Achieve a secure and efficient way to store sensitive data using AT24CM02 and STM32F469II

Store. Retrieve. Repeat.

Published Aug 23, 2023

Click board™

EEPROM 3 click

Dev Board

Fusion for STM32 v8

Compiler

NECTO Studio

MCU

STM32F469II

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

Fusion for STM32 v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from STMicroelectronics, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for STM32 v8 provides a fluid and immersive working experience, allowing

access anywhere and under any circumstances at any time. Each part of the Fusion for STM32 v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for STM32 v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development 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-M4

MCU Memory (KB)

2048

Silicon Vendor

STMicroelectronics

Pin count

176

RAM (Bytes)

393216

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

PF1

SCL

I2C Data

PF0

SDA

Power Supply

Ground

GND

Take a closer look

Schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for STM32 v8 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

Buck 22 Click front image hardware assembly

SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly

v8 SiBRAIN MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

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

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \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