkacem 2:f760e8507750 39 presence=true;
dahmani_belkacem 2:f760e8507750 40 wait_us(410);
dahmani_belkacem 2:f760e8507750 41 return presence;
dahmani_belkacem 2:f760e8507750 42 }
dahmani_belkacem 2:f760e8507750 43
dahmani_belkacem 2:f760e8507750 44 void DS1820::onewire_bit_out (bool bit_data) {
dahmani_belkacem 2:f760e8507750 45 _datapin.output();
dahmani_belkacem 2:f760e8507750 46 _datapin = 0;
dahmani_belkacem 2:f760e8507750 47 wait_us(5);
dahmani_belkacem 2:f760e8507750 48 if (bit_data) {
dahmani_belkacem 2:f760e8507750 49 _datapin.input(); // bring data line high
dahmani_belkacem 2:f760e8507750 50 _datapin.mode(PullUp);
dahmani_belkacem 2:f760e8507750 51 wait_us(55);
dahmani_belkacem 2:f760e8507750 52 } else {
dahmani_belkacem 2:f760e8507750 53 wait_us(55); // keep data line low
dahmani_belkacem 2:f760e8507750 54 _datapin.input();
dahmani_belkacem 2:f760e8507750 55 _datapin.mode(PullUp);
dahmani_belkacem 2:f760e8507750 56 }
dahmani_belkacem 2:f760e8507750 57 }
dahmani_belkacem 2:f760e8507750 58
dahmani_belkacem 2:f760e8507750 59 void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first).
dahmani_belkacem 2:f760e8507750 60 int n;
dahmani_belkacem 2:f760e8507750 61 for (n=0; n<8; n++) {
dahmani_belkacem 2:f760e8507750 62 onewire_bit_out(data & 0x01);
dahmani_belkacem 2:f760e8507750 63 data = data >> 1; // now the next bit is in the least sig bit position.
dahmani_belkacem 2:f760e8507750 64 }
dahmani_belkacem 2:f760e8507750 65 }
dahmani_belkacem 2:f760e8507750 66
dahmani_belkacem 2:f760e8507750 67 bool DS1820::onewire_bit_in() {
dahmani_belkacem 2:f760e8507750 68 bool answer;
dahmani_belkacem 2:f760e8507750 69 _datapin.output();
dahmani_belkacem 2:f760e8507750 70 _datapin = 0;
dahmani_belkacem 2:f760e8507750 71 wait_us(5);
dahmani_belkacem 2:f760e8507750 72 _datapin.input();
dahmani_belkacem 2:f760e8507750 73 _datapin.mode(PullUp);
dahmani_belkacem 2:f760e8507750 74 wait_us(5);
dahmani_belkacem 2:f760e8507750 75 answer = _datapin.read();
dahmani_belkacem 2:f760e8507750 76 wait_us(50);
dahmani_belkacem 2:f760e8507750 77 return answer;
dahmani_belkacem 2:f760e8507750 78 }
dahmani_belkacem 2:f760e8507750 79
dahmani_belkacem 2:f760e8507750 80 char DS1820::onewire_byte_in() { // read byte, least sig byte first
dahmani_belkacem 2:f760e8507750 81 char answer = 0x00;
dahmani_belkacem 2:f760e8507750 82 int i;
dahmani_belkacem 2:f760e8507750 83 for (i=0; i<8; i++) {
dahmani_belkacem 2:f760e8507750 84 answer = answer >> 1; // shift over to make room for the next bit
dahmani_belkacem 2:f760e8507750 85 if (onewire_bit_in())
dahmani_belkacem 2:f760e8507750 86 answer = answer | 0x80; // if the data port is high, make this bit a 1
dahmani_belkacem 2:f760e8507750 87 }
dahmani_belkacem 2:f760e8507750 88 return answer;
dahmani_belkacem 2:f760e8507750 89 }
dahmani_belkacem 2:f760e8507750 90
dahmani_belkacem 2:f760e8507750 91 bool DS1820::search_ROM() {
