HM Yoong
Dependents: BMS_BMUCore_Max_DummyData
DS1820.cpp@0:245af9360f0d, 2012-02-28 (annotated)
- Committer:
- yoonghm
- Date:
- Tue Feb 28 07:42:07 2012 +0000
- Revision:
- 0:245af9360f0d
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| yoonghm | 0:245af9360f0d | 1 | #include "DS1820.h" |
| yoonghm | 0:245af9360f0d | 2 | #include "mbed.h" |
| yoonghm | 0:245af9360f0d | 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]; |
| yoonghm | 0:245af9360f0d | 8 | |
| yoonghm | 0:245af9360f0d | 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; |
| yoonghm | 0:245af9360f0d | 13 | for(byte_counter=0;byte_counter<8;byte_counter++) |
| yoonghm | 0:245af9360f0d | 14 | ROM[byte_counter] = 0xFF; |
| yoonghm | 0:245af9360f0d | 15 | for(byte_counter=0;byte_counter<9;byte_counter++) |
| yoonghm | 0:245af9360f0d | 16 | RAM[byte_counter] = 0x00; |
| yoonghm | 0:245af9360f0d | 17 | } |
| yoonghm | 0:245af9360f0d | 18 | DS1820::DS1820 (PinName data_pin) : _datapin(data_pin), _parasitepin(NC) { |
| yoonghm | 0:245af9360f0d | 19 | int byte_counter; |
| yoonghm | 0:245af9360f0d | 20 | _parasite_power = false; |
| yoonghm | 0:245af9360f0d | 21 | for(byte_counter=0;byte_counter<8;byte_counter++) |
| yoonghm | 0:245af9360f0d | 22 | ROM[byte_counter] = 0xFF; |
| yoonghm | 0:245af9360f0d | 23 | for(byte_counter=0;byte_counter<9;byte_counter++) |
| yoonghm | 0:245af9360f0d | 24 | RAM[byte_counter] = 0x00; |
| yoonghm | 0:245af9360f0d | 25 | } |
| yoonghm | 0:245af9360f0d | 26 | |
| yoonghm | 0:245af9360f0d | 27 | bool DS1820::onewire_reset() { |
| yoonghm | 0:245af9360f0d | 28 | // This will return false if no devices are present on the data bus |
| yoonghm | 0:245af9360f0d | 29 | bool presence=false; |
| yoonghm | 0:245af9360f0d | 30 | _datapin.output(); |
| yoonghm | 0:245af9360f0d | 31 | _datapin = 0; // bring low for 500 us |
| yoonghm | 0:245af9360f0d | 32 | wait_us(500); |
| yoonghm | 0:245af9360f0d | 33 | _datapin.input(); // let the data line float high |
| yoonghm | 0:245af9360f0d | 34 | wait_us(90); // wait 90us |
| yoonghm | 0:245af9360f0d | 35 | if (_datapin.read()==0) // see if any devices are pulling the data line low |
| yoonghm | 0:245af9360f0d | 36 | presence=true; |
| yoonghm | 0:245af9360f0d | 37 | wait_us(410); |
| yoonghm | 0:245af9360f0d | 38 | return presence; |
| yoonghm | 0:245af9360f0d | 39 | } |
| yoonghm | 0:245af9360f0d | 40 | |
| yoonghm | 0:245af9360f0d | 41 | void DS1820::onewire_bit_out (bool bit_data) { |
| yoonghm | 0:245af9360f0d | 42 | _datapin.output(); |
| yoonghm | 0:245af9360f0d | 43 | _datapin = 0; |
| yoonghm | 0:245af9360f0d | 44 | wait_us(5); |
| yoonghm | 0:245af9360f0d | 45 | if (bit_data) { |
| yoonghm | 0:245af9360f0d | 46 | _datapin.input(); // bring data line high |
| yoonghm | 0:245af9360f0d | 47 | wait_us(55); |
