3 * Copyright 2003 Free Software Foundation, Inc.
5 * This file is part of GNU Radio
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
28 // issue a stop bus cycle and wait for completion
31 // returns non-zero if successful, else 0
33 i2c_read (unsigned char addr, xdata unsigned char *buf, unsigned char len)
35 volatile unsigned char junk;
37 if (len == 0) // reading zero bytes always works
40 while (I2CS & bmSTOP) // wait for stop to clear
44 I2DAT = (addr << 1) | 1; // write address and direction (1's the read bit)
46 while ((I2CS & bmDONE) == 0)
49 if ((I2CS & bmBERR) || (I2CS & bmACK) == 0) // no device answered...
55 junk = I2DAT; // trigger the first read cycle
58 while ((I2CS & bmDONE) == 0)
67 *buf++ = I2DAT; // get data, trigger another read
70 // wait for final byte
72 while ((I2CS & bmDONE) == 0)
90 // returns non-zero if successful, else 0
92 i2c_write (unsigned char addr, xdata const unsigned char *buf, unsigned char len)
94 while (I2CS & bmSTOP) // wait for stop to clear
98 I2DAT = (addr << 1) | 0; // write address and direction (0's the write bit)
100 while ((I2CS & bmDONE) == 0)
103 if ((I2CS & bmBERR) || (I2CS & bmACK) == 0) // no device answered...
110 while ((I2CS & bmDONE) == 0)
113 if ((I2CS & bmBERR) || (I2CS & bmACK) == 0) // no device answered...