dahmani_belkacem 2:f760e8507750 92 return search_ROM_routine(0xF0); // Search ROM command
dahmani_belkacem 2:f760e8507750 93 }
dahmani_belkacem 2:f760e8507750 94
dahmani_belkacem 2:f760e8507750 95 bool DS1820::search_alarm() {
dahmani_belkacem 2:f760e8507750 96 return search_ROM_routine(0xEC); // Search Alarm command
dahmani_belkacem 2:f760e8507750 97 }
dahmani_belkacem 2:f760e8507750 98
dahmani_belkacem 2:f760e8507750 99 bool DS1820::search_ROM_routine(char command) {
dahmani_belkacem 2:f760e8507750 100 extern bool DS1820_done_flag;
dahmani_belkacem 2:f760e8507750 101 extern int DS1820_last_descrepancy;
dahmani_belkacem 2:f760e8507750 102 extern char DS1820_search_ROM[8];
dahmani_belkacem 2:f760e8507750 103 int descrepancy_marker, ROM_bit_index;
dahmani_belkacem 2:f760e8507750 104 bool return_value, Bit_A, Bit_B;
dahmani_belkacem 2:f760e8507750 105 char byte_counter, bit_mask;
dahmani_belkacem 2:f760e8507750 106
dahmani_belkacem 2:f760e8507750 107 return_value=false;
dahmani_belkacem 2:f760e8507750 108 if (!DS1820_done_flag) {
dahmani_belkacem 2:f760e8507750 109 if (!onewire_reset()) {
dahmani_belkacem 2:f760e8507750 110 DS1820_last_descrepancy = 0; // no devices present
dahmani_belkacem 2:f760e8507750 111 } else {
dahmani_belkacem 2:f760e8507750 112 ROM_bit_index=1;
dahmani_belkacem 2:f760e8507750 113 descrepancy_marker=0;
dahmani_belkacem 2:f760e8507750 114 onewire_byte_out(command); // Search ROM command or Search Alarm command
dahmani_belkacem 2:f760e8507750 115 byte_counter = 0;
dahmani_belkacem 2:f760e8507750 116 bit_mask = 0x01;
dahmani_belkacem 2:f760e8507750 117 while (ROM_bit_index<=64) {
dahmani_belkacem 2:f760e8507750 118 Bit_A = onewire_bit_in();
dahmani_belkacem 2:f760e8507750 119 Bit_B = onewire_bit_in();
dahmani_belkacem 2:f760e8507750 120 if (Bit_A & Bit_B) {
dahmani_belkacem 2:f760e8507750 121 descrepancy_marker = 0; // data read error, this should never happen
dahmani_belkacem 2:f760e8507750 122 ROM_bit_index = 0xFF;
dahmani_belkacem 2:f760e8507750 123 } else {
dahmani_belkacem 2:f760e8507750 124 if (Bit_A | Bit_B) {
dahmani_belkacem 2:f760e8507750 125 // Set ROM bit to Bit_A
dahmani_belkacem 2:f760e8507750 126 if (Bit_A) {
dahmani_belkacem 2:f760e8507750 127 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
dahmani_belkacem 2:f760e8507750 128 } else {
dahmani_belkacem 2:f760e8507750 129 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
dahmani_belkacem 2:f760e8507750 130 }
dahmani_belkacem 2:f760e8507750 131 } else {
dahmani_belkacem 2:f760e8507750 132 // both bits A and B are low, so there are two or more devices present
dahmani_belkacem 2:f760e8507750 133 if ( ROM_bit_index == DS1820_last_descrepancy ) {
dahmani_belkacem 2:f760e8507750 134 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
dahmani_belkacem 2:f760e8507750 135 } else {
dahmani_belkacem 2:f760e8507750 136 if ( ROM_bit_index > DS1820_last_descrepancy ) {
