Zoltan Hudak / OneWire

Dallas' 1-Wire bus protocol library

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

OneWire.h@16:4c3edd30ad6e, 2020-12-28 (annotated)

Committer:
hudakz
Date:
Mon Dec 28 21:13:05 2020 +0000
Revision:
16:4c3edd30ad6e
Parent:
15:7f7759008807
Child:
17:bbe8bf32e8bc
1-wire bus: Added implementation over UART

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 10:c89b9ad6097c 8 #if defined(TARGET_STM)
hudakz 16:4c3edd30ad6e 9 #define MODE() _gpio->output(); \
hudakz 16:4c3edd30ad6e 10 _gpio->mode(OpenDrain)
hudakz 16:4c3edd30ad6e 11 #define OUTPUT() // configured as output in the constructor and stays like that forever
hudakz 13:016b84669050 12 #else
hudakz 16:4c3edd30ad6e 13 #define MODE() _gpio->mode(PullUp)
hudakz 16:4c3edd30ad6e 14 #define OUTPUT() _gpio->output()
hudakz 13:016b84669050 15 #endif
hudakz 16:4c3edd30ad6e 16
hudakz 16:4c3edd30ad6e 17 #define INPUT() _gpio->input()
hudakz 16:4c3edd30ad6e 18 #define READ() _gpio->read()
hudakz 16:4c3edd30ad6e 19 #define WRITE(x) _gpio->write(x)
hudakz 10:c89b9ad6097c 20
hudakz 12:27a1b359b95c 21 #ifdef TARGET_NORDIC
hudakz 12:27a1b359b95c 22 //NORDIC targets (NRF) use software delays since their ticker uses a 32kHz clock
hudakz 12:27a1b359b95c 23 static uint32_t loops_per_us = 0;
hudakz 16:4c3edd30ad6e 24
hudakz 12:27a1b359b95c 25 #define INIT_WAIT init_soft_delay()
hudakz 12:27a1b359b95c 26 #define WAIT_US(x) for(int cnt = 0; cnt < (x * loops_per_us) >> 5; cnt++) {__NOP(); __NOP(); __NOP();}
hudakz 16:4c3edd30ad6e 27
hudakz 12:27a1b359b95c 28 void init_soft_delay( void ) {
hudakz 12:27a1b359b95c 29 if (loops_per_us == 0) {
hudakz 12:27a1b359b95c 30 loops_per_us = 1;
hudakz 16:4c3edd30ad6e 31 Timer timey;
hudakz 12:27a1b359b95c 32 timey.start();
hudakz 16:4c3edd30ad6e 33 ONEWIRE_DELAY_US(320000);
hudakz 12:27a1b359b95c 34 timey.stop();
hudakz 16:4c3edd30ad6e 35 loops_per_us = (320000 + timey.read_us() / 2) / timey.read_us();
hudakz 12:27a1b359b95c 36 }
hudakz 12:27a1b359b95c 37 }
hudakz 12:27a1b359b95c 38 #else
hudakz 12:27a1b359b95c 39 #define INIT_WAIT
hudakz 12:27a1b359b95c 40 #define WAIT_US(x) wait_us(x)
hudakz 12:27a1b359b95c 41 #endif
hudakz 12:27a1b359b95c 42
hudakz 0:acf75feb0947 43 // You can exclude certain features from OneWire. In theory, this
hudakz 0:acf75feb0947 44 // might save some space. In practice, the compiler automatically
hudakz 0:acf75feb0947 45 // removes unused code (technically, the linker, using -fdata-sections
hudakz 0:acf75feb0947 46 // and -ffunction-sections when compiling, and Wl,--gc-sections
hudakz 0:acf75feb0947 47 // when linking), so most of these will not result in any code size
hudakz 0:acf75feb0947 48 // reduction. Well, unless you try to use the missing features
hudakz 0:acf75feb0947 49 // and redesign your program to not need them! ONEWIRE_CRC8_TABLE
hudakz 0:acf75feb0947 50 // is the exception, because it selects a fast but large algorithm
hudakz 0:acf75feb0947 51 // or a small but slow algorithm.
hudakz 0:acf75feb0947 52
hudakz 0:acf75feb0947 53 // you can exclude onewire_search by defining that to 0
hudakz 0:acf75feb0947 54 #ifndef ONEWIRE_SEARCH
hudakz 0:acf75feb0947 55 #define ONEWIRE_SEARCH 1
hudakz 0:acf75feb0947 56 #endif
hudakz 0:acf75feb0947 57
hudakz 0:acf75feb0947 58 // You can exclude CRC checks altogether by defining this to 0
hudakz 0:acf75feb0947 59 #ifndef ONEWIRE_CRC
hudakz 0:acf75feb0947 60 #define ONEWIRE_CRC 1
hudakz 0:acf75feb0947 61 #endif
hudakz 0:acf75feb0947 62
hudakz 16:4c3edd30ad6e 63 class UART :
hudakz 16:4c3edd30ad6e 64 public SerialBase,
hudakz 16:4c3edd30ad6e 65 private NonCopyable<UART>
hudakz 0:acf75feb0947 66 {
hudakz 16:4c3edd30ad6e 67 UART(const UART&);
hudakz 16:4c3edd30ad6e 68 public:
hudakz 16:4c3edd30ad6e 69 UART(PinName tx, PinName rx, int baud) : SerialBase(tx, rx, baud) {}
