141 lines
4.5 KiB
C
141 lines
4.5 KiB
C
#include "eeprom_93C66.h"
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uint8* eeprom_93C66_storage;
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uint8 eeprom_93C66_opcode;
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uint8 eeprom_93C66_data;
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uint16 eeprom_93C66_address;
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uint8 eeprom_93C66_state;
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uint8 eeprom_93C66_lastCLK;
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uint8 eeprom_93C66_writeEnabled;
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uint8 eeprom_93C66_output;
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#define OPCODE_MISC 0
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#define OPCODE_WRITE 1
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#define OPCODE_READ 2
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#define OPCODE_ERASE 3
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#define OPCODE_WRITEDISABLE 10
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#define OPCODE_WRITEALL 11
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#define OPCODE_ERASEALL 12
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#define OPCODE_WRITEENABLE 13
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#define STATE_STANDBY 0
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#define STATE_STARTBIT 1
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#define STATE_OPCODE 3
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#define STATE_ADDRESS 12
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#define STATE_DATA 20
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#define STATE_FINISHED 99
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void eeprom_93C66_init ()
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{
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eeprom_93C66_address =0;
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eeprom_93C66_state =STATE_STANDBY;
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eeprom_93C66_lastCLK =0;
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eeprom_93C66_writeEnabled =0;
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}
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uint8 eeprom_93C66_read ()
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{
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return eeprom_93C66_output;
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}
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void eeprom_93C66_write (uint8 CS, uint8 CLK, uint8 DAT)
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{
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if (!CS && eeprom_93C66_state <= STATE_ADDRESS)
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eeprom_93C66_state =STATE_STANDBY;
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else
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if (eeprom_93C66_state ==STATE_STANDBY && CS && CLK)
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{
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eeprom_93C66_state =STATE_STARTBIT;
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eeprom_93C66_opcode =0;
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eeprom_93C66_address =0;
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eeprom_93C66_output =1;
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}
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else
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if (CLK && !eeprom_93C66_lastCLK)
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{
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if (eeprom_93C66_state >=STATE_STARTBIT && eeprom_93C66_state <STATE_OPCODE)
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eeprom_93C66_opcode =(eeprom_93C66_opcode <<1) | (DAT? 1: 0);
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else
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if (eeprom_93C66_state >=STATE_OPCODE && eeprom_93C66_state <STATE_ADDRESS)
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eeprom_93C66_address =(eeprom_93C66_address <<1) | (DAT? 1: 0);
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else
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if (eeprom_93C66_state >=STATE_ADDRESS && eeprom_93C66_state <STATE_DATA)
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{
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if (eeprom_93C66_opcode ==OPCODE_WRITE || eeprom_93C66_opcode ==OPCODE_WRITEALL)
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eeprom_93C66_data =(eeprom_93C66_data <<1) | (DAT? 1: 0);
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else
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if (eeprom_93C66_opcode ==OPCODE_READ)
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{
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eeprom_93C66_output =!!(eeprom_93C66_data &0x80);
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eeprom_93C66_data = eeprom_93C66_data <<1;
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}
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}
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eeprom_93C66_state++;
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if (eeprom_93C66_state ==STATE_ADDRESS) {
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switch (eeprom_93C66_opcode)
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{
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case OPCODE_MISC:
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eeprom_93C66_opcode =(eeprom_93C66_address >>7) + 10;
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switch (eeprom_93C66_opcode)
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{
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case OPCODE_WRITEDISABLE:
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eeprom_93C66_writeEnabled = 0;
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eeprom_93C66_state = STATE_FINISHED;
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break;
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case OPCODE_WRITEENABLE:
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eeprom_93C66_writeEnabled = 1;
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eeprom_93C66_state = STATE_FINISHED;
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break;
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case OPCODE_ERASEALL:
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if (eeprom_93C66_writeEnabled)
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{
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int i;
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for (i =0; i <512; i++)
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eeprom_93C66_storage[i] = 0xFF;
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}
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eeprom_93C66_state = STATE_FINISHED;
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break;
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case OPCODE_WRITEALL:
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eeprom_93C66_address = 0;
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break;
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}
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break;
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case OPCODE_ERASE:
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if (eeprom_93C66_writeEnabled) eeprom_93C66_storage[eeprom_93C66_address] = 0xFF;
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eeprom_93C66_state = STATE_FINISHED;
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break;
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case OPCODE_READ:
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eeprom_93C66_data = eeprom_93C66_storage[eeprom_93C66_address++];
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break;
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}
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}
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else
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if (eeprom_93C66_state ==STATE_DATA)
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{
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if (eeprom_93C66_opcode ==OPCODE_WRITE)
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{
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eeprom_93C66_storage[eeprom_93C66_address++] = eeprom_93C66_data;
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eeprom_93C66_state = STATE_FINISHED;
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}
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else
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if (eeprom_93C66_opcode ==OPCODE_WRITEALL)
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{
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eeprom_93C66_storage[eeprom_93C66_address++] = eeprom_93C66_data;
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eeprom_93C66_state = CS && eeprom_93C66_address <512? STATE_ADDRESS: STATE_FINISHED;
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}
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else
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if (eeprom_93C66_opcode ==OPCODE_READ)
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{
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if (eeprom_93C66_address <512) eeprom_93C66_data = eeprom_93C66_storage[eeprom_93C66_address];
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eeprom_93C66_state = CS && ++eeprom_93C66_address <=512? STATE_ADDRESS: STATE_FINISHED;
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}
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}
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if (eeprom_93C66_state == STATE_FINISHED)
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{
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eeprom_93C66_output = 0;
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eeprom_93C66_state = STATE_STANDBY;
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}
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}
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eeprom_93C66_lastCLK = CLK;
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}
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