Dallas / Maxim DS1820 1-Wire library. For communication with multiple DS1820 on a single 1-Wire bus. Also supports DS18S20 and DS18B20.
DS1820.cpp@5:31e245719610, 2019-02-17 (annotated)
- Committer:
- lamell
- Date:
- Sun Feb 17 22:21:24 2019 +0000
- Revision:
- 5:31e245719610
- Parent:
- 4:c2b93dbd6a9e
No changes
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
lamell | 3:3e89eafb60c2 | 1 | #include "DS1820.h" |
lamell | 3:3e89eafb60c2 | 2 | #include "mbed.h" |
lamell | 3:3e89eafb60c2 | 3 | |
lamell | 3:3e89eafb60c2 | 4 | // Global variables shared between all DS1820 objects |
lamell | 3:3e89eafb60c2 | 5 | bool DS1820_done_flag; |
lamell | 3:3e89eafb60c2 | 6 | int DS1820_last_descrepancy; |
lamell | 3:3e89eafb60c2 | 7 | char DS1820_search_Rom[8]; |
lamell | 3:3e89eafb60c2 | 8 | |
lamell | 5:31e245719610 | 9 | extern Serial pc; |
lamell | 3:3e89eafb60c2 | 10 | |
lamell | 3:3e89eafb60c2 | 11 | DS1820::DS1820 (PinName data_pin, PinName power_pin) : _datapin(data_pin), _parasitepin(power_pin) { |
lamell | 3:3e89eafb60c2 | 12 | int byte_counter; |
lamell | 3:3e89eafb60c2 | 13 | _parasite_power = true; |
lamell | 3:3e89eafb60c2 | 14 | for(byte_counter=0;byte_counter<8;byte_counter++) |
lamell | 3:3e89eafb60c2 | 15 | Rom[byte_counter] = 0xFF; |
lamell | 3:3e89eafb60c2 | 16 | for(byte_counter=0;byte_counter<9;byte_counter++) |
lamell | 3:3e89eafb60c2 | 17 | RAM[byte_counter] = 0x00; |
lamell | 3:3e89eafb60c2 | 18 | } |
lamell | 3:3e89eafb60c2 | 19 | DS1820::DS1820 (PinName data_pin) : _datapin(data_pin), _parasitepin(NC) { |
lamell | 3:3e89eafb60c2 | 20 | int byte_counter; |
lamell | 3:3e89eafb60c2 | 21 | _parasite_power = false; |
lamell | 3:3e89eafb60c2 | 22 | for(byte_counter=0;byte_counter<8;byte_counter++) |
lamell | 3:3e89eafb60c2 | 23 | Rom[byte_counter] = 0xFF; |
lamell | 3:3e89eafb60c2 | 24 | for(byte_counter=0;byte_counter<9;byte_counter++) |
lamell | 3:3e89eafb60c2 | 25 | RAM[byte_counter] = 0x00; |
lamell | 3:3e89eafb60c2 | 26 | } |
lamell | 3:3e89eafb60c2 | 27 | |
lamell | 3:3e89eafb60c2 | 28 | bool DS1820::onewire_reset() { |
lamell | 3:3e89eafb60c2 | 29 | // This will return false if no devices are present on the data bus |
lamell | 3:3e89eafb60c2 | 30 | bool presence=false; |
lamell | 3:3e89eafb60c2 | 31 | _datapin.output(); |
lamell | 3:3e89eafb60c2 | 32 | _datapin = 0; // bring low for 500 us |
lamell | 3:3e89eafb60c2 | 33 | wait_us(500); |
lamell | 3:3e89eafb60c2 | 34 | _datapin.input(); // let the data line float high |
lamell | 3:3e89eafb60c2 | 35 | wait_us(90); // wait 90us |
lamell | 3:3e89eafb60c2 | 36 | if (_datapin.read()==0) // see if any devices are pulling the data line low |
lamell | 3:3e89eafb60c2 | 37 | presence=true; |
lamell | 3:3e89eafb60c2 | 38 | wait_us(410); |
lamell | 3:3e89eafb60c2 | 39 | return presence; |
lamell | 3:3e89eafb60c2 | 40 | } |
lamell | 3:3e89eafb60c2 | 41 | |
lamell | 3:3e89eafb60c2 | 42 | void DS1820::onewire_bit_out (bool bit_data) { |
lamell | 3:3e89eafb60c2 | 43 | _datapin.output(); |
lamell | 3:3e89eafb60c2 | 44 | _datapin = 0; |
lamell | 3:3e89eafb60c2 | 45 | wait_us(5); |
