KL25Z Hardware

This development board has some hardware included, but before start we need to give some basics characteristics in order to be able not to “burn it”.


Freescale Freedom Deveopment Platform for KL25Z. Image from: https://community.freescale.com/docs/DOC-93404


The basics

This board has several pins that you can configure to be digital inputs, digital outputs, some can be serial, I2C, SPI and other functions, see the image below for more details.

KL25Z - Pinout

 Clic to enlarge. Image from: http://developer.mbed.org/platforms/KL25Z/

So lets start with the power pins:

  • GND – Ground connection, there are 3 GND pins.
  • P3V3 – This is 3.3V output to power some devices, current is limited to ___ mA. You have two 3V3 pins.
  • P5V_USB – This pin provides 5V ONLY WORKS IF THE USB CABLE IS CONNECTED. This pin comes directly from your UBS port.
  • P5-9V_VIN – This pin is made to provide an external source to your microcontroller, connect this pin to an external regulated source between 5 to 9V. DO NOT EXCEED 9V NEVER OR YOU WILL DAMAGE YOUR BOARD.

About the GPIOs (General Purpose Input / Output pins):

  • All GPIOs are digital input and output 3.3V tolerant.
  • Some GPIOs have secondary functions like, PWM, SPI, I2C, etc. (Check other sections for detailed explication)
  • Pins can drive or source 40 mA on a single I/O pin, 400 mA maximum in total.


Aditional peripherals

This board comes with some extra peripherals like an RGB Led, accelerometer, capacitive touch slider and USB host and device as you can see in the following image:

Additional peripherals

Clic to enlarge. Image from: http://developer.mbed.org/platforms/KL25Z/

RGB Led:

The RGB Led its an common anode type so in order to light up you will need to connect the RGB pins to ground.

  • Red cathode: PTB18
  • Green cathode: PTB19
  • Blue cathode: PTD1

It includes a three axis accelerometer that is interfaced throught an I2C bus and two GPIO signals. By default the I2C address is 0x1D (SA0 pulled high).

  • SCL: PTE24
  • SDA: PTE25
  • INT1: PTA14
  • INT2: PTA15
Capacitive Touch Slider

Two Touch Sense Input (TSI) signals are connected to capacitive electrodes configured as a touch slider.

  • TSI0_CH9
  • TSI0_CH10


Powering your board

There are several options to power your board, the easy ones are:

  • Through the USB connector: Just connect a usb cable to a USB port (5 Volts)
  • Vin pin: Connect a regulated source between 4.5 and 9 Volts


  • It also has the option to power it using a coin cell battery.
  • When using Vin there is not 5V though the 5V pin.


More information

Visit Freescale official web site for the KL25Z 

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