REVO / OneWire

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Fork of OneWire by Zoltan Hudak

OneWire.h@6:28e60d774095, 2017-09-09 (annotated)

Committer:
mooreaa
Date:
Sat Sep 09 09:10:49 2017 +0000
Revision:
6:28e60d774095
Parent:
0:acf75feb0947 
initial not working

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 0:acf75feb0947 7 // You can exclude certain features from OneWire. In theory, this
hudakz 0:acf75feb0947 8 // might save some space. In practice, the compiler automatically
hudakz 0:acf75feb0947 9 // removes unused code (technically, the linker, using -fdata-sections
hudakz 0:acf75feb0947 10 // and -ffunction-sections when compiling, and Wl,--gc-sections
hudakz 0:acf75feb0947 11 // when linking), so most of these will not result in any code size
hudakz 0:acf75feb0947 12 // reduction. Well, unless you try to use the missing features
hudakz 0:acf75feb0947 13 // and redesign your program to not need them! ONEWIRE_CRC8_TABLE
hudakz 0:acf75feb0947 14 // is the exception, because it selects a fast but large algorithm
hudakz 0:acf75feb0947 15 // or a small but slow algorithm.
hudakz 0:acf75feb0947 16
hudakz 0:acf75feb0947 17 // you can exclude onewire_search by defining that to 0
hudakz 0:acf75feb0947 18 #ifndef ONEWIRE_SEARCH
hudakz 0:acf75feb0947 19 #define ONEWIRE_SEARCH 1
hudakz 0:acf75feb0947 20 #endif
hudakz 0:acf75feb0947 21
hudakz 0:acf75feb0947 22 // You can exclude CRC checks altogether by defining this to 0
hudakz 0:acf75feb0947 23 #ifndef ONEWIRE_CRC
hudakz 0:acf75feb0947 24 #define ONEWIRE_CRC 1
hudakz 0:acf75feb0947 25 #endif
hudakz 0:acf75feb0947 26
hudakz 0:acf75feb0947 27 class OneWire
hudakz 0:acf75feb0947 28 {
hudakz 0:acf75feb0947 29 private:
hudakz 0:acf75feb0947 30 DigitalInOut wire;
hudakz 0:acf75feb0947 31
hudakz 0:acf75feb0947 32 #if ONEWIRE_SEARCH
hudakz 0:acf75feb0947 33 // global search state
hudakz 0:acf75feb0947 34 unsigned char ROM_NO[8];
hudakz 0:acf75feb0947 35 uint8_t LastDiscrepancy;
hudakz 0:acf75feb0947 36 uint8_t LastFamilyDiscrepancy;
hudakz 0:acf75feb0947 37 uint8_t LastDeviceFlag;
hudakz 0:acf75feb0947 38 #endif
hudakz 0:acf75feb0947 39
hudakz 0:acf75feb0947 40 public:
mooreaa 6:28e60d774095 41
mooreaa 6:28e60d774095 42 enum ONEWIRE_RESULT
mooreaa 6:28e60d774095 43 {
mooreaa 6:28e60d774095 44 ONEWIRE_OK = 0,
mooreaa 6:28e60d774095 45 ONEWIRE_NO_RESPONSE,
mooreaa 6:28e60d774095 46 ONEWIRE_ERROR,
mooreaa 6:28e60d774095 47 ONEWIRE_ERROR_SHORT_CIRCUIT
mooreaa 6:28e60d774095 48 };
mooreaa 6:28e60d774095 49
hudakz 0:acf75feb0947 50 OneWire(PinName pin);
mooreaa 6:28e60d774095 51
mooreaa 6:28e60d774095 52
mooreaa 6:28e60d774095 53
mooreaa 6:28e60d774095 54 // Perform a 1-Wire reset cycle. Returns ONEWIRE_OK if a device responds
mooreaa 6:28e60d774095 55 // with a presence pulse. Returns ONEWIRE_NO_RESPONCE if there is no device or the
mooreaa 6:28e60d774095 56 // bus is shorted or otherwise held low for more than 250uS
mooreaa 6:28e60d774095 57
mooreaa 6:28e60d774095 58 uint8_t init_sequence();
hudakz 0:acf75feb0947 59
mooreaa 6:28e60d774095 60 uint8_t reset( bool force = true );
mooreaa 6:28e60d774095 61
mooreaa 6:28e60d774095 62
mooreaa 6:28e60d774095 63
hudakz 0:acf75feb0947 64
hudakz 0:acf75feb0947 65 // Issue a 1-Wire rom select command, you do the reset first.
hudakz 0:acf75feb0947 66 void select(const uint8_t rom[8]);
hudakz 0:acf75feb0947 67
hudakz 0:acf75feb0947 68 // Issue a 1-Wire rom skip command, to address all on bus.
hudakz 0:acf75feb0947 69 void skip(void);
hudakz 0:acf75feb0947 70
hudakz 0:acf75feb0947 71 // Write a byte. If 'power' is one then the wire is held high at
hudakz 0:acf75feb0947 72 // the end for parasitically powered devices. You are responsible
hudakz 0:acf75feb0947 73 // for eventually depowering it by calling depower() or doing
hudakz 0:acf75feb0947 74 // another read or write.
hudakz 0:acf75feb0947 75 void write(uint8_t v, uint8_t power = 0);
hudakz 0:acf75feb0947 76
hudakz 0:acf75feb0947 77 void write_bytes(const uint8_t *buf, uint16_t count, bool power = 0);
hudakz 0:acf75feb0947 78
hudakz 0:acf75feb0947 79 // Read a byte.
hudakz 0:acf75feb0947 80 uint8_t read(void);
hudakz 0:acf75feb0947 81
hudakz 0:acf75feb0947 82 void read_bytes(uint8_t *buf, uint16_t count);
hudakz 0:acf75feb0947 83
hudakz 0:acf75feb0947 84 // Write a bit. The bus is always left powered at the end, see
hudakz 0:acf75feb0947 85 // note in write() about that.
hudakz 0:acf75feb0947 86 void write_bit(uint8_t v);
hudakz 0:acf75feb0947 87
hudakz 0:acf75feb0947 88 // Read a bit.
hudakz 0:acf75feb0947 89 uint8_t read_bit(void);
