Robin Hourahane / I2CEeprom

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.

Dependents:   Test_I2CEeprom Alternator2020_06

This class provides a simple read write interface for I2C EEPROMs like Microchip's 24LC range and AMTELS AT24C range. The class ensure that writes respect the page size of the chip to ensure larger blocks can be written in one call. The class uses the supplied buffer to directly write to the chip so no extra RAM is used.

I2CEeprom.h@1:b23f5561266c, 2015-07-19 (annotated)

Committer:
rhourahane
Date:
Sun Jul 19 09:34:04 2015 +0000
Revision:
1:b23f5561266c
Updates to make library more generic to allow support for more I2C EEPROM chips.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rhourahane 1:b23f5561266c 1 /* Simple access class for I2C EEPROM chips like Microchip 24LC
rhourahane 1:b23f5561266c 2 * Copyright (c) 2015 Robin Hourahane
rhourahane 1:b23f5561266c 3 *
rhourahane 1:b23f5561266c 4 * Licensed under the Apache License, Version 2.0 (the "License");
rhourahane 1:b23f5561266c 5 * you may not use this file except in compliance with the License.
rhourahane 1:b23f5561266c 6 * You may obtain a copy of the License at
rhourahane 1:b23f5561266c 7 *
rhourahane 1:b23f5561266c 8 * http://www.apache.org/licenses/LICENSE-2.0
rhourahane 1:b23f5561266c 9 *
rhourahane 1:b23f5561266c 10 * Unless required by applicable law or agreed to in writing, software
rhourahane 1:b23f5561266c 11 * distributed under the License is distributed on an "AS IS" BASIS,
rhourahane 1:b23f5561266c 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rhourahane 1:b23f5561266c 13 * See the License for the specific language governing permissions and
rhourahane 1:b23f5561266c 14 * limitations under the License.
rhourahane 1:b23f5561266c 15 */
rhourahane 1:b23f5561266c 16 #ifndef __I2CEEPROM_H__
rhourahane 1:b23f5561266c 17 #define __I2CEEPROM_H__
rhourahane 1:b23f5561266c 18
rhourahane 1:b23f5561266c 19 #include <mbed.h>
rhourahane 1:b23f5561266c 20
rhourahane 1:b23f5561266c 21 /// Class to provide simple access to I2C EEPROM chiles like Microchip's 24LC range
rhourahane 1:b23f5561266c 22 /// or AMTELS AT24C range.
rhourahane 1:b23f5561266c 23 /// Chips up to 64Kb in size are directly supported.
rhourahane 1:b23f5561266c 24 /// The class handles multiple page writes so any amount of data can be written in
rhourahane 1:b23f5561266c 25 /// a single call to write. The writes are not buffered so additional memory use
rhourahane 1:b23f5561266c 26 /// is kept to a minimum.
rhourahane 1:b23f5561266c 27 ///
rhourahane 1:b23f5561266c 28 /// Although not tested it should work with the MAC versions of Microchip range
rhourahane 1:b23f5561266c 29 /// as well but the chipSize will need to be set to include the ROM area as well.
rhourahane 1:b23f5561266c 30 class I2CEeprom {
rhourahane 1:b23f5561266c 31 public:
rhourahane 1:b23f5561266c 32 /// Constructor to create a new instance of the class.
rhourahane 1:b23f5561266c 33 /// @param sda The pin name for the sda line of the I2C bus.
rhourahane 1:b23f5561266c 34 /// @param scl The pin name for the scl line of the I2C bus.
rhourahane 1:b23f5561266c 35 /// @param address The 8bit I2C address of the chip in the range 0xA0 - 0xAE.
rhourahane 1:b23f5561266c 36 /// @param pageSize The size of the page used in writing to the chip.
rhourahane 1:b23f5561266c 37 /// @param chipSize The size of the memory in the chip to allow range checkng. Set to
rhourahane 1:b23f5561266c 38 /// 0 to disable checks.
rhourahane 1:b23f5561266c 39 /// @param busSpeed The frequency of the I2C bus defaults to 400K.
rhourahane 1:b23f5561266c 40 I2CEeprom(PinName sda, PinName scl, int address, size_t pageSize, size_t chipSize, int busSpeed = 400000);
rhourahane 1:b23f5561266c 41
rhourahane 1:b23f5561266c 42 /// Read a single byte from the address in memory.
rhourahane 1:b23f5561266c 43 /// @param address Memory address to read from.
rhourahane 1:b23f5561266c 44 /// @param value Variable to receive value read.
rhourahane 1:b23f5561266c 45 /// @returns Number of bytes read from memory.
rhourahane 1:b23f5561266c 46 size_t read(size_t address, char &value);
rhourahane 1:b23f5561266c 47
