TWR-TFC-K20 Kinetis K20 Freescale Cup Tower Card

Document created by Eli Hughes on Dec 28, 2012Last modified by Eli Hughes on Jan 2, 2013
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The TWR-TFC-K20  is an all-in-one tower CPU card that can be used to create an autonomous race vehicle for the the Freescale Cup.   It has all the interfaces necessary for the car to sense the track and control the vehicle    This card is also a great platform for teaching embedded systems.   The TWR-TFC-K20 uses a Freescale Kinetis K20 MCU and has some really cool I/O to keep students interested.



Servo Outputs


    1. 3-pin Header to connector directly to steering Servo
    2. 1 Extra Servo header.


Camera Interfaces


1. 5-pin header to connect directly to a Freescale Line Scan Camera

2. Header for 2nd linescan camera (optional)

3. RCA Camera Interface. Includes an LMH1981 Sync Extraction chip and connection to MCU to allow for low resolution (64x64) image capture at 60FPS



    1. Accepts direct battery power – onboard switching regulator 5-18v
    2. All circuitry except for motor controller can be optionally powered over USB Connector


DC Motor Drivers


  1. QTY 2 MC33887APVW : Dual, Independent 5A Motor Driving Circuit.
  2. Supports forward, reverse and braking.
  3. Independent control over each drive motor allows for an active differential implementation
  4. Current Feedback to MCU ADC to allow for closed loop torque control


CPU/ Programming


  1. Integrated Kinetis MK20DN512ZVLL10MCU with OSJTAG


Additional I/O


  1. Some basic I/O for debugging. 4-poistion DIP Switch + 4 LEDs + 2 pushbuttons.
  2. Inputs for Tach Signal/Speed Sensor



Design Files


Rev Beta [B] (Current Production version)

Schematics, Assembly Prints, BOM, etc. - Includes 3d view

Rev B Errata:

  • None known!


Example Code:


All software relating to the TWR-TFC-K20 is held in an Google Code Subversion repository.   This is the only way the source is distributed.   Never used a version control system yet?   Now is the time to learn (Google is your friend)!   All "real" software development processes use some form of version control.  TortoiseSVN is a nice client for SVN!


Google Code Repository:



This code works with Rev B of the board. All major interfaces & peripherals have been tested. At some point we will make a video going through the code. By default, the Linescan camera code is enabled. The code in main.c is pretty easy to follow. There is also code for the NTSC camera but must enabled in the TFC_Config.h file via a pre-processor directive.


There is also code used for the OSTAG interface, Labview demo applications and drivers for the USB