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This example demonstrates how to display graphics on an OLED display using emWin graphics library in Mbed OS.

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PSoC6 MCU: emWin OLED with Mbed OS

This code example demonstrates how to display graphics on an OLED display using emWin graphics library in Mbed OS. The example uses the CY8CKIT-032 AFE Shield. This shield has a monochrome OLED display with the SSD1306 controller with a resolution of 128x64 pixels.

Tested with Mbed OS v6.2.1.

Provide feedback on this code example.


Note: You do not need to install ModusToolbox to build and run this code example. However, installing it is required when you need to:

  • Debug using the Eclipse IDE for ModusToolbox. See the user guide for details.

  • Customize the default device configuration using any of the Configurator tools

  • Port this code example to a new target that is not listed under the Supported Kits

Supported Toolchains (Mbed CLI argument -t)

Supported Kits (Mbed CLI argument -m)

Hardware Setup

This code example requires CY8CKIT-032 PSoC Analog Front End (AFE) Arduino Shield.

Note: The PSoC 6 BLE Pioneer Kit (CY8CKIT-062-BLE) and the PSoC 6 WiFi-BT Pioneer Kit (CY8CKIT-062-WIFI-BT) ship with KitProg2 installed. The ModusToolbox software requires KitProg3. Before using this code example, make sure that the board is upgraded to KitProg3. The tool and instructions are available in the Firmware Loader GitHub repository. If you do not upgrade, you will see an error like “unable to find CMSIS-DAP device” or “KitProg firmware is out of date”.

For Mbed OS, the kit must be in DAPLink mode. See the KitProg3 User Guide (see Documentation tab in the Cypress Programming Solutions web page) to learn how to put the Pioneer Kit into DAPLink mode.

Software Setup

Install a terminal emulator if you don’t have one. Instructions in this document use Tera Term.

This example requires no additional software or tools.

Import the Code Example Using Mbed CLI

Mbed CLI commands are used to import the code example and compile. See Working with Mbed CLI web page.

mbed import

This command first clones the code example repository from GitHub, and then deploys all the libraries.

If you wish to perform the deploy process manually, use the following commands:

  1. Clone the GitHub code example repository:

git clone && cd mbed-os-example-emwin-oled

  1. Deploy the dependent libraries. The library files are identified with the .lib extension.

mbed deploy

  1. Set the current directory as root:

mbed new .


If using a PSoC 64 Secure MCU kit (like CY8CKIT-064B0S2-4343W), the PSoC 64 Secure MCU must be provisioned with keys and policies before being programmed. Follow the instructions in the Secure Boot SDK User Guide to provision the device. If the kit is already provisioned, copy-paste the keys and policy folder to the application folder.

  1. Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.

  2. Program the board using the Mbed command to compile and flash the application using hte default toolchain to the default target:

    mbed compile -m <TARGET> -t <TOOLCHAIN> --flash --sterm

    For example, to build for the target CY8CKIT-062-BLE with the toolchain GCC_ARM, use the following command:

    mbed compile -m CY8CKIT_062_BLE -t GCC_ARM --flash --sterm

Note: With the --sterm option, Mbed CLI opens a new terminal with 9600-8N1 as the setting after programming completes. Do not use this option if you want to connect using another serial terminal application such as PuTTY or Tera Term.

  1. After programming, the application starts automatically. Confirm that the the startup screen with Cypress logo is displayed on the OLED display for 3 seconds. After 3 seconds, another screen with instructions to press the user switch to scroll through the display pages is displayed.

  2. Press the user switch to scroll through various display pages that demonstrate the emWin graphic library’s 2D graphics features:
    - Text wrap and rotation
    - Font sizes - normal fonts
    - Font sizes - bold fonts
    - Text alignments and styles
    - 2D Graphics with vertical lines of various thickness, rectangles and circles

    Figure 1. Startup Screen

Figure 2. 2D Graphics


You can debug the example to step through the code. In the IDE, use the \ Debug (KitProg3_MiniProg4) configuration in the Quick Panel. For more details, see the “Program and Debug” section in the Eclipse IDE for ModusToolbox User Guide.

Follow the steps from Eclipse IDE for ModusToolbox User Guide to export the Mbed OS code example and import it into Eclipse IDE for ModusToolbox for programming and debugging.

Mbed OS also supports debugging using any IDE that supports GDB. See Arm Mbed documentation to learn about debugging steps.

