Subversion Repositories idreammicro-arduino

#ifndef OneWire_h

#define OneWire_h

#include <inttypes.h>

#if ARDUINO >= 100

#include "Arduino.h"       // for delayMicroseconds, digitalPinToBitMask, etc

#else

#include "WProgram.h"      // for delayMicroseconds

#include "pins_arduino.h"  // for digitalPinToBitMask, etc

#endif

// You can exclude certain features from OneWire.  In theory, this

// might save some space.  In practice, the compiler automatically

// removes unused code (technically, the linker, using -fdata-sections

// and -ffunction-sections when compiling, and Wl,--gc-sections

// when linking), so most of these will not result in any code size

// reduction.  Well, unless you try to use the missing features

// and redesign your program to not need them!  ONEWIRE_CRC8_TABLE

// is the exception, because it selects a fast but large algorithm

// or a small but slow algorithm.

// 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

// Select the table-lookup method of computing the 8-bit CRC

// by setting this to 1.  The lookup table enlarges code size by

// about 250 bytes.  It does NOT consume RAM (but did in very

// old versions of OneWire).  If you disable this, a slower

// but very compact algorithm is used.

#ifndef ONEWIRE_CRC8_TABLE

#define ONEWIRE_CRC8_TABLE 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

// Platform specific I/O definitions

#if defined(__AVR__)

#define PIN_TO_BASEREG(pin)             (portInputRegister(digitalPinToPort(pin)))

#define PIN_TO_BITMASK(pin)             (digitalPinToBitMask(pin))

#define IO_REG_TYPE uint8_t

#define IO_REG_ASM asm("r30")

#define DIRECT_READ(base, mask)         (((*(base)) & (mask)) ? 1 : 0)

#define DIRECT_MODE_INPUT(base, mask)   ((*(base+1)) &= ~(mask))

#define DIRECT_MODE_OUTPUT(base, mask)  ((*(base+1)) |= (mask))

#define DIRECT_WRITE_LOW(base, mask)    ((*(base+2)) &= ~(mask))

#define DIRECT_WRITE_HIGH(base, mask)   ((*(base+2)) |= (mask))

#elif defined(__PIC32MX__)

#include <plib.h>  // is this necessary?

#define PIN_TO_BASEREG(pin)             (portModeRegister(digitalPinToPort(pin)))

#define PIN_TO_BITMASK(pin)             (digitalPinToBitMask(pin))

#define IO_REG_TYPE uint32_t

#define IO_REG_ASM

#define DIRECT_READ(base, mask)         (((*(base+4)) & (mask)) ? 1 : 0)  //PORTX + 0x10

#define DIRECT_MODE_INPUT(base, mask)   ((*(base+2)) = (mask))            //TRISXSET + 0x08

#define DIRECT_MODE_OUTPUT(base, mask)  ((*(base+1)) = (mask))            //TRISXCLR + 0x04

#define DIRECT_WRITE_LOW(base, mask)    ((*(base+8+1)) = (mask))          //LATXCLR  + 0x24

#define DIRECT_WRITE_HIGH(base, mask)   ((*(base+8+2)) = (mask))          //LATXSET + 0x28

#else

#error "Please define I/O register types here"

#endif

class OneWire

{

  private:

    IO_REG_TYPE bitmask;

    volatile IO_REG_TYPE *baseReg;

#if ONEWIRE_SEARCH

    // global search state

    unsigned char ROM_NO[8];

    uint8_t LastDiscrepancy;

    uint8_t LastFamilyDiscrepancy;

    uint8_t LastDeviceFlag;

#endif

  public:

    OneWire( 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[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();

    // 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.

    // @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);

#endif

#endif

};

#endif