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@11:c3609e691623, 2020-03-28 (annotated)
- Committer:
- skyscraper
- Date:
- Sat Mar 28 17:01:58 2020 +0000
- Revision:
- 11:c3609e691623
- Parent:
- 10:3824e507953c
- Child:
- 12:d9a44fb3b9a6
doc mods
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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skyscraper | 9:acc133240c9d | 1 | |
skyscraper | 10:3824e507953c | 2 | /*! \file I2CEeprom.h */ |
skyscraper | 10:3824e507953c | 3 | /*! \class I2CEeprom */ |
skyscraper | 10:3824e507953c | 4 | /*! \brief Simple access class for I2C EEPROM chips like Microchip 24LC |
skyscraper | 9:acc133240c9d | 5 | */ |
skyscraper | 9:acc133240c9d | 6 | |
skyscraper | 10:3824e507953c | 7 | /* Copyright (c) 2015 Robin Hourahane |
skyscraper | 10:3824e507953c | 8 | * Copyright (c) 2020 Andy Little |
rhourahane | 1:b23f5561266c | 9 | * |
rhourahane | 1:b23f5561266c | 10 | * Licensed under the Apache License, Version 2.0 (the "License"); |
rhourahane | 1:b23f5561266c | 11 | * you may not use this file except in compliance with the License. |
rhourahane | 1:b23f5561266c | 12 | * You may obtain a copy of the License at |
rhourahane | 1:b23f5561266c | 13 | * |
rhourahane | 1:b23f5561266c | 14 | * http://www.apache.org/licenses/LICENSE-2.0 |
rhourahane | 1:b23f5561266c | 15 | * |
rhourahane | 1:b23f5561266c | 16 | * Unless required by applicable law or agreed to in writing, software |
rhourahane | 1:b23f5561266c | 17 | * distributed under the License is distributed on an "AS IS" BASIS, |
rhourahane | 1:b23f5561266c | 18 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
rhourahane | 1:b23f5561266c | 19 | * See the License for the specific language governing permissions and |
rhourahane | 1:b23f5561266c | 20 | * limitations under the License. |
rhourahane | 1:b23f5561266c | 21 | */ |
skyscraper | 6:0b18a49e03b9 | 22 | |
skyscraper | 6:0b18a49e03b9 | 23 | #ifndef __I2CEEPROM_H__ |
skyscraper | 6:0b18a49e03b9 | 24 | #define __I2CEEPROM_H__ |
rhourahane | 1:b23f5561266c | 25 | |
rhourahane | 1:b23f5561266c | 26 | #include <mbed.h> |
rhourahane | 1:b23f5561266c | 27 | |
skyscraper | 10:3824e507953c | 28 | /// Based on the original Mbed I2CEeprom library by Robin Hourahane. |
skyscraper | 9:acc133240c9d | 29 | /// |
skyscraper | 9:acc133240c9d | 30 | /// Class to provide simple access to I2C EEPROM chips like Microchip's 24LC |
skyscraper | 9:acc133240c9d | 31 | /// or AMTELS AT24C series. Chips up to 64Kb in size are directly supported. |
skyscraper | 9:acc133240c9d | 32 | /// |
skyscraper | 9:acc133240c9d | 33 | /// The library was tested on a Microchip 24LC128. |
skyscraper | 9:acc133240c9d | 34 | /// |
skyscraper | 9:acc133240c9d | 35 | /// The I2CEeprom class handles multiple page writes so any amount of data can |
skyscraper | 9:acc133240c9d | 36 | /// be written in a single call to write. |
skyscraper | 9:acc133240c9d | 37 | /// |
skyscraper | 8:0c122f839dc9 | 38 | /// The code is modified from the original to better support RTOS. |
skyscraper | 7:29e505d37158 | 39 | /// At start of a write(addr,buffer,size), a buffer of up to pageSize + 2 |
skyscraper | 7:29e505d37158 | 40 | /// is allocated on the heap, and the data and address are copied to it. |
skyscraper | 9:acc133240c9d | 41 | /// This allows the cuurent write chunk to proceed without unlocking, which |
skyscraper | 9:acc133240c9d | 42 | /// prevents another device on the bus access and so aborting the write. |
skyscraper | 9:acc133240c9d | 43 | /// |
skyscraper | 7:29e505d37158 | 44 | /// This allocation per write fits my usecase, where eeeprom variables |
