4.9 KiB
I2C_24LC1025 - I2C 1MB EEPROM
Arduino library for for external I2C EEPROM - 24LC1025 and equivalents e.g. 24AA1025/24FC1025.
Description
This library is to access external I2C EEPROM of 128 KB in size, typically the 24LC1025 and equivalents e.g. 24AA1025/24FC1025.
Warning A2 = Non-Configurable Chip Select. This pin must be connected to VCC (+5V). The device will NOT work when this pin floats or is connected to GND (0V).
This library follows the I2C_EEPROM library, see links below.
Links
Interface
#include "I2C_24LC1025.h"
The interface is kept quite identical to the I2C_EEPROM library. https://github.com/RobTillaart/I2C_EEPROM
Most important change is 32 bit memory addresses.
Constructor
- I2C_24LC1025(uint8_t deviceAddress, TwoWire *wire = &Wire) constructor, optional Wire interface.
- bool begin() initializes the I2C bus and checks if the device is available on the I2C bus.
- bool begin(uint8_t sda, uint8_t scl) idem for ESP32 / ESP8266 / RP2040 and alike.
- bool isConnected() test to see if deviceAddress is found on the bus.
Write functions
- int writeByte(uint32_t memoryAddress, uint8_t value) write a single byte to the specified memory address. Returns I2C status, 0 = OK.
- int writeBlock(uint32_t memoryAddress, uint8_t * buffer, uint32_t length) write a buffer starting at the specified memory address. Returns I2C status, 0 = OK.
- int setBlock(uint32_t memoryAddress, uint8_t value, uint32_t length) writes the same byte to length places starting at the specified memory address. Returns I2C status, 0 = OK.
Update functions
- int updateByte(uint32_t memoryAddress, uint8_t value) write a single byte, but only if changed. Returns 0 if value was same or write succeeded.
- uint32_t updateBlock(uint32_t memoryAddress, uint8_t * buffer, uint32_t length) write a buffer starting at the specified memory address, but only if changed. Returns bytes written.
Read functions
- uint8_t readByte(uint32_t memoryAddress) read a single byte from a given address
- uint32_t readBlock(uint32_t memoryAddress, uint8_t * buffer, uint32_t length) read length bytes into buffer starting at specified memory address. Returns the number of bytes read, which should be length.
Verify functions
Since 0.2.0 - experimental, needs extensive testing.
Same as write and update functions above. Returns true if successful, false indicates an error.
- bool writeByteVerify(uint32_t memoryAddress, uint8_t value)
- bool writeBlockVerify(uint32_t memoryAddress, uint8_t * buffer, uint32_t length)
- bool setBlockVerify(uint32_t memoryAddress, uint8_t value, uint32_t length)
- bool updateByteVerify(uint32_t memoryAddress, uint8_t value)
- bool updateBlockVerify(uint32_t memoryAddress, uint8_t * buffer, uint32_t length)
Other
- uint32_t getDeviceSize() idem
- uint8_t getPageSize() idem
- uint32_t getLastWrite() idem
UpdateBlock()
(new since 0.1.3)
The function updateBlock() reads the block of data and compares it with the new values to see if it needs rewriting.
As the function reads/writes the data in blocks with a maximum length of I2C_TWIBUFFERSIZE (== 30 AVR limitation; 128 for ESP32) It does this comparison in chunks if the length exceeds this number. The result is that an updateBlock() call can result e.g. in 4 reads and only 2 writes under the hood.
If data is changed often between writes, updateBlock() is slower than writeBlock(). So you should verify if your sketch can make use of the advantages of updateBlock()
ExtraWriteCycleTime (experimental)
To improve support older I2C EEPROMs e.g. IS24C16 two functions were added to increase the waiting time before a read and/or write as some older devices have a larger timeout than 5 milliseconds which is the minimum.
- void setExtraWriteCycleTime(uint8_t ms) idem
- uint8_t getExtraWriteCycleTime() idem
Limitation
The library does not offer multiple EEPROMS as one continuous storage device.
Operation
See examples
Future
- See I2C EEPROM as this library is following.
- add examples