NXP Semiconductors Freedom FRDM-K32L3A6 User manual

© 2017 NXP B.V.
FRDM-K32L3A6 Freedom Development
Board
1. Introduction
This guide describes the hardware for the FRDM-
K32L3A6 Freedom Development Board. The FRDM-
K32L3A6 freedom development board is a small, low-
power, and cost-effective evaluation and development
board for application prototyping and demonstration of the
K32 L3 family of devices. These evaluation boards offer
easy-to-use mass-storage-device mode flash programmer,
a virtual serial port, and standard programming and run-
control capabilities.
The K32L3A6 is an ultra-low power solution for
embedded products requiring extended battery life.
NXP Semiconductors
Document Number: FRDMK32L3A6
ZUG
User’s Guide Rev.
B0
, 09/2019
Contents
1. Introduction ........................................................................ 1
2 Overview and description ................................................... 2
2.1 Overview ................................................................. 2
2.2 Feature description .................................................. 3
2.3 OpenSDA serial and debug ..................................... 5
3 Functional description ........................................................ 6
3.1 Clocks ..................................................................... 6
3.2 Power management ................................................. 6
3.3 Universal Serial Bus (USB) .................................... 8
3.4 Secure Digital Host Controller (SDHC) .................. 9
3.5 Serial flash memory ................................................ 9
3.6 Accelerometer + Magnetometer Combo Sensor .... 10
3.7 Visible light sensor ................................................ 11
3.8 User application LEDs .......................................... 12
3.9 User buttons .......................................................... 12
4 Headers and jumpers ........................................................ 14
4.1 Arduino compatible I/O headers ........................... 14
4.2 Jumper table .......................................................... 24
5 References ........................................................................ 26
6 Appendix A ...................................................................... 26
7 Revision history ............................................................... 26
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Overview and description
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2 Overview and description
The FRDM-K32L3A6 development board is an evaluation environment supporting NXP’s K32L3A6
Microcontroller (MCU). The K32L3A6 integrates an ARM Cortex-M4 MCU and an ARM Cortex-M0+
MCU into a single package. NXP supports the K32L3A6 with tools and software that include hardware
evaluation and development boards, software development IDE, applications, and drivers,. The FRDM-
K32L3A6 development board consists of the K32L3A6 device with a 32-Mbit external serial flash,
FXOS8700 Accelerometer/Magnetometer, visible light sensor, SDHC circuit, general purpose LEDs,
and general purpose pushbuttons in the popular Freedom board form-factor. The board is a standalone
PCB and supports application development with NXP’s SDK software package.
2.1 Overview
Figure 1 is a high-level block diagram of the FRDM-K32L3A6 board features:
Figure 1. FRDM-K32L3A6 block diagram
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Overview and description
FRDM-K32L3A6 Freedom Development Board, User’s Guide, Rev. B0, 09/2019
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2.2 Feature description
The FRDM-K32L3A6 development board is based on NXP Freedom development platform. It is the
most diverse reference design containing the K32L3A6 device and all necessary I/O connections for use
as a stand-alone board or connected to an application. Figure 2 shows the FRDM-K32L3A6
development board.
Figure 2. FRDM-K32L3A6 Freedom development board
The FRDM K32L3A6 development board has these features:
 NXP’s ultra-low-power K32L3A6 Dual-core MCU
 Selectable power sources
 DC-DC converter with Buck and Bypass operation modes
 32.768 kHz reference oscillator
 USB device mode interface with micro USB connector
 32-Mbit (4 MB) external serial flash memory for
 NXP FXOS8700CQ Digital Sensor, 3D Accelerometer (±2g/±4g/±8g) + 3D Magnetometer
 Integrated Open-Standard Serial and Debug Adapter (OpenSDA)
 One RGB LED indicator
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Overview and description
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 One red LED status indicator
 One green LED power indicator
 One red LED reset indicator
 One amber LED OpenSDA activity indicator
 Four push-button switches
Figure 3 shows the main board features and Input/output headers for the FRDM-K32L3A6 board:
Figure 3. FRDM-K32L3A6 component placement
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Overview and description
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2.3 OpenSDA serial and debug
The FRDM-K32L3A6 development board includes OpenSDA v3.0-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 4. The hardware circuit is based on a NXP Kinetis K26 family MCU
(MK26FN2M0VMI18) with 2 MB of embedded flash and an integrated USB controller. OpenSDAv3.0
comes preloaded with the DAPLink bootloader - an open-source mass storage device (MSD) bootloader
and the Interface firmware, which provides an MSD flash programming interface, a virtual serial port
interface, and a CMSIS-DAP debug protocol interface. For more information on the OpenSDAv3.0
software, see mbed.org, https://github.com/mbedmicro/DAPLink.
Figure 4. OpenSDAv3.0 high-level block diagram
OpenSDAv3.0 is managed by a Kinetis K26 MCU built on the ARM Cortex-M4 core. The
OpenSDAv3.0 circuit includes a status LED (D4) and a pushbutton (SW1). The pushbutton asserts the
Reset signal to the K32L3A6 target MCU. It can also be used to place the OpenSDAv3.0 circuit into
bootloader mode. UART and GPIO signals provide an interface to either the SWD debug port or the
K26. The OpenSDAv3.0 circuit receives power when the USB connector J12 is plugged into a USB
host.
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Functional description
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2.3.1 Virtual serial port
A serial port connection is available between the OpenSDAv3.0 MCU and pins PTC7 and PTC8 of the
K32L3A6.
