FRDM-KW40Z Freescale Freedom Development Board User’s Guide, Rev. 2, 10/2015

Freescale Semiconductor, Inc.

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FRDM-KW40Z overview and description

3.3

Serial and Debug Adapter

The FRDM-KW40Z development board includes OpenSDA v2.1-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 Figure 3. The hardware circuit is based on a Freescale Kinetis K20 family microcontroller (MCU) with

128 KB of embedded flash and an integrated USB controller. OpenSDAv2.1 comes preloaded with the

CMSIS-DAP bootloader - an open-source mass storage device (MSD) bootloader and the CMSIS-DAP

Interface firmware (aka mbed interface), which provides a MSD flash programming interface, a virtual

serial port interface, and a CMSIS-DAP debug protocol interface.

For more information on the OpenSDAv2.1 software, see mbed.org and

https://github.com/mbedmicro/CMSIS-DAP.

Figure 3. OpenSDAv2.1 high-level block diagram

OpenSDAv2.1 is managed by a Kinetis K20 MCU built on the ARM Cortex-M4 core. The OpenSDAv2.1

circuit includes a status LED (D2) and a pushbutton (SW6). The pushbutton asserts the Reset signal to the

MKW40Z target MCU. It can also be used to place the OpenSDAv2.1 circuit into bootloader mode. UART

and GPIO signals provide an interface to either the SWD debug port or the K20. The OpenSDAv2.1 circuit

receives power when the USB connector J6 is plugged into a USB host.

3.3.1

Virtual serial port

A serial port connection is available between the OpenSDAv2.1 MCU and pins PTC6 and PTC7 of the

MKW40Z.

NOTE

To enable the Virtual COM, Debug, and MSD features, mbed drivers must

be installed. Download the drivers at