rhourahane 1:b23f5561266c 48 /// Read multiple bytes starting from the address in memory.
rhourahane 1:b23f5561266c 49 /// @param address Memory address to start reading from.
rhourahane 1:b23f5561266c 50 /// @param buffer Pointer to buffer to hold bytes read from memory.
rhourahane 1:b23f5561266c 51 /// @param size Number of bytes to be read from memory.
rhourahane 1:b23f5561266c 52 /// @returns Number of bytes read from memory.
rhourahane 1:b23f5561266c 53 size_t read(size_t address, char *buffer, size_t size);
rhourahane 1:b23f5561266c 54
rhourahane 1:b23f5561266c 55 /// Read either an instance or an array of a POD type from memory.
rhourahane 1:b23f5561266c 56 /// Note the value of the type can't contain pointers.
rhourahane 1:b23f5561266c 57 /// @param address Start address for reading memory.
rhourahane 1:b23f5561266c 58 /// @param value Object to be read from memory.
rhourahane 1:b23f5561266c 59 /// @returns Number of bytes read from memory.
rhourahane 1:b23f5561266c 60 template<typename T> size_t read(size_t address, T &value) {
rhourahane 1:b23f5561266c 61 return read(address, reinterpret_cast<char *>(&value), sizeof(T));
rhourahane 1:b23f5561266c 62 }
rhourahane 1:b23f5561266c 63
rhourahane 1:b23f5561266c 64 /// Write a single byte to the address in memory.
rhourahane 1:b23f5561266c 65 /// @param address Memory address to write to.
rhourahane 1:b23f5561266c 66 /// @param value Value to be written to memory.
rhourahane 1:b23f5561266c 67 /// @returns Number of bytes written to memory.
rhourahane 1:b23f5561266c 68 size_t write(size_t address, char value);
rhourahane 1:b23f5561266c 69
rhourahane 1:b23f5561266c 70 /// Write multiple bytes starting from the address in memory.
rhourahane 1:b23f5561266c 71 /// @param address Memory address to start writting to.
rhourahane 1:b23f5561266c 72 /// @param buffer Pointer to buffer holding the bytes to write to memory.
rhourahane 1:b23f5561266c 73 /// @param size Number of bytes to be written to memory.
rhourahane 1:b23f5561266c 74 /// @returns Number of bytes written to memory.
rhourahane 1:b23f5561266c 75 size_t write(size_t address, const char *buffer, size_t size);
rhourahane 1:b23f5561266c 76
rhourahane 1:b23f5561266c 77 /// Write either an instance or an array of a POD type to memory.
rhourahane 1:b23f5561266c 78 /// Note the value of the type can't contain pointers.
rhourahane 1:b23f5561266c 79 /// @param address Start address to write to memory.
rhourahane 1:b23f5561266c 80 /// @returns Number of bytes written to memory.
rhourahane 1:b23f5561266c 81 template<typename T> size_t write(size_t address, const T &value) {
rhourahane 1:b23f5561266c 82 return write(address, reinterpret_cast<const char *>(&value), sizeof(T));
rhourahane 1:b23f5561266c 83 }
rhourahane 1:b23f5561266c 84
rhourahane 1:b23f5561266c 85 /// Fill a range of memory with a single value. No memory is allocated
rhourahane 1:b23f5561266c 86 /// so large areas can be filled with minimal memory usage.
rhourahane 1:b23f5561266c 87 /// @param address Starting address to write to.
rhourahane 1:b23f5561266c 88 /// @param value Value to be written to memory.
rhourahane 1:b23f5561266c 89 /// @Param size Number of bytes to be written.
rhourahane 1:b23f5561266c 90 /// @returns Number of bytes written to memory.
rhourahane 1:b23f5561266c 91 size_t fill(size_t address, char value, size_t size);
rhourahane 1:b23f5561266c 92
rhourahane 1:b23f5561266c 93 private:
rhourahane 1:b23f5561266c 94 // Wait for a write cycle to complete using polling and small waits.
rhourahane 1:b23f5561266c 95 void waitForWrite();
rhourahane 1:b23f5561266c 96
rhourahane 1:b23f5561266c 97 // Validate that the proposed opperation will fit in the size of
rhourahane 1:b23f5561266c 98 // the chip.
rhourahane 1:b23f5561266c 99 bool checkSpace(size_t address, size_t size);
rhourahane 1:b23f5561266c 100
rhourahane 1:b23f5561266c 101 private:
rhourahane 1:b23f5561266c 102 I2C m_i2c;
rhourahane 1:b23f5561266c 103 int m_i2cAddress;
rhourahane 1:b23f5561266c 104 size_t m_chipSize;
rhourahane 1:b23f5561266c 105 size_t m_pageSize;
rhourahane 1:b23f5561266c 106 };
rhourahane 1:b23f5561266c 107
rhourahane 1:b23f5561266c 108 #endif