Remarks

At24Cxx
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

The AT24Cxx series of chips provide a mechanism for storing data that will survive a power outage or battery failure. These EEPROMs are available in varying sizes and are accessible using the I2C interface.

Purchasing

• DS3231 with integrated EEPROM

Code Example

At24Cxx eeprom;

public override Task Initialize()
{
    Resolver.Log.Info("Initialize...");

    //256kbit = 256*1024 bits = 262144 bits = 262144 / 8 bytes = 32768 bytes
    //if you're using the ZS-042 board, it has an AT24C32 and uses the default value of 8192
    eeprom = new At24Cxx(i2cBus: Device.CreateI2cBus(), memorySize: 32768);

    return base.Initialize();
}

public override Task Run()
{
    Resolver.Log.Info("Write to eeprom");
    eeprom.Write(0, new byte[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 });

    Resolver.Log.Info("Read from eeprom");
    var memory = eeprom.Read(0, 16);

    for (ushort index = 0; index < 16; index++)
    {
        Thread.Sleep(50);
        Resolver.Log.Info("Byte: " + index + ", Value: " + memory[index]);
    }

    eeprom.Write(3, new byte[] { 10 });
    eeprom.Write(7, new byte[] { 1, 2, 3, 4 });
    memory = eeprom.Read(0, 16);

    for (ushort index = 0; index < 16; index++)
    {
        Thread.Sleep(50);
        Resolver.Log.Info("Byte: " + index + ", Value: " + memory[index]);
    }

    return base.Run();
}

Sample project(s) available on GitHub

Wiring Example

To wire a At24Cxx to your Meadow board, connect the following:

At24Cxx	Meadow Pin
GND	GND
SCL	D08 (SCL)
SDA	D07 (SDA)
VCC	3V3

It should look like the following diagram:

Characteristic	Locus
Inheritance	System.Object > At24Cxx
Namespace	Meadow.Foundation.ICs.EEPROM
Assembly	At24Cxx.dll

Syntax

public class At24Cxx : object

Constructors

At24Cxx(II2cBus, Byte, UInt16, UInt16)

Create a new AT24Cxx object using the default parameters for the component.

Declaration

public At24Cxx(II2cBus i2cBus, byte address = null, ushort pageSize = null, ushort memorySize = null)

Parameters

Type	Name	Description
II2cBus	i2cBus	I2CBus connected to display
System.Byte	address	Address of the At24Cxx (default = 0x50).
System.UInt16	pageSize	Number of bytes in a page (default = 32 - AT24C32).
System.UInt16	memorySize	Total number of bytes in the EEPROM (default = 8192 - AT24C32).

Properties

MemorySize

Number of bytes in the EEPROM module.

Declaration

public ushort MemorySize { get; }

Property Value

Type	Description
System.UInt16

PageSize

Number of bytes in a page.

Declaration

public ushort PageSize { get; }

Property Value

Type	Description
System.UInt16

Methods

Read(UInt16, UInt16)

Force the sensor to make a reading and update the relevant properties.

Declaration

public byte[] Read(ushort startAddress, ushort amount)

Parameters

Type	Name	Description
System.UInt16	startAddress	Start address for the read operation.
System.UInt16	amount	Amount of data to read from the EEPROM.

Returns

Type	Description
System.Byte[]

Write(UInt16, Byte[])

Write a number of bytes to the EEPROM.

Declaration

public void Write(ushort startAddress, params byte[] data)

Parameters

Type	Name	Description
System.UInt16	startAddress	Address of he first byte to be written.
System.Byte[]	data	Data to be written to the EEPROM.