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- //onewire.h
- #ifndef OneWire_h
- #define OneWire_h
- #include <inttypes.h>
- // you can exclude onewire_search by defining that to 0
- #ifndef ONEWIRE_SEARCH
- #define ONEWIRE_SEARCH 1
- #endif
- // You can exclude CRC checks altogether by defining this to 0
- #ifndef ONEWIRE_CRC
- #define ONEWIRE_CRC 1
- #endif
- // You can allow 16-bit CRC checks by defining this to 1
- // (Note that ONEWIRE_CRC must also be 1.)
- #ifndef ONEWIRE_CRC16
- #define ONEWIRE_CRC16 1
- #endif
- #define FALSE 0
- #define TRUE 1
- class OneWire
- {
- private:
- uint16_t _pin;
- void DIRECT_WRITE_LOW(void);
- void DIRECT_MODE_OUTPUT(void);
- void DIRECT_WRITE_HIGH(void);
- void DIRECT_MODE_INPUT(void);
- uint8_t DIRECT_READ(void);
- #if ONEWIRE_SEARCH
- // global search state
- unsigned char ROM_NO[8];
- uint8_t LastDiscrepancy;
- uint8_t LastFamilyDiscrepancy;
- uint8_t LastDeviceFlag;
- #endif
- public:
- OneWire( uint16_t pin);
- // Perform a 1-Wire reset cycle. Returns 1 if a device responds
- // with a presence pulse. Returns 0 if there is no device or the
- // bus is shorted or otherwise held low for more than 250uS
- uint8_t reset(void);
- // Issue a 1-Wire rom select command, you do the reset first.
- void select(const uint8_t rom[8]);
- // Issue a 1-Wire rom skip command, to address all on bus.
- void skip(void);
- // Write a byte. If 'power' is one then the wire is held high at
- // the end for parasitically powered devices. You are responsible
- // for eventually depowering it by calling depower() or doing
- // another read or write.
- void write(uint8_t v, uint8_t power = 0);
- void write_bytes(const uint8_t *buf, uint16_t count, bool power = 0);
- // Read a byte.
- uint8_t read(void);
- void read_bytes(uint8_t *buf, uint16_t count);
- // Write a bit. The bus is always left powered at the end, see
- // note in write() about that.
- void write_bit(uint8_t v);
- // Read a bit.
- uint8_t read_bit(void);
- // Stop forcing power onto the bus. You only need to do this if
- // you used the 'power' flag to write() or used a write_bit() call
- // and aren't about to do another read or write. You would rather
- // not leave this powered if you don't have to, just in case
- // someone shorts your bus.
- void depower(void);
- #if ONEWIRE_SEARCH
- // Clear the search state so that if will start from the beginning again.
- void reset_search();
- // Setup the search to find the device type 'family_code' on the next call
- // to search(*newAddr) if it is present.
- void target_search(uint8_t family_code);
- // Look for the next device. Returns 1 if a new address has been
- // returned. A zero might mean that the bus is shorted, there are
- // no devices, or you have already retrieved all of them. It
- // might be a good idea to check the CRC to make sure you didn't
- // get garbage. The order is deterministic. You will always get
- // the same devices in the same order.
- uint8_t search(uint8_t *newAddr);
- #endif
- #if ONEWIRE_CRC
- // Compute a Dallas Semiconductor 8 bit CRC, these are used in the
- // ROM and scratchpad registers.
- static uint8_t crc8(uint8_t *addr, uint8_t len);
- #if ONEWIRE_CRC16
- // Compute the 1-Wire CRC16 and compare it against the received CRC.
- // Example usage (reading a DS2408):
- // // Put everything in a buffer so we can compute the CRC easily.
- // uint8_t buf[13];
- // buf[0] = 0xF0; // Read PIO Registers
- // buf[1] = 0x88; // LSB address
- // buf[2] = 0x00; // MSB address
- // WriteBytes(net, buf, 3); // Write 3 cmd bytes
- // ReadBytes(net, buf+3, 10); // Read 6 data bytes, 2 0xFF, 2 CRC16
- // if (!CheckCRC16(buf, 11, &buf[11])) {
- // // Handle error.
- // }
- //
- // @param input - Array of bytes to checksum.
- // @param len - How many bytes to use.
- // @param inverted_crc - The two CRC16 bytes in the received data.