lamell | 3:3e89eafb60c2 | 46 | if (bit_data) { |
lamell | 3:3e89eafb60c2 | 47 | _datapin.input(); // bring data line high |
lamell | 3:3e89eafb60c2 | 48 | wait_us(55); |
lamell | 3:3e89eafb60c2 | 49 | } else { |
lamell | 3:3e89eafb60c2 | 50 | wait_us(55); // keep data line low |
lamell | 3:3e89eafb60c2 | 51 | _datapin.input(); |
lamell | 3:3e89eafb60c2 | 52 | } |
lamell | 3:3e89eafb60c2 | 53 | } |
lamell | 3:3e89eafb60c2 | 54 | |
lamell | 3:3e89eafb60c2 | 55 | void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first). |
lamell | 3:3e89eafb60c2 | 56 | int n; |
lamell | 3:3e89eafb60c2 | 57 | for (n=0; n<8; n++) { |
lamell | 3:3e89eafb60c2 | 58 | onewire_bit_out(data & 0x01); |
lamell | 3:3e89eafb60c2 | 59 | data = data >> 1; // now the next bit is in the least sig bit position. |
lamell | 3:3e89eafb60c2 | 60 | } |
lamell | 3:3e89eafb60c2 | 61 | } |
lamell | 3:3e89eafb60c2 | 62 | |
lamell | 3:3e89eafb60c2 | 63 | bool DS1820::onewire_bit_in() { |
lamell | 3:3e89eafb60c2 | 64 | bool answer; |
lamell | 3:3e89eafb60c2 | 65 | _datapin.output(); |
lamell | 3:3e89eafb60c2 | 66 | _datapin = 0; |
lamell | 3:3e89eafb60c2 | 67 | wait_us(5); |
lamell | 3:3e89eafb60c2 | 68 | _datapin.input(); |
lamell | 3:3e89eafb60c2 | 69 | wait_us(5); |
lamell | 3:3e89eafb60c2 | 70 | answer = _datapin.read(); |
lamell | 3:3e89eafb60c2 | 71 | wait_us(50); |
lamell | 3:3e89eafb60c2 | 72 | return answer; |
lamell | 3:3e89eafb60c2 | 73 | } |
lamell | 3:3e89eafb60c2 | 74 | |
lamell | 3:3e89eafb60c2 | 75 | char DS1820::onewire_byte_in() { // read byte, least sig byte first |
lamell | 3:3e89eafb60c2 | 76 | char answer = 0x00; |
lamell | 3:3e89eafb60c2 | 77 | int i; |
lamell | 3:3e89eafb60c2 | 78 | for (i=0; i<8; i++) { |
lamell | 3:3e89eafb60c2 | 79 | answer = answer >> 1; // shift over to make room for the next bit |
lamell | 3:3e89eafb60c2 | 80 | if (onewire_bit_in()) |
lamell | 3:3e89eafb60c2 | 81 | answer = answer | 0x80; // if the data port is high, make this bit a 1 |
lamell | 3:3e89eafb60c2 | 82 | } |
lamell | 3:3e89eafb60c2 | 83 | return answer; |
lamell | 3:3e89eafb60c2 | 84 | } |
lamell | 3:3e89eafb60c2 | 85 | |
lamell | 3:3e89eafb60c2 | 86 | bool DS1820::search_Rom() { |
lamell | 3:3e89eafb60c2 | 87 | return search_Rom_routine(0xF0); // Search Rom command |
lamell | 3:3e89eafb60c2 | 88 | } |
lamell | 3:3e89eafb60c2 | 89 | |
lamell | 3:3e89eafb60c2 | 90 | bool DS1820::search_alarm() { |
lamell | 3:3e89eafb60c2 | 91 | return search_Rom_routine(0xEC); // Search Alarm command |
lamell | 3:3e89eafb60c2 | 92 | } |
lamell | 3:3e89eafb60c2 | 93 | |
lamell | 3:3e89eafb60c2 | 94 | bool DS1820::search_Rom_routine(char command) { |
lamell | 3:3e89eafb60c2 | 95 | extern bool DS1820_done_flag; |
lamell | 3:3e89eafb60c2 | 96 | extern int DS1820_last_descrepancy; |
lamell | 3:3e89eafb60c2 | 97 | extern char DS1820_search_Rom[8]; |
lamell | 3:3e89eafb60c2 | 98 | int descrepancy_marker, Rom_bit_index; |
lamell | 3:3e89eafb60c2 | 99 | bool return_value, Bit_A, Bit_B; |
lamell | 3:3e89eafb60c2 | 100 | char byte_counter, bit_mask; |
lamell | 3:3e89eafb60c2 | 101 | |
lamell | 3:3e89eafb60c2 | 102 | return_value=false; |
