Arduino + 24LC1025

**HFernandes** Ter Nov 15, 2011 10:57 pm

Este é um exemplo de um chip de EEPROM que testei com 1Mb e interface I2C da Microchip

Código:: /* Simple read & write to a 24LC256 256K EEPROM using the Wire library. * Addresses are ints - 0000-7FFF (32767) Data is bytes (8 bits x 32767 = 256K) * Functions for R/W of single byte or a page of bytes. Max page is 28 bytes. * SETUP: _ _ * Arduino GND- A0-|oU |-Vcc to Arduino Vcc * Arduino GND- A1-| |-WP to GND for now. Set to Vcc for write protection. * Arduino GND- A2-| |-SCL to Arduino 5 * Arduino GND-Vss-| |-SDA to Arduino 4 * --- (A2, A1, A0 to GND for 1010000 (0x50) address.) * If set to Vcc adds to address (1010,A2,A1,A0) */ #include <Wire.h> #define EEPROM_ADDR 0x51 // I2C Buss address of 24LC256 256K EEPROM void setup(){ Wire.begin(); // join I2C bus (address optional for master) Serial.begin(9600); Serial.println("\n----------------\n"); // TESTS FOR EACH FUNCTION BEGIN HERE Serial.println("Writing Test:"); for (int i=0; i<32; i++){ // loop for first 20 slots i2c_eeprom_write_byte(EEPROM_ADDR,i,77-i); // write address + 65 A or 97 a Serial.print(". "); delay(5); // NEED THIS DELAY! (tests suggest it can be as // small as delay(3) -- BBR } Serial.println(""); delay(500); Serial.println("Reading Test:"); for (int i=0; i<32; i++){ // loop for first 20 slots Serial.print(i2c_eeprom_read_byte(EEPROM_ADDR, i),BYTE); Serial.print(" "); } // setup for page tests . . . byte PageData[30]; // array that will hold test data for a page byte PageRead[30]; // array that will hold result of data for a page for (int i=0; i<30; i++){ // zero both arrays for next test PageData[i] = 0; PageRead[i] = 0; } Serial.println(""); for (int i=0; i<30; i++) PageData[i] = i+33; // fill up array for next test char 33 = ! Serial.println("Writing Page Test:"); Serial.println(millis()); i2c_eeprom_write_page(EEPROM_ADDR, 100, PageData, 28 ); // 28 bytes/page is max Serial.println(millis()); Serial.println("Reading Page Test:"); i2c_eeprom_read_buffer( EEPROM_ADDR, 100, PageRead, 28); for (int i=0; i<28; i++){ Serial.print(PageRead[i],BYTE); // display the array read Serial.print(" "); } } void loop(){ } void i2c_eeprom_write_byte( int deviceaddress, unsigned int eeaddress, byte data ) { int rdata = data; Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddress >> 8)); // Address High Byte Wire.send((int)(eeaddress & 0xFF)); // Address Low Byte Wire.send(rdata); Wire.endTransmission(); } // Address is a page address, 6-bit (63). More and end will wrap around // But data can be maximum of 28 bytes, because the Wire library has a buffer of 32 bytes void i2c_eeprom_write_page( int deviceaddress, unsigned int eeaddresspage, byte* data, byte length ) { Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddresspage >> 8)); // Address High Byte Wire.send((int)(eeaddresspage & 0xFF)); // Address Low Byte byte c; for ( c = 0; c < length; c++) Wire.send(data[c]); Wire.endTransmission(); delay(10); // need some delay } byte i2c_eeprom_read_byte( int deviceaddress, unsigned int eeaddress ) { byte rdata = 0xFF; Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddress >> 8)); // Address High Byte Wire.send((int)(eeaddress & 0xFF)); // Address Low Byte Wire.endTransmission(); Wire.requestFrom(deviceaddress,1); if (Wire.available()) rdata = Wire.receive(); return rdata; } // should not read more than 28 bytes at a time! void i2c_eeprom_read_buffer( int deviceaddress, unsigned int eeaddress, byte *buffer, int length ) { Wire.beginTransmission(deviceaddress); Wire.send((int)(eeaddress >> 8)); // Address High Byte Wire.send((int)(eeaddress & 0xFF)); // Address Low Byte Wire.endTransmission(); Wire.requestFrom(deviceaddress,length); //int c = 0; for ( int c = 0; c < length; c++ ) if (Wire.available()) buffer[c] = Wire.receive(); }

Datasheet

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