mirror of
https://github.com/RobTillaart/Arduino.git
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256 lines
6.5 KiB
C++
256 lines
6.5 KiB
C++
//
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// FILE: I2C_eeprom.cpp
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// AUTHOR: Rob Tillaart
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// VERSION: 1.1.00
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// PURPOSE: I2C_eeprom library for Arduino with EEPROM 24LC256 et al.
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//
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// HISTORY:
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// 0.1.00 - 2011-01-21 initial version
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// 0.1.01 - 2011-02-07 added setBlock function
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// 0.2.00 - 2011-02-11 fixed 64 bit boundary bug
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// 0.2.01 - 2011-08-13 _readBlock made more robust + return value
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// 1.0.00 - 2013-06-09 support for Arduino 1.0.x
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// 1.0.01 - 2013-11-01 fixed writeBlock bug, refactor
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// 1.0.02 - 2013-11-03 optimize internal buffers, refactor
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// 1.0.03 - 2013-11-03 refactor 5 millis() write-latency
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// 1.0.04 - 2013-11-03 fix bug in readBlock, moved waitEEReady()
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// -> more efficient.
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// 1.0.05 - 2013-11-06 improved waitEEReady(),
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// added determineSize()
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// 1.1.00 - 2013-11-13 added begin() function (Note breaking interface)
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// use faster block Wire.write()
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// int casting removed
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// 1.2.00 - 2015-05-21 Added support for Arduino DUE ( thanks to Tyler F.)
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// 1.2.01 - 2013-05-21 Refactoring
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//
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// Released to the public domain
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//
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#include <I2C_eeprom.h>
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#if defined(ARDUINO) && ARDUINO >= 100
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#define WIRE_WRITE Wire.write
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#define WIRE_READ Wire.read
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#else
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#define WIRE_WRITE Wire.send
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#define WIRE_READ Wire.receive
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#endif
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I2C_eeprom::I2C_eeprom(uint8_t deviceAddress)
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{
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I2C_eeprom(deviceAddress, I2C_EEPROM_PAGESIZE);
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}
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I2C_eeprom::I2C_eeprom(uint8_t deviceAddress, unsigned int deviceSize)
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{
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_deviceAddress = deviceAddress;
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// Chips 16Kbit (2048KB) or smaller only have one-word addresses.
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// Also try to guess page size from device size (going by Microchip 24LCXX datasheets here).
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if (deviceSize <= 256)
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{
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this->_isAddressSizeTwoWords = false;
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this->_pageSize = 8;
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}
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else if (deviceSize <= 256 * 8)
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{
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this->_isAddressSizeTwoWords = false;
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this->_pageSize = 16;
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}
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else
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{
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this->_isAddressSizeTwoWords = true;
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this->_pageSize = 32;
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}
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}
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void I2C_eeprom::begin()
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{
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Wire.begin();
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_lastWrite = 0;
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// TWBR is not available on Arduino Due
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#ifdef TWBR
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TWBR = 72;
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// 0=1000 1=888 2=800 8=500
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// 12=400KHz 24=250 32=200 72=100 152=50
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// F_CPU/16+(2*TWBR) // TWBR is a uint8_t
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#endif
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}
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int I2C_eeprom::writeByte(uint16_t memoryAddress, uint8_t data)
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{
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int rv = _WriteBlock(memoryAddress, &data, 1);
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return rv;
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}
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int I2C_eeprom::setBlock(uint16_t memoryAddress, uint8_t data, uint16_t length)
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{
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uint8_t buffer[I2C_TWIBUFFERSIZE];
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for (uint8_t i = 0; i< I2C_TWIBUFFERSIZE; i++) buffer[i] = data;
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int rv = _pageBlock(memoryAddress, buffer, length, false);
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return rv;
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}
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int I2C_eeprom::writeBlock(uint16_t memoryAddress, uint8_t* buffer, uint16_t length)
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{
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int rv = _pageBlock(memoryAddress, buffer, length, true);
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return rv;
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}
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uint8_t I2C_eeprom::readByte(uint16_t memoryAddress)
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{
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uint8_t rdata;
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_ReadBlock(memoryAddress, &rdata, 1);
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return rdata;
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}
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uint16_t I2C_eeprom::readBlock(uint16_t memoryAddress, uint8_t* buffer, uint16_t length)
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{
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uint16_t rv = 0;
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while (length > 0)
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{
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uint8_t cnt = min(length, I2C_TWIBUFFERSIZE);
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rv += _ReadBlock(memoryAddress, buffer, cnt);
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memoryAddress += cnt;
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buffer += cnt;
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length -= cnt;
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}
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return rv;
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}
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#ifdef I2C_EEPROM_EXTENDED
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// returns 64, 32, 16, 8, 4, 2, 1, 0
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// 0 is smaller than 1K
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uint8_t I2C_eeprom::determineSize()
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{
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uint8_t rv = 0; // unknown
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uint8_t orgValues[8];
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uint16_t addr;
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// remember old values, non destructive
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for (uint8_t i=0; i<8; i++)
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{
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addr = (512 << i) + 1;
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orgValues[i] = readByte(addr);
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}
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// scan page folding
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for (uint8_t i=0; i<8; i++)
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{
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rv = i;
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uint16_t addr1 = (512 << i) + 1;
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uint16_t addr2 = (512 << (i+1)) + 1;
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writeByte(addr1, 0xAA);
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writeByte(addr2, 0x55);
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if (readByte(addr1) == 0x55) // folded!
