FRDMKL27Z User’s Guide, Rev. 0, 02/2015
6
Freescale Semiconductor, Inc.
FRDM-KL27Z hardware description
NOTES
J9 and J17 are not populated by default. The two pins of these headers are
in parallel with 0
Ω
resistors. In addition, J17 is also in parallel with a 10
Ω
resistor. To measure the energy consumption of the KL27Z, either a
voltmeter or an ammeter may be used. To use a voltmeter, R2 (0
Ω
) must be
removed before connecting the voltmeter probes to the pins of J17. Both R1
and R2 (10
Ω
) must be removed to measure current with an ammeter. For
the OpenSDA MCU, energy consumption can be measured by removing R4
(0
Ω
) and connecting ammeter probes to the pins of J9.
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
Figure 3
. The hardware circuit is
based on a Freescale Kinetis K20 family 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, run-control debug
interfaces, serial-to-USB converters, and more. Two or more OpenSDA applications can run simulta-
neously. For example, run-control debug application and serial-to-USB converter runs in parallel to pro-
vide a virtual COM communication interface while allowing code debugging via OpenSDA with just a
single USB connection. These two applications are provided in a single code package. Refer to the
OpenSDA User’s Guide
for more details.
Figure 3. OpenSDA block diagram
P3V3_VREG
Regulated 3.3V supply
. Sources power to the P3V3 supply rail through an optional back drive
protection Schottky diode.
P3V3
Main supply rail
for the FRDM-KL27Z. Can be sourced from P3V3_VREG.
P3V3_KL27Z
KL27Z MCU power supply.
Header J17 provides a convenient means for KL27Z energy consumption
measurements.
P3V3_SDA
OpenSDA circuit power supply.
Table 2. FRDM-KL27Z power supplies
