src/main/drivers/temperature/ds18b20.c

   1 /*
   2  * This file is part of Cleanflight.
   3  *
   4  * Cleanflight is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Cleanflight is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <stdbool.h>
  19 #include <stdint.h>
  20
  21 #include "platform.h"
  22
  23 #include "build/debug.h"
  24
  25 #include "drivers/1-wire.h"
  26 #include "drivers/1-wire/ds2482.h"
  27 #include "drivers/1-wire/ds_crc.h"
  28 #include "drivers/temperature/ds18b20.h"
  29
  30
  31 #define DS18B20_FAMILY_CODE 0x28
  32
  33 #define DS18B20_ALARM_SEARCH_CMD 0xEC
  34 #define DS18B20_START_CONVERSION_CMD 0x44
  35 #define DS18B20_WRITE_SCRATCHPAD_CMD 0x4E
  36 #define DS18B20_READ_SCRATCHPAD_CMD 0xBE
  37 #define DS18B20_COPY_SCRATCHPAD_CMD 0x48
  38 #define DS18B20_RECALL_EEPROM_CMD 0xB8
  39 #define DS18B20_READ_POWER_SUPPLY_CMD 0xB4
  40
  41 #if defined(USE_1WIRE) && defined(USE_TEMPERATURE_DS18B20)
  42
  43
  44 bool ds18b20Enumerate(owDev_t *owDev, uint64_t *rom_table, uint8_t *rom_table_len)
  45 {
  46     return owDev->owSearchRom(owDev, DS18B20_FAMILY_CODE, rom_table, rom_table_len);
  47 }
  48
  49 bool ds18b20Configure(owDev_t *owDev, uint64_t rom, uint8_t config)
  50 {
  51     bool ack = owDev->owMatchRom(owDev, rom);
  52     if (!ack) return false;
  53
  54     uint8_t buf[4] = { DS18B20_WRITE_SCRATCHPAD_CMD, 0, 0, config };
  55     return owDev->owWriteBuf(owDev, buf, sizeof(buf));
  56 }
  57
  58 static bool readPowerSupply(owDev_t *owDev, bool *result)
  59 {
  60     bool ack = owDev->owWriteByte(owDev, DS18B20_READ_POWER_SUPPLY_CMD);
  61     if (!ack) return false;
  62
  63     bool sbr;
  64     ack = owDev->owSingleBit(owDev, OW_SINGLE_BIT_WRITE1_READ, &sbr);
  65     if (!ack) return false;
  66
  67     *result = !sbr;
  68     return true;
  69 }
  70
  71 bool ds18b20ParasiticPoweredPresent(owDev_t *owDev, bool *result)
  72 {
  73     bool ack = owDev->owSkipRom(owDev);
  74     if (!ack) return false;
  75
  76     return readPowerSupply(owDev, result);
  77 }
  78
  79 bool ds18b20ReadPowerSupply(owDev_t *owDev, uint64_t rom, bool *parasiticPowered)
  80 {
  81     bool ack = owDev->owMatchRom(owDev, rom);
  82     if (!ack) return false;
  83
  84     return readPowerSupply(owDev, parasiticPowered);
  85 }
  86
  87 bool ds18b20ReadScratchpadCommand(owDev_t *owDev)
  88 {
  89     return owDev->owWriteByteCommand(owDev, DS18B20_READ_SCRATCHPAD_CMD);
  90 }
  91
  92 static bool ds18b20ReadScratchpadBuf(owDev_t *owDev, uint8_t *buf, uint8_t len)
  93 {
  94     bool ack = ds18b20ReadScratchpadCommand(owDev);
  95     if (!ack) return false;
  96     ack = owDev->waitForBus(owDev);
  97     if (!ack) return false;
  98     return owDev->owReadBuf(owDev, buf, len);
  99 }
 100
 101 bool ds18b20StartConversionCommand(owDev_t *owDev)
 102 {
 103     return owDev->owWriteByteCommand(owDev, DS18B20_START_CONVERSION_CMD);
 104 }
 105
 106 // start conversion on all devices present on the bus
 107 // note: parasitic power only supports one device converting at a time
 108 bool ds18b20StartConversion(owDev_t *owDev)
 109 {
 110     bool ack = owDev->owSkipRom(owDev);
 111     if (!ack) return false;
 112     return ds18b20StartConversionCommand(owDev);
 113 }
 114
 115 bool ds18b20WaitForConversion(owDev_t *owDev)
 116 {
 117     bool ack = owDev->waitForBus(owDev);
 118     if (!ack) return false;
 119
 120     bool read_bit;
 121     do {
 122         ack = owDev->owSingleBit(owDev, OW_SINGLE_BIT_WRITE1_READ, &read_bit);
 123         if (!ack) return false;
 124     } while (!read_bit);
 125
 126     return true;
 127 }
 128
 129 bool ds18b20ReadTemperatureFromScratchPadBuf(const uint8_t *buf, int16_t *temperature)
 130 {
 131     if (buf[8] != ds_crc8(buf, 8)) return false;
 132     *temperature = (int16_t)(((buf[0] | (buf[1] << 8)) >> 3) | ((buf[1] & 0x80) ? 0xE000 : 0)) * 5;
 133     return true;
 134 }
 135
 136 bool ds18b20ReadTemperature(owDev_t *owDev, uint64_t rom, int16_t *temperature)
 137 {
 138     bool ack = owDev->owMatchRom(owDev, rom);
 139     if (!ack) return false;
 140
 141     uint8_t buf[9];
 142     ack = ds18b20ReadScratchpadBuf(owDev, buf, 9);
 143     if (!ack) return false;
 144
 145     return ds18b20ReadTemperatureFromScratchPadBuf(buf, temperature);
 146 }
 147
 148 #endif /* defined(USE_1WIRE) && defined(USE_TEMPERATURE_DS18B20) */