lamell | 3:3e89eafb60c2 | 103 | if (!DS1820_done_flag) { |
lamell | 3:3e89eafb60c2 | 104 | if (!onewire_reset()) { |
lamell | 3:3e89eafb60c2 | 105 | DS1820_last_descrepancy = 0; // no devices present |
lamell | 3:3e89eafb60c2 | 106 | } else { |
lamell | 3:3e89eafb60c2 | 107 | Rom_bit_index=1; |
lamell | 3:3e89eafb60c2 | 108 | descrepancy_marker=0; |
lamell | 3:3e89eafb60c2 | 109 | onewire_byte_out(command); // Search Rom command or Search Alarm command |
lamell | 3:3e89eafb60c2 | 110 | byte_counter = 0; |
lamell | 3:3e89eafb60c2 | 111 | bit_mask = 0x01; |
lamell | 3:3e89eafb60c2 | 112 | while (Rom_bit_index<=64) { |
lamell | 3:3e89eafb60c2 | 113 | Bit_A = onewire_bit_in(); |
lamell | 3:3e89eafb60c2 | 114 | Bit_B = onewire_bit_in(); |
lamell | 3:3e89eafb60c2 | 115 | if (Bit_A & Bit_B) { |
lamell | 3:3e89eafb60c2 | 116 | descrepancy_marker = 0; // data read error, this should never happen |
lamell | 3:3e89eafb60c2 | 117 | Rom_bit_index = 0xFF; |
lamell | 3:3e89eafb60c2 | 118 | } else { |
lamell | 3:3e89eafb60c2 | 119 | if (Bit_A | Bit_B) { |
lamell | 3:3e89eafb60c2 | 120 | // Set Rom bit to Bit_A |
lamell | 3:3e89eafb60c2 | 121 | if (Bit_A) { |
lamell | 3:3e89eafb60c2 | 122 | DS1820_search_Rom[byte_counter] = DS1820_search_Rom[byte_counter] | bit_mask; // Set Rom bit to one |
lamell | 3:3e89eafb60c2 | 123 | } else { |
lamell | 3:3e89eafb60c2 | 124 | DS1820_search_Rom[byte_counter] = DS1820_search_Rom[byte_counter] & ~bit_mask; // Set Rom bit to zero |
lamell | 3:3e89eafb60c2 | 125 | } |
lamell | 3:3e89eafb60c2 | 126 | } else { |
lamell | 3:3e89eafb60c2 | 127 | // both bits A and B are low, so there are two or more devices present |
lamell | 3:3e89eafb60c2 | 128 | if ( Rom_bit_index == DS1820_last_descrepancy ) { |
lamell | 3:3e89eafb60c2 | 129 | DS1820_search_Rom[byte_counter] = DS1820_search_Rom[byte_counter] | bit_mask; // Set Rom bit to one |
lamell | 3:3e89eafb60c2 | 130 | } else { |
lamell | 3:3e89eafb60c2 | 131 | if ( Rom_bit_index > DS1820_last_descrepancy ) { |
lamell | 3:3e89eafb60c2 | 132 | DS1820_search_Rom[byte_counter] = DS1820_search_Rom[byte_counter] & ~bit_mask; // Set Rom bit to zero |
lamell | 3:3e89eafb60c2 | 133 | descrepancy_marker = Rom_bit_index; |
lamell | 3:3e89eafb60c2 | 134 | } else { |
lamell | 3:3e89eafb60c2 | 135 | if (( DS1820_search_Rom[byte_counter] & bit_mask) == 0x00 ) |
lamell | 3:3e89eafb60c2 | 136 | descrepancy_marker = Rom_bit_index; |
lamell | 3:3e89eafb60c2 | 137 | } |
lamell | 3:3e89eafb60c2 | 138 | } |
lamell | 3:3e89eafb60c2 | 139 | } |
lamell | 3:3e89eafb60c2 | 140 | onewire_bit_out (DS1820_search_Rom[byte_counter] & bit_mask); |
lamell | 3:3e89eafb60c2 | 141 | Rom_bit_index++; |
lamell | 3:3e89eafb60c2 | 142 | if (bit_mask & 0x80) { |
lamell | 3:3e89eafb60c2 | 143 | byte_counter++; |
lamell | 3:3e89eafb60c2 | 144 | bit_mask = 0x01; |
lamell | 3:3e89eafb60c2 | 145 | } else { |
lamell | 3:3e89eafb60c2 | 146 | bit_mask = bit_mask << 1; |
lamell | 3:3e89eafb60c2 | 147 | } |
lamell | 3:3e89eafb60c2 | 148 | } |
lamell | 3:3e89eafb60c2 | 149 | } |
