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Generalized the 93C66 EEPROM emulation to other capacities, and add 16-bit word size support. Update mapper 529 to use 93C56 EEPROM in 16-bit mode.

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NewRisingSun
2025-04-07 22:22:44 +02:00
committed by LibretroAdmin
parent 6cbb11bdd1
commit 553865663d
7 changed files with 201 additions and 162 deletions
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162
src/boards/eeprom_93Cx6.c Normal file
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#include "eeprom_93Cx6.h"
uint8* eeprom_93Cx6_storage;
uint8 eeprom_93Cx6_opcode;
uint16 eeprom_93Cx6_data;
uint16 eeprom_93Cx6_address;
uint8 eeprom_93Cx6_state;
uint8 eeprom_93Cx6_lastCLK;
uint8 eeprom_93Cx6_writeEnabled;
uint8 eeprom_93Cx6_output;
size_t eeprom_93Cx6_capacity;
uint8 eeprom_93Cx6_wordSize;
static uint8 STATE_ADDRESS;
static uint8 STATE_DATA;
#define OPCODE_MISC 0
#define OPCODE_WRITE 1
#define OPCODE_READ 2
#define OPCODE_ERASE 3
#define OPCODE_WRITEDISABLE 10
#define OPCODE_WRITEALL 11
#define OPCODE_ERASEALL 12
#define OPCODE_WRITEENABLE 13
#define STATE_STANDBY 0
#define STATE_STARTBIT 1
#define STATE_OPCODE 3
#define STATE_ADDRESS8 12
#define STATE_DATA8 20
#define STATE_ADDRESS16 11
#define STATE_DATA16 27
#define STATE_FINISHED 99
void eeprom_93Cx6_init (size_t capacity, uint8 wordSize) {
eeprom_93Cx6_capacity =capacity;
eeprom_93Cx6_wordSize =wordSize;
eeprom_93Cx6_address =0;
eeprom_93Cx6_state =STATE_STANDBY;
eeprom_93Cx6_lastCLK =0;
eeprom_93Cx6_writeEnabled =0;
STATE_ADDRESS =wordSize ==16? STATE_ADDRESS16: STATE_ADDRESS8;
STATE_DATA =wordSize ==16? STATE_DATA16: STATE_DATA8;
if (capacity ==128) {
STATE_ADDRESS -=2;
STATE_DATA -=2;
}
}
uint8 eeprom_93Cx6_read () {
return eeprom_93Cx6_output;
}
void eeprom_93Cx6_write (uint8 CS, uint8 CLK, uint8 DAT) {
if (!CS && eeprom_93Cx6_state <= STATE_ADDRESS)
eeprom_93Cx6_state =STATE_STANDBY;
else
if (eeprom_93Cx6_state ==STATE_STANDBY && CS && CLK && !eeprom_93Cx6_lastCLK) {
if (DAT) eeprom_93Cx6_state =STATE_STARTBIT;
eeprom_93Cx6_opcode =0;
eeprom_93Cx6_address =0;
eeprom_93Cx6_output =1;
} else
if (CLK && !eeprom_93Cx6_lastCLK && eeprom_93Cx6_state >=STATE_STARTBIT) {
if (eeprom_93Cx6_state >=STATE_STARTBIT && eeprom_93Cx6_state <STATE_OPCODE)
eeprom_93Cx6_opcode =(eeprom_93Cx6_opcode <<1) | (DAT? 1: 0);
else
if (eeprom_93Cx6_state >=STATE_OPCODE && eeprom_93Cx6_state <STATE_ADDRESS)
eeprom_93Cx6_address =(eeprom_93Cx6_address <<1) | (DAT? 1: 0);
else
if (eeprom_93Cx6_state >=STATE_ADDRESS && eeprom_93Cx6_state <STATE_DATA) {
if (eeprom_93Cx6_opcode ==OPCODE_WRITE || eeprom_93Cx6_opcode ==OPCODE_WRITEALL)
eeprom_93Cx6_data =(eeprom_93Cx6_data <<1) | (DAT? 1: 0);
else
if (eeprom_93Cx6_opcode ==OPCODE_READ) {
eeprom_93Cx6_output =eeprom_93Cx6_wordSize ==16? !!(eeprom_93Cx6_data &0x8000): !!(eeprom_93Cx6_data &0x80);
eeprom_93Cx6_data = eeprom_93Cx6_data <<1;
