lib/general/ownet.c

//---------------------------------------------------------------------------
// Copyright (C) 2000 Dallas Semiconductor Corporation, 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 DALLAS SEMICONDUCTOR 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 Dallas Semiconductor
// shall not be used except as stated in the Dallas Semiconductor
// Branding Policy.
//---------------------------------------------------------------------------
//
//  ownet.C - Network functions for 1-Wire net devices.
//
//  Version: 2.01
//
//  History: 1.00 -> 1.01  Change to owFamilySearchSetup, LastDiscrepancy[portnum]
//                         was set to 64 instead of 8 to enable devices with
//                         early contention to go in the '0' direction first.
//           1.02 -> 1.03  Initialized goodbits in  owVerify
//           1.03 -> 2.00  Changed 'MLan' to 'ow'. Added support for
//                         multiple ports.
//           2.00 -> 2.01  Added support for owError library
//

#include <stdio.h>
#include "ownet.h"

// external functions defined in system specific link file
extern SMALLINT owTouchReset(int);
extern SMALLINT owTouchBit(int,SMALLINT);
extern SMALLINT owWriteByte(int,SMALLINT);
extern SMALLINT owReadByte(int);
extern SMALLINT owSpeed(int,SMALLINT);
extern SMALLINT owLevel(int,SMALLINT);
extern void usDelay(int);

// external functions defined in owtran.c
extern uchar owBlock(int,SMALLINT,uchar *,SMALLINT);

extern void setcrc8(int,uchar);
extern uchar docrc8(int,uchar);

// exportable functions defined in ownet.c
SMALLINT owFirst(int,SMALLINT,SMALLINT);
SMALLINT owNext(int,SMALLINT,SMALLINT);
void     owSerialNum(int,uchar *,SMALLINT);
void     owFamilySearchSetup(int,SMALLINT);
void     owSkipFamily(int);
SMALLINT owAccess(int);
SMALLINT owVerify(int,SMALLINT);
SMALLINT owOverdriveAccess(int);
SMALLINT bitacc(SMALLINT,SMALLINT,SMALLINT,uchar *);

// global variables for this module to hold search state information
static SMALLINT LastDiscrepancy[MAX_PORTNUM];
static SMALLINT LastFamilyDiscrepancy[MAX_PORTNUM];
static SMALLINT LastDevice[MAX_PORTNUM];
uchar SerialNum[MAX_PORTNUM][8];

//--------------------------------------------------------------------------
// The 'owFirst' finds the first device on the 1-Wire Net  This function
// contains one parameter 'alarm_only'.  When
// 'alarm_only' is TRUE (1) the find alarm command 0xEC is
// sent instead of the normal search command 0xF0.
// Using the find alarm command 0xEC will limit the search to only
// 1-Wire devices that are in an 'alarm' state.
//
// 'portnum'    - number 0 to MAX_PORTNUM-1.  This number is provided to
//                indicate the symbolic port number.
// 'do_reset'   - TRUE (1) perform reset before search, FALSE (0) do not
//                perform reset before search.
// 'alarm_only' - TRUE (1) the find alarm command 0xEC is
//                sent instead of the normal search command 0xF0
//
// Returns:   TRUE (1) : when a 1-Wire device was found and it's
//                        Serial Number placed in the global SerialNum[portnum]
//            FALSE (0): There are no devices on the 1-Wire Net.
//
SMALLINT owFirst(int portnum, SMALLINT do_reset, SMALLINT alarm_only)
{
   // reset the search state
   LastDiscrepancy[portnum] = 0;
   LastDevice[portnum] = FALSE;
   LastFamilyDiscrepancy[portnum] = 0;

   return owNext(portnum,do_reset,alarm_only);
}

//--------------------------------------------------------------------------
// The 'owNext' function does a general search.  This function
// continues from the previos search state. The search state
// can be reset by using the 'owFirst' function.
// This function contains one parameter 'alarm_only'.
// When 'alarm_only' is TRUE (1) the find alarm command
// 0xEC is sent instead of the normal search command 0xF0.
// Using the find alarm command 0xEC will limit the search to only
// 1-Wire devices that are in an 'alarm' state.
//
// 'portnum'    - number 0 to MAX_PORTNUM-1.  This number is provided to
//                indicate the symbolic port number.
// 'do_reset'   - TRUE (1) perform reset before search, FALSE (0) do not
//                perform reset before search.
// 'alarm_only' - TRUE (1) the find alarm command 0xEC is
//                sent instead of the normal search command 0xF0
//
// Returns:   TRUE (1) : when a 1-Wire device was found and it's
//                       Serial Number placed in the global SerialNum[portnum]
//            FALSE (0): when no new device was found.  Either the
//                       last search was the last device or there
//                       are no devices on the 1-Wire Net.
//
SMALLINT owNext(int portnum, SMALLINT do_reset, SMALLINT alarm_only)
{
   uchar bit_test, search_direction, bit_number;
   uchar last_zero, serial_byte_number, next_result;
   uchar serial_byte_mask;
   uchar lastcrc8;

