fx2/firmware/include/i2c.h

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2013-10-02 10:43:54 +02:00
// Copyright (C) 2009 Ubixum, Inc.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
/** \file i2c.h
* Utilities for reading and writing to i2c devices and as eeproms.
**/
#ifndef I2C_H
#define I2C_H
#include "fx2types.h"
/**
* i2c_write and i2c_read set this to FALSE at the beginning of a
* transaction. If for some reason, the read/write is taking too
* long or not returning, firmware can set this to TRUE to cause the
* routine to abort. (Usually done via an interrupt).
**/
extern volatile __xdata BOOL cancel_i2c_trans;
/**
* \brief write data to i2c bus.
*
* Writes data from addr buffer 1st, then data buffer.
* Either buffer can be NULL (as long as you set lenN to 0).
*
* Two buffers allows writing data all in one i2c write command without
* having to write a hardware address and a data byte with each
* i2c transaction.
*
* \param addr i2c address
* \param len1 length of addr data
* \param addr_buf addr data
* \param len2 length of data
* \param data_buf data bytes
**/
BOOL i2c_write(BYTE addr, WORD len1, BYTE * addr_buf, WORD len2,
BYTE * data_buf);
/**
* \brief read data on the i2c bus.
*
* \param addr i2c address
* \param len number of bytes to read
* \param buf buffer to store data
**/
BOOL i2c_read(BYTE addr, WORD len, BYTE * buf);
/**
* \brief read data from an attached eeprom.
*
* Writes the address of the data to read then reads len bytes into buf.
* This function checks the I2CS register to determine if a one or two
* byte address eepom was detected on the i2c bus. Reading from proms
* at non-standard addresses my require using the i2c_read/write commands
* explicitly.
*
* \param prom_addr eeprom i2c address
* \param addr address of bytes to start reading
* \param len number of bytes to read
* \param buf data buffer
**/
BOOL eeprom_read(BYTE prom_addr, WORD addr, WORD len, BYTE * buf);
/**
* \brief write data to the eeprom
*
* This function checks the I2CS register to determin if a one or two
* two byte eeprom is detected. If the prom is not detected at boot time
* or is connected to alternate addresses, the i2c_read/write commands should
* be used explicitly insread of using this function.
*
* For each byte in buf, the address is written and then the data byte. Many
* proms support writing multiple bytes at the same time. For these, it is
* also better to use i2c_read/write explicitly. This function is rather slow
* but is effective.
*
* \param prom_addr eeprom i2c address
* \param addr address of bytes to start writing
* \param len number of bytes to write
* \param buf data buffer
**/
BOOL eeprom_write(BYTE prom_addr, WORD addr, WORD len, BYTE * buf);
#endif