Explorer Board

This example application demonstrates various capabilities of the Explorer board using FreeRTOS. The application uses I2C, I2S, SPI, UART, flash, mic array, and GPIO devices.

The FreeRTOS application creates a single stage audio pipeline which applies a variable gain. The output audio is sent to the DAC and can be listened to via the 3.5mm audio jack. The audio gain can be adjusted via GPIO, where button A is volume up and button B is volume down.

Preparing the hardware

The UART loopback section of the demo requires that a jumper cable be connected between X1D36 and X1D39. This connects the Tx pin to the Rx pin.

Building the firmware

Run the following commands in the xcore_sdk root folder to build the firmware:

cmake -B build -DCMAKE_TOOLCHAIN_FILE=xmos_cmake_toolchain/xs3a.cmake
cd build
make example_freertos_explorer_board
cmake -G "NMake Makefiles" -B build -DCMAKE_TOOLCHAIN_FILE=xmos_cmake_toolchain/xs3a.cmake
cd build
nmake example_freertos_explorer_board


The host applications are required to create the filesystem. See the SDK Installation instructions for more information.

From the xcore_sdk build folder, create the filesystem and flash the device with the following command:

make flash_fs_example_freertos_explorer_board
nmake flash_fs_example_freertos_explorer_board

Running the firmware

From the xcore_sdk build folder run:

make run_example_freertos_explorer_board
nmake run_example_freertos_explorer_board

Debugging the firmware with xgdb

From the xcore_sdk build folder run:

make debug_example_freertos_explorer_board
nmake debug_example_freertos_explorer_board