   // initialize for search
   bit_number = 1;
   last_zero = 0;
   serial_byte_number = 0;
   serial_byte_mask = 1;
   next_result = 0;
   setcrc8(portnum,0);

   // if the last call was not the last one
   if (!LastDevice[portnum])
   {
      // check if reset first is requested
      if (do_reset)
      {
         // reset the 1-wire
         // if there are no parts on 1-wire, return FALSE
         if (!owTouchReset(portnum))
         {
            // printf("owTouchReset failed\r\n");
            // reset the search
            LastDiscrepancy[portnum] = 0;
            LastFamilyDiscrepancy[portnum] = 0;
            OWERROR(OWERROR_NO_DEVICES_ON_NET);
            return FALSE;
         }
      }

      // If finding alarming devices issue a different command
      if (alarm_only)
         owWriteByte(portnum,0xEC);  // issue the alarming search command
      else
         owWriteByte(portnum,0xF0);  // issue the search command

      //pause before beginning the search
      //usDelay(100);

      // loop to do the search
      do
      {
         // read a bit and its compliment
         bit_test = owTouchBit(portnum,1) << 1;
         bit_test |= owTouchBit(portnum,1);

         // check for no devices on 1-wire
         if (bit_test == 3)
            break;
         else
         {
            // all devices coupled have 0 or 1
            if (bit_test > 0)
              search_direction = !(bit_test & 0x01);  // 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 (bit_number < LastDiscrepancy[portnum])
                  search_direction = ((SerialNum[portnum][serial_byte_number] & serial_byte_mask) > 0);
               else
                  // if equal to last pick 1, if not then pick 0
                  search_direction = (bit_number == LastDiscrepancy[portnum]);

               // if 0 was picked then record its position in LastZero
               if (search_direction == 0)
                  last_zero = bit_number;

               // check for Last discrepancy in family
               if (last_zero < 9)
                  LastFamilyDiscrepancy[portnum] = last_zero;
            }

            // set or clear the bit in the SerialNum[portnum] byte serial_byte_number
            // with mask serial_byte_mask
            if (search_direction == 1)
              SerialNum[portnum][serial_byte_number] |= serial_byte_mask;
            else
              SerialNum[portnum][serial_byte_number] &= ~serial_byte_mask;

            // serial number search direction write bit
            owTouchBit(portnum,search_direction);

            // increment the byte counter bit_number
            // and shift the mask serial_byte_mask
            bit_number++;
            serial_byte_mask <<= 1;

            // if the mask is 0 then go to new SerialNum[portnum] byte serial_byte_number
            // and reset mask
            if (serial_byte_mask == 0)
            {
                lastcrc8 = docrc8(portnum,SerialNum[portnum][serial_byte_number]);  // accumulate the CRC
                serial_byte_number++;
                serial_byte_mask = 1;
            }
         }
      }
      while(serial_byte_number < 8);  // loop until through all SerialNum[portnum] bytes 0-7

      // if the search was successful then
      if (!((bit_number < 65) || lastcrc8))
      {
         // search successful so set LastDiscrepancy[portnum],LastDevice[portnum],next_result
         LastDiscrepancy[portnum] = last_zero;
         LastDevice[portnum] = (LastDiscrepancy[portnum] == 0);
         next_result = TRUE;
      }
   }

   // if no device found then reset counters so next 'next' will be
   // like a first
   if (!next_result || !SerialNum[portnum][0])
   {
      LastDiscrepancy[portnum] = 0;
      LastDevice[portnum] = FALSE;
      LastFamilyDiscrepancy[portnum] = 0;
      next_result = FALSE;
   }

   return next_result;
}

//--------------------------------------------------------------------------
// The 'owSerialNum' function either reads or sets the SerialNum buffer
// that is used in the search functions 'owFirst' and 'owNext'.
// This function contains two parameters, 'serialnum_buf' is a pointer
// to a buffer provided by the caller.  'serialnum_buf' should point to
// an array of 8 unsigned chars.  The second parameter is a flag called
// 'do_read' that is TRUE (1) if the operation is to read and FALSE
// (0) if the operation is to set the internal SerialNum buffer from
// the data in the provided buffer.
//
// 'portnum'       - number 0 to MAX_PORTNUM-1.  This number is provided to
//                   indicate the symbolic port number.
// 'serialnum_buf' - buffer to that contains the serial number to set
//                   when do_read = FALSE (0) and buffer to get the serial
//                   number when do_read = TRUE (1).
// 'do_read'       - flag to indicate reading (1) or setting (0) the current
//                   serial number.
//
void owSerialNum(int portnum, uchar *serialnum_buf, SMALLINT do_read)
{
   uchar i;