| yoonghm | 0:245af9360f0d | 48 | } else { |
| yoonghm | 0:245af9360f0d | 49 | wait_us(55); // keep data line low |
| yoonghm | 0:245af9360f0d | 50 | _datapin.input(); |
| yoonghm | 0:245af9360f0d | 51 | } |
| yoonghm | 0:245af9360f0d | 52 | } |
| yoonghm | 0:245af9360f0d | 53 | |
| yoonghm | 0:245af9360f0d | 54 | void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first). |
| yoonghm | 0:245af9360f0d | 55 | int n; |
| yoonghm | 0:245af9360f0d | 56 | for (n=0; n<8; n++) { |
| yoonghm | 0:245af9360f0d | 57 | onewire_bit_out(data & 0x01); |
| yoonghm | 0:245af9360f0d | 58 | data = data >> 1; // now the next bit is in the least sig bit position. |
| yoonghm | 0:245af9360f0d | 59 | } |
| yoonghm | 0:245af9360f0d | 60 | } |
| yoonghm | 0:245af9360f0d | 61 | |
| yoonghm | 0:245af9360f0d | 62 | bool DS1820::onewire_bit_in() { |
| yoonghm | 0:245af9360f0d | 63 | bool answer; |
| yoonghm | 0:245af9360f0d | 64 | _datapin.output(); |
| yoonghm | 0:245af9360f0d | 65 | _datapin = 0; |
| yoonghm | 0:245af9360f0d | 66 | wait_us(5); |
| yoonghm | 0:245af9360f0d | 67 | _datapin.input(); |
| yoonghm | 0:245af9360f0d | 68 | wait_us(5); |
| yoonghm | 0:245af9360f0d | 69 | answer = _datapin.read(); |
| yoonghm | 0:245af9360f0d | 70 | wait_us(50); |
| yoonghm | 0:245af9360f0d | 71 | return answer; |
| yoonghm | 0:245af9360f0d | 72 | } |
| yoonghm | 0:245af9360f0d | 73 | |
| yoonghm | 0:245af9360f0d | 74 | char DS1820::onewire_byte_in() { // read byte, least sig byte first |
| yoonghm | 0:245af9360f0d | 75 | char answer = 0x00; |
| yoonghm | 0:245af9360f0d | 76 | int i; |
| yoonghm | 0:245af9360f0d | 77 | for (i=0; i<8; i++) { |
| yoonghm | 0:245af9360f0d | 78 | answer = answer >> 1; // shift over to make room for the next bit |
| yoonghm | 0:245af9360f0d | 79 | if (onewire_bit_in()) |
| yoonghm | 0:245af9360f0d | 80 | answer = answer | 0x80; // if the data port is high, make this bit a 1 |
| yoonghm | 0:245af9360f0d | 81 | } |
| yoonghm | 0:245af9360f0d | 82 | return answer; |
| yoonghm | 0:245af9360f0d | 83 | } |
| yoonghm | 0:245af9360f0d | 84 | |
| yoonghm | 0:245af9360f0d | 85 | bool DS1820::search_ROM() { |
| yoonghm | 0:245af9360f0d | 86 | return search_ROM_routine(0xF0); // Search ROM command |
| yoonghm | 0:245af9360f0d | 87 | } |
| yoonghm | 0:245af9360f0d | 88 | |
| yoonghm | 0:245af9360f0d | 89 | bool DS1820::search_alarm() { |
| yoonghm | 0:245af9360f0d | 90 | return search_ROM_routine(0xEC); // Search Alarm command |
| yoonghm | 0:245af9360f0d | 91 | } |
| yoonghm | 0:245af9360f0d | 92 | |
| yoonghm | 0:245af9360f0d | 93 | bool DS1820::search_ROM_routine(char command) { |
| yoonghm | 0:245af9360f0d | 94 | extern bool DS1820_done_flag; |
| yoonghm | 0:245af9360f0d | 95 | extern int DS1820_last_descrepancy; |