hudakz 16:4c3edd30ad6e 70
hudakz 16:4c3edd30ad6e 71 using SerialBase::_base_getc;
hudakz 16:4c3edd30ad6e 72 using SerialBase::_base_putc;
hudakz 16:4c3edd30ad6e 73 };
hudakz 16:4c3edd30ad6e 74
hudakz 16:4c3edd30ad6e 75 class OneWire
hudakz 16:4c3edd30ad6e 76 {
hudakz 16:4c3edd30ad6e 77 DigitalInOut* _gpio;
hudakz 16:4c3edd30ad6e 78 UART* _uart;
hudakz 16:4c3edd30ad6e 79
hudakz 16:4c3edd30ad6e 80 int _samplePoint_us;
hudakz 16:4c3edd30ad6e 81 int _outToInTransition_us;
hudakz 0:acf75feb0947 82
hudakz 0:acf75feb0947 83 #if ONEWIRE_SEARCH
hudakz 0:acf75feb0947 84 // global search state
hudakz 0:acf75feb0947 85 unsigned char ROM_NO[8];
hudakz 0:acf75feb0947 86 uint8_t LastDiscrepancy;
hudakz 0:acf75feb0947 87 uint8_t LastFamilyDiscrepancy;
hudakz 0:acf75feb0947 88 uint8_t LastDeviceFlag;
hudakz 0:acf75feb0947 89 #endif
hudakz 0:acf75feb0947 90
hudakz 9:4af0015b0f47 91 public:
hudakz 16:4c3edd30ad6e 92
hudakz 16:4c3edd30ad6e 93 // Constructors
hudakz 16:4c3edd30ad6e 94 OneWire(PinName gpioPin, int samplePoint_us = 13); // GPIO
hudakz 16:4c3edd30ad6e 95 OneWire(PinName txPin, PinName rxPin, int baud = 115200); // UART
hudakz 16:4c3edd30ad6e 96
hudakz 16:4c3edd30ad6e 97 // Destructor
hudakz 16:4c3edd30ad6e 98 ~OneWire();
hudakz 0:acf75feb0947 99
hudakz 0:acf75feb0947 100 // Perform a 1-Wire reset cycle. Returns 1 if a device responds
hudakz 0:acf75feb0947 101 // with a presence pulse. Returns 0 if there is no device or the
hudakz 0:acf75feb0947 102 // bus is shorted or otherwise held low for more than 250uS
hudakz 0:acf75feb0947 103 uint8_t reset(void);
hudakz 0:acf75feb0947 104
hudakz 0:acf75feb0947 105 // Issue a 1-Wire rom select command, you do the reset first.
hudakz 0:acf75feb0947 106 void select(const uint8_t rom[8]);
hudakz 0:acf75feb0947 107
hudakz 0:acf75feb0947 108 // Issue a 1-Wire rom skip command, to address all on bus.
hudakz 0:acf75feb0947 109 void skip(void);
hudakz 0:acf75feb0947 110
hudakz 0:acf75feb0947 111 // Write a byte. If 'power' is one then the wire is held high at
hudakz 0:acf75feb0947 112 // the end for parasitically powered devices. You are responsible
hudakz 0:acf75feb0947 113 // for eventually depowering it by calling depower() or doing
hudakz 0:acf75feb0947 114 // another read or write.
hudakz 9:4af0015b0f47 115 void write_byte(uint8_t v, uint8_t power = 0);
hudakz 0:acf75feb0947 116
hudakz 0:acf75feb0947 117 void write_bytes(const uint8_t *buf, uint16_t count, bool power = 0);
hudakz 0:acf75feb0947 118
hudakz 0:acf75feb0947 119 // Read a byte.
hudakz 9:4af0015b0f47 120 uint8_t read_byte(void);
hudakz 0:acf75feb0947 121
hudakz 0:acf75feb0947 122 void read_bytes(uint8_t *buf, uint16_t count);
hudakz 0:acf75feb0947 123
hudakz 0:acf75feb0947 124 // Write a bit. The bus is always left powered at the end, see
hudakz 0:acf75feb0947 125 // note in write() about that.
hudakz 0:acf75feb0947 126 void write_bit(uint8_t v);
hudakz 0:acf75feb0947 127
hudakz 0:acf75feb0947 128 // Read a bit.
hudakz 0:acf75feb0947 129 uint8_t read_bit(void);
hudakz 0:acf75feb0947 130
hudakz 0:acf75feb0947 131 // Stop forcing power onto the bus. You only need to do this if
hudakz 0:acf75feb0947 132 // you used the 'power' flag to write() or used a write_bit() call
hudakz 0:acf75feb0947 133 // and aren't about to do another read or write. You would rather
hudakz 0:acf75feb0947 134 // not leave this powered if you don't have to, just in case
hudakz 0:acf75feb0947 135 // someone shorts your bus.
hudakz 0:acf75feb0947 136 void depower(void);
hudakz 0:acf75feb0947 137
hudakz 0:acf75feb0947 138 #if ONEWIRE_SEARCH
hudakz 0:acf75feb0947 139 // Clear the search state so that if will start from the beginning again.
hudakz 0:acf75feb0947 140 void reset_search();
hudakz 0:acf75feb0947 141
hudakz 0:acf75feb0947 142 // Setup the search to find the device type 'family_code' on the next call
