library

/*! \file ds2482.c \brief Dallas DS2482 I2C-to-Dallas1Wire Master Library. */
//*****************************************************************************
//
// File Name    : 'ds2482.c'
// Title                : Dallas DS2482 I2C-to-Dallas1Wire Master Library
// Author               : Pascal Stang - Copyright (C) 2004
// Created              : 2004.09.27
// Revised              : 2004.09.27
// Version              : 0.1
// Target MCU   : Atmel AVR Series
// Editor Tabs  : 4
//
// NOTE: This code is currently below version 1.0, and therefore is considered
// to be lacking in some functionality or documentation, or may not be fully
// tested.  Nonetheless, you can expect most functions to work.
//
// This code is distributed under the GNU Public License
//              which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************

#include <avr/io.h>
#include <avr/interrupt.h>

#include "global.h"
#include "i2c.h"
#include "ds2482.h"

#include "rprintf.h"
#include "timer.h"

// global variables
u08 DS2482I2cAddr;

// Functions
u08 ds2482Init(u08 i2cAddr)
{
        // select device
        DS2482I2cAddr = i2cAddr;
        // reset DS2482 chip
        return ds2482Reset(DS2482I2cAddr);

}

u08 ds2482Reset(u08 i2cAddr)
{
        // select device
        DS2482I2cAddr = i2cAddr;
        return ds2482SendCmd(DS2482_CMD_DRST);
}

u08 ds2482SendCmd(u08 cmd)
{
        u08 data;
        u08 i2cStat;

        // send command
        i2cStat = i2cMasterSendNI(DS2482I2cAddr, 1, &cmd);
        if(i2cStat == I2C_ERROR_NODEV)
        {
                rprintf("No I2C Device\r\n");
                return i2cStat;
        }
        // check status
        i2cStat = i2cMasterReceiveNI(DS2482I2cAddr, 1, &data);

//      rprintf("Cmd=0x%x  Status=0x%x\r\n", cmd, data);

        return (i2cStat == I2C_OK);
}

u08 ds2482SendCmdArg(u08 cmd, u08 arg)
{
        u08 data[2];
        u08 i2cStat;

        // prepare command
        data[0] = cmd;
        data[1] = arg;
        // send command
        i2cStat = i2cMasterSendNI(DS2482I2cAddr, 2, data);
        if(i2cStat == I2C_ERROR_NODEV)
        {
                rprintf("No I2C Device\r\n");
                return i2cStat;
        }
        // check status
        i2cStat = i2cMasterReceiveNI(DS2482I2cAddr, 1, data);

//      rprintf("Cmd=0x%x  Arg=0x%x  Status=0x%x\r\n", cmd, arg, data[0]);

        return (i2cStat == I2C_OK);
}

u08 ds2482BusyWait(void)
{
        u08 status;
        // set read pointer to status register
        ds2482SendCmdArg(DS2482_CMD_SRP, DS2482_READPTR_SR);
        // check status until busy bit is cleared
        do
        {
                i2cMasterReceiveNI(DS2482I2cAddr, 1, &status);
        } while(status & DS2482_STATUS_1WB);
        // return the status register value
        return status;
}

u08 ds2482BusReset(void)
{
        u08 status;
        // send 1-Wire bus reset command
        ds2482SendCmd(DS2482_CMD_1WRS);
        // wait for bus reset to finish, and get status
        status = ds2482BusyWait();
        // return state of the presence bit
        return (status & DS2482_STATUS_PPD);
}

u08 ds2482BusTransferBit(u08 bit)
{
        u08 status;
        // writes and reads a bit on the bus
        // wait for DS2482 to be ready
        ds2482BusyWait();
        // send 1WSB command
        ds2482SendCmdArg(DS2482_CMD_1WSB, bit?0x00:0x80);
        // wait for command to finish
        status = ds2482BusyWait();
        // return read-slot bit value
        if(status & DS2482_STATUS_SBR)
                return 1;
        else
                return 0;
}

u08 ds2482BusTriplet(u08 dir)
{
        u08 status;
        // this command is used to simplify search-rom operations
        // generates two read timeslots and one write timeslot
        // dir input determines value of write if reads are both 0

        // wait for DS2482 to be ready
        ds2482BusyWait();
        // send 1WSB command
        ds2482SendCmdArg(DS2482_CMD_1WT, dir?0x00:0x80);
        // wait for command to finish
        status = ds2482BusyWait();
        // return the value of the read slots
        return (status & (DS2482_STATUS_SBR|DS2482_STATUS_TSB))>>5;
}

u08 ds2482BusLevel(void)
{
        u08 status;
        // get status
        status = ds2482BusyWait();
        // return bus level value
        if(status & DS2482_STATUS_LL)
                return 1;
        else
                return 0;
}

void ds2482BusWriteByte(u08 data)
{
        // wait for DS2482 to be ready
        ds2482BusyWait();
        // send 1WWB command
        ds2482SendCmdArg(DS2482_CMD_1WWB, data);
}

u08 ds2482BusReadByte(void)
{
        u08 data;
        // wait for DS2482 to be ready
        ds2482BusyWait();
        // send 1WRB command
        ds2482SendCmd(DS2482_CMD_1WRB);
        // wait for read to finish
        ds2482BusyWait();
        // set read pointer to data register
        ds2482SendCmdArg(DS2482_CMD_SRP, DS2482_READPTR_RDR);
        // read data
        i2cMasterReceiveNI(DS2482I2cAddr, 1, &data);
        // return data
        return data;
}