dahmani_belkacem 2:f760e8507750 137 DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
dahmani_belkacem 2:f760e8507750 138 descrepancy_marker = ROM_bit_index;
dahmani_belkacem 2:f760e8507750 139 } else {
dahmani_belkacem 2:f760e8507750 140 if (( DS1820_search_ROM[byte_counter] & bit_mask) == 0x00 )
dahmani_belkacem 2:f760e8507750 141 descrepancy_marker = ROM_bit_index;
dahmani_belkacem 2:f760e8507750 142 }
dahmani_belkacem 2:f760e8507750 143 }
dahmani_belkacem 2:f760e8507750 144 }
dahmani_belkacem 2:f760e8507750 145 onewire_bit_out (DS1820_search_ROM[byte_counter] & bit_mask);
dahmani_belkacem 2:f760e8507750 146 ROM_bit_index++;
dahmani_belkacem 2:f760e8507750 147 if (bit_mask & 0x80) {
dahmani_belkacem 2:f760e8507750 148 byte_counter++;
dahmani_belkacem 2:f760e8507750 149 bit_mask = 0x01;
dahmani_belkacem 2:f760e8507750 150 } else {
dahmani_belkacem 2:f760e8507750 151 bit_mask = bit_mask << 1;
dahmani_belkacem 2:f760e8507750 152 }
dahmani_belkacem 2:f760e8507750 153 }
dahmani_belkacem 2:f760e8507750 154 }
dahmani_belkacem 2:f760e8507750 155 DS1820_last_descrepancy = descrepancy_marker;
dahmani_belkacem 2:f760e8507750 156 if (ROM_bit_index != 0xFF) {
dahmani_belkacem 2:f760e8507750 157 for(byte_counter=0;byte_counter<8;byte_counter++)
dahmani_belkacem 2:f760e8507750 158 ROM[byte_counter] = DS1820_search_ROM[byte_counter];
dahmani_belkacem 2:f760e8507750 159 return_value = true;
dahmani_belkacem 2:f760e8507750 160 }
dahmani_belkacem 2:f760e8507750 161 }
dahmani_belkacem 2:f760e8507750 162 if (DS1820_last_descrepancy == 0)
dahmani_belkacem 2:f760e8507750 163 DS1820_done_flag = true;
dahmani_belkacem 2:f760e8507750 164 }
dahmani_belkacem 2:f760e8507750 165 return return_value;
dahmani_belkacem 2:f760e8507750 166 }
dahmani_belkacem 2:f760e8507750 167
dahmani_belkacem 2:f760e8507750 168 void DS1820::search_ROM_setup() {
dahmani_belkacem 2:f760e8507750 169 extern bool DS1820_done_flag;
dahmani_belkacem 2:f760e8507750 170 extern int DS1820_last_descrepancy;
dahmani_belkacem 2:f760e8507750 171 extern char DS1820_search_ROM[8];
dahmani_belkacem 2:f760e8507750 172 DS1820_done_flag = false;
dahmani_belkacem 2:f760e8507750 173 DS1820_last_descrepancy = 0;
dahmani_belkacem 2:f760e8507750 174 int i;
dahmani_belkacem 2:f760e8507750 175 for (i=0; i<8; i++)
dahmani_belkacem 2:f760e8507750 176 DS1820_search_ROM[i]=0x00;
dahmani_belkacem 2:f760e8507750 177 }
dahmani_belkacem 2:f760e8507750 178
dahmani_belkacem 2:f760e8507750 179 void DS1820::read_ROM() {
dahmani_belkacem 2:f760e8507750 180 // NOTE: This command can only be used when there is one DS1820 on the bus. If this command
dahmani_belkacem 2:f760e8507750 181 // is used when there is more than one slave present on the bus, a data collision will occur
dahmani_belkacem 2:f760e8507750 182 // when all the DS1820s attempt to respond at the same time.