hudakz 0:acf75feb0947 143 // to search(*newAddr) if it is present.
hudakz 0:acf75feb0947 144 void target_search(uint8_t family_code);
hudakz 0:acf75feb0947 145
hudakz 0:acf75feb0947 146 // Look for the next device. Returns 1 if a new address has been
hudakz 0:acf75feb0947 147 // returned. A zero might mean that the bus is shorted, there are
hudakz 0:acf75feb0947 148 // no devices, or you have already retrieved all of them. It
hudakz 0:acf75feb0947 149 // might be a good idea to check the CRC to make sure you didn't
hudakz 0:acf75feb0947 150 // get garbage. The order is deterministic. You will always get
hudakz 0:acf75feb0947 151 // the same devices in the same order.
hudakz 0:acf75feb0947 152 uint8_t search(uint8_t *newAddr);
hudakz 0:acf75feb0947 153 #endif
hudakz 0:acf75feb0947 154
hudakz 0:acf75feb0947 155 #if ONEWIRE_CRC
hudakz 0:acf75feb0947 156 // Compute a Dallas Semiconductor 8 bit CRC, these are used in the
hudakz 0:acf75feb0947 157 // ROM and scratchpad registers.
hudakz 0:acf75feb0947 158 static uint8_t crc8(const uint8_t *addr, uint8_t len);
hudakz 0:acf75feb0947 159
hudakz 0:acf75feb0947 160 #if ONEWIRE_CRC16
hudakz 0:acf75feb0947 161 // Compute the 1-Wire CRC16 and compare it against the received CRC.
hudakz 0:acf75feb0947 162 // Example usage (reading a DS2408):
hudakz 0:acf75feb0947 163 // // Put everything in a buffer so we can compute the CRC easily.
hudakz 0:acf75feb0947 164 // uint8_t buf[13];
hudakz 0:acf75feb0947 165 // buf[0] = 0xF0; // Read PIO Registers
hudakz 0:acf75feb0947 166 // buf[1] = 0x88; // LSB address
hudakz 0:acf75feb0947 167 // buf[2] = 0x00; // MSB address
hudakz 0:acf75feb0947 168 // WriteBytes(net, buf, 3); // Write 3 cmd bytes
hudakz 0:acf75feb0947 169 // ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
hudakz 0:acf75feb0947 170 // if (!CheckCRC16(buf, 11, &buf[11])) {
hudakz 0:acf75feb0947 171 // // Handle error.
hudakz 16:4c3edd30ad6e 172 // }
hudakz 16:4c3edd30ad6e 173 //
hudakz 0:acf75feb0947 174 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 175 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 176 // @param inverted_crc - The two CRC16 bytes in the received data.
hudakz 0:acf75feb0947 177 // This should just point into the received data,
hudakz 0:acf75feb0947 178 // *not* at a 16-bit integer.
hudakz 0:acf75feb0947 179 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 180 // @return True, iff the CRC matches.
hudakz 0:acf75feb0947 181 static bool check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc = 0);
hudakz 0:acf75feb0947 182
hudakz 0:acf75feb0947 183 // Compute a Dallas Semiconductor 16 bit CRC. This is required to check
hudakz 0:acf75feb0947 184 // the integrity of data received from many 1-Wire devices. Note that the
hudakz 0:acf75feb0947 185 // CRC computed here is *not* what you'll get from the 1-Wire network,
hudakz 0:acf75feb0947 186 // for two reasons:
hudakz 0:acf75feb0947 187 // 1) The CRC is transmitted bitwise inverted.
hudakz 0:acf75feb0947 188 // 2) Depending on the endian-ness of your processor, the binary
hudakz 0:acf75feb0947 189 // representation of the two-byte return value may have a different
hudakz 0:acf75feb0947 190 // byte order than the two bytes you get from 1-Wire.
hudakz 0:acf75feb0947 191 // @param input - Array of bytes to checksum.
hudakz 0:acf75feb0947 192 // @param len - How many bytes to use.
hudakz 0:acf75feb0947 193 // @param crc - The crc starting value (optional)
hudakz 0:acf75feb0947 194 // @return The CRC16, as defined by Dallas Semiconductor.
hudakz 0:acf75feb0947 195 static uint16_t crc16(const uint8_t* input, uint16_t len, uint16_t crc = 0);
hudakz 0:acf75feb0947 196 #endif
hudakz 0:acf75feb0947 197 #endif
hudakz 0:acf75feb0947 198 };
hudakz 0:acf75feb0947 199
hudakz 16:4c3edd30ad6e 200 #endif