Datasheet

FRDM-KE02Z40M User’s Guide, Rev. 0, 03/2014
Freescale Semiconductor, Inc. 7
to-USB converter run in parallel to provide a virtual COM communication interface while allowing code
debugging via OpenSDA with just single USB connection. These two applications are provided in a
single code package.
See to the OpenSDA User’s Guide, available on freescale.com, for more details.
Figure 3. OpenSDA block diagram
OpenSDA is managed by a Kinetis K20 MCU built on the ARM Cortex-M4 core. The OpenSDA circuit
includes a status LED (D4) and a RESET pushbutton (SW1). The pushbutton asserts the Reset signal to
the KE02Z target MCU. It can also be used to place the OpenSDA circuit into Bootloader mode by
holding down the RESET pushbutton while plugging the USB cable to USB connector J6. Once the
OpenSDA enters bootloader mode, other OpenSDA applications such as debug application can be
programmed.
SPI and GPIO signals provide an interface to the SWD debug port of the KE02Z. Additionally, signal
connections are available to implement a UART serial channel. The OpenSDA circuit receives power
when the USB connector J6 is plugged into a USB host.
4.2.1 Debugging interface
Signals with SPI and GPIO capability are used to connect directly to the SWD of the KE02Z. These
signals are also brought out to a standard 10-pin (0.05”) Cortex Debug connector (J7) as shown in
Figure 4. It is possible to isolate the KE02Z MCU from the OpenSDA circuit and use J7 to connect to an
off-board MCU. To accomplish this, cut off the 0-ohm resistor R58. This will disconnect the
SWD_CLK pin to the KE02Z so that it will not interfere with the communications to an off-board MCU
connected to J7.