dahmani_belkacem 2:f760e8507750 183 int i;
dahmani_belkacem 2:f760e8507750 184 onewire_reset();
dahmani_belkacem 2:f760e8507750 185 onewire_byte_out(0x33); // Read ROM id
dahmani_belkacem 2:f760e8507750 186 for (i=0; i<8; i++)
dahmani_belkacem 2:f760e8507750 187 ROM[i]=onewire_byte_in();
dahmani_belkacem 2:f760e8507750 188 }
dahmani_belkacem 2:f760e8507750 189
dahmani_belkacem 2:f760e8507750 190 void DS1820::match_ROM() {
dahmani_belkacem 2:f760e8507750 191 // Used to select a specific device
dahmani_belkacem 2:f760e8507750 192 int i;
dahmani_belkacem 2:f760e8507750 193 onewire_reset();
dahmani_belkacem 2:f760e8507750 194 onewire_byte_out( 0x55); //Match ROM command
dahmani_belkacem 2:f760e8507750 195 for (i=0;i<8;i++)
dahmani_belkacem 2:f760e8507750 196 onewire_byte_out(ROM[i]);
dahmani_belkacem 2:f760e8507750 197 }
dahmani_belkacem 2:f760e8507750 198
dahmani_belkacem 2:f760e8507750 199 void DS1820::skip_ROM() {
dahmani_belkacem 2:f760e8507750 200 onewire_reset();
dahmani_belkacem 2:f760e8507750 201 onewire_byte_out(0xCC); // Skip ROM command
dahmani_belkacem 2:f760e8507750 202 }
dahmani_belkacem 2:f760e8507750 203
dahmani_belkacem 2:f760e8507750 204 bool DS1820::ROM_checksum_error() {
dahmani_belkacem 2:f760e8507750 205 char xCRC=0x00;
dahmani_belkacem 2:f760e8507750 206 int i;
dahmani_belkacem 2:f760e8507750 207 for(i=0;i<7;i++) // Only going to shift the lower 7 bytes
dahmani_belkacem 2:f760e8507750 208 xCRC = CRC_byte(xCRC, ROM[i]);
dahmani_belkacem 2:f760e8507750 209 // After 7 bytes CRC should equal the 8th byte (ROM CRC)
dahmani_belkacem 2:f760e8507750 210 return (xCRC!=ROM[7]); // will return true if there is a CRC checksum error
dahmani_belkacem 2:f760e8507750 211 }
dahmani_belkacem 2:f760e8507750 212
dahmani_belkacem 2:f760e8507750 213 bool DS1820::RAM_checksum_error() {
dahmani_belkacem 2:f760e8507750 214 char xCRC=0x00;
dahmani_belkacem 2:f760e8507750 215 int i;
dahmani_belkacem 2:f760e8507750 216 read_RAM();
dahmani_belkacem 2:f760e8507750 217 for(i=0;i<8;i++) // Only going to shift the lower 8 bytes
dahmani_belkacem 2:f760e8507750 218 xCRC = CRC_byte(xCRC, RAM[i]);
dahmani_belkacem 2:f760e8507750 219 // After 8 bytes CRC should equal the 9th byte (RAM CRC)
dahmani_belkacem 2:f760e8507750 220 return (xCRC!=RAM[8]); // will return true if there is a CRC checksum error
dahmani_belkacem 2:f760e8507750 221 }
dahmani_belkacem 2:f760e8507750 222
dahmani_belkacem 2:f760e8507750 223 char DS1820::CRC_byte (char xCRC, char byte ) {
dahmani_belkacem 2:f760e8507750 224 int j;
dahmani_belkacem 2:f760e8507750 225 for(j=0;j<8;j++) {
dahmani_belkacem 2:f760e8507750 226 if ((byte & 0x01 ) ^ (xCRC & 0x01)) {
dahmani_belkacem 2:f760e8507750 227 // DATA ^ LSB CRC = 1
dahmani_belkacem 2:f760e8507750 228 xCRC = xCRC>>1;
dahmani_belkacem 2:f760e8507750 229 // Set the MSB to 1
dahmani_belkacem 2:f760e8507750 230 xCRC = xCRC | 0x80;
dahmani_belkacem 2:f760e8507750 231 // Check bit 3
dahmani_belkacem 2:f760e8507750 232 if (xCRC & 0x04) {
dahmani_belkacem 2:f760e8507750 233 xCRC = xCRC & 0xFB; // Bit 3 is set, so clear it
dahmani_belkacem 2:f760e8507750 234 } else {