- // This should just point into the received data,
- // *not* at a 16-bit integer.
- // @param crc - The crc starting value (optional)
- // @return True, iff the CRC matches.
- static bool check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc = 0);
- // Compute a Dallas Semiconductor 16 bit CRC. This is required to check
- // the integrity of data received from many 1-Wire devices. Note that the
- // CRC computed here is *not* what you'll get from the 1-Wire network,
- // for two reasons:
- // 1) The CRC is transmitted bitwise inverted.
- // 2) Depending on the endian-ness of your processor, the binary
- // representation of the two-byte return value may have a different
- // byte order than the two bytes you get from 1-Wire.
- // @param input - Array of bytes to checksum.
- // @param len - How many bytes to use.
- // @param crc - The crc starting value (optional)
- // @return The CRC16, as defined by Dallas Semiconductor.
- static uint16_t crc16(const uint8_t* input, uint16_t len, uint16_t crc = 0);
- #endif
- #endif
- };
- #endif
- OneWire::OneWire(uint16_t pin)
- {
- pinMode(pin, INPUT);
- _pin = pin;
- }
- void OneWire::DIRECT_WRITE_LOW(void)
- {
- PIN_MAP[_pin].gpio_peripheral->BRR = PIN_MAP[_pin].gpio_pin;
- }
- void OneWire::DIRECT_MODE_OUTPUT(void)
- {
- GPIO_TypeDef *gpio_port = PIN_MAP[_pin].gpio_peripheral;
- uint16_t gpio_pin = PIN_MAP[_pin].gpio_pin;
- GPIO_InitTypeDef GPIO_InitStructure;
- if (gpio_port == GPIOA )
- {
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
- }
- else if (gpio_port == GPIOB )
- {
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
- }
- GPIO_InitStructure.GPIO_Pin = gpio_pin;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- PIN_MAP[_pin].pin_mode = OUTPUT;
- GPIO_Init(gpio_port, &GPIO_InitStructure);
- }
- void OneWire::DIRECT_WRITE_HIGH(void)
- {
- PIN_MAP[_pin].gpio_peripheral->BSRR = PIN_MAP[_pin].gpio_pin;
- }
- void OneWire::DIRECT_MODE_INPUT(void)
- {
- GPIO_TypeDef *gpio_port = PIN_MAP[_pin].gpio_peripheral;
- uint16_t gpio_pin = PIN_MAP[_pin].gpio_pin;
- GPIO_InitTypeDef GPIO_InitStructure;
- if (gpio_port == GPIOA )
- {
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
- }
- else if (gpio_port == GPIOB )
- {
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
- }
- GPIO_InitStructure.GPIO_Pin = gpio_pin;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
- PIN_MAP[_pin].pin_mode = INPUT;
- GPIO_Init(gpio_port, &GPIO_InitStructure);
- }
- uint8_t OneWire::DIRECT_READ(void)
- {
- return GPIO_ReadInputDataBit(PIN_MAP[_pin].gpio_peripheral, PIN_MAP[_pin].gpio_pin);
- }
- // Perform the onewire reset function. We will wait up to 250uS for
- // the bus to come high, if it doesn't then it is broken or shorted
- // and we return a 0;
- //
- // Returns 1 if a device asserted a presence pulse, 0 otherwise.
- //
- uint8_t OneWire::reset(void)
- {
- uint8_t r;
- uint8_t retries = 125;
- noInterrupts();
- DIRECT_MODE_INPUT();
- interrupts();
- // wait until the wire is high... just in case
- do {
- if (--retries == 0) return 0;
- delayMicroseconds(2);
- } while ( !DIRECT_READ());
- noInterrupts();
- DIRECT_WRITE_LOW();
- DIRECT_MODE_OUTPUT(); // drive output low
- interrupts();
- delayMicroseconds(480);
- noInterrupts();
- DIRECT_MODE_INPUT(); // allow it to float
- delayMicroseconds(70);
- r = !DIRECT_READ();
- interrupts();
- delayMicroseconds(410);
- return r;
- }
- void OneWire::write_bit(uint8_t v)
- {
- if (v & 1) {
- noInterrupts();
- DIRECT_WRITE_LOW();
- DIRECT_MODE_OUTPUT(); // drive output low
- delayMicroseconds(10);
- DIRECT_WRITE_HIGH(); // drive output high
- interrupts();
- delayMicroseconds(55);
- } else {
- noInterrupts();
- DIRECT_WRITE_LOW();
- DIRECT_MODE_OUTPUT(); // drive output low
- delayMicroseconds(65);
- DIRECT_WRITE_HIGH(); // drive output high
- interrupts();
- delayMicroseconds(5);
- }
- }
- //
- // Read a bit. Port and bit is used to cut lookup time and provide
- // more certain timing.
