Zoltan Hudak / OneWire

Dallas' 1-Wire bus protocol library

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

OneWire.h@17:bbe8bf32e8bc, 2020-12-29 (annotated)

Committer:
hudakz
Date:
Tue Dec 29 16:06:46 2020 +0000
Revision:
17:bbe8bf32e8bc
Parent:
16:4c3edd30ad6e 
1-wre bus: Modified.

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 16:4c3edd30ad6e 6 #include "SerialBase.h"
hudakz 0:acf75feb0947 7
hudakz 17:bbe8bf32e8bc 8 #define MODE() _gpio->mode(PullUp)
hudakz 17:bbe8bf32e8bc 9 #define INPUT() _gpio->input()
hudakz 17:bbe8bf32e8bc 10 #define OUTPUT() _gpio->output()
hudakz 17:bbe8bf32e8bc 11 #define READ() _gpio->read()
hudakz 17:bbe8bf32e8bc 12 #define WRITE(x) _gpio->write(x)
hudakz 10:c89b9ad6097c 13
hudakz 12:27a1b359b95c 14 #ifdef TARGET_NORDIC
hudakz 12:27a1b359b95c 15 //NORDIC targets (NRF) use software delays since their ticker uses a 32kHz clock
hudakz 12:27a1b359b95c 16 static uint32_t loops_per_us = 0;
hudakz 16:4c3edd30ad6e 17
hudakz 12:27a1b359b95c 18 #define INIT_WAIT init_soft_delay()
hudakz 12:27a1b359b95c 19 #define WAIT_US(x) for(int cnt = 0; cnt < (x * loops_per_us) >> 5; cnt++) {__NOP(); __NOP(); __NOP();}
hudakz 16:4c3edd30ad6e 20
hudakz 12:27a1b359b95c 21 void init_soft_delay( void ) {
hudakz 12:27a1b359b95c 22 if (loops_per_us == 0) {
hudakz 12:27a1b359b95c 23 loops_per_us = 1;
hudakz 16:4c3edd30ad6e 24 Timer timey;
hudakz 12:27a1b359b95c 25 timey.start();
hudakz 16:4c3edd30ad6e 26 ONEWIRE_DELAY_US(320000);
hudakz 12:27a1b359b95c 27 timey.stop();
hudakz 16:4c3edd30ad6e 28 loops_per_us = (320000 + timey.read_us() / 2) / timey.read_us();
hudakz 12:27a1b359b95c 29 }
hudakz 12:27a1b359b95c 30 }
hudakz 12:27a1b359b95c 31 #else
hudakz 12:27a1b359b95c 32 #define INIT_WAIT
hudakz 12:27a1b359b95c 33 #define WAIT_US(x) wait_us(x)
hudakz 12:27a1b359b95c 34 #endif
hudakz 12:27a1b359b95c 35
hudakz 0:acf75feb0947 36 // You can exclude certain features from OneWire. In theory, this
hudakz 0:acf75feb0947 37 // might save some space. In practice, the compiler automatically
hudakz 0:acf75feb0947 38 // removes unused code (technically, the linker, using -fdata-sections
hudakz 0:acf75feb0947 39 // and -ffunction-sections when compiling, and Wl,--gc-sections
hudakz 0:acf75feb0947 40 // when linking), so most of these will not result in any code size
hudakz 0:acf75feb0947 41 // reduction. Well, unless you try to use the missing features
hudakz 0:acf75feb0947 42 // and redesign your program to not need them! ONEWIRE_CRC8_TABLE
hudakz 0:acf75feb0947 43 // is the exception, because it selects a fast but large algorithm
hudakz 0:acf75feb0947 44 // or a small but slow algorithm.
hudakz 0:acf75feb0947 45
hudakz 0:acf75feb0947 46 // you can exclude onewire_search by defining that to 0
hudakz 0:acf75feb0947 47 #ifndef ONEWIRE_SEARCH
hudakz 0:acf75feb0947 48 #define ONEWIRE_SEARCH 1
hudakz 0:acf75feb0947 49 #endif
hudakz 0:acf75feb0947 50
hudakz 0:acf75feb0947 51 // You can exclude CRC checks altogether by defining this to 0
hudakz 0:acf75feb0947 52 #ifndef ONEWIRE_CRC
hudakz 0:acf75feb0947 53 #define ONEWIRE_CRC 1
hudakz 0:acf75feb0947 54 #endif
hudakz 0:acf75feb0947 55
hudakz 16:4c3edd30ad6e 56 class UART :
hudakz 16:4c3edd30ad6e 57 public SerialBase,
hudakz 16:4c3edd30ad6e 58 private NonCopyable<UART>
hudakz 0:acf75feb0947 59 {
hudakz 16:4c3edd30ad6e 60 UART(const UART&);
hudakz 16:4c3edd30ad6e 61 public:
hudakz 16:4c3edd30ad6e 62 UART(PinName tx, PinName rx, int baud) : SerialBase(tx, rx, baud) {}
hudakz 16:4c3edd30ad6e 63
hudakz 16:4c3edd30ad6e 64 using SerialBase::_base_getc;
