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Genesis-Plus-GX/source/cart_hw/eeprom.c

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/****************************************************************************
* Genesis Plus 1.2a
* Serial EEPROM support
*
* Copyright (C) Eke-Eke, GC/Wii port
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
***************************************************************************/
#include "shared.h"
typedef struct
{
char game_id[14];
uint16 chk;
T_EEPROM_TYPE type;
} T_GAME_ENTRY;
T_GAME_ENTRY database[25] =
{
/* ACCLAIM mappers */
/* 24C02 (old mapper) */
{{"T-081326" }, 0, {8, 0xFF, 0xFF, 0x200001, 0x200001, 0x200001, 0, 1, 1}}, /* NBA Jam (UE) */
{{"T-81033" }, 0, {8, 0xFF, 0xFF, 0x200001, 0x200001, 0x200001, 0, 1, 1}}, /* NBA Jam (J) */
/* 24C02 */
{{"T-81406" }, 0, {8, 0xFF, 0xFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* NBA Jam TE */
{{"T-081276" }, 0, {8, 0xFF, 0xFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* NFL Quarterback Club */
/* 24C16 */
{{"T-081586" }, 0, {8, 0x7FF, 0x7FF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* NFL Quarterback Club '96 */
/* 24C65 */
{{"T-81576" }, 0, {16, 0x1FFF, 0x1FFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* College Slam */
{{"T-81476" }, 0, {16, 0x1FFF, 0x1FFF, 0x200001, 0x200001, 0x200000, 0, 0, 0}}, /* Frank Thomas Big Hurt Baseball */
/* EA mapper (24C01 only) */
{{"T-50396" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 7, 7, 6}}, /* NHLPA Hockey 93 (UE) */
{{"T-50176" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 7, 7, 6}}, /* Rings of Power */
/* SEGA mapper (24C01 only) */
{{"T-12046" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Megaman - The Wily Wars */
{{"T-12053" }, 0xEA80, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Rockman Mega World (J) [A] */
{{"MK-1215" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Evander 'Real Deal' Holyfield's Boxing */
{{"MK-1228" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Greatest Heavyweights of the Ring (U) */
{{"G-5538" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Greatest Heavyweights of the Ring (J) */
{{"PR-1993" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Greatest Heavyweights of the Ring (E) */
{{"G-4060" }, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Wonderboy in Monster World */
{{"00001211-00"}, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Sports Talk Baseball */
{{"00004076-00"}, 0, {7, 0x7F, 0x7F, 0x200001, 0x200001, 0x200001, 0, 0, 1}}, /* Honoo no Toukyuuji Dodge Danpei */
/* CODEMASTERS mapper */
/* 24C01 */
{{"T-120106"}, 0, {7, 0x7F, 0x7F, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Brian Lara Cricket */
/* 24C08 */
{{"T-120096" }, 0, {8, 0x3FF, 0x3FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines 2 - Turbo Tournament (E) */
{{"00000000-00"}, 0x168B, {8, 0x3FF, 0x3FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines Military */
{{"00000000-00"}, 0xCEE0, {8, 0x3FF, 0x3FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines Military (Bad)*/
/* 24C16 */
{{"00000000-00"}, 0x165E, {8, 0x7FF, 0x7FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines Turbo Tournament 96 */
{{"00000000-00"}, 0x2C41, {8, 0x7FF, 0x7FF, 0x300000, 0x380001, 0x300000, 0, 7, 1}}, /* Micro Machines Turbo Tournament 96 (Bad)*/
/* 24C65 */
{{"T-120146-50"}, 0, {16, 0x1FFF, 0x1FFF, 0x300000, 0x380001, 0x300000, 0, 7, 1}} /* Brian Lara Cricket 96, Shane Warne Cricket */
};
T_EEPROM eeprom;
void eeprom_init()
{
uint8 i = 0;
/* initialize eeprom */
memset(&eeprom, 0, sizeof(T_EEPROM));
eeprom.sda = eeprom.old_sda = 1;
eeprom.scl = eeprom.old_scl = 1;
eeprom.state = STAND_BY;
sram.custom = 0;
/* look into game database */
while ((i<25) && (!sram.custom))
{
