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[/] [gecko3/] [trunk/] [GECKO3COM/] [gecko3com-fw/] [firmware/] [lib/] [i2c.c] - Blame information for rev 9

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Line No. Rev Author Line
1 9 nussgipfel
/* -*- c++ -*- */
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/*
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 * Copyright 2003 Free Software Foundation, Inc.
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 *
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 * This file is part of GNU Radio
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 *
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 * GNU Radio is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 3, or (at your option)
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 * any later version.
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 *
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 * GNU Radio is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with GNU Radio; see the file COPYING.  If not, write to
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 * the Free Software Foundation, Inc., 51 Franklin Street,
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 * Boston, MA 02110-1301, USA.
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 */
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#include "i2c.h"
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#include "fx2regs.h"
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#include <string.h>
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// issue a stop bus cycle and wait for completion
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// returns non-zero if successful, else 0
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unsigned char
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i2c_read (unsigned char addr, xdata unsigned char *buf, unsigned char len)
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{
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  volatile unsigned char        junk;
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  if (len == 0)                  // reading zero bytes always works
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    return 1;
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  while (I2CS & bmSTOP)         // wait for stop to clear
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    ;
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  I2CS = bmSTART;
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  I2DAT = (addr << 1) | 1;      // write address and direction (1's the read bit)
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  while ((I2CS & bmDONE) == 0)
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    ;
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  if ((I2CS & bmBERR) || (I2CS & bmACK) == 0)    // no device answered...
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    goto fail;
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  if (len == 1)
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    I2CS |= bmLASTRD;
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  junk = I2DAT;                 // trigger the first read cycle
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  while (--len != 0){
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    while ((I2CS & bmDONE) == 0)
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      ;
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    if (I2CS & bmBERR)
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      goto fail;
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    if (len == 1)
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      I2CS |= bmLASTRD;
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    *buf++ = I2DAT;             // get data, trigger another read
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  }
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  // wait for final byte
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  while ((I2CS & bmDONE) == 0)
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    ;
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  if (I2CS & bmBERR)
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    goto fail;
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  I2CS |= bmSTOP;
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  *buf = I2DAT;
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  return 1;
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 fail:
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  I2CS |= bmSTOP;
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  return 0;
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}
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// returns non-zero if successful, else 0
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unsigned char
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i2c_write (unsigned char addr, xdata const unsigned char *buf, unsigned char len)
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{
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  while (I2CS & bmSTOP)         // wait for stop to clear
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    ;
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  I2CS = bmSTART;
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  I2DAT = (addr << 1) | 0;       // write address and direction (0's the write bit)
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  while ((I2CS & bmDONE) == 0)
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    ;
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  if ((I2CS & bmBERR) || (I2CS & bmACK) == 0)    // no device answered...
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    goto fail;
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  while (len > 0){
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    I2DAT = *buf++;
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    len--;
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    while ((I2CS & bmDONE) == 0)
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      ;
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    if ((I2CS & bmBERR) || (I2CS & bmACK) == 0)  // no device answered...
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      goto fail;
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  }
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  I2CS |= bmSTOP;
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  return 1;
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 fail:
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  I2CS |= bmSTOP;
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  return 0;
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}

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