Genesis-Plus-GX/source/cart_hw/gg_eeprom.h

76 lines
2.9 KiB
C

/****************************************************************************
* Genesis Plus
* Microwire Serial EEPROM (93C46) support
*
* Copyright (C) 2011 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 _GG_EEPROM_H_
#define _GG_EEPROM_H_
typedef enum
{
WAIT_STANDBY,
WAIT_START,
GET_OPCODE,
WRITE_WORD,
READ_WORD
} T_STATE;
typedef struct
{
uint8 enabled; /* 1: chip enabled */
uint8 cs; /* CHIP SELECT line state */
uint8 clk; /* CLK line state */
uint8 data; /* DATA OUT line state */
uint8 cycles; /* current operation cycle */
uint8 we; /* 1: write enabled */
uint8 opcode; /* 8-bit opcode + address */
uint16 buffer; /* 16-bit data buffer */
T_STATE state; /* current operation state */
} T_EEPROM_93C;
/* global variables */
extern T_EEPROM_93C gg_eeprom;
/* Function prototypes */
extern void gg_eeprom_init();
extern void gg_eeprom_ctrl(unsigned char data);
extern void gg_eeprom_write(unsigned char data);
extern unsigned char gg_eeprom_read(void);
#endif