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

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---------------------- Genesis Plus GX 1.6.0 ---------------------- [Core/Sound] --------------- * added YM2413 emulation in Master System compatibility mode. * fixed SN76489 noise boost initialization. * minor YM2612 core optimizations. [Core/VDP] --------------- * added accurate emulation of SG-1000, Master System (315-5124, 315-5246) & Game Gear VDP. * added support for all TMS9918 rendering modes. * improved Mega Drive VDP timings accuracy in Master System Compatibility mode. * fixed color palette initialization. * fixed shifted sprites rendering in Mode 4. * modified pixel rendering support (pixel depth is now forced at compilation time). [Core/CPU] --------------- * optimized 68k core (rewrote 68k interrupt handling, removed multiple CPU types support & unused code) for 5~8% speed improvment [Core/IO] --------------- * added accurate emulation of Master System (315-5216, 315-5237, 315-5297) & Game Gear I/O controllers. * added Terebi Oekaki tablet emulation. * improved Mouse emulation (fixes mouse support in Cannon Fodder). * improved Justifier emulation (fixes gun support in Lethal Enforcers 2). * improved 6-Buttons control pad emulation (fixes Duke Nukem 3D) * modified lightgun emulation to use common key inputs for all devices. * 2-buttons controller is now picked by default for Master System games. [Core/MD] --------------- * added copy-protection hardware emulation for some new dumped games (Tiny Toon Adventures 3, Mighty Morphin Power Rangers & The Battle of Red Cliffs). * added Game Toshokan in EEPROM database (verified on real cartridge). * fixed Micro Machines 2 - Turbo Tournament EEPROM size (verified on real cartridge). * modified SRAM banswitch hardware emulation to be more compatible with some hacks. [Core/MS] --------------- * added Cyborg Z to Korean mapper database. [Core/GG] --------------- * added 93C46 EEPROM emulation (Majors Pro Baseball, World Series Baseball & World Series Baseball 95). [Core/General] --------------- * added support for .mdx ROM format. * added Game Gear & SG-1000 ROM support. * added accurate emulation of SG-1000, Master System (I, II) & Game Gear hardware models for 100% compatibility. * updated to new Genesis Plus license (see http://cgfm2.emuviews.com/) * removed DOS port * various code cleanup. [Gamecube/Wii] --------------- * IMPORTANT: cheats, screenshots & save files are now stored in console-specific directories (ex: /snaps/md, /cheats/ms, /saves/gg, ...) * added 8-bit Action Replay & Game Genie codes support (for Master System & Game Gear games). * improved audio/video synchronization for PAL games in 50Hz TV modes (now use VSYNC like NTSC games in 60hz modes). * improved gun cursor positioning accuracy. * improved horizontal scaling & screenshots rendering in H32 mode. * fixed a bug with ROM file extension handling that would affect cheats, snapshots, sram & savestate files. * removed ARAM/injected ROM support (unused). * removed WPAD_ and PAD_ update from VSYNC callback. * increased GCC inlining limits for some speed improvment. * compiled with devkitPPC r24 & libogc 1.8.7.
2011-08-07 19:49:46 +02:00
/****************************************************************************
* 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.