   // read the internal buffer and place in 'serialnum_buf'
   if (do_read)
   {
      for (i = 0; i < 8; i++)
         serialnum_buf[i] = SerialNum[portnum][i];
   }
   // set the internal buffer from the data in 'serialnum_buf'
   else
   {
      for (i = 0; i < 8; i++)
         SerialNum[portnum][i] = serialnum_buf[i];
   }
}

//--------------------------------------------------------------------------
// Setup the search algorithm to find a certain family of devices
// the next time a search function is called 'owNext'.
//
// 'portnum'       - number 0 to MAX_PORTNUM-1.  This number was provided to
//                   OpenCOM to indicate the port number.
// 'search_family' - family code type to set the search algorithm to find
//                   next.
//
void owFamilySearchSetup(int portnum, SMALLINT search_family)
{
   uchar i;

   // set the search state to find SearchFamily type devices
   SerialNum[portnum][0] = search_family;
   for (i = 1; i < 8; i++)
      SerialNum[portnum][i] = 0;
   LastDiscrepancy[portnum] = 64;
   LastDevice[portnum] = FALSE;
}

//--------------------------------------------------------------------------
// Set the current search state to skip the current family code.
//
// 'portnum'     - number 0 to MAX_PORTNUM-1.  This number is provided to
//                 indicate the symbolic port number.
//
void owSkipFamily(int portnum)
{
   // set the Last discrepancy to last family discrepancy
   LastDiscrepancy[portnum] = LastFamilyDiscrepancy[portnum];

   // check for end of list
   if (LastDiscrepancy[portnum] == 0)
      LastDevice[portnum] = TRUE;
}

//--------------------------------------------------------------------------
// The 'owAccess' function resets the 1-Wire and sends a MATCH Serial
// Number command followed by the current SerialNum code. After this
// function is complete the 1-Wire device is ready to accept device-specific
// commands.
//
// 'portnum'     - number 0 to MAX_PORTNUM-1.  This number is provided to
//                 indicate the symbolic port number.
//
// Returns:   TRUE (1) : reset indicates present and device is ready
//                       for commands.
//            FALSE (0): reset does not indicate presence or echos 'writes'
//                       are not correct.
//
SMALLINT owAccess(int portnum)
{
   uchar sendpacket[9];
   uchar i;

   // reset the 1-wire
   if (owTouchReset(portnum))
   {
      // create a buffer to use with block function
      // match Serial Number command 0x55
      sendpacket[0] = 0x55;
      // Serial Number
      for (i = 1; i < 9; i++)
         sendpacket[i] = SerialNum[portnum][i-1];

      // send/recieve the transfer buffer
      if (owBlock(portnum,FALSE,sendpacket,9))
      {
         // verify that the echo of the writes was correct
         for (i = 1; i < 9; i++)
            if (sendpacket[i] != SerialNum[portnum][i-1])
               return FALSE;
         if (sendpacket[0] != 0x55)
         {
            OWERROR(OWERROR_WRITE_VERIFY_FAILED);
            return FALSE;
         }
         else
            return TRUE;
      }
      else
         OWERROR(OWERROR_BLOCK_FAILED);
   }
   else
      OWERROR(OWERROR_NO_DEVICES_ON_NET);

   // reset or match echo failed
   return FALSE;
}

//----------------------------------------------------------------------
// The function 'owVerify' verifies that the current device
// is in contact with the 1-Wire Net.
// Using the find alarm command 0xEC will verify that the device
// is in contact with the 1-Wire Net and is in an 'alarm' state.
//
// 'portnum'     - number 0 to MAX_PORTNUM-1.  This number is provided to
//                 indicate the symbolic port number.
// 'alarm_only'  - TRUE (1) the find alarm command 0xEC
//                 is sent instead of the normal search
//                 command 0xF0.
//
// Returns:   TRUE (1) : when the 1-Wire device was verified
//                       to be on the 1-Wire Net
//                       with alarm_only == FALSE
//                       or verified to be on the 1-Wire Net
//                       AND in an alarm state when
//                       alarm_only == TRUE.
//            FALSE (0): the 1-Wire device was not on the
//                       1-Wire Net or if alarm_only
//                       == TRUE, the device may be on the
//                       1-Wire Net but in a non-alarm state.
//
SMALLINT owVerify(int portnum, SMALLINT alarm_only)
{
   uchar i,sendlen=0,goodbits=0,cnt=0,s,tst;
   uchar sendpacket[50];

