Unlock the potential of data storage with MB85AS4MT and STM32F302VC

ReRAM: Your gateway to speed, efficiency, and data density

ReRAM Click with CLICKER 4 for STM32F302VCT6

Published Jul 22, 2025

Click board™

ReRAM Click

Dev. board

CLICKER 4 for STM32F302VCT6

Compiler

NECTO Studio

MCU

STM32F302VC

Explore how ReRAM is reshaping the memory landscape, delivering faster, more efficient data storage solutions for the modern world

Hardware Overview

How does it work?

ReRAM Click board is based on the MB85AS4MT, a 4Mb serial SPI ReRAM memory module from Fujitsu. This module contains 524.288 x 8 bits of memory that can be randomly accessed. The pinout of the used memory module is the same as most commonly used EEPROM modules so that it can directly replace it. The usual SPI lines - SO, SI, SCK and #CS pins from the MB85AS4MT IC are routed to the mikroBUS™ SPI port (MISO, MOSI, SCK and CS pins). Besides the SPI serial bus, there are two more pins routed to the mikroBUS™. The #HOLD pin of the MB85AS4MT IC is routed to the RST pin of the mikroBUS™ and it is used to hold the data transfer. When this pin is pulled to a LOW logic level, all data transfer operations are suspended. However, this function is enabled only when the device is already addressed with the CS

pin pulled to a LOW level. This allows to pause the data transfer and resume it later without the need to first address it via the CS pin, reducing the output latency that way. While the data transfer is paused, the SO pin will switch to a high impedance mode (HIGH Z) and will remain inactive. The SCK pulses are completely ignored. The #HOLD pin of the MB85AS4MT IC is pulled to a HIGH logic level by an onboard pull-up resistor. The #WP pin of the MB85AS4MT IC is routed to the PWM pin of the mikroBUS™ and it is used to prevent writes to the status register, acting as a hardware write protect pin. It is routed to the RST pin of the mikroBUS™. The logical organization of the module, such as read and write commands and the status register of the MB85AS4MT IC are the same as with most commonly used

EEPROM modules, such as the one used in EEPROM 4 click. That allows this memory module, as well as ReRAM click to replace the existing EEPROM module with not too much additional work. The provided libraries offer all the functions needed to work with the ReRAM click. Their usage is demonstrated in the included example application which can be used as a reference for further development. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

Features overview

Development board

Clicker 4 for STM32F3 is a compact development board designed as a complete solution, you can use it to quickly build your own gadgets with unique functionalities. Featuring a STM32F302VCT6, four mikroBUS™ sockets for Click boards™ connectivity, power managment, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core, there is a STM32F302VCT6 MCU, a powerful microcontroller by STMicroelectronics, based on the high-

performance Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the development

board much simpler and thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution which can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws. For most applications, a nice stylish casing is all that is needed to turn the Clicker 4 development board into a fully functional, custom design.

CLICKER 4 for STM32F302VCT6 double image

Microcontroller Overview

MCU Card / MCU

Architecture

ARM Cortex-M4

MCU Memory (KB)

256

Silicon Vendor

STMicroelectronics

Pin count

100

RAM (Bytes)

40960

Used MCU Pins

mikroBUS™ mapper

Data Transfer Pause

PC15

RST

SPI Chip Select

PA4

SPI Clock

PA5

SCK

SPI Data OUT

PA6

MISO

SPI Data IN

PA7

MOSI

Power Supply

3.3V

Ground

GND

Write Protect

PE9

PWM

INT

SCL

SDA

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

PIC32MZ MXS Data Capture Board front image hardware assembly

Start by selecting your development board and Click board™. Begin with the CLICKER 4 for STM32F302VCT6 as your development board.

Thermo 21 Click front image hardware assembly

Board mapper by product6 hardware assembly

PIC32MZ MXS Data Capture Board NECTO MCU Selection Step hardware assembly

Necto No Display image step 8 hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for ReRAM Click driver.

Key functions:

reram_send_cmd - Command Send function
reram_read_status - Status Read function
reram_write_memory - Memory Write function

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 main.c
 * \brief ReRAM Click example
 *
 * # Description
 * This example demonstrates the use of the ReRAM Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes SPI serial interface and puts a device to the initial state.
 * Data from 0 to 255 will be written in memory block from address 0x0 to
 * address 0xFF.
 *
 * ## Application Task
 * Reads same memory block starting from address 0x0 to address 0xFF and
 * sends memory content to USB UART, to verify memory write operation.
 *
 * *note:*
 * Write Enable Latch is reset after the following operations:
 *  - After 'Write Disable'command recognition.
 *  - The end of writing process after 'Write Status' command recognition.
 *  - The end of writing process after 'Write Memory' command recognition.
 *
 * Data will not be written in the protected blocks of the ReRAM array.
 *  - Upper 1/4 goes from address 0x60000 to 0x7FFFF.
 *  - Upper 1/2 goes from address 0x40000 to 0x7FFFF.
 *  - The entire ReRAM array goes from address 0x00000 to 0x7FFFF.
 *
 * \author Nemanja Medakovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "reram.h"


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

static reram_t reram;
static log_t logger;

static char write_buf[  ] = "MikroE";
static char read_buf[ 10 ] = { 0 };

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

void application_init( void )
{
    reram_cfg_t reram_cfg;
    log_cfg_t logger_cfg;

    //  Click object initialization.
    reram_cfg_setup( &reram_cfg );
    RERAM_MAP_MIKROBUS( reram_cfg, MIKROBUS_1 );
    reram_init( &reram, &reram_cfg );

    //  Click start configuration.
    reram_default_cfg( &reram );

    /** 
     * 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( logger_cfg );
    log_init( &logger, &logger_cfg );
    
    reram_wake_up( &reram );
    
    uint32_t id_data = reram_read_id( &reram );
    
    if ( RERAM_ID_DATA != id_data )
    {
        log_printf( &logger, "***  ReRAM Error ID  ***\r\n" );
        for( ; ; );
    }
    else
    {    
        log_printf( &logger, "***  ReRAM Initialization Done  ***\r\n" );
        log_printf( &logger, "***********************************\r\n" );
    }


    reram_send_cmd( &reram, RERAM_CMD_WREN );
    Delay_ms ( 1000 );
}

void application_task( void )
{   
    log_printf( &logger, "* Writing data *\r\n" );
    
    reram_write_memory( &reram, RERAM_MEM_ADDR_START, write_buf, 6 );
    Delay_ms ( 1000 );
    reram_read_memory( &reram, RERAM_MEM_ADDR_START, read_buf, 6 );

    log_printf( &logger, "* Read data:%s\r\n", read_buf );
    Delay_ms ( 1000 );
    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