Unleash your creative potential with MI9639BO-B2 and STM32F302VC
Shine brighter with monochrome
Published Jul 22, 2025
Click board™
OLED B Click
Dev. board
CLICKER 4 for STM32F302VCT6
Compiler
NECTO Studio
MCU
STM32F302VC
See how our OLED solution empowers you to push the boundaries of design, functionality, and energy efficiency, making your products stand out in the market
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Hardware Overview
How does it work?
OLED B Click is based on the MI9639BO-B2, a 19.3x7.8mm 96x39px light blue monochrome passive matrix OLED display from Multi-Inno Technology. The MI9639BO-B2 display features an SSD1306, a 128x64 dot-matrix OLED/PLED segment/common driver with a controller. The controller has built-in functionalities like contrast control (256-step brightness control), normal or inverse image display, vertical and horizontal scrolling functions, and much more accessible through the I2C serial interface. OLEDs are emissive and don't require a separate backlight as LCD technology does, reducing the OLED display's overall power consumption compared to LCDs. It also does not suffer from loss of contrast due to bleed-through of the backlight in the "off" pixels. OLEDs, being emissive, have a consistent contrast ratio greater than 100:1 with no limitation in viewing angle. In addition, they don't suffer from temperature-related response time delays and
contrast changes. Like any OLED display, the MI9639BO-B2 is made from a thin film of an organic compound that emits light when exposed to a current. A small monochrome display like this represents an ideal solution for displaying text or icons. The MI9639BO-B2 display is bright, has a wide viewing angle, and has low power consumption. In addition to the display's main power supply, taken from the +3.3V microBUS™ power rail, the MI9639BO-B2 has another power pin, more precisely, the power supply for the DC/DC converter circuit. This pin is the power supply pin for the internal buffer of the DC/DC voltage converter. Therefore, for this pin, the Click board™ uses a low dropout linear regulator AP7331 from Diodes Incorporated, providing a 3.6V power supply out of 5V mikroBUS™ rail. OLED B Click communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings. It allows the communication-enable
feature to be routed to the CS pin of the mikroBUS™ socket, enabling the OLED B Click for MCU communication only when the CS pin is pulled to a low logic state. In addition, it has two more pins. The first is related to the reset function, routed to the RST pin on the mikroBUS™ socket (when the pin is in a low logic state, the initialization of the chip is executed), and the second is labeled as D/C and routed to the PWM pin on the mikroBUS™ socket is I2C slave address selection pin. This Click board™ is designed to be operated only with a 3.3V logic voltage level, while 5V is used as a supply voltage of the AP7331 LDO. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the 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
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.
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
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the CLICKER 4 for STM32F302VCT6 as your development board.
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 OLED B Click driver.
Key functions:
oledb_display_picture- This function allows user to display picture for on the screenoledb_clear_display- This function clears SSD1306 controller displayoledb_write_string- This function writes a text string from the selected position in a 5x7 or 6x8 font size
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 OLEDB Click example
*
# Description
* This example demonstrates the use (control) of the OLED B display.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Configures the microcontroller for communication and initializes the Click
* board to default state.
*
* ## Application Task
* This section contains the main program that is executed showing a practical
* example on how to use the implemented functions.
*
* @author MikroE Team
*
*/
#include "board.h"
#include "log.h"
#include "oledb.h"
static oledb_t oledb;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
oledb_cfg_t oledb_cfg; /**< Click config object. */
/**
* 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.
oledb_cfg_setup( &oledb_cfg );
OLEDB_MAP_MIKROBUS( oledb_cfg, MIKROBUS_1 );
err_t init_flag = oledb_init( &oledb, &oledb_cfg );
if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) )
{
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
oledb_default_cfg ( &oledb );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
oledb_clear_display( &oledb );
Delay_ms ( 100 );
oledb_write_string( &oledb, OLEDB_FONT_6X8, 0, 0, " MIKROE " );
oledb_write_string( &oledb, OLEDB_FONT_6X8, 1, 0, " OLED B Click " );
oledb_write_string( &oledb, OLEDB_FONT_6X8, 2, 0, " with SSD1306 " );
oledb_write_string( &oledb, OLEDB_FONT_6X8, 3, 0, " controller " );
oledb_write_string( &oledb, OLEDB_FONT_6X8, 4, 0, " TEST EXAMPLE " );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
oledb_write_string( &oledb, OLEDB_FONT_6X8, 0, 0, " TEXT SCROLL EXAMPLE " );
oledb_write_string( &oledb, OLEDB_FONT_6X8, 4, 0, " TEXT SCROLL EXAMPLE " );
Delay_ms ( 1000 );
oledb_scroll_right( &oledb, 4, 0 );
// 6 seconds delay
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
oledb_stop_scroll( &oledb );
oledb_clear_display( &oledb );
Delay_ms ( 100 );
oledb_display_picture( &oledb, oledb_img_mikroe );
Delay_ms ( 500 );
oledb_send_cmd( &oledb, OLEDB_INVERTDISPLAY );
Delay_ms ( 500 );
oledb_send_cmd( &oledb, OLEDB_NORMALDISPLAY );
Delay_ms ( 500 );
oledb_send_cmd( &oledb, OLEDB_INVERTDISPLAY );
Delay_ms ( 500 );
oledb_send_cmd( &oledb, OLEDB_NORMALDISPLAY );
Delay_ms ( 300 );
for ( uint8_t contrast = 0xAF; contrast > 0x00; contrast-- )
{
oledb_set_contrast( &oledb, contrast );
Delay_ms ( 5 );
}
for ( uint8_t contrast = 0x00; contrast < 0xAF; contrast++ )
{
oledb_set_contrast( &oledb, contrast );
Delay_ms ( 5 );
}
oledb_scroll_left( &oledb, 0, 4 );
Delay_ms ( 1000 );
oledb_stop_scroll( &oledb );
oledb_scroll_right( &oledb, 0, 4 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
oledb_stop_scroll( &oledb );
oledb_scroll_left( &oledb, 0, 4 );
Delay_ms ( 1000 );
oledb_stop_scroll( &oledb );
}
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
Additional Support
Resources
Category:OLED
