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File content as of revision 6:1faafa0b3cd7:

/******************************************************************//**
* @file ds248x.cpp
*
* @author Justin Jordan
*
* @version 0.0.0
*
* Started: 30JAN16
*
* Updated: 
*
* @brief Source file for Ds248x I2C to 1-wire master 
***********************************************************************
* Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Except as contained in this notice, the name of Maxim Integrated
* Products, Inc. shall not be used except as stated in the Maxim Integrated
* Products, Inc. Branding Policy.
*
* The mere transfer of this software does not imply any licenses
* of trade secrets, proprietary technology, copyrights, patents,
* trademarks, maskwork rights, or any other form of intellectual
* property whatsoever. Maxim Integrated Products, Inc. retains all
* ownership rights.
**********************************************************************/


#include "ds248x.h"


//*********************************************************************
Ds248x::Ds248x(I2C &i2c_bus, DS248X_I2C_ADRS adrs)
:_p_i2c_bus(&i2c_bus), _i2c_owner(false)
{
    set_i2c_adrs(adrs);
}


//*********************************************************************
Ds248x::Ds248x(PinName sda, PinName scl, DS248X_I2C_ADRS adrs)
:_p_i2c_bus(new I2C(sda, scl)), _i2c_owner(true)
{
    set_i2c_adrs(adrs);
}


//*********************************************************************
Ds248x::~Ds248x()
{
    if(_i2c_owner)
    {
        delete _p_i2c_bus;
    }
}


//*********************************************************************
bool Ds248x::detect(void)
{
    bool rtn_val = false;
    
    // reset the ds2484 ON selected address
    if (!reset())
    {
        rtn_val = false;
    }
    else
    {
        // default configuration
        _c1WS = false;
        _cSPU = false;
        _cPDN = false;
        _cAPU = false;
        
        // write the default configuration setup
        if (!write_config(_c1WS | _cSPU | _cPDN | _cAPU))
        {
            rtn_val = false;
        }
        else
        {
            rtn_val = true;
        }
    }
    
    return(rtn_val);
}


//*********************************************************************
bool Ds248x::reset(void)
{
    char status;
    char packet[] = {CMD_DRST};
    
    // Device Reset
    //   S AD,0 [A] DRST [A] Sr AD,1 [A] [SS] A\ P
    //  [] indicates from slave
    //  SS status byte to read to verify state
    
    _p_i2c_bus->write(_w_adrs, packet, 1);
    _p_i2c_bus->read(_r_adrs, &status, 1);
    
    return((status & 0xF7) == 0x10);   
}


//*********************************************************************
bool Ds248x::write_config(uint8_t config)
{
    bool rtn_val = false;
    char read_config;
    char packet [] = {CMD_WCFG, (config | (~config << 4))};
    
    _p_i2c_bus->write(_w_adrs, packet, 2);
    _p_i2c_bus->read(_r_adrs, &read_config, 1);
    
    // check for failure due to incorrect read back
    if (config != read_config)
    {
        // handle error
        // ...
        reset();
        rtn_val = false;
    }
    else
    {
        rtn_val = true;
    }
    
    return(rtn_val);
}


//*********************************************************************
bool Ds248x::channel_select(uint8_t channel)
{
    
    char ch, ch_read, check;
    char packet [2];
    
    packet[0] = CMD_CHSL;
    
    // Channel Select (Case A)
    //   S AD,0 [A] CHSL [A] CC [A] Sr AD,1 [A] [RR] A\ P
    //  [] indicates from slave
    //  CC channel value
    //  RR channel read back
    
    switch (channel)
    {
      default: case 0: ch = 0xF0; ch_read = 0xB8; break;
      case 1: ch = 0xE1; ch_read = 0xB1; break;
      case 2: ch = 0xD2; ch_read = 0xAA; break;
      case 3: ch = 0xC3; ch_read = 0xA3; break;
      case 4: ch = 0xB4; ch_read = 0x9C; break;
      case 5: ch = 0xA5; ch_read = 0x95; break;
      case 6: ch = 0x96; ch_read = 0x8E; break;
      case 7: ch = 0x87; ch_read = 0x87; break;
    };
    
    packet[1] = ch;
    
