Achieve a secure and efficient way to store sensitive data using AT24CM02 and STM32F205RB

Store. Retrieve. Repeat.

Published Aug 23, 2023

Click board™

EEPROM 3 click

Dev Board

UNI Clicker

Compiler

NECTO Studio

MCU

STM32F205RB

Our solution leverages EEPROM memory for seamless integration of over-the-air updates, simplifying software deployment and enhancing the agility of your technology

Hardware Overview

How does it work?

EEPROM 3 Click is based on the AT24CM02, an I2C serial EEPROM from Microchip. The EEPROM density is usually expressed in bits, so exactly 2,097,152 bits are organized in units or words of 8 bits, which gives 262,144 bytes of data memory. Furthermore, the EEPROM is organized in so-called pages. One page holds 256 bytes, and there are 1024 pages (1024 pages x 256 bytes = 262,144 bytes total). Having insight into how the memory cells are organized is important for Write and Erase operations. One of the key features of the

AT24CM02 IC is the Error Detection and Correction scheme (EDC), which allows error correction by utilizing six additional bits internally assigned to a group of four bytes. This protection scheme can correct some types of bit errors, staying transparent to the end user. The bit comparison and error correction are done internally. EEPROM 3 Click uses a standard 2-Wire I2C interface to communicate with the host MCU, supporting clock speeds of up to 1MHz. The I2C address can be selected over the ADD jumper, where 1 is set by

default. Several read modes are available, including current address read, random address read, and sequential address read. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Microcontroller Overview

MCU Card / MCU

Type

8th Generation

Architecture

ARM Cortex-M3

MCU Memory (KB)

128

Silicon Vendor

STMicroelectronics

Pin count

RAM (Bytes)

65536

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

PB6

SCL

I2C Data

PB7

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

Thermo 28 Click front image hardware assembly

SiBRAIN for STM32F745VG front image hardware assembly

UNI Clicker MB 1 - upright/with-background hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

This Click board can be interfaced and monitored in two ways:

Application Output - Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.

UART Terminal - Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.

Software Support

Library Description

This library contains API for EEPROM 3 Click driver.

Key functions:

eeprom3_write_byte - This function writes data to the desired register
eeprom3_write_page - This function writes given number of data to the desired register
eeprom3_read - This function reads data from the desired register.

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * \file 
 * \brief Eeprom3 Click example
 * 
 * # Description
 * This application demonstrates the process of reading and writing to the EEPROM.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes EEPROM 3 driver.
 * 
 * ## Application Task  
 * Writing data to EEPROM, reading that data and displaying it via UART
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "eeprom3.h"

// ------------------------------------------------------------------ VARIABLES

static eeprom3_t eeprom3;
static log_t logger;
uint8_t text[ 7 ] = { 'M','i','k','r','o','e' };
uint8_t mem_value[ 7 ] = { 0 };

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    eeprom3_cfg_t cfg;

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, "---- Application Init ----" );

    //  Click initialization.
    eeprom3_cfg_setup( &cfg );
    EEPROM3_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    eeprom3_init( &eeprom3, &cfg );
}

void application_task ( void )
{
    eeprom3_write_page( &eeprom3, 0x100, text, 6 );
    log_printf( &logger, "Writing Mikroe to EEPROM 3 click\r\n" );
    Delay_ms ( 1000 );
    
    eeprom3_read( &eeprom3, 0x100, mem_value, 6 );
    log_printf( &logger, "Data read: %s\r\n", mem_value );
    Delay_ms ( 1000 );
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}


// ------------------------------------------------------------------------ END