*
****************************************************************************************/
#include "shared.h"
#define BIT_DATA (0)
#define BIT_CLK (1)
#define BIT_CS (2)
T_EEPROM_93C gg_eeprom;
void gg_eeprom_init()
{
/* default eeprom state */
memset(&gg_eeprom, 0, sizeof(T_EEPROM_93C));
gg_eeprom.data = 1;
gg_eeprom.state = WAIT_START;
}
void gg_eeprom_ctrl(unsigned char data)
{
/* Reset EEPROM */
if (data & 0x80)
{
gg_eeprom_init();
return;
}
/* Enable EEPROM */
gg_eeprom.enabled = data & 0x08;
}
void gg_eeprom_write(unsigned char data)
{
/* Make sure CS is HIGH */
if (data & (1 << BIT_CS))
{
/* Data latched on CLK postive edge */
if ((data & (1 << BIT_CLK)) && !gg_eeprom.clk)
{
/* Current EEPROM state */
switch (gg_eeprom.state)
{
case WAIT_START:
{
/* Wait for START bit */
if (data & (1 << BIT_DATA))
{
gg_eeprom.opcode = 0;
gg_eeprom.cycles = 0;
gg_eeprom.state = GET_OPCODE;
}
break;
}
case GET_OPCODE:
{
/* 8-bit buffer (opcode + address) */
gg_eeprom.opcode |= ((data >> BIT_DATA) & 1) << (7 - gg_eeprom.cycles);
gg_eeprom.cycles++;
if (gg_eeprom.cycles == 8)
{
/* Decode instruction */
switch ((gg_eeprom.opcode >> 6) & 3)
{
case 1:
{
/* WRITE */
gg_eeprom.buffer = 0;
gg_eeprom.cycles = 0;
gg_eeprom.state = WRITE_WORD;
break;
}
case 2:
{
/* READ */
gg_eeprom.buffer = *(uint16 *)(sram.sram + ((gg_eeprom.opcode & 0x3F) << 1));
gg_eeprom.cycles = 0;
gg_eeprom.state = READ_WORD;
/* Force DATA OUT */
gg_eeprom.data = 0;
break;
}
case 3:
{
/* ERASE */
if (gg_eeprom.we)
{
*(uint16 *)(sram.sram + ((gg_eeprom.opcode & 0x3F) << 1)) = 0xFFFF;
}
/* wait for next command */
gg_eeprom.state = WAIT_STANDBY;
break;
}
default:
{
/* special command */
switch ((gg_eeprom.opcode >> 4) & 3)
{
case 1:
{
/* WRITE ALL */
gg_eeprom.buffer = 0;
gg_eeprom.cycles = 0;
gg_eeprom.state = WRITE_WORD;
break;
}
case 2:
{
/* ERASE ALL */
if (gg_eeprom.we)
{
memset(sram.sram, 0xFF, 128);
}
/* wait for next command */
gg_eeprom.state = WAIT_STANDBY;
break;
}
default:
{
/* WRITE ENABLE/DISABLE */
gg_eeprom.we = (gg_eeprom.opcode >> 4) & 1;
/* wait for next command */
gg_eeprom.state = WAIT_STANDBY;
break;
}
}
break;
}
}
}
break;
}
case WRITE_WORD:
{
/* 16-bit data buffer */
gg_eeprom.buffer |= ((data >> BIT_DATA) & 1) << (15 - gg_eeprom.cycles);
gg_eeprom.cycles++;
if (gg_eeprom.cycles == 16)
{
/* check EEPROM write protection */
if (gg_eeprom.we)
{
if (gg_eeprom.opcode & 0x40)
{
/* write one word */
*(uint16 *)(sram.sram + ((gg_eeprom.opcode & 0x3F) << 1)) = gg_eeprom.buffer;
}
else
{
/* write 64 words */
int i;
for (i=0; i<64; i++)
{
*(uint16 *)(sram.sram + (i << 1)) = gg_eeprom.buffer;
}
}
}
/* wait for next command */
gg_eeprom.state = WAIT_STANDBY;
}
break;
}
case READ_WORD:
{
/* set DATA OUT */
gg_eeprom.data = ((gg_eeprom.buffer >> (15 - gg_eeprom.cycles)) & 1);
gg_eeprom.cycles++;
if (gg_eeprom.cycles == 16)
{
/* read next word (93C46B) */
gg_eeprom.opcode++;
gg_eeprom.cycles = 0;
gg_eeprom.buffer = *(uint16 *)(sram.sram + ((gg_eeprom.opcode & 0x3F) << 1));
}
break;
}
default:
{
/* wait for STANDBY mode */
break;
}
}
}
}
else
{
/* CS HIGH->LOW transition */
if (gg_eeprom.cs)
{
/* standby mode */
gg_eeprom.data = 1;
gg_eeprom.state = WAIT_START;
}
}
/* Update input lines */
gg_eeprom.cs = (data >> BIT_CS) & 1;
gg_eeprom.clk = (data >> BIT_CLK) & 1;
}
unsigned char gg_eeprom_read(void)
{
return ((gg_eeprom.cs << BIT_CS) | (gg_eeprom.data << BIT_DATA) | (1 << BIT_CLK));
}