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