| yoonghm | 0:245af9360f0d | 96 | extern char DS1820_search_ROM[8]; |
| yoonghm | 0:245af9360f0d | 97 | int descrepancy_marker, ROM_bit_index; |
| yoonghm | 0:245af9360f0d | 98 | bool return_value, Bit_A, Bit_B; |
| yoonghm | 0:245af9360f0d | 99 | char byte_counter, bit_mask; |
| yoonghm | 0:245af9360f0d | 100 | |
| yoonghm | 0:245af9360f0d | 101 | return_value=false; |
| yoonghm | 0:245af9360f0d | 102 | if (!DS1820_done_flag) { |
| yoonghm | 0:245af9360f0d | 103 | if (!onewire_reset()) { |
| yoonghm | 0:245af9360f0d | 104 | DS1820_last_descrepancy = 0; // no devices present |
| yoonghm | 0:245af9360f0d | 105 | } else { |
| yoonghm | 0:245af9360f0d | 106 | ROM_bit_index=1; |
| yoonghm | 0:245af9360f0d | 107 | descrepancy_marker=0; |
| yoonghm | 0:245af9360f0d | 108 | onewire_byte_out(command); // Search ROM command or Search Alarm command |
| yoonghm | 0:245af9360f0d | 109 | byte_counter = 0; |
| yoonghm | 0:245af9360f0d | 110 | bit_mask = 0x01; |
| yoonghm | 0:245af9360f0d | 111 | while (ROM_bit_index<=64) { |
| yoonghm | 0:245af9360f0d | 112 | Bit_A = onewire_bit_in(); |
| yoonghm | 0:245af9360f0d | 113 | Bit_B = onewire_bit_in(); |
| yoonghm | 0:245af9360f0d | 114 | if (Bit_A & Bit_B) { |
| yoonghm | 0:245af9360f0d | 115 | descrepancy_marker = 0; // data read error, this should never happen |
| yoonghm | 0:245af9360f0d | 116 | ROM_bit_index = 0xFF; |
| yoonghm | 0:245af9360f0d | 117 | } else { |
| yoonghm | 0:245af9360f0d | 118 | if (Bit_A | Bit_B) { |
| yoonghm | 0:245af9360f0d | 119 | // Set ROM bit to Bit_A |
| yoonghm | 0:245af9360f0d | 120 | if (Bit_A) { |
| yoonghm | 0:245af9360f0d | 121 | DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one |
| yoonghm | 0:245af9360f0d | 122 | } else { |
| yoonghm | 0:245af9360f0d | 123 | DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero |
| yoonghm | 0:245af9360f0d | 124 | } |
| yoonghm | 0:245af9360f0d | 125 | } else { |
| yoonghm | 0:245af9360f0d | 126 | // both bits A and B are low, so there are two or more devices present |
| yoonghm | 0:245af9360f0d | 127 | if ( ROM_bit_index == DS1820_last_descrepancy ) { |
| yoonghm | 0:245af9360f0d | 128 | DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one |
| yoonghm | 0:245af9360f0d | 129 | } else { |
| yoonghm | 0:245af9360f0d | 130 | if ( ROM_bit_index > DS1820_last_descrepancy ) { |
| yoonghm | 0:245af9360f0d | 131 | DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero |
| yoonghm | 0:245af9360f0d | 132 | descrepancy_marker = ROM_bit_index; |
| yoonghm | 0:245af9360f0d | 133 | } else { |
| yoonghm | 0:245af9360f0d | 134 | if (( DS1820_search_ROM[byte_counter] & bit_mask) == 0x00 ) |
| yoonghm | 0:245af9360f0d | 135 | descrepancy_marker = ROM_bit_index; |
| yoonghm | 0:245af9360f0d | 136 | } |
| yoonghm | 0:245af9360f0d | 137 | } |