- //
- uint8_t OneWire::read_bit(void)
- {
- uint8_t r;
- noInterrupts();
- DIRECT_MODE_OUTPUT();
- DIRECT_WRITE_LOW();
- delayMicroseconds(3);
- DIRECT_MODE_INPUT(); // let pin float, pull up will raise
- delayMicroseconds(10);
- r = DIRECT_READ();
- interrupts();
- delayMicroseconds(53);
- return r;
- }
- //
- // Write a byte. The writing code uses the active drivers to raise the
- // pin high, if you need power after the write (e.g. DS18S20 in
- // parasite power mode) then set 'power' to 1, otherwise the pin will
- // go tri-state at the end of the write to avoid heating in a short or
- // other mishap.
- //
- void OneWire::write(uint8_t v, uint8_t power /* = 0 */) {
- uint8_t bitMask;
- for (bitMask = 0x01; bitMask; bitMask <<= 1) {
- OneWire::write_bit( (bitMask & v)?1:0);
- }
- if ( !power) {
- noInterrupts();
- DIRECT_MODE_INPUT();
- DIRECT_WRITE_LOW();
- interrupts();
- }
- }
- void OneWire::write_bytes(const uint8_t *buf, uint16_t count, bool power /* = 0 */) {
- for (uint16_t i = 0 ; i < count ; i++)
- write(buf[i]);
- if (!power) {
- noInterrupts();
- DIRECT_MODE_INPUT();
- DIRECT_WRITE_LOW();
- interrupts();
- }
- }
- //
- // Read a byte
- //
- uint8_t OneWire::read() {
- uint8_t bitMask;
- uint8_t r = 0;
- for (bitMask = 0x01; bitMask; bitMask <<= 1) {
- if ( OneWire::read_bit()) r |= bitMask;
- }
- return r;
- }
- void OneWire::read_bytes(uint8_t *buf, uint16_t count) {
- for (uint16_t i = 0 ; i < count ; i++)
- buf[i] = read();
- }
- //
- // Do a ROM select
- //
- void OneWire::select(const uint8_t rom[8])
- {
- uint8_t i;
- write(0x55); // Choose ROM
- for (i = 0; i < 8; i++) write(rom[i]);
- }
- //
- // Do a ROM skip
- //
- void OneWire::skip()
- {
- write(0xCC); // Skip ROM
- }
- void OneWire::depower()
- {
- noInterrupts();
- DIRECT_MODE_INPUT();
- interrupts();
- }
- #if ONEWIRE_SEARCH
- //
- // You need to use this function to start a search again from the beginning.
- // You do not need to do it for the first search, though you could.
- //
- void OneWire::reset_search()
- {
- // reset the search state
- LastDiscrepancy = 0;
- LastDeviceFlag = FALSE;
- LastFamilyDiscrepancy = 0;
- for(int i = 7; ; i--) {
- ROM_NO[i] = 0;
- if ( i == 0) break;
- }
- }
- // Setup the search to find the device type 'family_code' on the next call
- // to search(*newAddr) if it is present.
- //
- void OneWire::target_search(uint8_t family_code)
- {
- // set the search state to find SearchFamily type devices
- ROM_NO[0] = family_code;
- for (uint8_t i = 1; i < 8; i++)
- ROM_NO[i] = 0;
- LastDiscrepancy = 64;
- LastFamilyDiscrepancy = 0;
- LastDeviceFlag = FALSE;
- }
- //
- // Perform a search. If this function returns a '1' then it has
- // enumerated the next device and you may retrieve the ROM from the
- // OneWire::address variable. If there are no devices, no further
- // devices, or something horrible happens in the middle of the
- // enumeration then a 0 is returned. If a new device is found then
- // its address is copied to newAddr. Use OneWire::reset_search() to
- // start over.