lamell | 3:3e89eafb60c2 | 150 | DS1820_last_descrepancy = descrepancy_marker; |
lamell | 3:3e89eafb60c2 | 151 | if (Rom_bit_index != 0xFF) { |
lamell | 3:3e89eafb60c2 | 152 | for(byte_counter=0;byte_counter<8;byte_counter++) |
lamell | 3:3e89eafb60c2 | 153 | Rom[byte_counter] = DS1820_search_Rom[byte_counter]; |
lamell | 3:3e89eafb60c2 | 154 | return_value = true; |
lamell | 3:3e89eafb60c2 | 155 | } |
lamell | 3:3e89eafb60c2 | 156 | } |
lamell | 3:3e89eafb60c2 | 157 | if (DS1820_last_descrepancy == 0) |
lamell | 3:3e89eafb60c2 | 158 | DS1820_done_flag = true; |
lamell | 3:3e89eafb60c2 | 159 | } |
lamell | 3:3e89eafb60c2 | 160 | return return_value; |
lamell | 3:3e89eafb60c2 | 161 | } |
lamell | 3:3e89eafb60c2 | 162 | |
lamell | 3:3e89eafb60c2 | 163 | void DS1820::search_Rom_setup() { |
lamell | 3:3e89eafb60c2 | 164 | extern bool DS1820_done_flag; |
lamell | 3:3e89eafb60c2 | 165 | extern int DS1820_last_descrepancy; |
lamell | 3:3e89eafb60c2 | 166 | extern char DS1820_search_Rom[8]; |
lamell | 3:3e89eafb60c2 | 167 | DS1820_done_flag = false; |
lamell | 3:3e89eafb60c2 | 168 | DS1820_last_descrepancy = 0; |
lamell | 3:3e89eafb60c2 | 169 | int i; |
lamell | 3:3e89eafb60c2 | 170 | for (i=0; i<8; i++) |
lamell | 3:3e89eafb60c2 | 171 | DS1820_search_Rom[i]=0x00; |
lamell | 3:3e89eafb60c2 | 172 | } |
lamell | 3:3e89eafb60c2 | 173 | |
lamell | 3:3e89eafb60c2 | 174 | void DS1820::read_Rom(){ |
lamell | 3:3e89eafb60c2 | 175 | // NOTE: This command can only be used when there is one DS1820 on the bus. If this command |
lamell | 3:3e89eafb60c2 | 176 | // is used when there is more than one slave present on the bus, a data collision will occur |
lamell | 3:3e89eafb60c2 | 177 | // when all the DS1820s attempt to respond at the same time. |
lamell | 3:3e89eafb60c2 | 178 | int i; |
lamell | 3:3e89eafb60c2 | 179 | onewire_reset(); |
lamell | 3:3e89eafb60c2 | 180 | onewire_byte_out(0x33); // Read Rom id |
lamell | 3:3e89eafb60c2 | 181 | for (i=0; i<8; i++) |
lamell | 3:3e89eafb60c2 | 182 | Rom[i]=onewire_byte_in(); |
lamell | 3:3e89eafb60c2 | 183 | } |
lamell | 3:3e89eafb60c2 | 184 | |
lamell | 3:3e89eafb60c2 | 185 | void DS1820::match_Rom() { |
lamell | 3:3e89eafb60c2 | 186 | // Used to select a specific device |
lamell | 3:3e89eafb60c2 | 187 | int i; |
lamell | 3:3e89eafb60c2 | 188 | onewire_reset(); |
lamell | 3:3e89eafb60c2 | 189 | onewire_byte_out( 0x55); //Match Rom command |
lamell | 3:3e89eafb60c2 | 190 | for (i=0;i<8;i++) |
lamell | 3:3e89eafb60c2 | 191 | onewire_byte_out(Rom[i]); |
lamell | 3:3e89eafb60c2 | 192 | } |
lamell | 3:3e89eafb60c2 | 193 | |
lamell | 3:3e89eafb60c2 | 194 | void DS1820::skip_Rom() { |
lamell | 3:3e89eafb60c2 | 195 | onewire_reset(); |
lamell | 3:3e89eafb60c2 | 196 | onewire_byte_out(0xCC); // Skip Rom command |
lamell | 3:3e89eafb60c2 | 197 | } |
lamell | 3:3e89eafb60c2 | 198 | |
lamell | 3:3e89eafb60c2 | 199 | bool DS1820::Rom_checksum_error() { |
lamell | 3:3e89eafb60c2 | 200 | char ow_CRC=0x00; |
lamell | 3:3e89eafb60c2 | 201 | int i; |
lamell | 3:3e89eafb60c2 | 202 | for(i=0;i<7;i++) // Only going to shift the lower 7 bytes |