| yoonghm | 0:245af9360f0d | 138 | } |
| yoonghm | 0:245af9360f0d | 139 | onewire_bit_out (DS1820_search_ROM[byte_counter] & bit_mask); |
| yoonghm | 0:245af9360f0d | 140 | ROM_bit_index++; |
| yoonghm | 0:245af9360f0d | 141 | if (bit_mask & 0x80) { |
| yoonghm | 0:245af9360f0d | 142 | byte_counter++; |
| yoonghm | 0:245af9360f0d | 143 | bit_mask = 0x01; |
| yoonghm | 0:245af9360f0d | 144 | } else { |
| yoonghm | 0:245af9360f0d | 145 | bit_mask = bit_mask << 1; |
| yoonghm | 0:245af9360f0d | 146 | } |
| yoonghm | 0:245af9360f0d | 147 | } |
| yoonghm | 0:245af9360f0d | 148 | } |
| yoonghm | 0:245af9360f0d | 149 | DS1820_last_descrepancy = descrepancy_marker; |
| yoonghm | 0:245af9360f0d | 150 | if (ROM_bit_index != 0xFF) { |
| yoonghm | 0:245af9360f0d | 151 | for(byte_counter=0;byte_counter<8;byte_counter++) |
| yoonghm | 0:245af9360f0d | 152 | ROM[byte_counter] = DS1820_search_ROM[byte_counter]; |
| yoonghm | 0:245af9360f0d | 153 | return_value = true; |
| yoonghm | 0:245af9360f0d | 154 | } |
| yoonghm | 0:245af9360f0d | 155 | } |
| yoonghm | 0:245af9360f0d | 156 | if (DS1820_last_descrepancy == 0) |
| yoonghm | 0:245af9360f0d | 157 | DS1820_done_flag = true; |
| yoonghm | 0:245af9360f0d | 158 | } |
| yoonghm | 0:245af9360f0d | 159 | return return_value; |
| yoonghm | 0:245af9360f0d | 160 | } |
| yoonghm | 0:245af9360f0d | 161 | |
| yoonghm | 0:245af9360f0d | 162 | void DS1820::search_ROM_setup() { |
| yoonghm | 0:245af9360f0d | 163 | extern bool DS1820_done_flag; |
| yoonghm | 0:245af9360f0d | 164 | extern int DS1820_last_descrepancy; |
| yoonghm | 0:245af9360f0d | 165 | extern char DS1820_search_ROM[8]; |
| yoonghm | 0:245af9360f0d | 166 | DS1820_done_flag = false; |
| yoonghm | 0:245af9360f0d | 167 | DS1820_last_descrepancy = 0; |
| yoonghm | 0:245af9360f0d | 168 | int i; |
| yoonghm | 0:245af9360f0d | 169 | for (i=0; i<8; i++) |
| yoonghm | 0:245af9360f0d | 170 | DS1820_search_ROM[i]=0x00; |
| yoonghm | 0:245af9360f0d | 171 | } |
| yoonghm | 0:245af9360f0d | 172 | |
| yoonghm | 0:245af9360f0d | 173 | void DS1820::read_ROM() { |
| yoonghm | 0:245af9360f0d | 174 | // NOTE: This command can only be used when there is one DS1820 on the bus. If this command |
| yoonghm | 0:245af9360f0d | 175 | // is used when there is more than one slave present on the bus, a data collision will occur |
| yoonghm | 0:245af9360f0d | 176 | // when all the DS1820s attempt to respond at the same time. |
| yoonghm | 0:245af9360f0d | 177 | int i; |
| yoonghm | 0:245af9360f0d | 178 | onewire_reset(); |
| yoonghm | 0:245af9360f0d | 179 | onewire_byte_out(0x33); // Read ROM id |
| yoonghm | 0:245af9360f0d | 180 | for (i=0; i<8; i++) |
| yoonghm | 0:245af9360f0d | 181 | ROM[i]=onewire_byte_in(); |
| yoonghm | 0:245af9360f0d | 182 | } |
| yoonghm | 0:245af9360f0d | 183 | |