if (strstr(rominfo.product,database[i].game_id) != NULL)
{
/* additional check (Micro Machines, Rockman Mega World) */
if ((database[i].chk == 0) || (database[i].chk == rominfo.checksum))
{
sram.custom = 1;
sram.on = 1;
sram.write = 1;
memcpy(&eeprom.type, &database[i].type, sizeof(T_EEPROM_TYPE));
}
}
i++;
}
/* Game not found in database but header seems to indicate it uses EEPROM */
if (!sram.custom)
{
if ((sram.end - sram.start) < 2)
{
sram.custom = 1;
sram.on = 1;
sram.write = 1;
/* set SEGA mapper as default */
memcpy(&eeprom.type, &database[9].type, sizeof(T_EEPROM_TYPE));
}
}
}
static inline void Detect_START()
{
if (eeprom.old_scl && eeprom.scl)
{
if (eeprom.old_sda && !eeprom.sda)
{
eeprom.cycles = 0;
eeprom.slave_mask = 0;
if (eeprom.type.address_bits == 7)
{
eeprom.word_address = 0;
eeprom.state = GET_WORD_ADR_7BITS;
}
else eeprom.state = GET_SLAVE_ADR;
}
}
}
static inline void Detect_STOP()
{
if (eeprom.old_scl && eeprom.scl)
{
if (!eeprom.old_sda && eeprom.sda)
{
eeprom.state = STAND_BY;
}
}
}
void eeprom_write(uint32 address, uint32 value, uint32 word_access)
{
/* decode SCL and SDA value */
if (word_access)
{
/* 16-bits access */
if (eeprom.type.sda_in_adr == address) eeprom.sda = (value >> (8 + eeprom.type.sda_in_bit)) & 1; /* MSB */
else if (eeprom.type.sda_in_adr == (address | 1)) eeprom.sda = (value >> eeprom.type.sda_in_bit) & 1; /* LSB */
else eeprom.sda = eeprom.old_sda;
if (eeprom.type.scl_adr == address) eeprom.scl = (value >> (8 + eeprom.type.scl_bit)) & 1; /* MSB */
else if (eeprom.type.scl_adr == (address | 1)) eeprom.scl = (value >> eeprom.type.scl_bit) & 1; /* LSB */
else eeprom.scl = eeprom.old_scl;
}
else
{
if (eeprom.type.sda_in_adr == address) eeprom.sda = (value >> eeprom.type.sda_in_bit) & 1;
else eeprom.sda = eeprom.old_sda;
if (eeprom.type.scl_adr == address) eeprom.scl = (value >> eeprom.type.scl_bit) & 1;
else eeprom.scl = eeprom.old_scl;
}
/* EEPROM current state */
switch (eeprom.state)
{
/* Standby Mode */
case STAND_BY:
Detect_START();
Detect_STOP();
break;
/* Suspended Mode */
case WAIT_STOP:
Detect_STOP();
break;
/* Get Word Address 7 bits: MODE-1 only (24C01)
* and R/W bit
*/
case GET_WORD_ADR_7BITS:
Detect_START();
Detect_STOP();
/* look for SCL LOW to HIGH transition */
if (!eeprom.old_scl && eeprom.scl)
{
if (eeprom.cycles == 0) eeprom.cycles ++;
}
/* look for SCL HIGH to LOW transition */
if (eeprom.old_scl && !eeprom.scl && (eeprom.cycles > 0))
{
if (eeprom.cycles < 8)
{
eeprom.word_address |= (eeprom.old_sda << (7 - eeprom.cycles));
}
else if (eeprom.cycles == 8)
{
eeprom.rw = eeprom.old_sda;
}
else
{ /* ACK CYCLE */
eeprom.cycles = 0;
eeprom.word_address &= eeprom.type.size_mask;
eeprom.state = eeprom.rw ? READ_DATA : WRITE_DATA;
}
eeprom.cycles ++;
}
break;
/* Get Slave Address (3bits) : MODE-2 & MODE-3 only (24C01 - 24C512) (0-3bits, depending on the array size)
* or/and Word Address MSB: MODE-2 only (24C04 - 24C16) (0-3bits, depending on the array size)
* and R/W bit
*/
case GET_SLAVE_ADR:
Detect_START();
Detect_STOP();
/* look for SCL LOW to HIGH transition */
if (!eeprom.old_scl && eeprom.scl)
{
if (eeprom.cycles == 0) eeprom.cycles ++;
}
/* look for SCL HIGH to LOW transition */
if (eeprom.old_scl && !eeprom.scl && (eeprom.cycles > 0))
{
if ((eeprom.cycles > 4) && (eeprom.cycles <8))
{
if ((eeprom.type.address_bits == 16) ||
(eeprom.type.size_mask < (1 << (15 - eeprom.cycles))))
{
/* this is a SLAVE ADDRESS bit */
eeprom.slave_mask |= (eeprom.old_sda << (7 - eeprom.cycles));
}
else
{
/* this is a WORD ADDRESS high bit */
if (eeprom.old_sda) eeprom.word_address |= (1 << (15 - eeprom.cycles));
else eeprom.word_address &= ~(1 << (15 - eeprom.cycles));
}
}
else if (eeprom.cycles == 8) eeprom.rw = eeprom.old_sda;
else if (eeprom.cycles > 8)
{
/* ACK CYCLE */
eeprom.cycles = 0;
if (eeprom.type.address_bits == 16)