lamell | 3:3e89eafb60c2 | 203 | ow_CRC = ow_CRC_byte(ow_CRC, Rom[i]); |
lamell | 3:3e89eafb60c2 | 204 | // After 7 bytes ow_CRC should equal the 8th byte (Rom ow_CRC) |
lamell | 3:3e89eafb60c2 | 205 | return (ow_CRC!=Rom[7]); // will return true if there is a ow_CRC checksum error |
lamell | 3:3e89eafb60c2 | 206 | } |
lamell | 3:3e89eafb60c2 | 207 | |
lamell | 3:3e89eafb60c2 | 208 | bool DS1820::RAM_checksum_error() { |
lamell | 3:3e89eafb60c2 | 209 | char ow_CRC=0x00; |
lamell | 3:3e89eafb60c2 | 210 | int i; |
lamell | 3:3e89eafb60c2 | 211 | read_RAM(); |
lamell | 3:3e89eafb60c2 | 212 | for(i=0;i<8;i++) // Only going to shift the lower 8 bytes |
lamell | 3:3e89eafb60c2 | 213 | ow_CRC = ow_CRC_byte(ow_CRC, RAM[i]); |
lamell | 3:3e89eafb60c2 | 214 | // After 8 bytes ow_CRC should equal the 9th byte (RAM ow_CRC) |
lamell | 3:3e89eafb60c2 | 215 | return (ow_CRC!=RAM[8]); // will return true if there is a ow_CRC checksum error |
lamell | 3:3e89eafb60c2 | 216 | } |
lamell | 3:3e89eafb60c2 | 217 | |
lamell | 3:3e89eafb60c2 | 218 | char DS1820::ow_CRC_byte (char ow_CRC, char byte ) { |
lamell | 3:3e89eafb60c2 | 219 | int j; |
lamell | 3:3e89eafb60c2 | 220 | for(j=0;j<8;j++) { |
lamell | 3:3e89eafb60c2 | 221 | if ((byte & 0x01 ) ^ (ow_CRC & 0x01)) { |
lamell | 3:3e89eafb60c2 | 222 | // DATA ^ LSB ow_CRC = 1 |
lamell | 3:3e89eafb60c2 | 223 | ow_CRC = ow_CRC>>1; |
lamell | 3:3e89eafb60c2 | 224 | // Set the MSB to 1 |
lamell | 3:3e89eafb60c2 | 225 | ow_CRC = ow_CRC | 0x80; |
lamell | 3:3e89eafb60c2 | 226 | // Check bit 3 |
lamell | 3:3e89eafb60c2 | 227 | if (ow_CRC & 0x04) { |
lamell | 3:3e89eafb60c2 | 228 | ow_CRC = ow_CRC & 0xFB; // Bit 3 is set, so clear it |
lamell | 3:3e89eafb60c2 | 229 | } else { |
lamell | 3:3e89eafb60c2 | 230 | ow_CRC = ow_CRC | 0x04; // Bit 3 is clear, so set it |
lamell | 3:3e89eafb60c2 | 231 | } |
lamell | 3:3e89eafb60c2 | 232 | // Check bit 4 |
lamell | 3:3e89eafb60c2 | 233 | if (ow_CRC & 0x08) { |
lamell | 3:3e89eafb60c2 | 234 | ow_CRC = ow_CRC & 0xF7; // Bit 4 is set, so clear it |
lamell | 3:3e89eafb60c2 | 235 | } else { |
lamell | 3:3e89eafb60c2 | 236 | ow_CRC = ow_CRC | 0x08; // Bit 4 is clear, so set it |
lamell | 3:3e89eafb60c2 | 237 | } |
lamell | 3:3e89eafb60c2 | 238 | } else { |
lamell | 3:3e89eafb60c2 | 239 | // DATA ^ LSB ow_CRC = 0 |
lamell | 3:3e89eafb60c2 | 240 | ow_CRC = ow_CRC>>1; |
lamell | 3:3e89eafb60c2 | 241 | // clear MSB |
lamell | 3:3e89eafb60c2 | 242 | ow_CRC = ow_CRC & 0x7F; |
lamell | 3:3e89eafb60c2 | 243 | // No need to check bits, with DATA ^ LSB ow_CRC = 0, they will remain unchanged |
lamell | 3:3e89eafb60c2 | 244 | } |
lamell | 3:3e89eafb60c2 | 245 | byte = byte>>1; |
lamell | 3:3e89eafb60c2 | 246 | } |
lamell | 3:3e89eafb60c2 | 247 | return ow_CRC; |
lamell | 3:3e89eafb60c2 | 248 | } |
lamell | 3:3e89eafb60c2 | 249 | |
lamell | 3:3e89eafb60c2 | 250 | void DS1820::convert_temperature(devices device) { |
lamell | 3:3e89eafb60c2 | 251 | // Convert temperature into scratchpad RAM for all devices at once |
lamell | 3:3e89eafb60c2 | 252 | int delay_time = 750; // Default delay time |
lamell | 3:3e89eafb60c2 | 253 | char resolution; |