    _p_i2c_bus->write(_w_adrs, packet, 2);
    _p_i2c_bus->read(_r_adrs, &check, 1);
    
    // check for failure due to incorrect read back of channel
    return (check == ch_read);
}


//*********************************************************************
bool Ds248x::adjust_timing(uint8_t param, uint8_t val)
{
    bool rtn_val = false;
    char read_port_config;
    char control_byte;

    control_byte = (((param & 0x0F) << 4) | (val & 0x0F));

    char packet [] = {CMD_A1WP, control_byte};

    _p_i2c_bus->write(_w_adrs, packet, 2);
    _p_i2c_bus->read(_r_adrs, &read_port_config, 1);

    // check for failure due to incorrect read back
    if ((control_byte & 0x0F) != read_port_config) 
    {
        // handle error
        // ...
        reset();

        rtn_val = false;
    } 
    else 
    {
        rtn_val = true;
    }

    return(rtn_val);
}


//*********************************************************************
uint8_t Ds248x::search_triplet(uint8_t search_direction)
{
    uint8_t rtn_val = 0;
    uint8_t poll_count = 0;
    char status;
    char packet [] = {CMD_1WT, search_direction ? 0x80 : 0x00};

    // 1-Wire Triplet (Case B)
    //   S AD,0 [A] 1WT [A] SS [A] Sr AD,1 [A] [Status] A [Status] A\ P
    //                                         \--------/
    //                           Repeat until 1WB bit has changed to 0
    //  [] indicates from slave
    //  SS indicates byte containing search direction bit value in msbit

    _p_i2c_bus->write(_w_adrs, packet, 2);

    // loop checking 1WB bit for completion of 1-Wire operation
    // abort if poll limit reached
    do 
    {
        _p_i2c_bus->read(_r_adrs, &status, 1);
    } 
    while ((status & STATUS_1WB) && (poll_count++ < POLL_LIMIT));

    // check for failure due to poll limit reached
    if (poll_count >= POLL_LIMIT) 
    {
        // handle error
        // ...
        reset();
        rtn_val = false;
    }
    else
    {
        rtn_val = status;
    }
    
    return(rtn_val);
}


//*********************************************************************
bool Ds248x::OWReset()
{
    bool rtn_val = false;
    
    uint8_t poll_count = 0;
    char status;
    char packet [] = {CMD_1WRS};

    // 1-Wire reset (Case B)
    //   S AD,0 [A] 1WRS [A] Sr AD,1 [A] [Status] A [Status] A\ P
    //                                   \--------/
    //                       Repeat until 1WB bit has changed to 0
    //  [] indicates from slave

    _p_i2c_bus->write(_w_adrs, packet, 1);

    // loop checking 1WB bit for completion of 1-Wire operation
    // abort if poll limit reached
    do 
    {
        _p_i2c_bus->read(_r_adrs, &status, 1);
    } 
    while ((status & STATUS_1WB) && (poll_count++ < POLL_LIMIT));

    // check for failure due to poll limit reached
    if (poll_count >= POLL_LIMIT) 
    {
        // handle error
        // ...
        reset();
        rtn_val = false; 
    }
    else
    {
        // check for short condition
        if (status & STATUS_SD)
        {
            _short_detected = true;
        }
        else
        {
            _short_detected = false;
        }
    
        // check for presence detect
        if (status & STATUS_PPD)
        {
            rtn_val = true;
        }
        else
        {
            rtn_val = false;
        }
    }

    return(rtn_val);
}


//*********************************************************************
void Ds248x::OWWriteBit(uint8_t sendbit)
{
    OWTouchBit(sendbit);
}


//*********************************************************************
uint8_t Ds248x::OWReadBit()
{
    return(OWTouchBit(0x01)); 
}


