2.3 OpenSDA serial and debug
The FRDM-KW36 development board includes OpenSDA v2.2- a serial and debug adapter circuit that includes an open-source
hardware design, an open-source bootloader, and debug interface software. It bridges serial and debug communications between
a USB host and an embedded target processor as shown in
. The hardware circuit is based on an NXP Kinetis K20 family
MCU (MK20DX128VFM5) with 128 KB of embedded flash and an integrated USB controller. OpenSDAv2.2 comes preloaded
with the DAPLink bootloader - an open-source Mass Storage Device (MSD) bootloader and the CMSIS-DAP Interface firmware,
which provides a MSD flash programming interface, a virtual serial port interface, and a CMSIS-DAP debug protocol interface.
For more information on the OpenSDAv2.2 software, see mbed.org,
https://github.com/mbedmicro/DAPLink
.
Figure 4. OpenSDAv2.2 high-level block diagram
OpenSDAv2.2 is managed by a Kinetis K20 MCU built on the Arm Cortex-M4 core. The OpenSDAv2.2 circuit includes a status
LED (D1) and a pushbutton (SW1). The pushbutton asserts the Reset signal to the KW36 target MCU. It can also be used to
place the OpenSDAv2.2 circuit into bootloader mode. UART and GPIO signals provide an interface to either the SWD debug port
or the K20. The OpenSDAv2.2 circuit receives power when the USB connector J11 is plugged into a USB host.
2.3.1 Virtual serial port
A serial port connection is available between the OpenSDAv2.2 MCU and pins PTC6 and PTC7 of the KW36.
To enable the Virtual COM, Debug, and MSD features, mbed drivers must be installed. Download the drivers at
https://developer.mbed.org/handbook/Windows-serial-configuration
.
NOTE
NXP Semiconductors
Overview and description
FRDM-KW36 Freedom Development Board User’s Guide, Rev. 4, 01/2020
User's Guide
5 / 28