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73 lines
2.8 KiB
C
73 lines
2.8 KiB
C
/****************************************************************************
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* Genesis Plus
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* Microwire Serial EEPROM (93C46 only) support
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*
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* Copyright (C) 2011 Eke-Eke (Genesis Plus GX)
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*
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* Redistribution and use of this code or any derivative works are permitted
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* provided that the following conditions are met:
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*
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* - Redistributions may not be sold, nor may they be used in a commercial
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* product or activity.
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*
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* - Redistributions that are modified from the original source must include the
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* complete source code, including the source code for all components used by a
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* binary built from the modified sources. However, as a special exception, the
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* source code distributed need not include anything that is normally distributed
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* (in either source or binary form) with the major components (compiler, kernel,
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* and so on) of the operating system on which the executable runs, unless that
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* component itself accompanies the executable.
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*
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* - Redistributions must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other
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* materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************************/
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#ifndef _EEPROM_93C_H_
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#define _EEPROM_93C_H_
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typedef enum
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{
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WAIT_STANDBY,
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WAIT_START,
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GET_OPCODE,
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WRITE_WORD,
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READ_WORD
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} T_STATE_93C;
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typedef struct
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{
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uint8 enabled; /* 1: chip enabled */
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uint8 cs; /* CHIP SELECT line state */
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uint8 clk; /* CLK line state */
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uint8 data; /* DATA OUT line state */
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uint8 cycles; /* current operation cycle */
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uint8 we; /* 1: write enabled */
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uint8 opcode; /* 8-bit opcode + address */
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uint16 buffer; /* 16-bit data buffer */
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T_STATE_93C state; /* current operation state */
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} T_EEPROM_93C;
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/* global variables */
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extern T_EEPROM_93C eeprom_93c;
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/* Function prototypes */
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extern void eeprom_93c_init();
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extern void eeprom_93c_write(unsigned char data);
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extern unsigned char eeprom_93c_read(void);
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#endif
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