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CX3 Firmware: Frequently Asked Questions – KBA91297

Last Updated: April 11, 2014
  1. Question

    Where can I find the CX3 firmware source code for example projects?


    You can find the CX3 firmware example projects as part of the FX3 SDK 1.3.1 or later release. These projects are in the following folder when FX3 SDK is installed in default path:
    C:\Program Files (x86)\Cypress\EZ-USB FX3 SDK\1.3\firmware\cx3_examples.

    These example firmware projects support OmniVision® OV5640 and Aptina® AS0260 image sensors. Contact the respective image sensor manufacturers to get access to image sensor datasheet, register description, and configuration data.

  2. Question

    What are the color formats supported by CX3?


    CX3 can support all the image data formats supported by Mobile Industry Processor Interface (MIPI) Camera Serial Interface (CSI)-2 specifications that is up to 24-bit wide. For example, the RAW, YUV, RGB, and JPEG data formats are supported.

  3. Question

    Can CX3 convert RAW images to RGB or YUV formats?


    No. CX3 cannot do any image format conversion. To convert image formats, an Image Signal Processor (ISP) or FPGA is required. CX3 does not have a built-in ISP. You should use an external ISP to convert or compress image data.

  4. Question

    Can CX3 take audio inputs over the I2S port?


    CX3 does not have an I2S input port; however, it has a serial peripheral interface (SPI) master. Therefore, by using an external I2S-to-SPI bridge, an audio input device that has an I2S port can be interfaced with CX3. CX3 also has an I2S output port to connect an audio output device with the I2S port.

  5. Question

    Does CX3 support boundary scan using the JTAG port?


    No. CX3 Does not support boundary scan feature using the JTAG port. Therefore, no boundary scan description language (BSDL) model files are available for CX3. JTAG port is provided only for debugging the ARM® processor code in CX3. The JTAG port of CX3 should not be connected to the JTAG chain in your board.

  6. Question

    What is the maximum resolution supported by CX3?


    CX3 can support up to 2.4 Gbps (300 MBps) throughput.

    You should make sure that the throughput determined by the formula given below does not exceed 2.4 Gbps.

    Image throughput = bits per pixel x (Horizontal resolution + Horizontal blanking) x (Vertical resolution + vertical blanking) x frames per second

    For example, some of the resolution, frame rate, and color format supported by CX3 are given below.

    • 1920 x 1080 (FHD) , 30fps in YUV422 format
    • 1280 x 720p (HD), 60fps in YUV422 format
    • 3840 x 2160 (uHD, 4k x 2k), 30fps in JPEG format with 6:1 compression
    • 4096 x 2160 (4k native), 30fps in RAW8 format

    Contact Cypress technical support if you have more questions on color format and frame rate support.

    Note: To display video from RAW format sensors, an external Image Signal Processor (ISP) is required.

  7. Question

    How do I build the CX3 RDK firmware example project supplied with the FX3 SDK?


    1. Download the FX3 SDK 1.3.1 from the webpage for FX3 SDK ( and install it.
    2. Open the Eclipse-based editor (EZ-USB® Suite). Click Start > All Programs > Cypress > Eclipse > EZ USB Suite.
    3. When prompted, create a new workspace, and assign a workspace name.
    4. Within Eclipse, import the SDK project for CX3 into the current workspace as follows:
      1. Select File > Import.
      2. Select General > Existing Projects into Workspace and click Next.
      3. Set the Root Directory to the following values:
        • On 32-bit Windows: C:\Program Files\Cypress\EZ-USB FX3 SDK\1.3\firmware\cx3_examples
        • On 64-bit Windows: C:\Program Files(x86)\Cypress\EZ-USB FX3 SDK\1.3\firmware\cx3_examples
      4. From the projects listed in the Projects list, select the cycx3_uvc_ov5640 project, and select the option Copy projects into workspace. The project will be copied into the workspace and available in Eclipse.
    5. Set the build mode for the project as Release.
    6. Build the project by selecting the arrow to the right of the Build icon (which looks like a hammer) in the toolbar and selecting Release.
      After the project is built, the img file for download to the CX3 RDK will be available in the Release folder in the project in the Project Explorer.
  8. Question

    How do I program the CX3 firmware image to the SPI or I2C Flash / EEPROM in CX3 RDK?


    1. Set the Boot Mode selection switch SW5 (Located between the Power switch and the Reset button) to USB Boot: This means that SW5.1 is ON, SW5.2 is ON, SW5.3 is OFF.
    2. Open Control Center from All Programs > Cypress > Cypress USB Suite > Control Center.
    3. Reset the CX3 RDK. It is listed in the Control Center window.
    4. Click Program > FX3, and then select the SPI Flash or I2C E2PROM option to download the firmware to the SPI Flash or I2C EEPROM on the RDK.
      A boot programmer firmware gets downloaded to the FX3 and it re-enumerates and opens a window allowing you to select the IMG file you want to download to the SPI Flash or I2C EEPROM.
    5. Browse to the location of the img file and select it. Once the FW img is downloaded a message is displayed at the bottom of control center indicating that the operation was successful.
    6. Set the Boot Mode Selection switch (SW5 as in step 1) to SPI Boot or I2C Boot based on where you downloaded the FW.
      • For SPI Boot, set switches to 1 to ON, 2 to OFF, 3 to ON.
      • For I2C EEPROM boot set to 1 to OFF, 2 to ON, 3 to OFF.
    7. Reset the CX3 to make it boot from the flash.

    See the CX3 RDK Quick Start Guide for switch location. Refer to the CX3 RDK schematic for the switch settings.

  9. Question

    What is the boot up time of CX3 when the firmware is stored in SPI flash?


    The boot up time is approximately 115 ms when CX3 boots from SPI flash.

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