5 ms max for 24LC and 24C – 10 ms max for 24AA 24C ( 24xx*) is a 32K x 8 (K bit) Serial Elec- CMOS Serial EEPROM. I2C is a . Adding External I2C EEPROM to Arduino (24LC). This tutorial was originally posted on the website, which now seems to be no longer with us. Buy low price, high quality 24c eeprom with worldwide shipping on

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Next lets go ahead and connect the data pins to the Arduino board. We first call the Wire. This website uses cookies for analytics, personalization, and other purposes. This means our 24LC chip gets the address and then which tells it to store the next byte in address location 20, Click to learn more. The 24LC gets the data and writes the data to that address location. Time to move on to software!

Next we do a bitwise AND to get just the eeprok eight bits. The WP pin stands for write-protected and this allows you to control if data can be written to the eeprom or not. Arduino Sketch Below is the entire tutorial code, scan over it and see if you understand it before I dive into what each section does. Below is the entire tutorial code, scan over it and see if you understand it before I dive into what each section does. The 24C is optimized for use in minimal storage applications where low-power and eeporm operation, driven using i2C serial communication bus to help you do much more multiple series of storage.

Adding External I2C EEPROM to Arduino (24LC)

The serial reading is more fluid and influenced by the speed of the serial communication which is running to bytes per second. This tutorial was originally posted on the 10kohms. See the address of the device below.

To illustrate this lets follow 24c56 steps below. The following code allows you to write all the bytes of memory. For more information please read http: If you are using Arduino 1.

Adding External I2C EEPROM to Arduino (24LC256)

For the purpose of explaining how the address works we can ignore the Start and Acknowledge bits. By continuing to browse, you agree to our use of cookies as described in our Cookies Statement. Finally we have to pass along the byte we want to store. As 2c256 can see the diagram above the pin A0, A1, A2 are connected to the ground these pins allow you to customize the device i2C bus address, below the data sheet we that we verify how it is formed the byte address.


Then connect the SCL pin 6 to pin 5 on the Arduino. Check out our videos Follow us on: Leave this field empty. The first argument is the address of the device you want to write to, in our case we only have one device disk1 so we pass this on.

Lets say we want to write to address location 20, which is in binary. Since our eeprom chip has 42c256, address locations we are using two bytes 16 bits to store the address but we can only send one byte at a time so we have to split it up.

The next function requestFrom sends the command to that chip to start sending the data at the address we set above. With the 24v256 pins connected the hardware part of this tutorial is complete and every pin of the 24LC should be connected to either Vcc, GND or the Arduino. This is written for Arduino versions before 1. For more details Please refer to the Datasheet below. Using the image above as a guide lets begin to wire the chip.

Next we start off just like we did with the write function by starting the process with beginTransmission and then we send the address we want to access; this works exactly the same way as the write function.

The Wire library allows you to pass an integer value so we could just make a bit-wise operation to device the integer variable into two bytes. This function takes three arguments, the device address the disk1 variablethe memory address on the eeprom and the byte of data you want to write. After our data and power pins are connected we have four left on 24LC chip, the WP pin and the three address pins. The arguments it accepts are the same first two arguments the write function, the device address and the address on the eeprom to read from.


The first send function takes the eeaddress and shifts the bits to the right by eight which moves the higher end of the 16 bit address down to the lower eight bits. Next we have to send the address on the eeprom we want to write to. The next argument is the address on the eeprom you want to write to and as stated above can be between 0 and 32, Leave a Reply Cancel reply Your email address will not be published. Your email address will not be published.

Some of microcontroller have limited storage like Arduino it has only bytes data space compare to AT24C has Kb EEPROM will be very suitable for small amount of data storage or extending data storage for your microcontroller.

This is a little confusing at first so lets look at the figure below to explain the address in a little 24c2556 detail. The next three bits A2,A1,A0 are the important bits that we can change so lets look at the simple table below to see what address the chip will have depending on what we set these pins to.

Working on 24C256 EEPROM 256Kbit / 32 Kbyte Serial Memory Data Storage on i2C Bus

Before we get into the software part lets hook up the 24LC chip up to our Arduino. This variable is not required but it allows us to easily change the address we want to access without going through all of the code and replacing the value.

This allows the chip time to complete the write operation, without this if you try to do sequential writes weird things might happen.

We need to send the MSB Most significant bits first so we have to shift our address to the right eight bits.