| yoonghm | 0:245af9360f0d | 184 | void DS1820::match_ROM() { |
| yoonghm | 0:245af9360f0d | 185 | // Used to select a specific device |
| yoonghm | 0:245af9360f0d | 186 | int i; |
| yoonghm | 0:245af9360f0d | 187 | onewire_reset(); |
| yoonghm | 0:245af9360f0d | 188 | onewire_byte_out( 0x55); //Match ROM command |
| yoonghm | 0:245af9360f0d | 189 | for (i=0;i<8;i++) |
| yoonghm | 0:245af9360f0d | 190 | onewire_byte_out(ROM[i]); |
| yoonghm | 0:245af9360f0d | 191 | } |
| yoonghm | 0:245af9360f0d | 192 | |
| yoonghm | 0:245af9360f0d | 193 | void DS1820::skip_ROM() { |
| yoonghm | 0:245af9360f0d | 194 | onewire_reset(); |
| yoonghm | 0:245af9360f0d | 195 | onewire_byte_out(0xCC); // Skip ROM command |
| yoonghm | 0:245af9360f0d | 196 | } |
| yoonghm | 0:245af9360f0d | 197 | |
| yoonghm | 0:245af9360f0d | 198 | bool DS1820::ROM_checksum_error() { |
| yoonghm | 0:245af9360f0d | 199 | char CRC=0x00; |
| yoonghm | 0:245af9360f0d | 200 | int i; |
| yoonghm | 0:245af9360f0d | 201 | for(i=0;i<7;i++) // Only going to shift the lower 7 bytes |
| yoonghm | 0:245af9360f0d | 202 | CRC = CRC_byte(CRC, ROM[i]); |
| yoonghm | 0:245af9360f0d | 203 | // After 7 bytes CRC should equal the 8th byte (ROM CRC) |
| yoonghm | 0:245af9360f0d | 204 | return (CRC!=ROM[7]); // will return true if there is a CRC checksum error |
| yoonghm | 0:245af9360f0d | 205 | } |
| yoonghm | 0:245af9360f0d | 206 | |
| yoonghm | 0:245af9360f0d | 207 | bool DS1820::RAM_checksum_error() { |
| yoonghm | 0:245af9360f0d | 208 | char CRC=0x00; |
| yoonghm | 0:245af9360f0d | 209 | int i; |
| yoonghm | 0:245af9360f0d | 210 | read_RAM(); |
| yoonghm | 0:245af9360f0d | 211 | for(i=0;i<8;i++) // Only going to shift the lower 8 bytes |
| yoonghm | 0:245af9360f0d | 212 | CRC = CRC_byte(CRC, RAM[i]); |
| yoonghm | 0:245af9360f0d | 213 | // After 8 bytes CRC should equal the 9th byte (RAM CRC) |
| yoonghm | 0:245af9360f0d | 214 | return (CRC!=RAM[8]); // will return true if there is a CRC checksum error |
| yoonghm | 0:245af9360f0d | 215 | } |
| yoonghm | 0:245af9360f0d | 216 | |
| yoonghm | 0:245af9360f0d | 217 | char DS1820::CRC_byte (char CRC, char byte ) { |
| yoonghm | 0:245af9360f0d | 218 | int j; |
| yoonghm | 0:245af9360f0d | 219 | for(j=0;j<8;j++) { |
| yoonghm | 0:245af9360f0d | 220 | if ((byte & 0x01 ) ^ (CRC & 0x01)) { |
| yoonghm | 0:245af9360f0d | 221 | // DATA ^ LSB CRC = 1 |
| yoonghm | 0:245af9360f0d | 222 | CRC = CRC>>1; |
| yoonghm | 0:245af9360f0d | 223 | // Set the MSB to 1 |
| yoonghm | 0:245af9360f0d | 224 | CRC = CRC | 0x80; |
| yoonghm | 0:245af9360f0d | 225 | // Check bit 3 |
| yoonghm | 0:245af9360f0d | 226 | if (CRC & 0x04) { |
| yoonghm | 0:245af9360f0d | 227 | CRC = CRC & 0xFB; // Bit 3 is set, so clear it |
| yoonghm | 0:245af9360f0d | 228 | } else { |