{
/* two ADDRESS bytes */
eeprom.state = eeprom.rw ? READ_DATA : GET_WORD_ADR_HIGH;
eeprom.slave_mask <<= 16;
}
else
{
/* one ADDRESS byte */
eeprom.state = eeprom.rw ? READ_DATA : GET_WORD_ADR_LOW;
eeprom.slave_mask <<= 8;
}
}
eeprom.cycles ++;
}
break;
/* Get Word Address MSB (4-8bits depending on the array size)
* MODE-3 only (24C32 - 24C512)
*/
case GET_WORD_ADR_HIGH:
Detect_START();
Detect_STOP();
/* look for SCL HIGH to LOW transition */
if (eeprom.old_scl && !eeprom.scl)
{
if (eeprom.cycles < 9)
{
if ((eeprom.type.size_mask + 1) < (1 << (17 - eeprom.cycles)))
{
/* ignored bit: slave mask should be right-shifted by one */
eeprom.slave_mask >>= 1;
}
else
{
/* this is a WORD ADDRESS high bit */
if (eeprom.old_sda) eeprom.word_address |= (1 << (16 - eeprom.cycles));
else eeprom.word_address &= ~(1 << (16 - eeprom.cycles));
}
eeprom.cycles ++;
}
else
{
/* ACK CYCLE */
eeprom.cycles = 1;
eeprom.state = GET_WORD_ADR_LOW;
}
}
break;
/* Get Word Address LSB: 7bits (24C01) or 8bits (24C02-24C512)
* MODE-2 and MODE-3 only (24C01 - 24C512)
*/
case GET_WORD_ADR_LOW:
Detect_START();
Detect_STOP();
/* look for SCL HIGH to LOW transition */
if (eeprom.old_scl && !eeprom.scl)
{
if (eeprom.cycles < 9)
{
if ((eeprom.type.size_mask + 1) < (1 << (9 - eeprom.cycles)))
{
/* ignored bit (X24C01): slave mask should be right-shifted by one */
eeprom.slave_mask >>= 1;
}
else
{
/* this is a WORD ADDRESS high bit */
if (eeprom.old_sda) eeprom.word_address |= (1 << (8 - eeprom.cycles));
else eeprom.word_address &= ~(1 << (8 - eeprom.cycles));
}
eeprom.cycles ++;
}
else
{
/* ACK CYCLE */
eeprom.cycles = 1;
eeprom.word_address &= eeprom.type.size_mask;
eeprom.state = WRITE_DATA;
}
}
break;
/*
* Read Cycle
*/
case READ_DATA:
Detect_START();
Detect_STOP();
/* look for SCL HIGH to LOW transition */
if (eeprom.old_scl && !eeprom.scl)
{
if (eeprom.cycles < 9) eeprom.cycles ++;
else
{
eeprom.cycles = 1;
/* ACK not received */
if (eeprom.old_sda) eeprom.state = WAIT_STOP;
}
}
break;
/*
* Write Cycle
*/
case WRITE_DATA:
Detect_START();
Detect_STOP();
/* look for SCL HIGH to LOW transition */
if (eeprom.old_scl && !eeprom.scl)
{
if (eeprom.cycles < 9)
{
/* Write DATA bits (max 64kBytes) */
uint16 sram_address = (eeprom.slave_mask | eeprom.word_address) & 0xFFFF;
if (eeprom.old_sda) sram.sram[sram_address] |= (1 << (8 - eeprom.cycles));
else sram.sram[sram_address] &= ~(1 << (8 - eeprom.cycles));
if (eeprom.cycles == 8)
{
/* WORD ADDRESS is incremented (roll up at maximum pagesize) */
eeprom.word_address = (eeprom.word_address & (0xFFFF - eeprom.type.pagewrite_mask)) |
((eeprom.word_address + 1) & eeprom.type.pagewrite_mask);
}
eeprom.cycles ++;
}
else eeprom.cycles = 1; /* ACK cycle */
}
break;
}
eeprom.old_scl = eeprom.scl;
eeprom.old_sda = eeprom.sda;
}
uint32 eeprom_read(uint32 address, uint32 word_access)
{
uint8 sda_out = eeprom.sda;
/* EEPROM state */
switch (eeprom.state)
{
case READ_DATA:
if (eeprom.cycles < 9)
{
/* Return DATA bits (max 64kBytes) */
uint16 sram_address = (eeprom.slave_mask | eeprom.word_address) & 0xffff;
sda_out = (sram.sram[sram_address] >> (8 - eeprom.cycles)) & 1;
if (eeprom.cycles == 8)
{
/* WORD ADDRESS is incremented (roll up at maximum array size) */
eeprom.word_address ++;
eeprom.word_address &= eeprom.type.size_mask;
}
}
break;
case GET_WORD_ADR_7BITS:
case GET_SLAVE_ADR:
case GET_WORD_ADR_HIGH:
case GET_WORD_ADR_LOW:
case WRITE_DATA:
if (eeprom.cycles == 9) sda_out = 0;
break;
default:
break;
}
/* memory access */
if (word_access)
{
/* 16-bits access */
if (eeprom.type.sda_out_adr & 1) return (sda_out << eeprom.type.sda_out_bit); /* LSB */
else return (sda_out << (eeprom.type.sda_out_bit + 8)); /* MSB */
}
else return (sda_out << eeprom.type.sda_out_bit);
}
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