NOTE
To enable the Virtual COM features, a driver must be installed. Download the driver at
https://developer.mbed.org/handbook/Windows-serial-configuration
3 Functional description
The six-layer board provides the K32L3A6 and power supply with a DC-DC Buck converter, and
Bypass modes. The layout for this base-level functionality can be used as a reference layout for your
target board.
3.1 Clocks
The FRDM-K32L3A6 board provides a 32.768 kHz to provide an accurate low power time base:
 32.768 kHz Crystal Oscillator (for accurate low-power time base)
o A 32.768 kHz crystal Y1 is provided
o Internal load capacitors provide the entire crystal load capacitance
o To measure the 32.768 kHz oscillator frequency, enable the RTC_CLKOUT signal to be
available on the TAMPER1 pin. This can be observed at J4-3
3.2 Power management
There are several different ways to power and measure current on the FRDM-K32L3A6 board. The
FRDM-K32L3A6 power distribution scheme is shown in Figure 5:
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Functional description
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Figure 5. FRDM-K32L3A6 power management circuit
The FRDM-K32L3A6 board will typically be powered by a 5V source by one of the following means:
 OpenSDA micro USB type B connector (J12)
 K32L3A6 micro USB type B connector (J8)
 Through the Freedom development board header J3 pin-10
 Optional 5V regulator populated at J15
The 5V supply then powers an adjustable regulator, U43, and a 1.8V regulator, U45. The adjustable
regulator is preset to provide a nominal 3.3V output. The adjustable regulator output can be controlled
by connecting an external supply in series with a 3.9k resistor to J52-1. The external supply range of
0.9V to 2.7V will adjust the regulator output from 3.6V to 1.8V.
The K32L3A6 and supporting circuitry can then be powered using the adjustable regulator or a CR2032
coin cell selected by means of J18. The 1.8V regulator provides the ability to run the device with split
supplies.
Typical power supply configurations are shown in Table 1
FRDM-K32L3A6 power supply configurations
Description J10 J48 J14 J16 J19
Single Supply Operation, IO @ 3.3V 1-2 1-2 1-2 1-2 1-2
Single Supply Operation, RF & IO @ 1.8V 1-2 1-2 2-3 2-3 open
Dual IO, 3.3V and 1.8V 1-2 1-2 1-2 1-2 2-3
Full bypass open open open open open
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Functional description
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These jumpers provide access to insert ammeters in all the supplies connecting to the K32L3A6 device.
They also provide a means of connecting external supplies to any of the K32L power pins.
In the case of using a single supply, an ammeter can be placed across J18 to measure the entire system
current. Alternatively, an ammeter can be placed across J53 pins 2 and 3 to measure current with the
LEDs and sensor core taken out of the reading. To minimize the current drawn by the other board
components and measure the current drawn by just the K32L3A6 device, the following steps are
recommended
 Cut the trace under J5 to isolate the power indicator LED (if using J18)
 Cut the trace under J47 to isolate the photo transistor
 Place the SPI flash in ultra-low power mode by writing the command value 0xB9.
3.3 Universal Serial Bus (USB)
The K32L3A6 MCU features a full-speed USB module with device capability and built-in transceiver.
The FRDM-K32L3A6 board routes the USB D+ and D- signals from the K32L3A6 MCU directly to the
onboard micro USB connector (J8) via the required 33 ohm resistors. Figure 6 shows the complete USB
circuit.
Figure 6. USB connector circuit
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Functional description
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3.4 Secure Digital Host Controller (SDHC)
A micro secure digital (SD) card slot is supported on the FRDM-K32L3A6. The SD card detect pin is an
open switch that shorts with VDD when the card is inserted. The SD card VDD is supplied by VDDI01
and it must be configured to be at least 2.7V. The SD card connections are shown in Figure 7.
Figure 7. Micro SD card connector circuit
The SDHC interface lines are directly connected to the SDHC connector with the exception of four
SDHC lines. These lines are multiplexed with the FlexIO connector via zero ohm resistors. These
multiplexed connections are shown in the following figure.
Figure 8. Micro SD card connector circuit
3.5 Serial flash memory
Component U15 is the MX25R3235FZNIL0 32-Mbit (4 MB) serial flash memory with SPI interface. It
is intended for storing the non-volatile system data, or parameters.
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Functional description
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Figure 9 below shows the memory circuit:
 Memory power supply is VDDIO1
 Discrete pull-up resistors pads are provided for the SPI port
 The memory uses a dedicated SPI port
 The SPI Write Protect and Reset has a discrete pull-up resistor
 Series zero ohm resistors are provided if it is desired to isolate the memory from the K32L3A6
device.
Figure 9. MX25R3235FZNIL0 32-Mbit (4 MB) serial flash memory circuit
3.6 Accelerometer + Magnetometer Combo Sensor
Component U14 is NXP FXOS8700CQ sensor, a six-axis sensor with integrated linear accelerometer
and magnetometer with very low power consumption, and selectable I2C. Figure 10 shows the sensor
circuit.
 The sensor core is powered by the BRD_PER rail and the sensor IO is powered by the
BRD_IO_PER rail
o This allows the sensor IO to be operated at a lower voltage than the sensor core supply
 Discrete pull-up resistors for the I2C bus lines are provided
 Default address is configured as 0x1E:
o Address can be changed by pull-up/pull-down resistors on SA0 and SA1 lines
 There are two interrupt signals routed
 The I2C uses dedicated lines for the I2C interface and GPIO connections
 Series zero ohm resistors and shorting links are provided if it is desired to isolate the sensor from
the K32L3A6 device.
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