mirror of https://gerrit.osmocom.org/libusrp
130 lines
2.6 KiB
C
130 lines
2.6 KiB
C
/* -*- 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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// memset (buf, 0, len); // FIXME, remove
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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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#if 1
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while (len != 1){
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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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len--;
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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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#endif
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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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