skyscraper | 7:29e505d37158 | 45 | /// are written in a special menu mode at start up, but it may be better to |
skyscraper | 7:29e505d37158 | 46 | /// preallocate a buffer once at startup, if writes are occurring at arbitrary |
skyscraper | 9:acc133240c9d | 47 | /// times during execution, to prevent surprises with out of memory issues |
skyscraper | 7:29e505d37158 | 48 | /// when trying to write during normal execution. |
skyscraper | 8:0c122f839dc9 | 49 | /// |
skyscraper | 9:acc133240c9d | 50 | /// The constructor takes the I2C bus by non-const reference argument. This |
skyscraper | 9:acc133240c9d | 51 | /// enables a single I2C bus to be shared among many i2c devices. |
skyscraper | 9:acc133240c9d | 52 | /// Mbed OS enforces a lock on the bus during a bus read/write so reads |
skyscraper | 9:acc133240c9d | 53 | /// are atomic. Writes are split into separate atomic chunks that only write |
skyscraper | 9:acc133240c9d | 54 | /// one eeprom page. After a chunk is sent, the thread is sent to sleep for |
skyscraper | 9:acc133240c9d | 55 | /// writeCycleTime_ms as in the constructor arg, and is then polled at 1 ms |
skyscraper | 9:acc133240c9d | 56 | /// intervals to discover whether the write has completed. |
skyscraper | 9:acc133240c9d | 57 | |
rhourahane | 1:b23f5561266c | 58 | class I2CEeprom { |
rhourahane | 1:b23f5561266c | 59 | public: |
rhourahane | 1:b23f5561266c | 60 | /// Constructor to create a new instance of the class. |
skyscraper | 10:3824e507953c | 61 | /// @param i2c A reference to the i2c bus the chip is connected to. |
skyscraper | 6:0b18a49e03b9 | 62 | /// @param address The 8bit I2C address of the chip. |
rhourahane | 1:b23f5561266c | 63 | /// @param pageSize The size of the page used in writing to the chip. |
skyscraper | 5:315872eec0ae | 64 | /// @param chipSize The size of the memory in the chip for range check. |
skyscraper | 6:0b18a49e03b9 | 65 | /// @param writeCycleTime_ms The write cycle time in ms. |
skyscraper | 2:f3188aaccf80 | 66 | I2CEeprom( |
skyscraper | 2:f3188aaccf80 | 67 | I2C& i2c, |
skyscraper | 2:f3188aaccf80 | 68 | int address, |
skyscraper | 2:f3188aaccf80 | 69 | size_t pageSize, |
skyscraper | 2:f3188aaccf80 | 70 | size_t chipSize, |
skyscraper | 5:315872eec0ae | 71 | uint8_t writeCycleTime_ms); |
rhourahane | 1:b23f5561266c | 72 | |
skyscraper | 10:3824e507953c | 73 | /// Read a single byte from the EEprom. |
skyscraper | 10:3824e507953c | 74 | /// @param address EEprom address to read from. |
skyscraper | 10:3824e507953c | 75 | /// @param value Reference of char to read into. |
skyscraper | 10:3824e507953c | 76 | /// @returns Number of bytes read . |
rhourahane | 1:b23f5561266c | 77 | size_t read(size_t address, char &value); |
rhourahane | 1:b23f5561266c | 78 | |
skyscraper | 10:3824e507953c | 79 | /// Read multiple bytes starting from EEprom memory. |
skyscraper | 10:3824e507953c | 80 | /// @param address EEprom Memory start read address. |
skyscraper | 10:3824e507953c | 81 | /// @param buffer Pointer to buffer to hold bytes read. |
skyscraper | 10:3824e507953c | 82 | /// @param size Number of bytes to read. |
skyscraper | 10:3824e507953c | 83 | /// @returns Number of bytes read. |
rhourahane | 1:b23f5561266c | 84 | size_t read(size_t address, char *buffer, size_t size); |
rhourahane | 1:b23f5561266c | 85 | |
skyscraper | 10:3824e507953c | 86 | /// Deserialise object of type T from Eeprom memory. |
skyscraper | 10:3824e507953c | 87 | /// @param address Start address of Object in EEprom. |
