Zoltan Hudak / OneWire

Dallas' 1-Wire bus protocol library

Dependents:   DS1825 DISCO-F746-Dessiccateur-V1 watersenor_and_temp_code DS1820 ... more

OneWire.h@13:016b84669050, 2019-04-04 (annotated)

Committer:
hudakz
Date:
Thu Apr 04 20:46:58 2019 +0000
Revision:
13:016b84669050
Parent:
12:27a1b359b95c
Child:
15:7f7759008807
Improved performance for the STM32L072 targets.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 0:acf75feb0947 1 #ifndef OneWire_h
hudakz 0:acf75feb0947 2 #define OneWire_h
hudakz 0:acf75feb0947 3
hudakz 0:acf75feb0947 4 #include <inttypes.h>
hudakz 0:acf75feb0947 5 #include <mbed.h>
hudakz 0:acf75feb0947 6
hudakz 10:c89b9ad6097c 7 #if defined(TARGET_STM)
hudakz 12:27a1b359b95c 8 #define MODE() output(); \
hudakz 12:27a1b359b95c 9 mode(OpenDrain)
hudakz 13:016b84669050 10 #define OUTPUT() // configured as output in the constructor and stays like that forever
hudakz 13:016b84669050 11 #if defined(TARGET_STM32L072xx)
hudakz 13:016b84669050 12 #define PORT ((GPIO_TypeDef *)(GPIOA_BASE + 0x0400 * STM_PORT(gpio.pin)))
hudakz 13:016b84669050 13 #define PINMASK (1 << STM_PIN(gpio.pin))
hudakz 13:016b84669050 14 #define INPUT() (PORT->MODER &= ~(GPIO_MODER_MODE0_0 << (STM_PIN(gpio.pin) * 2)))
hudakz 13:016b84669050 15 #define READ() ((PORT->IDR & gpio.mask) != 0)
hudakz 13:016b84669050 16 #define WRITE(x) (x == 1 ? PORT->BSRR = PINMASK : PORT->BRR = PINMASK)
hudakz 13:016b84669050 17 #else
hudakz 10:c89b9ad6097c 18 #define INPUT() (*gpio.reg_set = gpio.mask) // write 1 to open drain
hudakz 11:bc8ed7280966 19 #define READ() ((*gpio.reg_in & gpio.mask) != 0)
hudakz 10:c89b9ad6097c 20 #define WRITE(x) write(x)
hudakz 13:016b84669050 21 #endif
hudakz 10:c89b9ad6097c 22 #else
hudakz 10:c89b9ad6097c 23 #define MODE() mode(PullUp)
hudakz 10:c89b9ad6097c 24 #define INPUT() input()
hudakz 10:c89b9ad6097c 25 #define OUTPUT() output()
hudakz 10:c89b9ad6097c 26 #define READ() read()
hudakz 10:c89b9ad6097c 27 #define WRITE(x) write(x)
hudakz 10:c89b9ad6097c 28 #endif
hudakz 10:c89b9ad6097c 29
hudakz 12:27a1b359b95c 30 #ifdef TARGET_NORDIC
hudakz 12:27a1b359b95c 31 //NORDIC targets (NRF) use software delays since their ticker uses a 32kHz clock
hudakz 12:27a1b359b95c 32 static uint32_t loops_per_us = 0;
hudakz 12:27a1b359b95c 33
hudakz 12:27a1b359b95c 34 #define INIT_WAIT init_soft_delay()
hudakz 12:27a1b359b95c 35 #define WAIT_US(x) for(int cnt = 0; cnt < (x * loops_per_us) >> 5; cnt++) {__NOP(); __NOP(); __NOP();}
hudakz 12:27a1b359b95c 36
hudakz 12:27a1b359b95c 37 void init_soft_delay( void ) {
hudakz 12:27a1b359b95c 38 if (loops_per_us == 0) {
hudakz 12:27a1b359b95c 39 loops_per_us = 1;
hudakz 12:27a1b359b95c 40 Timer timey;
hudakz 12:27a1b359b95c 41 timey.start();
hudakz 12:27a1b359b95c 42 ONEWIRE_DELAY_US(320000);
hudakz 12:27a1b359b95c 43 timey.stop();
hudakz 12:27a1b359b95c 44 loops_per_us = (320000 + timey.read_us() / 2) / timey.read_us();
hudakz 12:27a1b359b95c 45 }
hudakz 12:27a1b359b95c 46 }
hudakz 12:27a1b359b95c 47 #else
hudakz 12:27a1b359b95c 48 #define INIT_WAIT
hudakz 12:27a1b359b95c 49 #define WAIT_US(x) wait_us(x)
hudakz 12:27a1b359b95c 50 #endif
hudakz 12:27a1b359b95c 51
hudakz 0:acf75feb0947 52 // You can exclude certain features from OneWire. In theory, this
hudakz 0:acf75feb0947 53 // might save some space. In practice, the compiler automatically
hudakz 0:acf75feb0947 54 // removes unused code (technically, the linker, using -fdata-sections
hudakz 0:acf75feb0947 55 // and -ffunction-sections when compiling, and Wl,--gc-sections
hudakz 0:acf75feb0947 56 // when linking), so most of these will not result in any code size
hudakz 0:acf75feb0947 57 // reduction. Well, unless you try to use the missing features
hudakz 0:acf75feb0947 58 // and redesign your program to not need them! ONEWIRE_CRC8_TABLE
hudakz 0:acf75feb0947 59 // is the exception, because it selects a fast but large algorithm
hudakz 0:acf75feb0947 60 // or a small but slow algorithm.
