EVK-R41Z - User guide
UBX-19033357 - R03
Hardware description
Page 10 of 23
Figure 7: Schematic: Current measurement headers
2.3
Debug interface
The R41Z evaluation board features an OpenSDA 2.1 interface which includes a SWD
connection and virtual COM port for easy programming and debugging of the R41Z module.
2.3.1
OpenSDA interface
The OpenSDA hardware is separated from the R41Z target by a set of level shifters to ensure
that debugging can be done regardless of the DC-DC mode used. The interface will operate in
a similar manner to other evaluation boards that use OpenSDA. When connected to a host
computer, the evaluation board will appear as a mass storage device named “FRDM-KW41Z”.
Binary files can be directly copied to this drive to load them to the R41Z target.
The R41Z evaluation board ships with a SEGGER debug application loaded though other
OpenSDA 2.1 applications may be used. To load a new OpenSDA application, apply power to
the board while holding the reset button. The evaluation board will appear as mass storage
device named “Maintenance” onto which the OpenSDA application binary can be copied.
2.3.2
Reset button
The primary function of the reset button is to reset the R41Z module. It is also used to put the
OpenSDA interface into “Maintenance” mode to allow for different debug applications to be
loaded. The reset pin on the R41Z module and the OpenSDA I/O are both connected to the
reset button and isolated from each other by diodes. Unlike the standard OpenSDA
implementation, a header is not needed to select which device the reset button is connected
to.
When power is initially applied, the OpenSDA interface momentarily ignores any reset signal
asserted by the R41Z in order to sample the state of the reset button. This is done by setting
the reset line level shifter between the OpenSDA interface and the R41Z to a high impedance
state.