lamell | 3:3e89eafb60c2 | 254 | if (device==all_devices) |
lamell | 3:3e89eafb60c2 | 255 | skip_Rom(); // Skip Rom command, will convert for ALL devices |
lamell | 3:3e89eafb60c2 | 256 | else { |
lamell | 3:3e89eafb60c2 | 257 | match_Rom(); |
lamell | 3:3e89eafb60c2 | 258 | if (FAMILY_CODE == FAMILY_CODE_DS18B20 ) { |
lamell | 3:3e89eafb60c2 | 259 | resolution = RAM[4] & 0x60; |
lamell | 3:3e89eafb60c2 | 260 | if (resolution == 0x00) // 9 bits |
lamell | 3:3e89eafb60c2 | 261 | delay_time = 94; |
lamell | 3:3e89eafb60c2 | 262 | if (resolution == 0x20) // 10 bits |
lamell | 3:3e89eafb60c2 | 263 | delay_time = 188; |
lamell | 3:3e89eafb60c2 | 264 | if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default |
lamell | 3:3e89eafb60c2 | 265 | delay_time = 375; |
lamell | 3:3e89eafb60c2 | 266 | } |
lamell | 3:3e89eafb60c2 | 267 | } |
lamell | 3:3e89eafb60c2 | 268 | onewire_byte_out( 0x44); // perform temperature conversion |
lamell | 3:3e89eafb60c2 | 269 | if (_parasite_power) |
lamell | 3:3e89eafb60c2 | 270 | _parasitepin = 1; // Parasite power strong pullup |
lamell | 3:3e89eafb60c2 | 271 | wait_ms(delay_time); |
lamell | 3:3e89eafb60c2 | 272 | if (_parasite_power) |
lamell | 3:3e89eafb60c2 | 273 | _parasitepin = 0; |
lamell | 3:3e89eafb60c2 | 274 | } |
lamell | 3:3e89eafb60c2 | 275 | |
lamell | 3:3e89eafb60c2 | 276 | void DS1820::read_RAM() { |
lamell | 3:3e89eafb60c2 | 277 | // This will copy the DS1820's 9 bytes of RAM data |
lamell | 3:3e89eafb60c2 | 278 | // into the objects RAM array. Functions that use |
lamell | 3:3e89eafb60c2 | 279 | // RAM values will automaticly call this procedure. |
lamell | 3:3e89eafb60c2 | 280 | int i; |
lamell | 3:3e89eafb60c2 | 281 | match_Rom(); // Select this device |
lamell | 3:3e89eafb60c2 | 282 | onewire_byte_out( 0xBE); //Read Scratchpad command |
lamell | 3:3e89eafb60c2 | 283 | for(i=0;i<9;i++) { |
lamell | 3:3e89eafb60c2 | 284 | RAM[i] = onewire_byte_in(); |
lamell | 3:3e89eafb60c2 | 285 | } |
lamell | 5:31e245719610 | 286 | |
lamell | 5:31e245719610 | 287 | // for(i=0;i<9;i++) { |
lamell | 5:31e245719610 | 288 | // pc.printf("RAM[%d] = %d\r\n",i,RAM[i]); |
lamell | 5:31e245719610 | 289 | // } |
lamell | 3:3e89eafb60c2 | 290 | } |
lamell | 3:3e89eafb60c2 | 291 | |
lamell | 3:3e89eafb60c2 | 292 | bool DS1820::set_configuration_bits(unsigned int resolution) { |
lamell | 3:3e89eafb60c2 | 293 | bool answer = false; |
lamell | 3:3e89eafb60c2 | 294 | resolution = resolution - 9; |
lamell | 3:3e89eafb60c2 | 295 | if (resolution < 4) { |
lamell | 3:3e89eafb60c2 | 296 | resolution = resolution<<5; // align the bits |
lamell | 3:3e89eafb60c2 | 297 | RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new |
lamell | 3:3e89eafb60c2 | 298 | write_scratchpad ((RAM[2]<<8) + RAM[3]); |
lamell | 3:3e89eafb60c2 | 299 | // store_scratchpad (DS1820::this_device); // Need to test if this is required |
lamell | 3:3e89eafb60c2 | 300 | answer = true; |
lamell | 3:3e89eafb60c2 | 301 | } |
lamell | 3:3e89eafb60c2 | 302 | return answer; |
lamell | 3:3e89eafb60c2 | 303 | } |
lamell | 3:3e89eafb60c2 | 304 | |
