FRDM-KL43Z User’s Guide, Rev. 1
6
NXP Semiconductors
FRDM-KL43Z hardware description
5.2
Serial and debug adapter (OpenSDA)
OpenSDA is an open-standard serial and debug adapter. It bridges serial and debug communications
between a USB host and an embedded target processor as shown in
. The hardware circuit is based
on a Freescale Kinetis K20 family microcontroller (MCU) with 128 KB of embedded flash and an
integrated USB controller. OpenSDA features a mass storage device (MSD) bootloader, which provides a
quick and easy mechanism for loading different OpenSDA applications such as flash programmers,
Table 3. FRDM-KL43Z power supplies
Power supply name
Description
P5-9V_VIN
Power supplied from the V
IN
pin of the I/O headers (J3 pin 16).
P5V_SDA
Power supplied from the OpenSDA USB connector A Schottky diode provides
back drive protection.
P5V_KL43Z
Power supplied from the KL43Z USB connector A Schottky diode provides back
drive protection.
P3V3_VREG
Regulated 3.3 V supply. Sources power to the P3V3 supply rail through a back
drive protection Schottky diode.
1
1
By default the linear regulator, U1, is a 3.3 V output regulator. However, this is a common footprint that would
allow the user to modify the assembly to utilize an alternative device such as a 1.8 V or 2.5 V regulator. The
KL43 microcontroller has an operating range of 1.71 V to 3.6 V.
P3V3_BATT
Coin cell battery supply voltage. Sources power to the P3V3 supply rail through
a back drive protection Schottky diode.
P3V3
Main supply rail for FRDM-KL43Z assembly. May be sourced from P3V3_VREG,
P3V3_BATT, or directly from the I/O headers (J3 pin 8).
P3V3_KL43Z
KL43Z MCU supply. Header J17 provides a convenient means for energy
consumption measurements.
2,3
2
J17 and J9 are not populated by default. The two pins of these headers are shorted together by a trace on
the bottom layer of the PCB. To measure the energy consumption of either the KL43 or the OpenSDA MCU,
the trace between these pins must first be cut. A current probe or a shunt resistor and voltage meter can then
be applied to measure the energy consumption on these rails.
3
J20 is not populated by default. The two pins of this header are shorted together by a trace on the bottom
layer of the PCB. To measure the energy consumption of digital part of KL43, the trace between these pins
must first be cut. A current probe or a shunt resistor and voltage meter can then be applied to measure the
energy consumption on these rails.
P3V3_SDA
OpenSDA circuit supply. Header J9 provides a convenient means for energy
consumption measurements.
P5V_USB
Nominal 5 V supplied to the I/O headers (J3 pin 10). Sourced from either the
P5V_KL43Z or P5V_SDA supply through a back drive protection Schottky diode.