- //
- // --- Replaced by the one from the Dallas Semiconductor web site ---
- //--------------------------------------------------------------------------
- // Perform the 1-Wire Search Algorithm on the 1-Wire bus using the existing
- // search state.
- // Return TRUE : device found, ROM number in ROM_NO buffer
- // FALSE : device not found, end of search
- //
- uint8_t OneWire::search(uint8_t *newAddr)
- {
- uint8_t id_bit_number;
- uint8_t last_zero, rom_byte_number, search_result;
- uint8_t id_bit, cmp_id_bit;
- unsigned char rom_byte_mask, search_direction;
- // initialize for search
- id_bit_number = 1;
- last_zero = 0;
- rom_byte_number = 0;
- rom_byte_mask = 1;
- search_result = 0;
- // if the last call was not the last one
- if (!LastDeviceFlag)
- {
- // 1-Wire reset
- if (!reset())
- {
- // reset the search
- LastDiscrepancy = 0;
- LastDeviceFlag = FALSE;
- LastFamilyDiscrepancy = 0;
- return FALSE;
- }
- // issue the search command
- write(0xF0);
- // loop to do the search
- do
- {
- // read a bit and its complement
- id_bit = read_bit();
- cmp_id_bit = read_bit();
- // check for no devices on 1-wire
- if ((id_bit == 1) && (cmp_id_bit == 1))
- break;
- else
- {
- // all devices coupled have 0 or 1
- if (id_bit != cmp_id_bit)
- search_direction = id_bit; // bit write value for search
- else
- {
- // if this discrepancy if before the Last Discrepancy
- // on a previous next then pick the same as last time
- if (id_bit_number < LastDiscrepancy)
- search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
- else
- // if equal to last pick 1, if not then pick 0
- search_direction = (id_bit_number == LastDiscrepancy);
- // if 0 was picked then record its position in LastZero
- if (search_direction == 0)
- {
- last_zero = id_bit_number;
- // check for Last discrepancy in family
- if (last_zero < 9)
- LastFamilyDiscrepancy = last_zero;
- }
- }
- // set or clear the bit in the ROM byte rom_byte_number
- // with mask rom_byte_mask
- if (search_direction == 1)
- ROM_NO[rom_byte_number] |= rom_byte_mask;
- else
- ROM_NO[rom_byte_number] &= ~rom_byte_mask;
- // serial number search direction write bit
- write_bit(search_direction);
- // increment the byte counter id_bit_number
- // and shift the mask rom_byte_mask
- id_bit_number++;
- rom_byte_mask <<= 1;
- // if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
- if (rom_byte_mask == 0)
- {
- rom_byte_number++;
- rom_byte_mask = 1;
- }
- }
- }
- while(rom_byte_number < 8); // loop until through all ROM bytes 0-7
- // if the search was successful then
- if (!(id_bit_number < 65))
- {
- // search successful so set LastDiscrepancy,LastDeviceFlag,search_result
- LastDiscrepancy = last_zero;
- // check for last device
- if (LastDiscrepancy == 0)
- LastDeviceFlag = TRUE;
- search_result = TRUE;
- }
- }
- // if no device found then reset counters so next 'search' will be like a first
- if (!search_result || !ROM_NO[0])
- {
- LastDiscrepancy = 0;
- LastDeviceFlag = FALSE;
- LastFamilyDiscrepancy = 0;
- search_result = FALSE;
- }
- for (int i = 0; i < 8; i++) newAddr[i] = ROM_NO[i];
- return search_result;
- }
- #endif
- #if ONEWIRE_CRC
- // The 1-Wire CRC scheme is described in Maxim Application Note 27:
- // "Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products"
- //
- //
- // Compute a Dallas Semiconductor 8 bit CRC directly.
- // this is much slower, but much smaller, than the lookup table.