lamell | 3:3e89eafb60c2 | 305 | int DS1820::read_scratchpad() { |
lamell | 3:3e89eafb60c2 | 306 | int answer; |
lamell | 3:3e89eafb60c2 | 307 | read_RAM(); |
lamell | 3:3e89eafb60c2 | 308 | answer = (RAM[2]<<8) + RAM[3]; |
lamell | 3:3e89eafb60c2 | 309 | return answer; |
lamell | 3:3e89eafb60c2 | 310 | } |
lamell | 3:3e89eafb60c2 | 311 | |
lamell | 3:3e89eafb60c2 | 312 | void DS1820::write_scratchpad(int data) { |
lamell | 3:3e89eafb60c2 | 313 | RAM[3] = data; |
lamell | 3:3e89eafb60c2 | 314 | RAM[2] = data>>8; |
lamell | 3:3e89eafb60c2 | 315 | match_Rom(); |
lamell | 3:3e89eafb60c2 | 316 | onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory |
lamell | 3:3e89eafb60c2 | 317 | onewire_byte_out(RAM[2]); // T(H) |
lamell | 3:3e89eafb60c2 | 318 | onewire_byte_out(RAM[3]); // T(L) |
lamell | 3:3e89eafb60c2 | 319 | if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) { |
lamell | 3:3e89eafb60c2 | 320 | onewire_byte_out(RAM[4]); // Configuration register |
lamell | 3:3e89eafb60c2 | 321 | } |
lamell | 3:3e89eafb60c2 | 322 | } |
lamell | 3:3e89eafb60c2 | 323 | |
lamell | 3:3e89eafb60c2 | 324 | void DS1820::store_scratchpad(devices device) { |
lamell | 3:3e89eafb60c2 | 325 | if (device==all_devices) |
lamell | 3:3e89eafb60c2 | 326 | skip_Rom(); // Skip Rom command, will store for ALL devices |
lamell | 3:3e89eafb60c2 | 327 | else |
lamell | 3:3e89eafb60c2 | 328 | match_Rom(); |
lamell | 3:3e89eafb60c2 | 329 | onewire_byte_out(0x48); // Write scratchpad into E2 command |
lamell | 3:3e89eafb60c2 | 330 | if (_parasite_power) |
lamell | 3:3e89eafb60c2 | 331 | _parasitepin=1; |
lamell | 3:3e89eafb60c2 | 332 | wait_ms(10); // Parasite power strong pullup for 10ms |
lamell | 3:3e89eafb60c2 | 333 | if (_parasite_power) |
lamell | 3:3e89eafb60c2 | 334 | _parasitepin=0; |
lamell | 3:3e89eafb60c2 | 335 | } |
lamell | 3:3e89eafb60c2 | 336 | |
lamell | 3:3e89eafb60c2 | 337 | int DS1820::recall_scratchpad(devices device) { |
lamell | 3:3e89eafb60c2 | 338 | // This copies the E2 values into the DS1820's memory. |
lamell | 3:3e89eafb60c2 | 339 | // If you specify all_devices this will return zero, otherwise |
lamell | 3:3e89eafb60c2 | 340 | // it will return the value of the scratchpad memory. |
lamell | 3:3e89eafb60c2 | 341 | int answer=0; |
lamell | 3:3e89eafb60c2 | 342 | if (device==all_devices) |
lamell | 3:3e89eafb60c2 | 343 | skip_Rom(); // Skip Rom command, will recall for ALL devices |
lamell | 3:3e89eafb60c2 | 344 | else |
lamell | 3:3e89eafb60c2 | 345 | match_Rom(); |
lamell | 3:3e89eafb60c2 | 346 | onewire_byte_out(0xB8); // Recall E2 data to scratchpad command |
lamell | 3:3e89eafb60c2 | 347 | wait_ms(10); // not sure I like polling for completion |
lamell | 3:3e89eafb60c2 | 348 | // it could cause an infinite loop |
lamell | 3:3e89eafb60c2 | 349 | if (device==DS1820::this_device) { |
lamell | 3:3e89eafb60c2 | 350 | read_RAM(); |
lamell | 3:3e89eafb60c2 | 351 | answer = read_scratchpad(); |
lamell | 3:3e89eafb60c2 | 352 | } |
lamell | 3:3e89eafb60c2 | 353 | return answer; |
lamell | 3:3e89eafb60c2 | 354 | } |
lamell | 3:3e89eafb60c2 | 355 | |
