Discovery Lab
School of Computing & Information System
Florida International University
»
»
»
»
»
»
»
»
»
First Day Lecture Review
Introduction to Embedded Systems
Digital I/O
Serial Communication
Lunch
Discovery Lab Tour
Analog I/O
Practice
Q&A
» Raspberry Pi
» Python
» An embedded system is a computer system with
a dedicated function
» Embedded systems control many devices in
common use today
» Processing Cores
˃ microcontrollers or digital signal processors (DSP)
˃ ATMega, PIC, ARM, etc.
» Consumer electronics
» Automobiles,
» Transportation systems
» Medical equipment
» Wireless sensor networking
» Home Automation
» Better Performance
» More GPIOs
» Accelerometer and Capacitive Slider Sensor
» One RGB LED
» Open SDA (Open-standard Serial and Debug Adapter)
» Login ID : team00
» Password : pw00team
» Plugin FRDM Board to USB port on PC
» https://mbed.org/handbook/Windows-serial-configuration
» http://mbed.org/handbook/mbed-FRDM-KL25Z-Getting-Started
» http://mbed.org/handbook/mbed-FRDM-KL25Z-Examples
» #include "mbed.h"
» DigitalOut myled(LED1);
» int main() {
»
while(1) {
»
myled = 1;
»
wait(0.2);
»
myled = 0;
»
wait(0.2);
»
}
» }
* Try to change wait time
» The most common function of a diode is to allow an electric
current to pass in one direction, while blocking current in the
opposite direction
˃ Protect circuits from high voltage surges
- Avalanche diodes
˃ Regulate voltage - Zener diodes
˃ Electronically tune radio and TV receivers
- Varicap diodes
˃ Generate radio frequency oscillations
- Tunnel diodes, Gunn diodes, IMPATT diodes
˃ Convert light into either current or voltage
- Photodiode
˃ Produce light
- Light Emitting Diodes (LED)
Vertically
5 pin
Connected
Bus
(power line)
» Busser
˃ Pin (-)  (e , 1)
˃ Pin (+)  (f , 6)
» Ground & Power line Connection
Dual Motor
Driver
LED
Voltage
Regulator
» Power Connection between Bread Board and FRDM
Power &
Ground
» Power Connection between Bread Board and FRDM
Power &
Ground
» Connect 4 LEDs
»
»
»
»
White  PTC5
Green  PTC6
Yellow  PTC10
Red  PTC16
» Make LEDs blink with below patterns
W
G
R
Y
» Make a led-control program which can control 4 leds with different blinking
time
˃ Using if else
˃ Using switch case
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
»
#include "mbed.h"
Serial pc(USBTX, USBRX); // tx, rx
PwmOut led(LED1);
float brightness = 0.0;
int main() {
pc.printf("Press 'u' to turn LED1 brightness up, 'd' to turn it down\n");
while(1) {
char c = pc.getc();
if((c == 'u') && (brightness < 0.5)) {
brightness += 0.01;
led = brightness;
}
if((c == 'd') && (brightness > 0.0)) {
brightness -= 0.01;
led = brightness;
}
}
}
Connect to your mbed Microcontroller with a Terminal program
and uses the 'u' and 'd' keys to make LED1 brighter or dimmer
» What is it?
˃ Controlling power to inertial electrical devices
˃ Average voltage and current controlled by turning switch
» What for?
˃ Modern electronic power switches
˃ The main advantage of PWM is that power loss in the switching
devices is very low
˃ Relatively low cost
» Applications
˃ Fans
˃ Pumps
˃ Robotic Servo
˃ Stepper Motor
˃ Telecommunication
#include "mbed.h"
PwmOut led(LED1);
int main() {
while(1) {
for(float p = 0.0f; p < 1.0f; p += 0.1f)
{
led = p; wait(0.1);
}
}
}
#include "mbed.h"
PwmOut led(LED1);
int main() {
while(1) {
for(float p = 0.0f; p < 1.0f; p += 0.1f)
{
led = p; wait(0.1);
}
}
}
#include "mbed.h"
PwmOut led(LED1);
int main() {
while(1) {
for(float p = 0.0f; p < 1.0f; p += 0.1f)
{
led = p; wait(0.1);
}
}
}
* Try to connect Buzzer and change delay
#include "mbed.h"
AnalogIn ain(p19);
DigitalOut led(LED1);
int main() {
while (1){
if(ain > 0.3) {
led = 1; } else { led = 0; }
}
}
* Try to connect Buzzer and change delay
#include "mbed.h"
AnalogOut signal(p18);
int main() {
while(1) {
for(float i=0.0; i<1.0; i+=0.1)
{ signal = i; wait(0.0001);
}
}
}
* Try to connect Buzzer and change delay
»
»
»
»
»
»
Dual-H-bridge motor driver: can drive two DC motors
Motor supply voltage: 2–11 V
Logic supply voltage: 2–7 V
Output current: 1.2 A continuous (1.5 A peak) per motor
One PWM and One DigitalOut per DC motor
Logic High for Enabling This Driver
»
»
»
»
»
Input voltage: 2.7 V to 11.8 V
Fixed 5 V output with +5/-3% accuracy
Typical continuous output current: 500 mA to 1 A
The SHDN pin can be driven low (under 0.4 V) to power
down the regulator .