//*********************************************************************
uint8_t Ds248x::OWTouchBit(uint8_t sendbit)
{
    uint8_t rtn_val;
    uint8_t poll_count = 0;
    char status;
    char packet[] = {CMD_1WSB, sendbit ? 0x80 : 0x00};

    // 1-Wire bit (Case B)
    //   S AD,0 [A] 1WSB [A] BB [A] Sr AD,1 [A] [Status] A [Status] A\ P
    //                                          \--------/
    //                           Repeat until 1WB bit has changed to 0
    //  [] indicates from slave
    //  BB indicates byte containing bit value in msbit

    _p_i2c_bus->write(_w_adrs, packet, 2);

    // loop checking 1WB bit for completion of 1-Wire operation
    // abort if poll limit reached
    do 
    {
        _p_i2c_bus->read(_r_adrs, &status, 1);
    } 
    while ((status & STATUS_1WB) && (poll_count++ < POLL_LIMIT));

    // check for failure due to poll limit reached
    if (poll_count >= POLL_LIMIT) 
    {
        // handle error
        // ...
        reset();
        rtn_val = 0;
    }
    else
    {
        // return bit state
        if (status & STATUS_SBR)
        {
            rtn_val = 1;
        }
        else
        {
            rtn_val = 0;
        }
    }
    
    return(rtn_val); 
}


//*********************************************************************
bool Ds248x::OWWriteByte(uint8_t sendbyte)
{
    bool rtn_val = false;
    
    uint8_t poll_count = 0;
    char status;
    char packet [] = {CMD_1WWB, sendbyte};

    // 1-Wire Write Byte (Case B)
    //   S AD,0 [A] 1WWB [A] DD [A] Sr AD,1 [A] [Status] A [Status] A\ P
    //                                          \--------/
    //                             Repeat until 1WB bit has changed to 0
    //  [] indicates from slave
    //  DD data to write

    _p_i2c_bus->write(_w_adrs, packet, 2);

    // loop checking 1WB bit for completion of 1-Wire operation
    // abort if poll limit reached
    do 
    {
        _p_i2c_bus->read(_r_adrs, &status, 1);
    } 
    while ((status & STATUS_1WB) && (poll_count++ < POLL_LIMIT));

    // check for failure due to poll limit reached
    if (poll_count >= POLL_LIMIT) 
    {
        // handle error
        // ...
        reset();
        rtn_val = false;
    }
    else
    {
        rtn_val = true;
    }

    return(rtn_val);
}


//*********************************************************************
uint8_t Ds248x::OWReadByte(void)
{
    uint8_t rtn_val;
    
    uint8_t poll_count = 0;
    char data, status;
    char packet[2] = {CMD_1WRB, 0};

    // 1-Wire Read Bytes (Case C)
    //   S AD,0 [A] 1WRB [A] Sr AD,1 [A] [Status] A [Status] A\
    //                                   \--------/
    //                     Repeat until 1WB bit has changed to 0
    //   Sr AD,0 [A] SRP [A] E1 [A] Sr AD,1 [A] DD A\ P
    //
    //  [] indicates from slave
    //  DD data read

    _p_i2c_bus->write(_w_adrs, packet, 1);

    // loop checking 1WB bit for completion of 1-Wire operation
    // abort if poll limit reached
    do 
    {
        _p_i2c_bus->read(_r_adrs, &status, 1);
    } 
    while ((status & STATUS_1WB) && (poll_count++ < POLL_LIMIT));

    // check for failure due to poll limit reached
    if (poll_count >= POLL_LIMIT) 
    {
        // handle error
        // ...
        reset();
        rtn_val = 0;
    }
    else
    {
        packet[0] = CMD_SRP;
        packet[1] = 0xE1;
    
