Back to topics

Analog control of the μC

Dao
Dao
View PDF

Table of Contents

View Students Feedback

Overview

The EDU MKII expansion board is equipped with a 2-Axis Joystick with pushbutton (ITEAD studio IM130330001), the 2-axis joystick is implemented with two potentiometers, one for each axis, that are controlled by the position of the joystick. The select button is actuated when the joystick is pressed d

The objective of the project is to implement an analog control of intensity and switching frequency of the
3 LEDs located at the HELP board (driven by PWM).

  • The pushbutton of the joystick selects which of the 3 LEDs to control
  • The Joystick X will control the LED intensity (PWM duty cycle for that LED) between 0 and 100%
    • Moving the Joystick to the right will increase the duty cycle proportional with the position
    • Moving the Joystick to the left will decrease the duty cycle proportional with the position
    • Releasing the Joystick will leave the duty cycle unchanged.
  • The Joystick y will control the LED blinking frequency (PWM frequency for that LED) between 10
    Hz and 1 kHz

    • Moving the Joystick to the up will increase the frequency proportional with the position
    • Moving the Joystick to the left will decrease the frequency proportional with the position
    • Releasing the Joystick will leave the frequency unchanged.

Key features for the project that have be used:

  • ADC to sample the 2-axis joystick (ADCINA6, B2) with 1 kHz
  • ePWMs (5A, 4B, 4A) controlling the LEDs located at HELP board with variable switching
    frequency and duty cycle
  • An external interrupt for GPIO (12) connected to pushbutton joystick select
  • Note that the frequency of the ePWM4A and ePWM4B cannot be controlled independently

Content (req.)

  1. Implementation of the ADC sampling
  2. Implementation of the GPIO monitoring
  3. Implementation of the PWM control
  4. Implementation of the LED control logic

Content (opt.)

  1. Display the ADC signals in a GUI (CCS Graph or GUI Composer 2)
  2. Display the status (duty cycle and frequency) of each LED in a GUI (GUI
    Composer 2), and the currently selected LED

Embedded Micro-processors: Applications and C Programming– mini project description

Previous Programmable Gain Amplifiers Next Motion detection system