   // construct the search
   if (alarm_only)
      sendpacket[sendlen++] = 0xEC; // issue the alarming search command
   else
      sendpacket[sendlen++] = 0xF0; // issue the search command
   // set all bits at first
   for (i = 1; i <= 24; i++)
      sendpacket[sendlen++] = 0xFF;
   // now set or clear apropriate bits for search
   for (i = 0; i < 64; i++)
      bitacc(WRITE_FUNCTION,bitacc(READ_FUNCTION,0,i,&SerialNum[portnum][0]),(int)((i+1)*3-1),&sendpacket[1]);

   // send/recieve the transfer buffer
   if (owBlock(portnum,TRUE,sendpacket,sendlen))
   {
      // check results to see if it was a success
      for (i = 0; i < 192; i += 3)
      {
         tst = (bitacc(READ_FUNCTION,0,i,&sendpacket[1]) << 1) |
                bitacc(READ_FUNCTION,0,(int)(i+1),&sendpacket[1]);

         s = bitacc(READ_FUNCTION,0,cnt++,&SerialNum[portnum][0]);

         if (tst == 0x03)  // no device on line
         {
              goodbits = 0;    // number of good bits set to zero
              break;     // quit
         }

         if (((s == 0x01) && (tst == 0x02)) ||
             ((s == 0x00) && (tst == 0x01))    )  // correct bit
            goodbits++;  // count as a good bit
      }

      // check too see if there were enough good bits to be successful
      if (goodbits >= 8)
         return TRUE;
   }
   else
      OWERROR(OWERROR_BLOCK_FAILED);

   // block fail or device not present
   return FALSE;
}

//----------------------------------------------------------------------
// Perform a overdrive MATCH command to select the 1-Wire device with
// the address in the ID data register.
//
// 'portnum'     - number 0 to MAX_PORTNUM-1.  This number is provided to
//                 indicate the symbolic port number.
//
// Returns:  TRUE: If the device is present on the 1-Wire Net and
//                 can do overdrive then the device is selected.
//           FALSE: Device is not present or not capable of overdrive.
//
//  *Note: This function could be converted to send DS2480
//         commands in one packet.
//
SMALLINT owOverdriveAccess(int portnum)
{
   uchar sendpacket[8];
   uchar i, bad_echo = FALSE;

   // make sure normal level
   owLevel(portnum,MODE_NORMAL);

   // force to normal communication speed
   owSpeed(portnum,MODE_NORMAL);

   // call the 1-Wire Net reset function
   if (owTouchReset(portnum))
   {
      // send the match command 0x69
      if (owWriteByte(portnum,0x69))
      {
         // switch to overdrive communication speed
         owSpeed(portnum,MODE_OVERDRIVE);

         // create a buffer to use with block function
         // Serial Number
         for (i = 0; i < 8; i++)
            sendpacket[i] = SerialNum[portnum][i];

         // send/recieve the transfer buffer
         if (owBlock(portnum,FALSE,sendpacket,8))
         {
            // verify that the echo of the writes was correct
            for (i = 0; i < 8; i++)
               if (sendpacket[i] != SerialNum[portnum][i])
                  bad_echo = TRUE;
            // if echo ok then success
            if (!bad_echo)
               return TRUE;
            else
               OWERROR(OWERROR_WRITE_VERIFY_FAILED);
         }
         else
            OWERROR(OWERROR_BLOCK_FAILED);
      }
      else
         OWERROR(OWERROR_WRITE_BYTE_FAILED);
   }
   else
      OWERROR(OWERROR_NO_DEVICES_ON_NET);

   // failure, force back to normal communication speed
   owSpeed(portnum,MODE_NORMAL);

   return FALSE;
}

//--------------------------------------------------------------------------
// Bit utility to read and write a bit in the buffer 'buf'.
//
// 'op'    - operation (1) to set and (0) to read
// 'state' - set (1) or clear (0) if operation is write (1)
// 'loc'   - bit number location to read or write
// 'buf'   - pointer to array of bytes that contains the bit
//           to read or write
//
// Returns: 1   if operation is set (1)
//          0/1 state of bit number 'loc' if operation is reading
//
SMALLINT bitacc(SMALLINT op, SMALLINT state, SMALLINT loc, uchar *buf)
{
   SMALLINT nbyt,nbit;

   nbyt = (loc / 8);
   nbit = loc - (nbyt * 8);

   if (op == WRITE_FUNCTION)
   {
      if (state)
         buf[nbyt] |= (0x01 << nbit);
      else
         buf[nbyt] &= ~(0x01 << nbit);

      return 1;
   }
   else
      return ((buf[nbyt] >> nbit) & 0x01);
}