hudakz 0:acf75feb0947 90
hudakz 0:acf75feb0947 91 // Stop forcing power onto the bus. You only need to do this if
hudakz 0:acf75feb0947 92 // you used the 'power' flag to write() or used a write_bit() call
hudakz 0:acf75feb0947 93 // and aren't about to do another read or write. You would rather
hudakz 0:acf75feb0947 94 // not leave this powered if you don't have to, just in case
hudakz 0:acf75feb0947 95 // someone shorts your bus.
hudakz 0:acf75feb0947 96 void depower(void);
hudakz 0:acf75feb0947 97
hudakz 0:acf75feb0947 98 #if ONEWIRE_SEARCH
hudakz 0:acf75feb0947 99 // Clear the search state so that if will start from the beginning again.
hudakz 0:acf75feb0947 100 void reset_search();
hudakz 0:acf75feb0947 101
hudakz 0:acf75feb0947 102 // Setup the search to find the device type 'family_code' on the next call
hudakz 0:acf75feb0947 103 // to search(*newAddr) if it is present.
hudakz 0:acf75feb0947 104 void target_search(uint8_t family_code);
hudakz 0:acf75feb0947 105
hudakz 0:acf75feb0947 106 // Look for the next device. Returns 1 if a new address has been
hudakz 0:acf75feb0947 107 // returned. A zero might mean that the bus is shorted, there are
hudakz 0:acf75feb0947 108 // no devices, or you have already retrieved all of them. It
hudakz 0:acf75feb0947 109 // might be a good idea to check the CRC to make sure you didn't
hudakz 0:acf75feb0947 110 // get garbage. The order is deterministic. You will always get
hudakz 0:acf75feb0947 111 // the same devices in the same order.
hudakz 0:acf75feb0947 112 uint8_t search(uint8_t *newAddr);
hudakz 0:acf75feb0947 113 #endif
hudakz 0:acf75feb0947 114
hudakz 0:acf75feb0947 115 #if ONEWIRE_CRC
hudakz 0:acf75feb0947 116 // Compute a Dallas Semiconductor 8 bit CRC, these are used in the
hudakz 0:acf75feb0947 117 // ROM and scratchpad registers.
hudakz 0:acf75feb0947 118 static uint8_t crc8(const uint8_t *addr, uint8_t len);
hudakz 0:acf75feb0947 119
hudakz 0:acf75feb0947 120 #if ONEWIRE_CRC16
hudakz 0:acf75feb0947 121 // Compute the 1-Wire CRC16 and compare it against the received CRC.
hudakz 0:acf75feb0947 122 // Example usage (reading a DS2408):
hudakz 0:acf75feb0947 123 // // Put everything in a buffer so we can compute the CRC easily.
hudakz 0:acf75feb0947 124 // uint8_t buf[13];
hudakz 0:acf75feb0947 125 // buf[0] = 0xF0; // Read PIO Registers
hudakz 0:acf75feb0947 126 // buf[1] = 0x88; // LSB address
hudakz 0:acf75feb0947 127 // buf[2] = 0x00; // MSB address
hudakz 0:acf75feb0947 128 // WriteBytes(net, buf, 3); // Write 3 cmd bytes
hudakz 0:acf75feb0947 129 // ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
hudakz 0:acf75feb0947 130 // if (!CheckCRC16(buf, 11, &buf[11])) {
hudakz 0:acf75feb0947 131 // // Handle error.
hudakz 0:acf75feb0947 132 // }
hudakz 0:acf75feb0947 133 //
hudakz 0:acf75feb0947 134 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 135 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 136 // @param inverted_crc - The two CRC16 bytes in the received data.
hudakz 0:acf75feb0947 137 // This should just point into the received data,
hudakz 0:acf75feb0947 138 // *not* at a 16-bit integer.
hudakz 0:acf75feb0947 139 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 140 // @return True, iff the CRC matches.
hudakz 0:acf75feb0947 141 static bool check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc = 0);
hudakz 0:acf75feb0947 142
hudakz 0:acf75feb0947 143 // Compute a Dallas Semiconductor 16 bit CRC. This is required to check
hudakz 0:acf75feb0947 144 // the integrity of data received from many 1-Wire devices. Note that the
hudakz 0:acf75feb0947 145 // CRC computed here is *not* what you'll get from the 1-Wire network,
hudakz 0:acf75feb0947 146 // for two reasons:
hudakz 0:acf75feb0947 147 // 1) The CRC is transmitted bitwise inverted.
hudakz 0:acf75feb0947 148 // 2) Depending on the endian-ness of your processor, the binary
hudakz 0:acf75feb0947 149 // representation of the two-byte return value may have a different
hudakz 0:acf75feb0947 150 // byte order than the two bytes you get from 1-Wire.
hudakz 0:acf75feb0947 151 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 152 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 153 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 154 // @return The CRC16, as defined by Dallas Semiconductor.
hudakz 0:acf75feb0947 155 static uint16_t crc16(const uint8_t* input, uint16_t len, uint16_t crc = 0);
hudakz 0:acf75feb0947 156 #endif
hudakz 0:acf75feb0947 157 #endif
hudakz 0:acf75feb0947 158 };
hudakz 0:acf75feb0947 159
hudakz 0:acf75feb0947 160 #endif