dahmani_belkacem 2:f760e8507750 235 xCRC = xCRC | 0x04; // Bit 3 is clear, so set it
dahmani_belkacem 2:f760e8507750 236 }
dahmani_belkacem 2:f760e8507750 237 // Check bit 4
dahmani_belkacem 2:f760e8507750 238 if (xCRC & 0x08) {
dahmani_belkacem 2:f760e8507750 239 xCRC = xCRC & 0xF7; // Bit 4 is set, so clear it
dahmani_belkacem 2:f760e8507750 240 } else {
dahmani_belkacem 2:f760e8507750 241 xCRC = xCRC | 0x08; // Bit 4 is clear, so set it
dahmani_belkacem 2:f760e8507750 242 }
dahmani_belkacem 2:f760e8507750 243 } else {
dahmani_belkacem 2:f760e8507750 244 // DATA ^ LSB xCRC = 0
dahmani_belkacem 2:f760e8507750 245 xCRC = xCRC>>1;
dahmani_belkacem 2:f760e8507750 246 // clear MSB
dahmani_belkacem 2:f760e8507750 247 xCRC = xCRC & 0x7F;
dahmani_belkacem 2:f760e8507750 248 // No need to check bits, with DATA ^ LSB xCRC = 0, they will remain unchanged
dahmani_belkacem 2:f760e8507750 249 }
dahmani_belkacem 2:f760e8507750 250 byte = byte>>1;
dahmani_belkacem 2:f760e8507750 251 }
dahmani_belkacem 2:f760e8507750 252 return xCRC;
dahmani_belkacem 2:f760e8507750 253 }
dahmani_belkacem 2:f760e8507750 254
dahmani_belkacem 2:f760e8507750 255 void DS1820::convert_temperature(devices device) {
dahmani_belkacem 2:f760e8507750 256 // Convert temperature into scratchpad RAM for all devices at once
dahmani_belkacem 2:f760e8507750 257 int delay_time = 750; // Default delay time
dahmani_belkacem 2:f760e8507750 258 char resolution;
dahmani_belkacem 2:f760e8507750 259 if (device==all_devices)
dahmani_belkacem 2:f760e8507750 260 skip_ROM(); // Skip ROM command, will convert for ALL devices
dahmani_belkacem 2:f760e8507750 261 else {
dahmani_belkacem 2:f760e8507750 262 match_ROM();
dahmani_belkacem 2:f760e8507750 263 if (FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
dahmani_belkacem 2:f760e8507750 264 resolution = RAM[4] & 0x60;
dahmani_belkacem 2:f760e8507750 265 if (resolution == 0x00) // 9 bits
dahmani_belkacem 2:f760e8507750 266 delay_time = 94;
dahmani_belkacem 2:f760e8507750 267 if (resolution == 0x20) // 10 bits
dahmani_belkacem 2:f760e8507750 268 delay_time = 188;
dahmani_belkacem 2:f760e8507750 269 if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default
dahmani_belkacem 2:f760e8507750 270 delay_time = 375;
dahmani_belkacem 2:f760e8507750 271 }
dahmani_belkacem 2:f760e8507750 272 }
dahmani_belkacem 2:f760e8507750 273 onewire_byte_out( 0x44); // perform temperature conversion
dahmani_belkacem 2:f760e8507750 274 if (_parasite_power)
dahmani_belkacem 2:f760e8507750 275 _parasitepin = 1; // Parasite power strong pullup
dahmani_belkacem 2:f760e8507750 276 wait_ms(delay_time);
dahmani_belkacem 2:f760e8507750 277 if (_parasite_power)
dahmani_belkacem 2:f760e8507750 278 _parasitepin = 0;
dahmani_belkacem 2:f760e8507750 279 }
dahmani_belkacem 2:f760e8507750 280
dahmani_belkacem 2:f760e8507750 281 void DS1820::read_RAM() {
dahmani_belkacem 2:f760e8507750 282 // This will copy the DS1820's 9 bytes of RAM data
dahmani_belkacem 2:f760e8507750 283 // into the objects RAM array. Functions that use
dahmani_belkacem 2:f760e8507750 284 // RAM values will automaticly call this procedure.