| yoonghm | 0:245af9360f0d | 229 | CRC = CRC | 0x04; // Bit 3 is clear, so set it |
| yoonghm | 0:245af9360f0d | 230 | } |
| yoonghm | 0:245af9360f0d | 231 | // Check bit 4 |
| yoonghm | 0:245af9360f0d | 232 | if (CRC & 0x08) { |
| yoonghm | 0:245af9360f0d | 233 | CRC = CRC & 0xF7; // Bit 4 is set, so clear it |
| yoonghm | 0:245af9360f0d | 234 | } else { |
| yoonghm | 0:245af9360f0d | 235 | CRC = CRC | 0x08; // Bit 4 is clear, so set it |
| yoonghm | 0:245af9360f0d | 236 | } |
| yoonghm | 0:245af9360f0d | 237 | } else { |
| yoonghm | 0:245af9360f0d | 238 | // DATA ^ LSB CRC = 0 |
| yoonghm | 0:245af9360f0d | 239 | CRC = CRC>>1; |
| yoonghm | 0:245af9360f0d | 240 | // clear MSB |
| yoonghm | 0:245af9360f0d | 241 | CRC = CRC & 0x7F; |
| yoonghm | 0:245af9360f0d | 242 | // No need to check bits, with DATA ^ LSB CRC = 0, they will remain unchanged |
| yoonghm | 0:245af9360f0d | 243 | } |
| yoonghm | 0:245af9360f0d | 244 | byte = byte>>1; |
| yoonghm | 0:245af9360f0d | 245 | } |
| yoonghm | 0:245af9360f0d | 246 | return CRC; |
| yoonghm | 0:245af9360f0d | 247 | } |
| yoonghm | 0:245af9360f0d | 248 | |
| yoonghm | 0:245af9360f0d | 249 | void DS1820::convert_temperature(devices device) { |
| yoonghm | 0:245af9360f0d | 250 | // Convert temperature into scratchpad RAM for all devices at once |
| yoonghm | 0:245af9360f0d | 251 | if (device==all_devices) |
| yoonghm | 0:245af9360f0d | 252 | skip_ROM(); // Skip ROM command, will convert for ALL devices |
| yoonghm | 0:245af9360f0d | 253 | else |
| yoonghm | 0:245af9360f0d | 254 | match_ROM(); |
| yoonghm | 0:245af9360f0d | 255 | onewire_byte_out( 0x44); // perform temperature conversion |
| yoonghm | 0:245af9360f0d | 256 | if (_parasite_power) |
| yoonghm | 0:245af9360f0d | 257 | _parasitepin = 1; // Parasite power strong pullup |
| yoonghm | 0:245af9360f0d | 258 | wait_ms(750); |
| yoonghm | 0:245af9360f0d | 259 | if (_parasite_power) |
| yoonghm | 0:245af9360f0d | 260 | _parasitepin = 0; |
| yoonghm | 0:245af9360f0d | 261 | } |
| yoonghm | 0:245af9360f0d | 262 | |
| yoonghm | 0:245af9360f0d | 263 | void DS1820::read_RAM() { |
| yoonghm | 0:245af9360f0d | 264 | // This will copy the DS1820's 9 bytes of RAM data |
| yoonghm | 0:245af9360f0d | 265 | // into the objects RAM array. Functions that use |
| yoonghm | 0:245af9360f0d | 266 | // RAM values will automaticly call this procedure. |
| yoonghm | 0:245af9360f0d | 267 | int i; |
| yoonghm | 0:245af9360f0d | 268 | match_ROM(); // Select this device |
| yoonghm | 0:245af9360f0d | 269 | onewire_byte_out( 0xBE); //Read Scratchpad command |
| yoonghm | 0:245af9360f0d | 270 | for(i=0;i<9;i++) { |
| yoonghm | 0:245af9360f0d | 271 | RAM[i] = onewire_byte_in(); |
| yoonghm | 0:245af9360f0d | 272 | } |
| yoonghm | 0:245af9360f0d | 273 | } |
| yoonghm | 0:245af9360f0d | 274 | |
