eeprom_i2c.h

/****************************************************************************
 *  Genesis Plus
 *  I2C Serial EEPROM (24Cxx) support
 *
 *  Copyright (C) 2007-2013  Eke-Eke (Genesis Plus GX)
 *
 *  Redistribution and use of this code or any derivative works are permitted
 *  provided that the following conditions are met:
 *
 *   - Redistributions may not be sold, nor may they be used in a commercial
 *     product or activity.
 *
 *   - Redistributions that are modified from the original source must include the
 *     complete source code, including the source code for all components used by a
 *     binary built from the modified sources. However, as a special exception, the
 *     source code distributed need not include anything that is normally distributed
 *     (in either source or binary form) with the major components (compiler, kernel,
 *     and so on) of the operating system on which the executable runs, unless that
 *     component itself accompanies the executable.
 *
 *   - Redistributions must reproduce the above copyright notice, this list of
 *     conditions and the following disclaimer in the documentation and/or other
 *     materials provided with the distribution.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************************/

#ifndef _EEPROM_I2C_H_
#define _EEPROM_I2C_H_

typedef struct
{
  uint8 address_bits;     /* number of bits needed to address memory: 7, 8 or 16 */
  uint16 size_mask;       /* depends on the max size of the memory (in bytes) */
  uint16 pagewrite_mask;  /* depends on the maximal number of bytes that can be written in a single write cycle */
  uint32 sda_in_adr;      /* 68000 memory address mapped to SDA_IN */
  uint32 sda_out_adr;     /* 68000 memory address mapped to SDA_OUT */
  uint32 scl_adr;         /* 68000 memory address mapped to SCL */
  uint8 sda_in_bit;       /* bit offset for SDA_IN */
  uint8 sda_out_bit;      /* bit offset for SDA_OUT */
  uint8 scl_bit;          /* bit offset for SCL */
} T_CONFIG_I2C;

typedef enum
{
  STAND_BY = 0,
  WAIT_STOP,
  GET_SLAVE_ADR,
  GET_WORD_ADR_7BITS,
  GET_WORD_ADR_HIGH,
  GET_WORD_ADR_LOW,
  WRITE_DATA,
  READ_DATA
} T_STATE_I2C;

typedef struct
{
  uint8 sda;            /* current /SDA line state */
  uint8 scl;            /* current /SCL line state */
  uint8 old_sda;        /* previous /SDA line state */
  uint8 old_scl;        /* previous /SCL line state */
  uint8 cycles;         /* current operation cycle number (0-9) */
  uint8 rw;             /* operation type (1:READ, 0:WRITE) */
  uint16 slave_mask;    /* device address (shifted by the memory address width)*/
  uint16 word_address;  /* memory address */
  T_STATE_I2C state;    /* current operation state */
  T_CONFIG_I2C config;  /* EEPROM characteristics for this game */
} T_EEPROM_I2C;

extern T_EEPROM_I2C eeprom_i2c;

/* Function prototypes */
extern void eeprom_i2c_init();

#endif