dahmani_belkacem 2:f760e8507750 285 int i;
dahmani_belkacem 2:f760e8507750 286 match_ROM(); // Select this device
dahmani_belkacem 2:f760e8507750 287 onewire_byte_out( 0xBE); //Read Scratchpad command
dahmani_belkacem 2:f760e8507750 288 for(i=0;i<9;i++) {
dahmani_belkacem 2:f760e8507750 289 RAM[i] = onewire_byte_in();
dahmani_belkacem 2:f760e8507750 290 }
dahmani_belkacem 2:f760e8507750 291 }
dahmani_belkacem 2:f760e8507750 292
dahmani_belkacem 2:f760e8507750 293 bool DS1820::set_configuration_bits(unsigned int resolution) {
dahmani_belkacem 2:f760e8507750 294 bool answer = false;
dahmani_belkacem 2:f760e8507750 295 resolution = resolution - 9;
dahmani_belkacem 2:f760e8507750 296 if (resolution < 4) {
dahmani_belkacem 2:f760e8507750 297 resolution = resolution<<5; // align the bits
dahmani_belkacem 2:f760e8507750 298 RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new
dahmani_belkacem 2:f760e8507750 299 write_scratchpad ((RAM[2]<<8) + RAM[3]);
dahmani_belkacem 2:f760e8507750 300 // store_scratchpad (DS1820::this_device); // Need to test if this is required
dahmani_belkacem 2:f760e8507750 301 answer = true;
dahmani_belkacem 2:f760e8507750 302 }
dahmani_belkacem 2:f760e8507750 303 return answer;
dahmani_belkacem 2:f760e8507750 304 }
dahmani_belkacem 2:f760e8507750 305
dahmani_belkacem 2:f760e8507750 306 int DS1820::read_scratchpad() {
dahmani_belkacem 2:f760e8507750 307 int answer;
dahmani_belkacem 2:f760e8507750 308 read_RAM();
dahmani_belkacem 2:f760e8507750 309 answer = (RAM[2]<<8) + RAM[3];
dahmani_belkacem 2:f760e8507750 310 return answer;
dahmani_belkacem 2:f760e8507750 311 }
dahmani_belkacem 2:f760e8507750 312
dahmani_belkacem 2:f760e8507750 313 void DS1820::write_scratchpad(int data) {
dahmani_belkacem 2:f760e8507750 314 RAM[3] = data;
dahmani_belkacem 2:f760e8507750 315 RAM[2] = data>>8;
dahmani_belkacem 2:f760e8507750 316 match_ROM();
dahmani_belkacem 2:f760e8507750 317 onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory
dahmani_belkacem 2:f760e8507750 318 onewire_byte_out(RAM[2]); // T(H)
dahmani_belkacem 2:f760e8507750 319 onewire_byte_out(RAM[3]); // T(L)
dahmani_belkacem 2:f760e8507750 320 if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
dahmani_belkacem 2:f760e8507750 321 onewire_byte_out(RAM[4]); // Configuration register
dahmani_belkacem 2:f760e8507750 322 }
dahmani_belkacem 2:f760e8507750 323 }
dahmani_belkacem 2:f760e8507750 324
dahmani_belkacem 2:f760e8507750 325 void DS1820::store_scratchpad(devices device) {
dahmani_belkacem 2:f760e8507750 326 if (device==all_devices)
dahmani_belkacem 2:f760e8507750 327 skip_ROM(); // Skip ROM command, will store for ALL devices
dahmani_belkacem 2:f760e8507750 328 else
dahmani_belkacem 2:f760e8507750 329 match_ROM();
dahmani_belkacem 2:f760e8507750 330 onewire_byte_out(0x48); // Write scratchpad into E2 command
dahmani_belkacem 2:f760e8507750 331 if (_parasite_power)
dahmani_belkacem 2:f760e8507750 332 _parasitepin=1;
dahmani_belkacem 2:f760e8507750 333 wait_ms(10); // Parasite power strong pullup for 10ms
dahmani_belkacem 2:f760e8507750 334 if (_parasite_power)
dahmani_belkacem 2:f760e8507750 335 _parasitepin=0;
dahmani_belkacem 2:f760e8507750 336 }
dahmani_belkacem 2:f760e8507750 337
dahmani_belkacem 2:f760e8507750 338 int DS1820::recall_scratchpad(devices device) {
dahmani_belkacem 2:f760e8507750 339 // This copies the E2 values into the DS1820's memory.
dahmani_belkacem 2:f760e8507750 340 // If you specify all_devices this will return zero, otherwise
dahmani_belkacem 2:f760e8507750 341 // it will return the value of the scratchpad memory.