| yoonghm | 0:245af9360f0d | 275 | int DS1820::read_scratchpad() { |
| yoonghm | 0:245af9360f0d | 276 | int answer; |
| yoonghm | 0:245af9360f0d | 277 | read_RAM(); |
| yoonghm | 0:245af9360f0d | 278 | answer = (RAM[2]<<8) + RAM[3]; |
| yoonghm | 0:245af9360f0d | 279 | return answer; |
| yoonghm | 0:245af9360f0d | 280 | } |
| yoonghm | 0:245af9360f0d | 281 | |
| yoonghm | 0:245af9360f0d | 282 | void DS1820::write_scratchpad(int data) { |
| yoonghm | 0:245af9360f0d | 283 | RAM[3] = data; |
| yoonghm | 0:245af9360f0d | 284 | RAM[2] = data>>8; |
| yoonghm | 0:245af9360f0d | 285 | match_ROM(); |
| yoonghm | 0:245af9360f0d | 286 | onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory |
| yoonghm | 0:245af9360f0d | 287 | onewire_byte_out(RAM[2]); // T(H) |
| yoonghm | 0:245af9360f0d | 288 | onewire_byte_out(RAM[3]); // T(L) |
| yoonghm | 0:245af9360f0d | 289 | } |
| yoonghm | 0:245af9360f0d | 290 | |
| yoonghm | 0:245af9360f0d | 291 | void DS1820::store_scratchpad(devices device) { |
| yoonghm | 0:245af9360f0d | 292 | if (device==all_devices) |
| yoonghm | 0:245af9360f0d | 293 | skip_ROM(); // Skip ROM command, will store for ALL devices |
| yoonghm | 0:245af9360f0d | 294 | else |
| yoonghm | 0:245af9360f0d | 295 | match_ROM(); |
| yoonghm | 0:245af9360f0d | 296 | onewire_byte_out(0x48); // Write scratchpad into E2 command |
| yoonghm | 0:245af9360f0d | 297 | if (_parasite_power) |
| yoonghm | 0:245af9360f0d | 298 | _parasitepin=1; |
| yoonghm | 0:245af9360f0d | 299 | wait_ms(10); // Parasite power strong pullup for 10ms |
| yoonghm | 0:245af9360f0d | 300 | if (_parasite_power) |
| yoonghm | 0:245af9360f0d | 301 | _parasitepin=0; |
| yoonghm | 0:245af9360f0d | 302 | } |
| yoonghm | 0:245af9360f0d | 303 | |
| yoonghm | 0:245af9360f0d | 304 | int DS1820::recall_scratchpad(devices device) { |
| yoonghm | 0:245af9360f0d | 305 | // This copies the E2 values into the DS1820's memory. |
| yoonghm | 0:245af9360f0d | 306 | // If you specify all_devices this will return zero, otherwise |
| yoonghm | 0:245af9360f0d | 307 | // it will return the value of the scratchpad memory. |
| yoonghm | 0:245af9360f0d | 308 | int answer=0; |
| yoonghm | 0:245af9360f0d | 309 | if (device==all_devices) |
| yoonghm | 0:245af9360f0d | 310 | skip_ROM(); // Skip ROM command, will recall for ALL devices |
| yoonghm | 0:245af9360f0d | 311 | else |
| yoonghm | 0:245af9360f0d | 312 | match_ROM(); |
| yoonghm | 0:245af9360f0d | 313 | onewire_byte_out(0xB8); // Recall E2 data to scratchpad command |
| yoonghm | 0:245af9360f0d | 314 | wait_ms(10); // not sure I like polling for completion |
| yoonghm | 0:245af9360f0d | 315 | // it could cause an infinite loop |
| yoonghm | 0:245af9360f0d | 316 | if (device==DS1820::this_device) { |
| yoonghm | 0:245af9360f0d | 317 | read_RAM(); |