hudakz 0:acf75feb0947 61
hudakz 0:acf75feb0947 62 // you can exclude onewire_search by defining that to 0
hudakz 0:acf75feb0947 63 #ifndef ONEWIRE_SEARCH
hudakz 0:acf75feb0947 64 #define ONEWIRE_SEARCH 1
hudakz 0:acf75feb0947 65 #endif
hudakz 0:acf75feb0947 66
hudakz 0:acf75feb0947 67 // You can exclude CRC checks altogether by defining this to 0
hudakz 0:acf75feb0947 68 #ifndef ONEWIRE_CRC
hudakz 0:acf75feb0947 69 #define ONEWIRE_CRC 1
hudakz 0:acf75feb0947 70 #endif
hudakz 0:acf75feb0947 71
hudakz 9:4af0015b0f47 72 class OneWire : public DigitalInOut
hudakz 0:acf75feb0947 73 {
hudakz 9:4af0015b0f47 74 Timer timer;
hudakz 0:acf75feb0947 75
hudakz 0:acf75feb0947 76 #if ONEWIRE_SEARCH
hudakz 0:acf75feb0947 77 // global search state
hudakz 0:acf75feb0947 78 unsigned char ROM_NO[8];
hudakz 0:acf75feb0947 79 uint8_t LastDiscrepancy;
hudakz 0:acf75feb0947 80 uint8_t LastFamilyDiscrepancy;
hudakz 0:acf75feb0947 81 uint8_t LastDeviceFlag;
hudakz 0:acf75feb0947 82 #endif
hudakz 0:acf75feb0947 83
hudakz 9:4af0015b0f47 84 public:
hudakz 0:acf75feb0947 85 OneWire(PinName pin);
hudakz 0:acf75feb0947 86
hudakz 0:acf75feb0947 87 // Perform a 1-Wire reset cycle. Returns 1 if a device responds
hudakz 0:acf75feb0947 88 // with a presence pulse. Returns 0 if there is no device or the
hudakz 0:acf75feb0947 89 // bus is shorted or otherwise held low for more than 250uS
hudakz 0:acf75feb0947 90 uint8_t reset(void);
hudakz 0:acf75feb0947 91
hudakz 0:acf75feb0947 92 // Issue a 1-Wire rom select command, you do the reset first.
hudakz 0:acf75feb0947 93 void select(const uint8_t rom[8]);
hudakz 0:acf75feb0947 94
hudakz 0:acf75feb0947 95 // Issue a 1-Wire rom skip command, to address all on bus.
hudakz 0:acf75feb0947 96 void skip(void);
hudakz 0:acf75feb0947 97
hudakz 0:acf75feb0947 98 // Write a byte. If 'power' is one then the wire is held high at
hudakz 0:acf75feb0947 99 // the end for parasitically powered devices. You are responsible
hudakz 0:acf75feb0947 100 // for eventually depowering it by calling depower() or doing
hudakz 0:acf75feb0947 101 // another read or write.
hudakz 9:4af0015b0f47 102 void write_byte(uint8_t v, uint8_t power = 0);
hudakz 0:acf75feb0947 103
hudakz 0:acf75feb0947 104 void write_bytes(const uint8_t *buf, uint16_t count, bool power = 0);
hudakz 0:acf75feb0947 105
hudakz 0:acf75feb0947 106 // Read a byte.
hudakz 9:4af0015b0f47 107 uint8_t read_byte(void);
hudakz 0:acf75feb0947 108
hudakz 0:acf75feb0947 109 void read_bytes(uint8_t *buf, uint16_t count);
hudakz 0:acf75feb0947 110
hudakz 0:acf75feb0947 111 // Write a bit. The bus is always left powered at the end, see
hudakz 0:acf75feb0947 112 // note in write() about that.
hudakz 0:acf75feb0947 113 void write_bit(uint8_t v);
hudakz 0:acf75feb0947 114
hudakz 0:acf75feb0947 115 // Read a bit.
hudakz 0:acf75feb0947 116 uint8_t read_bit(void);
hudakz 0:acf75feb0947 117
hudakz 0:acf75feb0947 118 // Stop forcing power onto the bus. You only need to do this if
hudakz 0:acf75feb0947 119 // you used the 'power' flag to write() or used a write_bit() call
hudakz 0:acf75feb0947 120 // and aren't about to do another read or write. You would rather
hudakz 0:acf75feb0947 121 // not leave this powered if you don't have to, just in case
hudakz 0:acf75feb0947 122 // someone shorts your bus.