skyscraper | 10:3824e507953c | 88 | /// @param value Reference to Object to deserialise into. |
skyscraper | 10:3824e507953c | 89 | /// @returns Number of bytes read. |
rhourahane | 1:b23f5561266c | 90 | template<typename T> size_t read(size_t address, T &value) { |
rhourahane | 1:b23f5561266c | 91 | return read(address, reinterpret_cast<char *>(&value), sizeof(T)); |
rhourahane | 1:b23f5561266c | 92 | } |
rhourahane | 1:b23f5561266c | 93 | |
skyscraper | 10:3824e507953c | 94 | /// Write a char to EEprom. |
skyscraper | 10:3824e507953c | 95 | /// @param address Eeprom address to write to. |
skyscraper | 10:3824e507953c | 96 | /// @param value Value of char to write. |
skyscraper | 10:3824e507953c | 97 | /// @returns Number of bytes written. |
rhourahane | 1:b23f5561266c | 98 | size_t write(size_t address, char value); |
rhourahane | 1:b23f5561266c | 99 | |
skyscraper | 10:3824e507953c | 100 | /// Write multiple bytes to EEprom |
skyscraper | 10:3824e507953c | 101 | /// Note that in this implementation, the write is split into chunks |
skyscraper | 11:c3609e691623 | 102 | /// of up to pageSize and for each chunk a buffer of up to pageSize + 2 |
skyscraper | 10:3824e507953c | 103 | /// is temporarily allocated on the heap while the write is in progress. |
skyscraper | 10:3824e507953c | 104 | /// @param address Start EEprom address. |
skyscraper | 10:3824e507953c | 105 | /// @param buffer Buffer holding the bytes to write. |
skyscraper | 10:3824e507953c | 106 | /// @param size Number of bytes to write. |
skyscraper | 10:3824e507953c | 107 | /// @returns Number of bytes written. |
rhourahane | 1:b23f5561266c | 108 | size_t write(size_t address, const char *buffer, size_t size); |
skyscraper | 2:f3188aaccf80 | 109 | |
skyscraper | 10:3824e507953c | 110 | /// Serialise an object of type T. |
skyscraper | 10:3824e507953c | 111 | /// @param address EEprom write start address. |
skyscraper | 11:c3609e691623 | 112 | /// @param value Object to be serialised. |
skyscraper | 10:3824e507953c | 113 | /// @returns Number of bytes written. |
rhourahane | 1:b23f5561266c | 114 | template<typename T> size_t write(size_t address, const T &value) { |
rhourahane | 1:b23f5561266c | 115 | return write(address, reinterpret_cast<const char *>(&value), sizeof(T)); |
rhourahane | 1:b23f5561266c | 116 | } |
skyscraper | 2:f3188aaccf80 | 117 | |
rhourahane | 1:b23f5561266c | 118 | private: |
skyscraper | 10:3824e507953c | 119 | /// Sleep thread while write completes. |
rhourahane | 1:b23f5561266c | 120 | void waitForWrite(); |
skyscraper | 10:3824e507953c | 121 | /// atomic chunk up to page aize write |
skyscraper | 2:f3188aaccf80 | 122 | size_t ll_write(size_t address, const char *buffer, size_t size); |
rhourahane | 1:b23f5561266c | 123 | |
skyscraper | 10:3824e507953c | 124 | /// Validate that proposed operation is in bounds. |
skyscraper | 4:d8f51b136dbd | 125 | bool checkSpace(size_t address, size_t size) |
skyscraper | 4:d8f51b136dbd | 126 | { |
skyscraper | 4:d8f51b136dbd | 127 | return (address + size) < m_chipSize ; |
skyscraper | 4:d8f51b136dbd | 128 | } |
rhourahane | 1:b23f5561266c | 129 | |
rhourahane | 1:b23f5561266c | 130 | private: |
skyscraper | 2:f3188aaccf80 | 131 | I2C & m_i2c; |
skyscraper | 2:f3188aaccf80 | 132 | int const m_i2cAddress; |
skyscraper | 2:f3188aaccf80 | 133 | size_t const m_chipSize; |
skyscraper | 2:f3188aaccf80 | 134 | size_t const m_pageSize; |
skyscraper | 2:f3188aaccf80 | 135 | uint8_t const m_writeCycleTime_ms; |
rhourahane | 1:b23f5561266c | 136 | }; |
rhourahane | 1:b23f5561266c | 137 | |
rhourahane | 1:b23f5561266c | 138 | #endif |