/* -*- c++ -*- */\r
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/*-----------------------------------------------------------------------------\r
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* I2C read/write functions for FX2\r
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*-----------------------------------------------------------------------------\r
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* Code taken from USRP2 firmware (GNU Radio Project), version 3.0.2,\r
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* Copyright 2003 Free Software Foundation, Inc.\r
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*-----------------------------------------------------------------------------\r
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* This code is part of usbjtag. usbjtag is free software; you can redistribute\r
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* it and/or modify it under the terms of the GNU General Public License as\r
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* published by the Free Software Foundation; either version 2 of the License,\r
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* or (at your option) any later version. usbjtag is distributed in the hope\r
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* that it will be useful, but WITHOUT ANY WARRANTY; without even the implied\r
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\r
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* GNU General Public License for more details. You should have received a\r
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* copy of the GNU General Public License along with this program in the file\r
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* COPYING; if not, write to the Free Software Foundation, Inc., 51 Franklin\r
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* St, Fifth Floor, Boston, MA 02110-1301 USA\r
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*-----------------------------------------------------------------------------\r
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*/\r
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#include "i2c.h"\r
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#include "fx2regs.h"\r
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#include <string.h>\r
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// issue a stop bus cycle and wait for completion\r
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// returns non-zero if successful, else 0\r
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unsigned char\r
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i2c_read (unsigned char addr, xdata unsigned char *buf, unsigned char len)\r
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{\r
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volatile unsigned char junk;\r
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\r
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if (len == 0) // reading zero bytes always works\r
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return 1;\r
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\r
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while (I2CS & bmSTOP) // wait for stop to clear\r
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;\r
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I2CS = bmSTART;\r
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I2DAT = (addr << 1) | 1; // write address and direction (1's the read bit)\r
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while ((I2CS & bmDONE) == 0)\r
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;\r
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if ((I2CS & bmBERR) || (I2CS & bmACK) == 0) // no device answered...\r
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goto fail;\r
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if (len == 1)\r
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I2CS |= bmLASTRD; \r
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junk = I2DAT; // trigger the first read cycle\r
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while (--len != 0){\r
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while ((I2CS & bmDONE) == 0)\r
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;\r
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if (I2CS & bmBERR)\r
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goto fail;\r
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if (len == 1)\r
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I2CS |= bmLASTRD;\r
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\r
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*buf++ = I2DAT; // get data, trigger another read\r
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}\r
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// wait for final byte\r
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while ((I2CS & bmDONE) == 0)\r
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;\r
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if (I2CS & bmBERR)\r
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goto fail;\r
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I2CS |= bmSTOP;\r
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*buf = I2DAT;\r
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return 1;\r
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fail:\r
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I2CS |= bmSTOP;\r
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return 0;\r
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}\r
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// returns non-zero if successful, else 0\r
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unsigned char\r
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i2c_write (unsigned char addr, xdata const unsigned char *buf, unsigned char len)\r
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{\r
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while (I2CS & bmSTOP) // wait for stop to clear\r
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;\r
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I2CS = bmSTART;\r
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I2DAT = (addr << 1) | 0; // write address and direction (0's the write bit)\r
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while ((I2CS & bmDONE) == 0)\r
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;\r
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if ((I2CS & bmBERR) || (I2CS & bmACK) == 0) // no device answered...\r
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goto fail;\r
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while (len > 0){\r
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I2DAT = *buf++;\r
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len--;\r
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while ((I2CS & bmDONE) == 0)\r
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;\r
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if ((I2CS & bmBERR) || (I2CS & bmACK) == 0) // no device answered...\r
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goto fail;\r
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}\r
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I2CS |= bmSTOP;\r
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return 1;\r
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fail:\r
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I2CS |= bmSTOP;\r
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return 0;\r
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}\r
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projects / fx2fw-sdcc / blobdiff