lamell | 3:3e89eafb60c2 | 356 | float DS1820::temperature(char scale) { |
lamell | 3:3e89eafb60c2 | 357 | // The data specs state that count_per_degree should be 0x10 (16), I found my devices |
lamell | 3:3e89eafb60c2 | 358 | // to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C |
lamell | 3:3e89eafb60c2 | 359 | // this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this |
lamell | 3:3e89eafb60c2 | 360 | // being super acurate, but it does allow for a smooth display in the 1/10ths of a |
lamell | 3:3e89eafb60c2 | 361 | // deg C or F scales. |
lamell | 3:3e89eafb60c2 | 362 | float answer, remaining_count, count_per_degree; |
lamell | 3:3e89eafb60c2 | 363 | int reading; |
lamell | 3:3e89eafb60c2 | 364 | read_RAM(); |
lamell | 3:3e89eafb60c2 | 365 | reading = (RAM[1] << 8) + RAM[0]; |
lamell | 3:3e89eafb60c2 | 366 | if (reading & 0x8000) { // negative degrees C |
lamell | 3:3e89eafb60c2 | 367 | reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int |
lamell | 3:3e89eafb60c2 | 368 | } |
lamell | 5:31e245719610 | 369 | |
lamell | 4:c2b93dbd6a9e | 370 | answer = reading +0.0f; // convert to floating point |
lamell | 3:3e89eafb60c2 | 371 | if ( FAMILY_CODE == FAMILY_CODE_DS18B20 ) { |
lamell | 4:c2b93dbd6a9e | 372 | answer = answer / 8.0f; |
lamell | 5:31e245719610 | 373 | //answer = (answer -256) / 10.0f; |
lamell | 5:31e245719610 | 374 | //printf("FAMILY_CODE_DS18B20 -> %d Temp: %1.1f\r\n",FAMILY_CODE, answer); |
lamell | 3:3e89eafb60c2 | 375 | } |
lamell | 3:3e89eafb60c2 | 376 | else { |
lamell | 4:c2b93dbd6a9e | 377 | remaining_count = RAM[2]; |
lamell | 4:c2b93dbd6a9e | 378 | count_per_degree = RAM[3]; |
lamell | 4:c2b93dbd6a9e | 379 | answer = answer - 0.25f + (count_per_degree - remaining_count) / count_per_degree; |
lamell | 5:31e245719610 | 380 | //printf("FAMILY_CODE_OTHER - Code: %d\r\n"),FAMILY_CODE; |
lamell | 3:3e89eafb60c2 | 381 | } |
lamell | 3:3e89eafb60c2 | 382 | if (scale=='C' or scale=='c') |
lamell | 4:c2b93dbd6a9e | 383 | answer = answer / 2.0f; |
lamell | 3:3e89eafb60c2 | 384 | else |
lamell | 3:3e89eafb60c2 | 385 | // Convert to deg F |
lamell | 4:c2b93dbd6a9e | 386 | answer = answer * 9.0f / 10.0f + 32.0f; |
lamell | 4:c2b93dbd6a9e | 387 | //return answer; |
lamell | 5:31e245719610 | 388 | return answer; |
lamell | 3:3e89eafb60c2 | 389 | } |
lamell | 3:3e89eafb60c2 | 390 | |
lamell | 3:3e89eafb60c2 | 391 | bool DS1820::read_power_supply(devices device) { |
lamell | 3:3e89eafb60c2 | 392 | // This will return true if the device (or all devices) are Vcc powered |
lamell | 3:3e89eafb60c2 | 393 | // This will return false if the device (or ANY device) is parasite powered |
lamell | 3:3e89eafb60c2 | 394 | if (device==all_devices) |
lamell | 3:3e89eafb60c2 | 395 | skip_Rom(); // Skip Rom command, will poll for any device using parasite power |
lamell | 3:3e89eafb60c2 | 396 | else |
lamell | 3:3e89eafb60c2 | 397 | match_Rom(); |
lamell | 3:3e89eafb60c2 | 398 | onewire_byte_out(0xB4); // Read power supply command |
lamell | 3:3e89eafb60c2 | 399 | return onewire_bit_in(); |
lamell | 3:3e89eafb60c2 | 400 | } |
lamell | 3:3e89eafb60c2 | 401 |