- //
- uint8_t OneWire::crc8( uint8_t *addr, uint8_t len)
- {
- uint8_t crc = 0;
- while (len--) {
- uint8_t inbyte = *addr++;
- for (uint8_t i = 8; i; i--) {
- uint8_t mix = (crc ^ inbyte) & 0x01;
- crc >>= 1;
- if (mix) crc ^= 0x8C;
- inbyte >>= 1;
- }
- }
- return crc;
- }
- #endif
- #if ONEWIRE_CRC16
- bool OneWire::check_crc16(const uint8_t* input, uint16_t len, const uint8_t* inverted_crc, uint16_t crc)
- {
- crc = ~crc16(input, len, crc);
- return (crc & 0xFF) == inverted_crc[0] && (crc >> 8) == inverted_crc[1];
- }
- uint16_t OneWire::crc16(const uint8_t* input, uint16_t len, uint16_t crc)
- {
- static const uint8_t oddparity[16] =
- { 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0 };
- for (uint16_t i = 0 ; i < len ; i++) {
- // Even though we're just copying a byte from the input,
- // we'll be doing 16-bit computation with it.
- uint16_t cdata = input[i];
- cdata = (cdata ^ crc) & 0xff;
- crc >>= 8;
- if (oddparity[cdata & 0x0F] ^ oddparity[cdata >> 4])
- crc ^= 0xC001;
- cdata <<= 6;
- crc ^= cdata;
- cdata <<= 1;
- crc ^= cdata;
- }
- return crc;
- }
- #endif
- OneWire ds = OneWire(D3); // on pin 10 (a 4.7K resistor is necessary)
- void setup() {
- Serial1.begin(9600);
- }
- void loop() {
- byte i;
- byte present = 0;
- byte type_s;
- byte data[12];
- byte addr[8];
- float celsius, fahrenheit;
- if ( !ds.search(addr)) {
- Serial1.println("No more addresses.");
- Serial1.println();
- ds.reset_search();
- delay(250);
- return;
- }
- Serial1.print("ROM =");
- for( i = 0; i < 8; i++) {
- Serial1.write(' ');
- Serial1.print(addr[i], HEX);
- }
- if (OneWire::crc8(addr, 7) != addr[7]) {
- Serial1.println("CRC is not valid!");
- return;
- }
- Serial1.println();
- // the first ROM byte indicates which chip
- switch (addr[0]) {
- case 0x10:
- Serial.println(" Chip = DS18S20"); // or old DS1820
- type_s = 1;
- break;
- case 0x28:
- Serial1.println(" Chip = DS18B20");
- type_s = 0;
- break;
- case 0x22:
- Serial1.println(" Chip = DS1822");
- type_s = 0;
- break;
- default:
- Serial1.println("Device is not a DS18x20 family device.");
- return;
- }
- ds.reset();
- ds.select(addr);
- ds.write(0x44, 1); // start conversion, with parasite power on at the end
- delay(1000); // maybe 750ms is enough, maybe not
- // we might do a ds.depower() here, but the reset will take care of it.
- present = ds.reset();
- ds.select(addr);
- ds.write(0xBE); // Read Scratchpad
- Serial1.print(" Data = ");
- Serial1.print(present, HEX);
- Serial1.print(" ");
- for ( i = 0; i < 9; i++) { // we need 9 bytes
- data[i] = ds.read();
- Serial1.print(data[i], HEX);
- Serial1.print(" ");
- }
- Serial1.print(" CRC=");
- Serial1.print(OneWire::crc8(data, 8), HEX);
- Serial1.println();
- // Convert the data to actual temperature
- // because the result is a 16 bit signed integer, it should
- // be stored to an "int16_t" type, which is always 16 bits
- // even when compiled on a 32 bit processor.
- int16_t raw = (data[1] << 8) | data[0];
- if (type_s) {
- raw = raw << 3; // 9 bit resolution default
- if (data[7] == 0x10) {
- // "count remain" gives full 12 bit resolution
- raw = (raw & 0xFFF0) + 12 - data[6];
- }
- } else {
- byte cfg = (data[4] & 0x60);
- // at lower res, the low bits are undefined, so let's zero them
- if (cfg == 0x00) raw = raw & ~7; // 9 bit resolution, 93.75 ms
- else if (cfg == 0x20) raw = raw & ~3; // 10 bit res, 187.5 ms
- else if (cfg == 0x40) raw = raw & ~1; // 11 bit res, 375 ms
- //// default is 12 bit resolution, 750 ms conversion time
- }
- celsius = (float)raw / 16.0;
- fahrenheit = celsius * 1.8 + 32.0;
- Serial1.print(" Temperature = ");
- Serial1.print(celsius);
- Serial1.print(" Celsius, ");
- Serial1.print(fahrenheit);
- Serial1.println(" Fahrenheit");
- }
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