hudakz 16:4c3edd30ad6e 65 using SerialBase::_base_putc;
hudakz 16:4c3edd30ad6e 66 };
hudakz 16:4c3edd30ad6e 67
hudakz 16:4c3edd30ad6e 68 class OneWire
hudakz 16:4c3edd30ad6e 69 {
hudakz 16:4c3edd30ad6e 70 DigitalInOut* _gpio;
hudakz 16:4c3edd30ad6e 71 UART* _uart;
hudakz 16:4c3edd30ad6e 72
hudakz 16:4c3edd30ad6e 73 int _samplePoint_us;
hudakz 16:4c3edd30ad6e 74 int _outToInTransition_us;
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 16:4c3edd30ad6e 85
hudakz 16:4c3edd30ad6e 86 // Constructors
hudakz 16:4c3edd30ad6e 87 OneWire(PinName gpioPin, int samplePoint_us = 13); // GPIO
hudakz 16:4c3edd30ad6e 88 OneWire(PinName txPin, PinName rxPin, int baud = 115200); // UART
hudakz 16:4c3edd30ad6e 89
hudakz 16:4c3edd30ad6e 90 // Destructor
hudakz 16:4c3edd30ad6e 91 ~OneWire();
hudakz 0:acf75feb0947 92
hudakz 0:acf75feb0947 93 // Perform a 1-Wire reset cycle. Returns 1 if a device responds
hudakz 0:acf75feb0947 94 // with a presence pulse. Returns 0 if there is no device or the
hudakz 0:acf75feb0947 95 // bus is shorted or otherwise held low for more than 250uS
hudakz 0:acf75feb0947 96 uint8_t reset(void);
hudakz 0:acf75feb0947 97
hudakz 0:acf75feb0947 98 // Issue a 1-Wire rom select command, you do the reset first.
hudakz 0:acf75feb0947 99 void select(const uint8_t rom[8]);
hudakz 0:acf75feb0947 100
hudakz 0:acf75feb0947 101 // Issue a 1-Wire rom skip command, to address all on bus.
hudakz 0:acf75feb0947 102 void skip(void);
hudakz 0:acf75feb0947 103
hudakz 0:acf75feb0947 104 // Write a byte. If 'power' is one then the wire is held high at
hudakz 0:acf75feb0947 105 // the end for parasitically powered devices. You are responsible
hudakz 0:acf75feb0947 106 // for eventually depowering it by calling depower() or doing
hudakz 0:acf75feb0947 107 // another read or write.
hudakz 9:4af0015b0f47 108 void write_byte(uint8_t v, uint8_t power = 0);
hudakz 0:acf75feb0947 109
hudakz 0:acf75feb0947 110 void write_bytes(const uint8_t *buf, uint16_t count, bool power = 0);
hudakz 0:acf75feb0947 111
hudakz 0:acf75feb0947 112 // Read a byte.
hudakz 9:4af0015b0f47 113 uint8_t read_byte(void);
hudakz 0:acf75feb0947 114
hudakz 0:acf75feb0947 115 void read_bytes(uint8_t *buf, uint16_t count);
hudakz 0:acf75feb0947 116
hudakz 0:acf75feb0947 117 // Write a bit. The bus is always left powered at the end, see
hudakz 0:acf75feb0947 118 // note in write() about that.
hudakz 0:acf75feb0947 119 void write_bit(uint8_t v);
hudakz 0:acf75feb0947 120
hudakz 0:acf75feb0947 121 // Read a bit.
hudakz 0:acf75feb0947 122 uint8_t read_bit(void);
hudakz 0:acf75feb0947 123
hudakz 0:acf75feb0947 124 // Stop forcing power onto the bus. You only need to do this if
hudakz 0:acf75feb0947 125 // you used the 'power' flag to write() or used a write_bit() call
hudakz 0:acf75feb0947 126 // and aren't about to do another read or write. You would rather
hudakz 0:acf75feb0947 127 // not leave this powered if you don't have to, just in case
hudakz 0:acf75feb0947 128 // someone shorts your bus.
hudakz 0:acf75feb0947 129 void depower(void);
hudakz 0:acf75feb0947 130
hudakz 0:acf75feb0947 131 #if ONEWIRE_SEARCH
hudakz 0:acf75feb0947 132 // Clear the search state so that if will start from the beginning again.
hudakz 0:acf75feb0947 133 void reset_search();
hudakz 0:acf75feb0947 134
hudakz 0:acf75feb0947 135 // Setup the search to find the device type 'family_code' on the next call
hudakz 0:acf75feb0947 136 // to search(*newAddr) if it is present.
hudakz 0:acf75feb0947 137 void target_search(uint8_t family_code);
hudakz 0:acf75feb0947 138
hudakz 0:acf75feb0947 139 // Look for the next device. Returns 1 if a new address has been