dahmani_belkacem 2:f760e8507750 342 int answer=0;
dahmani_belkacem 2:f760e8507750 343 if (device==all_devices)
dahmani_belkacem 2:f760e8507750 344 skip_ROM(); // Skip ROM command, will recall for ALL devices
dahmani_belkacem 2:f760e8507750 345 else
dahmani_belkacem 2:f760e8507750 346 match_ROM();
dahmani_belkacem 2:f760e8507750 347 onewire_byte_out(0xB8); // Recall E2 data to scratchpad command
dahmani_belkacem 2:f760e8507750 348 wait_ms(10); // not sure I like polling for completion
dahmani_belkacem 2:f760e8507750 349 // it could cause an infinite loop
dahmani_belkacem 2:f760e8507750 350 if (device==DS1820::this_device) {
dahmani_belkacem 2:f760e8507750 351 read_RAM();
dahmani_belkacem 2:f760e8507750 352 answer = read_scratchpad();
dahmani_belkacem 2:f760e8507750 353 }
dahmani_belkacem 2:f760e8507750 354 return answer;
dahmani_belkacem 2:f760e8507750 355 }
dahmani_belkacem 2:f760e8507750 356
dahmani_belkacem 2:f760e8507750 357 float DS1820::temperature(char scale) {
dahmani_belkacem 2:f760e8507750 358 // The data specs state that count_per_degree should be 0x10 (16), I found my devices
dahmani_belkacem 2:f760e8507750 359 // to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C
dahmani_belkacem 2:f760e8507750 360 // this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this
dahmani_belkacem 2:f760e8507750 361 // being super acurate, but it does allow for a smooth display in the 1/10ths of a
dahmani_belkacem 2:f760e8507750 362 // deg C or F scales.
dahmani_belkacem 2:f760e8507750 363 float answer, remaining_count, count_per_degree;
dahmani_belkacem 2:f760e8507750 364 int reading;
dahmani_belkacem 2:f760e8507750 365 read_RAM();
dahmani_belkacem 2:f760e8507750 366 reading = (RAM[1] << 8) + RAM[0];
dahmani_belkacem 2:f760e8507750 367 if (reading & 0x8000) { // negative degrees C
dahmani_belkacem 2:f760e8507750 368 reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int
dahmani_belkacem 2:f760e8507750 369 }
dahmani_belkacem 2:f760e8507750 370 answer = reading +0.0; // convert to floating point
dahmani_belkacem 2:f760e8507750 371 if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) {
dahmani_belkacem 2:f760e8507750 372 answer = answer / 8.0;
dahmani_belkacem 2:f760e8507750 373 }
dahmani_belkacem 2:f760e8507750 374 else {
dahmani_belkacem 2:f760e8507750 375 remaining_count = RAM[6];
dahmani_belkacem 2:f760e8507750 376 count_per_degree = RAM[7];
dahmani_belkacem 2:f760e8507750 377 answer = answer - 0.25 + (count_per_degree - remaining_count) / count_per_degree;
dahmani_belkacem 2:f760e8507750 378 }
dahmani_belkacem 2:f760e8507750 379 if (scale=='C' or scale=='c')
dahmani_belkacem 2:f760e8507750 380 answer = answer / 2.0;
dahmani_belkacem 2:f760e8507750 381 else
dahmani_belkacem 2:f760e8507750 382 // Convert to deg F
dahmani_belkacem 2:f760e8507750 383 answer = answer * 9.0 / 10.0 + 32.0;
dahmani_belkacem 2:f760e8507750 384 return answer;
dahmani_belkacem 2:f760e8507750 385 }
dahmani_belkacem 2:f760e8507750 386
dahmani_belkacem 2:f760e8507750 387 bool DS1820::read_power_supply(devices device) {
dahmani_belkacem 2:f760e8507750 388 // This will return true if the device (or all devices) are Vcc powered
dahmani_belkacem 2:f760e8507750 389 // This will return false if the device (or ANY device) is parasite powered
dahmani_belkacem 2:f760e8507750 390 if (device==all_devices)
dahmani_belkacem 2:f760e8507750 391 skip_ROM(); // Skip ROM command, will poll for any device using parasite power
dahmani_belkacem 2:f760e8507750 392 else
dahmani_belkacem 2:f760e8507750 393 match_ROM();
dahmani_belkacem 2:f760e8507750 394 onewire_byte_out(0xB4); // Read power supply command
dahmani_belkacem 2:f760e8507750 395 return onewire_bit_in();
dahmani_belkacem 2:f760e8507750 396 }