Hello JIN BUHM KIM,
You can download the demo source code from the following link.
If you are looking for demos and drivers with their source code for the FRDM-KL02Z I highly recommend you download the SDK instead. SDK is a collection of comprehensive software enablement for NXP® Kinetis Microcontrollers that includes system startup, peripheral drivers, USB and connectivity stacks, middleware, and real-time operating system (RTOS) kernels. Link to download the newest version of the SDK.
Hope it helps!
Victor.
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------