hudakz 0:acf75feb0947 123 void depower(void);
hudakz 0:acf75feb0947 124
hudakz 0:acf75feb0947 125 #if ONEWIRE_SEARCH
hudakz 0:acf75feb0947 126 // Clear the search state so that if will start from the beginning again.
hudakz 0:acf75feb0947 127 void reset_search();
hudakz 0:acf75feb0947 128
hudakz 0:acf75feb0947 129 // Setup the search to find the device type 'family_code' on the next call
hudakz 0:acf75feb0947 130 // to search(*newAddr) if it is present.
hudakz 0:acf75feb0947 131 void target_search(uint8_t family_code);
hudakz 0:acf75feb0947 132
hudakz 0:acf75feb0947 133 // Look for the next device. Returns 1 if a new address has been
hudakz 0:acf75feb0947 134 // returned. A zero might mean that the bus is shorted, there are
hudakz 0:acf75feb0947 135 // no devices, or you have already retrieved all of them. It
hudakz 0:acf75feb0947 136 // might be a good idea to check the CRC to make sure you didn't
hudakz 0:acf75feb0947 137 // get garbage. The order is deterministic. You will always get
hudakz 0:acf75feb0947 138 // the same devices in the same order.
hudakz 0:acf75feb0947 139 uint8_t search(uint8_t *newAddr);
hudakz 0:acf75feb0947 140 #endif
hudakz 0:acf75feb0947 141
hudakz 0:acf75feb0947 142 #if ONEWIRE_CRC
hudakz 0:acf75feb0947 143 // Compute a Dallas Semiconductor 8 bit CRC, these are used in the
hudakz 0:acf75feb0947 144 // ROM and scratchpad registers.
hudakz 0:acf75feb0947 145 static uint8_t crc8(const uint8_t *addr, uint8_t len);
hudakz 0:acf75feb0947 146
hudakz 0:acf75feb0947 147 #if ONEWIRE_CRC16
hudakz 0:acf75feb0947 148 // Compute the 1-Wire CRC16 and compare it against the received CRC.
hudakz 0:acf75feb0947 149 // Example usage (reading a DS2408):
hudakz 0:acf75feb0947 150 // // Put everything in a buffer so we can compute the CRC easily.
hudakz 0:acf75feb0947 151 // uint8_t buf[13];
hudakz 0:acf75feb0947 152 // buf[0] = 0xF0; // Read PIO Registers
hudakz 0:acf75feb0947 153 // buf[1] = 0x88; // LSB address
hudakz 0:acf75feb0947 154 // buf[2] = 0x00; // MSB address
hudakz 0:acf75feb0947 155 // WriteBytes(net, buf, 3); // Write 3 cmd bytes
hudakz 0:acf75feb0947 156 // ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
hudakz 0:acf75feb0947 157 // if (!CheckCRC16(buf, 11, &buf[11])) {
hudakz 0:acf75feb0947 158 // // Handle error.
hudakz 0:acf75feb0947 159 // }
hudakz 0:acf75feb0947 160 //
hudakz 0:acf75feb0947 161 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 162 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 163 // @param inverted_crc - The two CRC16 bytes in the received data.
hudakz 0:acf75feb0947 164 // This should just point into the received data,
hudakz 0:acf75feb0947 165 // *not* at a 16-bit integer.
hudakz 0:acf75feb0947 166 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 167 // @return True, iff the CRC matches.
hudakz 0:acf75feb0947 168 static bool check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc = 0);
hudakz 0:acf75feb0947 169
hudakz 0:acf75feb0947 170 // Compute a Dallas Semiconductor 16 bit CRC. This is required to check
hudakz 0:acf75feb0947 171 // the integrity of data received from many 1-Wire devices. Note that the
hudakz 0:acf75feb0947 172 // CRC computed here is *not* what you'll get from the 1-Wire network,
hudakz 0:acf75feb0947 173 // for two reasons:
hudakz 0:acf75feb0947 174 // 1) The CRC is transmitted bitwise inverted.
hudakz 0:acf75feb0947 175 // 2) Depending on the endian-ness of your processor, the binary
hudakz 0:acf75feb0947 176 // representation of the two-byte return value may have a different
hudakz 0:acf75feb0947 177 // byte order than the two bytes you get from 1-Wire.
hudakz 0:acf75feb0947 178 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 179 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 180 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 181 // @return The CRC16, as defined by Dallas Semiconductor.
hudakz 0:acf75feb0947 182 static uint16_t crc16(const uint8_t* input, uint16_t len, uint16_t crc = 0);
hudakz 0:acf75feb0947 183 #endif
hudakz 0:acf75feb0947 184 #endif
hudakz 0:acf75feb0947 185 };
hudakz 0:acf75feb0947 186
hudakz 0:acf75feb0947 187 #endif
hudakz 12:27a1b359b95c 188
hudakz 12:27a1b359b95c 189