hudakz 0:acf75feb0947 140 // returned. A zero might mean that the bus is shorted, there are
hudakz 0:acf75feb0947 141 // no devices, or you have already retrieved all of them. It
hudakz 0:acf75feb0947 142 // might be a good idea to check the CRC to make sure you didn't
hudakz 0:acf75feb0947 143 // get garbage. The order is deterministic. You will always get
hudakz 0:acf75feb0947 144 // the same devices in the same order.
hudakz 0:acf75feb0947 145 uint8_t search(uint8_t *newAddr);
hudakz 0:acf75feb0947 146 #endif
hudakz 0:acf75feb0947 147
hudakz 0:acf75feb0947 148 #if ONEWIRE_CRC
hudakz 0:acf75feb0947 149 // Compute a Dallas Semiconductor 8 bit CRC, these are used in the
hudakz 0:acf75feb0947 150 // ROM and scratchpad registers.
hudakz 0:acf75feb0947 151 static uint8_t crc8(const uint8_t *addr, uint8_t len);
hudakz 0:acf75feb0947 152
hudakz 0:acf75feb0947 153 #if ONEWIRE_CRC16
hudakz 0:acf75feb0947 154 // Compute the 1-Wire CRC16 and compare it against the received CRC.
hudakz 0:acf75feb0947 155 // Example usage (reading a DS2408):
hudakz 0:acf75feb0947 156 // // Put everything in a buffer so we can compute the CRC easily.
hudakz 0:acf75feb0947 157 // uint8_t buf[13];
hudakz 0:acf75feb0947 158 // buf[0] = 0xF0; // Read PIO Registers
hudakz 0:acf75feb0947 159 // buf[1] = 0x88; // LSB address
hudakz 0:acf75feb0947 160 // buf[2] = 0x00; // MSB address
hudakz 0:acf75feb0947 161 // WriteBytes(net, buf, 3); // Write 3 cmd bytes
hudakz 0:acf75feb0947 162 // ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
hudakz 0:acf75feb0947 163 // if (!CheckCRC16(buf, 11, &buf[11])) {
hudakz 0:acf75feb0947 164 // // Handle error.
hudakz 16:4c3edd30ad6e 165 // }
hudakz 16:4c3edd30ad6e 166 //
hudakz 0:acf75feb0947 167 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 168 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 169 // @param inverted_crc - The two CRC16 bytes in the received data.
hudakz 0:acf75feb0947 170 // This should just point into the received data,
hudakz 0:acf75feb0947 171 // *not* at a 16-bit integer.
hudakz 0:acf75feb0947 172 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 173 // @return True, iff the CRC matches.
hudakz 0:acf75feb0947 174 static bool check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc = 0);
hudakz 0:acf75feb0947 175
hudakz 0:acf75feb0947 176 // Compute a Dallas Semiconductor 16 bit CRC. This is required to check
hudakz 0:acf75feb0947 177 // the integrity of data received from many 1-Wire devices. Note that the
hudakz 0:acf75feb0947 178 // CRC computed here is *not* what you'll get from the 1-Wire network,
hudakz 0:acf75feb0947 179 // for two reasons:
hudakz 0:acf75feb0947 180 // 1) The CRC is transmitted bitwise inverted.
hudakz 0:acf75feb0947 181 // 2) Depending on the endian-ness of your processor, the binary
hudakz 0:acf75feb0947 182 // representation of the two-byte return value may have a different
hudakz 0:acf75feb0947 183 // byte order than the two bytes you get from 1-Wire.
hudakz 0:acf75feb0947 184 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 185 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 186 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 187 // @return The CRC16, as defined by Dallas Semiconductor.
hudakz 0:acf75feb0947 188 static uint16_t crc16(const uint8_t* input, uint16_t len, uint16_t crc = 0);
hudakz 0:acf75feb0947 189 #endif
hudakz 0:acf75feb0947 190 #endif
hudakz 0:acf75feb0947 191 };
hudakz 0:acf75feb0947 192
hudakz 17:bbe8bf32e8bc 193 #endif
hudakz 17:bbe8bf32e8bc 194
hudakz 17:bbe8bf32e8bc 195