USB CDC TX Counter Sample App

Description

The USB CDC TX Counter Sample application demonstrates USB CDC communication and periodic data transmission on the supported boards for this application. It performs comprehensive USB CDC testing including virtual COM port functionality, keep-alive message transmission, and connection monitoring to ensure reliable USB-based data transmission capabilities.

The sample includes multiple USB CDC operations:

• USB CDC initialization: Initialize USB CDC virtual COM port communication with host PC.

• Periodic transmission: Send incrementing keep-alive messages at regular intervals.

• Connection monitoring: Monitor USB connection status and activity.

• Counter functionality: Maintain and increment counter values for message generation.

• Virtual COM port: Demonstrate USB CDC virtual COM port capabilities.

• Data transmission validation: Ensure reliable data transmission over USB CDC.

During each run, the app logs initialization status, transmission progress, counter values, and connection status. This makes it easy for end users to confirm that USB CDC setup and periodic transmission operations are working as expected.

The latest example structure uses a common application source tree with board-specific hardware setup kept under hw/<BOARD>/. For this app:

• Common application sources such as main.c and USB CDC transmission files stay in the app root.

• Application defconfigs are stored under configs/.

• Board and hardware-specific setup is selected from hw/<BOARD>/, for example hw/SR110_RDK/.

The application can also be exported and built as a standalone app repository. In that flow, keep this app in its own directory, point SRSDK_DIR to the SDK root, and build from the app directory itself. For the full application workflow model, see Astra MCU SDK User Guide.

Supported Boards

This application supports:

• SR110_RDK

Select the defconfig that matches your target board, and the build system will pick the corresponding board-specific hardware setup from hw/<BOARD>/.

Prerequisites

• Choose one setup path:

  • CLI: Setup and Install SDK using CLI

  • VS Code: Setup and Install SDK using VS Code

Test Case Selection

Before building, choose the testcase defconfig that matches your target board.

You can:

• Select the required defconfig directly from the application’s configs/ directory.

• Run make list_defconfigs from the application directory to list all supported defconfigs.

Available defconfigs:

• sr110_rdk_cm55_usb_cdc_tx_counter_sample_app_defconfig

Building and Flashing the Example using VS Code

Use the VS Code flow described in the SR110 guide and the VS Code Extension guide:

• SR110 Build and Flash with VS Code

• Astra MCU SDK VS Code Extension User Guide

Build (VS Code):

1. Open Build and Deploy -> Build Configurations.

2. Select the usb_cdc_tx_counter_sample_app project configuration in the Project Configuration dropdown.

3. Build with Build (SDK+Project) for the first build, or Build (Project) for rebuilds.

Flash (VS Code):

1. Use Image Conversion to generate the flash image.

2. Use Image Flashing (SWD/JTAG) to flash the firmware image.

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Building and Flashing the Example using CLI

Use the CLI flow described in the SR110 guide:

• SR110 Build and Flash with CLI

Build (CLI):

1. Build from the application directory itself:

   cd <sdk-root>/examples/usb_examples/usb_cdc_tx_counter_sample_app
   export SRSDK_DIR=<sdk-root>
   make <app_defconfig> BUILD=SRSDK
   

2. For faster rebuilds when only app code changes, reuse the app-local installed SDK package:

   cd <sdk-root>/examples/usb_examples/usb_cdc_tx_counter_sample_app
   export SRSDK_DIR=<sdk-root>
   make build
   

3. If this app has been exported to its own repository, use the same commands from that exported app directory after setting SRSDK_DIR to the SDK root.

Flash (CLI):

1. Activate the SDK venv (required for image generation tools):

   # Linux/macOS
   source <sdk-root>/.venv/bin/activate
   # Windows PowerShell
   .\.venv\Scripts\Activate.ps1
   

2. Generate the flash image:

   cd <sdk-root>/tools/srsdk_image_generator
   python srsdk_image_generator.py \
     -B0 \
     -flash_image \
     -sdk_secured \
     -spk "<sdk-root>/tools/srsdk_image_generator/Inputs/spk_rc4_1_0_secure_otpk.bin" \
     -apbl "<sdk-root>/tools/srsdk_image_generator/Inputs/sr100_b0_bootloader_ver_0x012F_ASIC.axf" \
     -m55_image "<sdk-root>/examples/usb_examples/usb_cdc_tx_counter_sample_app/out/sr110_cm55_fw/release/sr110_cm55_fw.elf" \
     -flash_type "GD25LE128" \
     -flash_freq "67"
   

3. Flash the firmware image:

   cd <sdk-root>
   python tools/openocd/scripts/flash_xspi_tcl.py \
     --cfg_path tools/openocd/configs/sr110_m55.cfg \
     --image tools/srsdk_image_generator/Output/B0_Flash/B0_flash_full_image_GD25LE128_67Mhz_secured.bin \
     --erase-all
   

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Running the Application using VS Code Extension

1. In VS Code, open Video Streamer from the Synaptics sidebar.

   

2. Press RESET on the board after flashing.

3. For logging output, click SERIAL MONITOR and connect to the DAP logger port on J14.

   • To make it easier to identify, ensure only J14 is plugged in (not J13).

   • The logger port is not guaranteed to be consistent across OSes. As a starting point:

     • Windows: try the lower-numbered J14 COM port first.

     • Linux/macOS: try the higher-numbered J14 port first.

   • If you do not see logs after a reset, switch to the other J14 port.

4. Select the USB CDC COM port on list of COM ports and select Connect to Auto Run to observe periodic keep-alive counter messages.

   

Functionality

• Periodically transmits incrementing keep-alive messages over USB CDC.

• Useful for basic link validation and CDC transmit path testing.