        _p_i2c_bus->write(_w_adrs, packet, 2);
        _p_i2c_bus->read(_r_adrs, &data, 1);
    
        rtn_val = data;
    }
    
    return(rtn_val);
}


//*********************************************************************
uint8_t Ds248x::OWTouchByte(uint8_t sendbyte)
{
    uint8_t rtn_val;

    if (sendbyte == 0xFF) 
    {
        rtn_val = OWReadByte();
    } 
    else 
    {
        OWWriteByte(sendbyte);
        rtn_val = sendbyte;
    }
    
    return(rtn_val);
}


//*********************************************************************
void Ds248x::OWBlock(uint8_t *tran_buf, uint8_t tran_len)
{
    uint8_t i;
    
    for (i = 0; i < tran_len; i++)
    {
        tran_buf[i] = OWTouchByte(tran_buf[i]);
    }
}


//*********************************************************************
void Ds248x::OWWriteBlock(const uint8_t *tran_buf, uint8_t tran_len)
{
    uint8_t idx;
    
    for(idx = 0; idx < tran_len; idx++)
    {
        OWWriteByte(tran_buf[idx]);
    }
}
    
    
//*********************************************************************
void Ds248x::OWReadBlock(uint8_t *recv_buf, uint8_t recv_len)
{
    uint8_t idx;
    
    for(idx = 0; idx < recv_len; idx++)
    {
        recv_buf[idx] = OWReadByte();
    }
}


//*********************************************************************
bool Ds248x::OWFirst(void)
{
    // reset the search state
    _last_discrepancy = 0;
    _last_device_flag = false;
    _last_family_discrepancy = 0;

   return OWSearch();  
}


//*********************************************************************
bool Ds248x::OWNext(void)
{
    // leave the search state alone
    return OWSearch();
}


//*********************************************************************
bool Ds248x::OWVerify(void)
{
    bool rtn_val = false;

    uint8_t rom_backup[8];
    uint8_t i,rslt,ld_backup,ldf_backup,lfd_backup;

    // keep a backup copy of the current state
    for (i = 0; i < 8; i++)
    {
        rom_backup[i] = _rom_number[i];
    }
    
    ld_backup = _last_discrepancy;
    ldf_backup = _last_device_flag;
    lfd_backup = _last_family_discrepancy;

    // set search to find the same device
    _last_discrepancy = 64;
    _last_device_flag = false;

    if (OWSearch()) 
    {
        // check if same device found
        rslt = true;
        for (i = 0; i < 8; i++) 
        {
            if (rom_backup[i] != _rom_number[i]) 
            {
                rslt = false;
                break;
            }
        }
    } 
    else
    {
        rslt = false;
    }

    // restore the search state
    for (i = 0; i < 8; i++)
    {
        _rom_number[i] = rom_backup[i];
    }
    
    _last_discrepancy = ld_backup;
    _last_device_flag = ldf_backup;
    _last_family_discrepancy = lfd_backup;
    
    // return the result of the verify
    rtn_val = rslt;
    
    return(rtn_val);
}


//*********************************************************************
void Ds248x::OWTargetSetup(uint8_t family_code)
{
    uint8_t i;

    // set the search state to find SearchFamily type devices
    _rom_number[0] = family_code;
    for (i = 1; i < 8; i++)
    {
        _rom_number[i] = 0;
    }
    
    _last_discrepancy = 64;
    _last_family_discrepancy = 0;
    _last_device_flag = false;
}


//*********************************************************************
void Ds248x::OWFamilySkipSetup(void)
{
    // set the Last discrepancy to last family discrepancy
    _last_discrepancy = _last_family_discrepancy;
    
    // clear the last family discrpepancy
    _last_family_discrepancy = 0;
    
    // check for end of list
    if (_last_discrepancy == 0) 
    {
        _last_device_flag = true;
    }
}


//*********************************************************************
bool Ds248x::OWSearch(void)
{
    uint8_t id_bit_number;
    uint8_t last_zero, rom_byte_number, search_result;
    uint8_t id_bit, cmp_id_bit;
    uint8_t rom_byte_mask, search_direction, status;

    // initialize for search
    id_bit_number = 1;
    last_zero = 0;
    rom_byte_number = 0;
    rom_byte_mask = 1;
    search_result = false;
    _crc8 = 0;