| yoonghm | 0:245af9360f0d | 318 | answer = read_scratchpad(); |
| yoonghm | 0:245af9360f0d | 319 | } |
| yoonghm | 0:245af9360f0d | 320 | return answer; |
| yoonghm | 0:245af9360f0d | 321 | } |
| yoonghm | 0:245af9360f0d | 322 | |
| yoonghm | 0:245af9360f0d | 323 | float DS1820::temperature(char scale) { |
| yoonghm | 0:245af9360f0d | 324 | // The data specs state that count_per_degree should be 0x10 (16), I found my devices |
| yoonghm | 0:245af9360f0d | 325 | // to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C |
| yoonghm | 0:245af9360f0d | 326 | // this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this |
| yoonghm | 0:245af9360f0d | 327 | // being super acurate, but it does allow for a smooth display in the 1/10ths of a |
| yoonghm | 0:245af9360f0d | 328 | // deg C or F scales. |
| yoonghm | 0:245af9360f0d | 329 | float answer, remaining_count, count_per_degree; |
| yoonghm | 0:245af9360f0d | 330 | int reading; |
| yoonghm | 0:245af9360f0d | 331 | read_RAM(); |
| yoonghm | 0:245af9360f0d | 332 | reading = (RAM[1] << 8) + RAM[0]; |
| yoonghm | 0:245af9360f0d | 333 | if (reading & 0x8000) { // negative degrees C |
| yoonghm | 0:245af9360f0d | 334 | reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int |
| yoonghm | 0:245af9360f0d | 335 | } |
| yoonghm | 0:245af9360f0d | 336 | remaining_count = RAM[6]; |
| yoonghm | 0:245af9360f0d | 337 | count_per_degree = RAM[7]; |
| yoonghm | 0:245af9360f0d | 338 | answer = reading +0.0; |
| yoonghm | 0:245af9360f0d | 339 | answer = answer - 0.25 + (count_per_degree - remaining_count) / count_per_degree; |
| yoonghm | 0:245af9360f0d | 340 | if (scale=='C' or scale=='c') |
| yoonghm | 0:245af9360f0d | 341 | answer = answer / 2.0; |
| yoonghm | 0:245af9360f0d | 342 | else |
| yoonghm | 0:245af9360f0d | 343 | // Convert to deg F |
| yoonghm | 0:245af9360f0d | 344 | answer = answer * 9.0 / 10.0 + 32.0; |
| yoonghm | 0:245af9360f0d | 345 | return answer; |
| yoonghm | 0:245af9360f0d | 346 | } |
| yoonghm | 0:245af9360f0d | 347 | |
| yoonghm | 0:245af9360f0d | 348 | bool DS1820::read_power_supply(devices device) { |
| yoonghm | 0:245af9360f0d | 349 | // This will return true if the device (or all devices) are Vcc powered |
| yoonghm | 0:245af9360f0d | 350 | // This will return false if the device (or ANY device) is parasite powered |
| yoonghm | 0:245af9360f0d | 351 | if (device==all_devices) |
| yoonghm | 0:245af9360f0d | 352 | skip_ROM(); // Skip ROM command, will poll for any device using parasite power |
| yoonghm | 0:245af9360f0d | 353 | else |
| yoonghm | 0:245af9360f0d | 354 | match_ROM(); |
| yoonghm | 0:245af9360f0d | 355 | onewire_byte_out(0xB4); // Read power supply command |
| yoonghm | 0:245af9360f0d | 356 | return onewire_bit_in(); |
| yoonghm | 0:245af9360f0d | 357 | } |