diff options
| author | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-08-03 04:51:51 +0000 |
|---|---|---|
| committer | jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-08-03 04:51:51 +0000 |
| commit | 5d69a524f81f234b3fbc41d49ba18d6f6886baba (patch) | |
| tree | b71312bf7f1e8d10fef0f3ac6f28784065e73e72 /usrp/firmware/lib/i2c.c | |
Houston, we have a trunk.
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3122 221aa14e-8319-0410-a670-987f0aec2ac5
Diffstat (limited to 'usrp/firmware/lib/i2c.c')
| -rw-r--r-- | usrp/firmware/lib/i2c.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/usrp/firmware/lib/i2c.c b/usrp/firmware/lib/i2c.c new file mode 100644 index 0000000000..08a09cf06a --- /dev/null +++ b/usrp/firmware/lib/i2c.c @@ -0,0 +1,123 @@ +/* -*- 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 2, 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., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, 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; +} |