}
}
eeprom_93Cx6_state++;
if (eeprom_93Cx6_state ==STATE_ADDRESS) {
switch (eeprom_93Cx6_opcode) {
case OPCODE_MISC:
eeprom_93Cx6_opcode =(eeprom_93Cx6_address >>(eeprom_93Cx6_wordSize ==16? 6: 7)) + 10;
switch (eeprom_93Cx6_opcode) {
case OPCODE_WRITEDISABLE:
eeprom_93Cx6_writeEnabled = 0;
eeprom_93Cx6_state = STATE_FINISHED;
break;
case OPCODE_WRITEENABLE:
eeprom_93Cx6_writeEnabled = 1;
eeprom_93Cx6_state = STATE_FINISHED;
break;
case OPCODE_ERASEALL:
if (eeprom_93Cx6_writeEnabled) {
int i;
for (i =0; i <eeprom_93Cx6_capacity; i++)
eeprom_93Cx6_storage[i] = 0xFF;
}
eeprom_93Cx6_state = STATE_FINISHED;
break;
case OPCODE_WRITEALL:
eeprom_93Cx6_address = 0;
break;
}
break;
case OPCODE_ERASE:
if (eeprom_93Cx6_writeEnabled) {
if (eeprom_93Cx6_wordSize ==16) {
eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |0] = 0xFF;
eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |1] = 0xFF;
} else
eeprom_93Cx6_storage[eeprom_93Cx6_address] = 0xFF;
}
eeprom_93Cx6_state = STATE_FINISHED;
break;
case OPCODE_READ:
if (eeprom_93Cx6_wordSize ==16) {
eeprom_93Cx6_data = eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |0] | eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |1] <<8;
eeprom_93Cx6_address++;
} else
eeprom_93Cx6_data = eeprom_93Cx6_storage[eeprom_93Cx6_address++];
break;
}
} else
if (eeprom_93Cx6_state ==STATE_DATA) {
if (eeprom_93Cx6_opcode ==OPCODE_WRITE) {
if (eeprom_93Cx6_wordSize ==16) {
eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |0] = eeprom_93Cx6_data &0xFF;
eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |1] = eeprom_93Cx6_data >>8;
eeprom_93Cx6_address++;
} else
eeprom_93Cx6_storage[eeprom_93Cx6_address++] = eeprom_93Cx6_data;
eeprom_93Cx6_state = STATE_FINISHED;
} else
if (eeprom_93Cx6_opcode ==OPCODE_WRITEALL) {
if (eeprom_93Cx6_wordSize ==16) {
eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |0] = eeprom_93Cx6_data &0xFF;
eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |1] = eeprom_93Cx6_data >>8;
eeprom_93Cx6_address++;
} else
eeprom_93Cx6_storage[eeprom_93Cx6_address++] = eeprom_93Cx6_data;
eeprom_93Cx6_state = CS && eeprom_93Cx6_address <eeprom_93Cx6_capacity? STATE_ADDRESS: STATE_FINISHED;
} else
if (eeprom_93Cx6_opcode ==OPCODE_READ) {
if (eeprom_93Cx6_address <eeprom_93Cx6_capacity) {
if (eeprom_93Cx6_wordSize ==16)
eeprom_93Cx6_data = eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |0] | eeprom_93Cx6_storage[eeprom_93Cx6_address <<1 |1] <<8;
else
eeprom_93Cx6_data = eeprom_93Cx6_storage[eeprom_93Cx6_address];
}
eeprom_93Cx6_state = CS && ++eeprom_93Cx6_address <=eeprom_93Cx6_capacity? STATE_ADDRESS: STATE_FINISHED;
}
}
if (eeprom_93Cx6_state == STATE_FINISHED) {
eeprom_93Cx6_output = 0;
eeprom_93Cx6_state = STATE_STANDBY;
}
}
if (eeprom_93Cx6_opcode ==OPCODE_READ && eeprom_93Cx6_state ==(STATE_ADDRESS -2)) eeprom_93Cx6_output =0; /* Dummy Zero */
eeprom_93Cx6_lastCLK = CLK;
}