Note: (Only while debugging) On the CM4 CPU, some code in main() may execute before the debugger halts at the beginning of main(). This means that some code executes twice - once before the debugger stops execution, and again after the debugger resets the program counter to the beginning of main(). See KBA231071 to learn about this and for the workaround.

Design and Implementation

This code example requires the CY8CKIT-032 PSoC Analog Front End (AFE) Arduino Shield. It has a 128x64 graphics OLED display which can communicate through the I2C interface.

There are three important parts in this code example:

  1. emWin Graphics Library: The emWin Graphics Library is implemented as a middleware and has all the graphics functions. In this example, the library manages a display buffer and updates it with the pixel data in accordance with the graphics operations performed.

See the emWin middleware documentation on GitHub learn about the structure of the emWin package, supported drivers, and for a quick start guide to create and run your first emWin project from scratch. The documentation page also contains configuration details on a wide variety of display drivers provided my emWin.

  1. OLED Display Driver: The OLED display has a SSD1306 controller. The display-oled-ssd1306 library is used to drive the display. This library provides functions to support the dot matrix OLED display driven by the SSD1306 controller through the I2C interface.

  2. Application Code: The application code calls emWin graphics APIs to perform graphic functions.

Resources and Settings

Table 1. Application Resources

Resource Alias/Object Purpose
I2C(HAL) Display_I2C Interface to communicate with OLED shield

Related Resources

Application Notes
AN228571 – Getting Started with PSoC 6 MCU on ModusToolbox Describes PSoC 6 MCU devices and how to build your first application with ModusToolbox
AN221774 – Getting Started with PSoC 6 MCU on PSoC Creator Describes PSoC 6 MCU devices and how to build your first application with PSoC Creator
AN210781 – Getting Started with PSoC 6 MCU with Bluetooth Low Energy (BLE) Connectivity on PSoC Creator Describes PSoC 6 MCU with BLE Connectivity devices and how to build your first application with PSoC Creator
AN215656 – PSoC 6 MCU: Dual-CPU System Design Describes the dual-CPU architecture in PSoC 6 MCU, and shows how to build a simple dual-CPU design
Code Examples
Using ModusToolbox Using PSoC Creator
Device Documentation
PSoC 6 MCU Datasheets PSoC 6 Technical Reference Manuals
Development Kits Buy at
CY8CKIT-062-BLE PSoC 6 BLE Pioneer Kit CY8CKIT-062-WiFi-BT PSoC 6 WiFi-BT Pioneer Kit
CY8CPROTO-063-BLE PSoC 6 BLE Prototyping Kit CY8CPROTO-062-4343W PSoC 6 Wi-Fi BT Prototyping Kit
CY8CKIT-062S2-43012 PSoC 62S2 Wi-Fi BT Pioneer Kit CY8CPROTO-062S3-4343W PSoC 62S3 Wi-Fi BT Prototyping Kit
CYW9P62S1-43438EVB-01 PSoC 62S1 Wi-Fi BT Pioneer Kit CYW9P62S1-43012EVB-01 PSoC 62S1 Wi-Fi BT Pioneer Kit
CY8CKIT-064B0S2-4343W PSoC 64 Secure Boot Wi-Fi BT Pioneer Kit
PSoC 6 Peripheral Driver Library (PDL) and docs mtb-pdl-cat1 on GitHub
Cypress Hardware Abstraction Layer (HAL) Library and docs mtb-hal-cat1 on GitHub
Retarget IO - A utility library to retarget the standard input/output (STDIO) messages to a UART port retarget-io on GitHub
CapSense® library and docs capsense on GitHub
SEGGER emWin Middleware Library emwin on GitHub
Links to all PSoC 6 MCU Middleware psoc6-middleware on GitHub
Eclipse IDE for ModusToolbox The cross-platform, Eclipse-based IDE for IoT designers that supports application configuration and development targeting converged MCU and wireless systems.
PSoC Creator™ The Cypress IDE for PSoC and FM0+ MCU development.

Other Resources

Cypress provides a wealth of data at to help you select the right device, and quickly and effectively integrate it into your design.

For PSoC 6 MCU devices, see How to Design with PSoC 6 MCU - KBA223067 in the Cypress community.

Document History

Document Title: CE231993 - PSoC6 MCU emWin OLED with Mbed OS

Version Description of Change
1.0.0 New code example. Tested with Mbed OS Version 5.12.2.
1.1.0 Updated to Mbed OS 5.13.3.
2.0.0 Updated to Mbed OS 6.2.1.
Minor code changes - Updated to use sleep_for instead of wait_ms.

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