    // if the last call was not the last one
    if (!_last_device_flag) 
    {
        // 1-Wire reset
        if (!OWReset()) 
        {
            // reset the search
            _last_discrepancy = 0;
            _last_device_flag = false;
            _last_family_discrepancy = 0;
            return false;
        }

        // issue the search command
        OWWriteByte(SEARCH_ROM);

        // loop to do the search
        do 
        {
            // if this discrepancy if before the Last Discrepancy
            // on a previous next then pick the same as last time
            if (id_bit_number < _last_discrepancy) 
            {
                if ((_rom_number[rom_byte_number] & rom_byte_mask) > 0)
                    search_direction = 1;
                else
                    search_direction = 0;
            } 
            else 
            {
                // if equal to last pick 1, if not then pick 0
                if (id_bit_number == _last_discrepancy)
                    search_direction = 1;
                else
                    search_direction = 0;
            }

            // Perform a triple operation on the ds2484 which will perform 2 read bits and 1 write bit
            status = search_triplet(search_direction);

            // check bit results in status byte
            id_bit = ((status & STATUS_SBR) == STATUS_SBR);
            cmp_id_bit = ((status & STATUS_TSB) == STATUS_TSB);
            search_direction = ((status & STATUS_DIR) == STATUS_DIR) ? (unsigned char)1 : (unsigned char)0;

            // check for no devices on 1-Wire
            if ((id_bit) && (cmp_id_bit))
                break;
            else 
            {
                if ((!id_bit) && (!cmp_id_bit) && (search_direction == 0)) 
                {
                    last_zero = id_bit_number;

                    // check for Last discrepancy in family
                    if (last_zero < 9)
                        _last_family_discrepancy = last_zero;
                }

                // set or clear the bit in the ROM byte rom_byte_number
                // with mask rom_byte_mask
                if (search_direction == 1)
                    _rom_number[rom_byte_number] |= rom_byte_mask;
                else
                    _rom_number[rom_byte_number] &= (unsigned char)~rom_byte_mask;

                // 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) 
                {
                    _crc8 = OWCalc_crc8(_rom_number[rom_byte_number], _crc8);  // accumulate the CRC
                    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) || (_crc8 != 0))) 
        {
            // search successful so set LastDiscrepancy,LastDeviceFlag,search_result
            _last_discrepancy = last_zero;

            // check for last device
            if (_last_discrepancy == 0)
                _last_device_flag = true;

            search_result = true;
        }
    }

    // if no device found then reset counters so next 'search' will be like a first
    if (!search_result || (_rom_number[0] == 0)) 
    {
        _last_discrepancy = 0;
        _last_device_flag = false;
        _last_family_discrepancy = 0;
        search_result = false;
    }

    return search_result;
}


//*********************************************************************
bool Ds248x::OWReadROM(void)
{
    bool rtn_val = false;
    
    if(!OWReset())
    {
        rtn_val = false;
    }
    else
    {
        if(!OWWriteByte(READ_ROM))
        {
            rtn_val = false;
        }
        else
        {
            OWReadBlock(_rom_number, ROMnumberLen);
            rtn_val = true;
        }
    }
    
    return rtn_val;
}
    

//*********************************************************************    
bool Ds248x::OWSkipROM(void)
{
    bool rtn_val = false;
    
    if(!OWReset())
    {
        rtn_val = false;
    }
    else
    {
        if(!OWWriteByte(SKIP_ROM))
        {
            rtn_val = false;
        }
        else
        {
            rtn_val = true;
        }
    }
    
    return rtn_val;
}
    

//*********************************************************************    
bool Ds248x::OWMatchROM(void)
{
    bool rtn_val = false;
    uint8_t idx;
    
    if(!OWReset())
    {
        rtn_val = false;
    }
    else
    {
        if(!OWWriteByte(MATCH_ROM))
        {
            rtn_val = false;
        }
        else
        {
            for(idx = 0; idx < ROMnumberLen; idx++)
            {
                OWWriteByte(_rom_number[idx]);
            }
            rtn_val = true;
        }
    }
    
    return rtn_val;
}
    

//*********************************************************************    
bool Ds248x::OWOverdriveSkipROM(void)
{
    bool rtn_val = false;
    
