Class to provide simple access to I2C EEPROM chiles like Microchip's 24LC range or AMTELS AT24C range. Chips up to 64Kb in size are directly supported. Updated to Mbed OS v 5.1
I2CEeprom.h
- Committer:
- skyscraper
- Date:
- 2020-03-28
- Revision:
- 4:d8f51b136dbd
- Parent:
- 2:f3188aaccf80
- Child:
- 5:315872eec0ae
File content as of revision 4:d8f51b136dbd:
#ifndef __I2CEEPROM_H__ #define __I2CEEPROM_H__ /* Simple access class for I2C EEPROM chips like Microchip 24LC * Copyright (c) 2015 Robin Hourahane * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <mbed.h> /// Class to provide simple access to I2C EEPROM chips like Microchip's 24LC range /// or AMTELS AT24C range. /// Chips up to 64Kb in size are directly supported. /// The class handles multiple page writes so any amount of data can be written in /// a single call to write. /// /// Although not tested it should work with the MAC versions of Microchip range /// as well but the chipSize will need to be set to include the ROM area as well. class I2CEeprom { public: /// Constructor to create a new instance of the class. /// @param i2c a reference to the i2c bus the chip is connected to. /// @param address The 8bit I2C address of the chip in the range 0xA0 - 0xAE. /// @param pageSize The size of the page used in writing to the chip. /// @param chipSize The size of the memory in the chip to allow range checkng. Set to /// 0 to disable checks. /// @param The write cycle time in ms. /// TODO : Could use bus frequency to cap the speed of the bus I2CEeprom( I2C& i2c, int address, size_t pageSize, size_t chipSize, uint8_t write_cycle_time_ms); /// Read a single byte from the address in memory. /// @param address Memory address to read from. /// @param value Variable to receive value read. /// @returns Number of bytes read from memory. size_t read(size_t address, char &value); /// Read multiple bytes starting from the address in memory. /// @param address Memory address to start reading from. /// @param buffer Pointer to buffer to hold bytes read from memory. /// @param size Number of bytes to be read from memory. /// @returns Number of bytes read from memory. size_t read(size_t address, char *buffer, size_t size); /// Read either an instance or an array of a POD type from memory. /// Note the value of the type can't contain pointers. /// @param address Start address for reading memory. /// @param value Object to be read from memory. /// @returns Number of bytes read from memory. template<typename T> size_t read(size_t address, T &value) { return read(address, reinterpret_cast<char *>(&value), sizeof(T)); } /// Write a single byte to the address in memory. /// @param address Memory address to write to. /// @param value Value to be written to memory. /// @returns Number of bytes written to memory. size_t write(size_t address, char value); /// Write multiple bytes starting from the address in memory. /// @param address Memory address to start writting to. /// @param buffer Pointer to buffer holding the bytes to write to memory. /// @param size Number of bytes to be written to memory. /// @returns Number of bytes written to memory. size_t write(size_t address, const char *buffer, size_t size); /// Write either an instance or an array of a POD type to memory. /// Note the value of the type can't contain pointers. /// @param address Start address to write to memory. /// @returns Number of bytes written to memory. template<typename T> size_t write(size_t address, const T &value) { return write(address, reinterpret_cast<const char *>(&value), sizeof(T)); } private: // Wait for a write cycle to complete using polling and small waits. void waitForWrite(); size_t ll_write(size_t address, const char *buffer, size_t size); // Validate that the proposed opperation will fit in the size of // the chip. bool checkSpace(size_t address, size_t size) { return (address + size) < m_chipSize ; } private: I2C & m_i2c; int const m_i2cAddress; size_t const m_chipSize; size_t const m_pageSize; uint8_t const m_writeCycleTime_ms; }; #endif