Documentation Arduino base program code
Dp1WBasic Arduino library provide function for gething data form 1-Wire bus.
Most part of code come from original OneWire library http://www.arduino.cc/playground/Learning/OneWire !
Source code is provided as is, without any warranty.
Distributetd under CC BY v 3.0
#define NORMAL_SEARCH 0xF0 #define ALARM_SEARCH 0xEC Dp1WBasic( uint8_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( uint8_t rom); // 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); // Clear the search state so that if will start from the beginning again. void reset_search(); // 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, byte searchType = NORMAL_SEARCH); // 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); // Compute the 1-Wire CRC16 and compare it against the received CRC. // // @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. // @return True, iff the CRC matches. static bool check_crc16(uint8_t* input, uint16_t len, uint8_t* inverted_crc); // 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. // @return The CRC16, as defined by Dallas Semiconductor. static uint16_t crc16(uint8_t* input, uint16_t len);
Author: Dubravko Penezic