    if(!OWReset())
    {
        rtn_val = false;
    }
    else
    {
        if(!OWWriteByte(OVERDRIVE_SKIP))
        {
            rtn_val = false;
        }
        else
        {
            //change speed for subsequent comands
            OWSpeed(SPEED_OVERDRIVE);
            rtn_val = true;
        }
    }
    
    return rtn_val;
}
    

//*********************************************************************    
bool Ds248x::OWOverdriveMatchROM(void)
{
    bool rtn_val = false;
    uint8_t idx;
    
    if(!OWReset())
    {
        rtn_val = false;
    }
    else
    {
        if(!OWWriteByte(OVERDRIVE_MATCH))
        {
            rtn_val = false;
        }
        else
        {
            //change speed before sending ROM number
            OWSpeed(SPEED_OVERDRIVE);
            
            for(idx = 0; idx < ROMnumberLen; idx++)
            {
                OWWriteByte(_rom_number[idx]);
            }
            rtn_val = true;
        }
    }
    
    return rtn_val;
}
    

//*********************************************************************    
bool Ds248x::OWResume(void)
{
    bool rtn_val = false;
    
    if(!OWReset())
    {
        rtn_val = false;
    }
    else
    {
        if(!OWWriteByte(RESUME))
        {
            rtn_val = false;
        }
        else
        {
            rtn_val = true;
        }
    }
    
    return rtn_val;
}


//*********************************************************************
uint8_t Ds248x::OWSpeed(OW_SPEED new_speed)
{
    // set the speed
    if (new_speed == SPEED_OVERDRIVE)
    {
        _c1WS = CONFIG_1WS;
    }
    else
    {
        _c1WS = false;
    }

    // write the new config
    write_config(_c1WS | _cSPU | _cPDN | _cAPU);

    return(new_speed);
}


//*********************************************************************
uint8_t Ds248x::OWLevel(OW_LEVEL new_level)
{
    uint8_t rtn_val;
    
    // function only will turn back to non-strong pull-up
    if (new_level != LEVEL_NORMAL)
    {
        rtn_val = LEVEL_STRONG;
    }
    else
    {
        // clear the strong pull-up bit in the global config state
        _cSPU = false;
        // write the new config
        write_config(_c1WS | _cSPU | _cPDN | _cAPU);
        rtn_val = LEVEL_NORMAL;
    }

    return(rtn_val);
}


//*********************************************************************
bool Ds248x::OWWriteBytePower(uint8_t sendbyte)
{
    bool rtn_val = false;
    
    // set strong pull-up enable
    _cSPU = CONFIG_SPU;
    
    // write the new config
    if (!write_config(_c1WS | _cSPU | _cPDN | _cAPU))
    {
        rtn_val = false;
    }
    else
    {
        // perform write byte
        OWWriteByte(sendbyte);
        rtn_val = true;
    }
    
    return(rtn_val);
}


//*********************************************************************
bool Ds248x::OWReadBitPower(uint8_t applyPowerResponse)
{
    bool rtn_val = false;

    uint8_t rdbit;

    // set strong pull-up enable
    _cSPU = CONFIG_SPU;

    // write the new config
    if (!write_config(_c1WS | _cSPU | _cPDN | _cAPU))
    {
        rtn_val = false; 
    }
    else
    {
        // perform read bit
        rdbit = OWReadBit();

        // check if response was correct, if not then turn off strong pull-up
        if (rdbit != applyPowerResponse) 
        {
            OWLevel(LEVEL_NORMAL);
            rtn_val = false; 
        }

        rtn_val = true;
    }

    return(rtn_val);
}


//*********************************************************************
const uint8_t (&Ds248x::OWgetROMnumber() const)[ROMnumberLen]
{
    return _rom_number;
}


//*********************************************************************
void Ds248x::set_i2c_adrs(DS248X_I2C_ADRS adrs)
{
    _w_adrs = (adrs << 1);
    _r_adrs = (_w_adrs | 1);
}