Week 9 : Embedded Programming

• Read a microcontroller data sheet.
• Program your board to do something, with as many different programming languages and programming environments as possible.
• Optionally, experiment with other architectures

Group assignment

Embedded Programming

ATTiny 25/45/85 datasheet

Before programming my hello board, I read the Atmel ATTiny 25/45/85 datasheet.
The datasheet contains a lot of information useful to conceive your board like :

• Pin configurations
  General board configuration
• CPU Core
  contains micro controller architecture, register and stack informations
• Memories
  about different memories : Flash Program Memory, SRAM Data Memory, EEPROM Data Memory, I/O Memory
• Power Management and Sleep Modes
  To reduce power consumption
• Interrupts
  To execute code on external or internal events like pin change
• I/O Ports
  To know how you can set and use pins

Board programming

You can program your board using Fab ISP and typing :

make -f hello.ftdi.44.echo.c.make
sudo make -f hello.ftdi.44.echo.c.make program-usbtiny-fuses

You also can use an Arduino board as programmer. This way, you can use some Arduino librairies wich is quite interesting.
But I have to verify each time if the library I want to uses is compatible with ATTiny or other microcontroller.

Using arduino Uno as programmer

To use Arduino as a programmer, you first need to include AtTiny in known microcontrollers.
In File/Preferences of arduino Ide add https://raw.githubusercontent.com/damellis/attiny/ide-1.6.x-boards-manager/package_damellis_attiny_index.json in Additional Boards Manager URLs.
Now, in Tools/Board, you should have Attiny at the end. If not, restart your Ide.
After, connect your Arduino board to the computer, load Examples/ArduinoIsp/ArduinoIsp and upload the program on your Arduino uno.
Now, your board is ready to be a programmer.
Connect your hello board ISP to arduino pins like below.
In Tools, choose Board:ATTiny 24/44/84, Processor: ATTiny 44, Clock: External 20MHz, and Programmer: Arduino as ISP. Then, load Examples/Basics/Blink. Replace LED_BUILTIN by 7 and upload.
Your board should blink.

Programs on Hello board

Blink program

/*
 * Hello board
 * Blink
*/
 
const int ledPin = 7;
 
void setup() {
pinMode(ledPin, OUTPUT);
}
 
void loop() {
digitalWrite(ledPin, HIGH);
delay(500);
digitalWrite(ledPin, LOW);
delay(500);
}

Make the led on pin 7 blink.

Switch program

/*
 * Hello board
 * Switch
*/
 
const int ledPin = 7;
const int switchPin = 3;
int switchState = 0;
 
void setup() {
pinMode(ledPin, OUTPUT);
pinMode(switchPin,INPUT);
}
 
void loop() {
switchState = digitalRead(switchPin);
if (switchState) {
digitalWrite(ledPin, LOW);
} else {
digitalWrite(ledPin, HIGH);
}
}

Turn the led on if switch button is pressed.

Onoff program

/*
 * Hello board
 * Onoff
*/
 
const int ledPin = 7;
const int switchPin = 3;
int switchPrevious = 1;
int switchState = 0;
int isOn = 0;
 
void setup() {
pinMode(ledPin, OUTPUT);
pinMode(switchPin,INPUT);
switchPrevious = digitalRead(switchPin);
}
 
void loop() {
switchState = digitalRead(switchPin);
if ((switchState == 0) && (switchPrevious == 1)){
isOn = 1 - isOn;
digitalWrite(ledPin, isOn);
delay(20);
}
switchPrevious = switchState;
}

Turn the led on at first pressed and off at the second etc.

OnOffCom program

/*
 * Hello board
 * OnOffCom
*/
 
#include<SoftwareSerial.h>
#define rxPin 0
#define txPin 1
 
const int ledPin = 7;
const int switchPin = 3;
int switchPrevious = 1;
int switchState = 0;
int isOn = 0;
 
SoftwareSerial serial(rxPin,txPin);
 
void setup() {
pinMode(ledPin, OUTPUT);
pinMode(switchPin,INPUT);
switchPrevious = digitalRead(switchPin);
serial.begin(9600);
}
 
void loop() {
switchState = digitalRead(switchPin);
if ((switchState == 0) && (switchPrevious == 1)){
isOn = 1 - isOn;
digitalWrite(ledPin, isOn);
if (isOn) {
serial.println("O");
} else {
serial.println("X");
}
delay(20);
}
switchPrevious = switchState;
if (serial.available()) {
char inChar = (char)serial.read();
if (inChar == 'O') {
isOn = 1;
digitalWrite(ledPin, isOn);
} else if (inChar == 'X') {
isOn = 0;
digitalWrite(ledPin, isOn);
}
}
}

Turn the led on and off when pressing the switch button and send O if on or X if off. You can also turn led on or off by sending O or X from the computer via the serial communication.