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{
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break;
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}
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}
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// restore original values
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for (uint8_t i=0; i<8; i++)
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{
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uint16_t addr = (512 << i) + 1;
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writeByte(addr, orgValues[i]);
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}
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return 0x01 << (rv-1);
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}
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#endif
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////////////////////////////////////////////////////////////////////
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//
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// PRIVATE
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//
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// _pageBlock aligns buffer to page boundaries for writing.
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// and to TWI buffer size
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// returns 0 = OK otherwise error
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int I2C_eeprom::_pageBlock(uint16_t address, uint8_t* buffer, uint16_t length, bool incrBuffer)
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{
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int rv = 0;
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while (length > 0)
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{
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uint8_t bytesUntilPageBoundary = this->_pageSize - address % this->_pageSize;
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uint8_t cnt = min(length, bytesUntilPageBoundary);
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cnt = min(cnt, I2C_TWIBUFFERSIZE);
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int rv = _WriteBlock(address, buffer, cnt);
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if (rv != 0) return rv;
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address += cnt;
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if (incrBuffer) buffer += cnt;
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length -= cnt;
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}
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return rv;
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}
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// supports one and 2 bytes addresses
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void I2C_eeprom::_beginTransmission(uint16_t memoryAddress)
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{
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Wire.beginTransmission(_deviceAddress);
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if (this->_isAddressSizeTwoWords)
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{
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WIRE_WRITE((memoryAddress >> 8)); // Address High Byte
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}
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WIRE_WRITE((memoryAddress & 0xFF)); // Address Low Byte (or only byte for chips 16K or smaller that only have one-word addresses)
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}
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// pre: length <= this->_pageSize && length <= I2C_TWIBUFFERSIZE;
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// returns 0 = OK otherwise error
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int I2C_eeprom::_WriteBlock(uint16_t memoryAddress, uint8_t* buffer, uint8_t length)
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{
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waitEEReady();
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this->_beginTransmission(memoryAddress);
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WIRE_WRITE(buffer, length);
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int rv = Wire.endTransmission();
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_lastWrite = micros();
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return rv;
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}
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// pre: buffer is large enough to hold length bytes
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// returns bytes read
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uint8_t I2C_eeprom::_ReadBlock(uint16_t memoryAddress, uint8_t* buffer, uint8_t length)
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{
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waitEEReady();
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this->_beginTransmission(memoryAddress);
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int rv = Wire.endTransmission();
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if (rv != 0) return 0; // error
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Wire.requestFrom(_deviceAddress, length);
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uint8_t cnt = 0;
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uint32_t before = millis();
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while ((cnt < length) && ((millis() - before) < I2C_EEPROM_TIMEOUT))
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{
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if (Wire.available()) buffer[cnt++] = WIRE_READ();
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}
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return cnt;
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}
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void I2C_eeprom::waitEEReady()
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{
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#define I2C_WRITEDELAY 5000
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// Wait until EEPROM gives ACK again.
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// this is a bit faster than the hardcoded 5 milliSeconds
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while ((micros() - _lastWrite) <= I2C_WRITEDELAY)
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{
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Wire.beginTransmission(_deviceAddress);
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int x = Wire.endTransmission();
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if (x == 0) break;
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}
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}
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// END OF FILE
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