Back to the main intro to the lessons Fast Track to Arduino Programming
Below is the intro code for Lesson 3, in order to not make the blog entry too long, part two of lesson three can be found here:
Fast Track to Arduino Programming - Lesson 3 pt 2, Improved Parsing and memory usage (Optimized)
The third part in this series is to improve the way we parse the input from the console and make use of SRAM. this initial program is the starting program for this lesson and is presented first to allow you to test and become familiar with its operation.
It is fully working and will read digital inputs, set up PWM outputs and read Analog Inputs, compensating the values to a 0-5V range. There should be nothing new here, I am assuming you will have already run the standard blinky program and know a bit about the analogue capability of the Arduino
The Pins are assigned as follows
All command parsing are changeed to use the previously described strcmp() string comparison function, if you do not understand this, please watch the previous video lesson
Digital Output pin assignments
Program Name Pin Number
#define D0 0
#define D1 1
#define D2 2
#define D3 4
#define D4 7
#define D5 8
#define D6 12
#define D7 13
// define the PWM Pins, Maximum value accepted is 1023
#define PWM0 3
#define PWM1 5
#define PWM2 6
#define PWM3 9
#define PWM4 10
#define PWM5 11
The Analogue Inputs are all default. A0 - A5
Digital outputs will simply toggle as long as any second parameter is provided, If no second parameter is provided it will return the current state, example command "D0" or "DO 1"
PWM output commands are like this : "PWM 0" to "PWM 1023", if you provide a none numeric second parameter it will not accept it
Analog inputs are simply "A0" through "A5"
There are more commands than that listed above, read to program to discover them. A video and second part will be posted in a few days.
Now the starting program
/*
Title: Lesson 3. Improved parsing and reduced SRAM consumption - "Case" Statements
Description: Reading a line of text from the Serial Port and sending to a command process function.
the processing function only echos back to the console for this lesson
This sketch also demonstrates the use of compiler directives to turn on and off blocks of functionality
Date created: 5th June 2014
Created By: Peter Oakes
Additional Comments:
Feel free to use and abuse as you wish, I imply NO Warranty
NOTE: defines take no program space untill used so use instead of ints etc when it will never change
Lessons Available
lesson 0. How big is an Empty Sketch anyway
Lesson 1. Reading the Serial input a line at time
Lesson 2. Parsing the line using "if else if" statements and == or strcmp
Lesson 3a. Preperation for Improved parsing and reduced SRAM consumption - "Case" Statements
*/
/* Include needed Lbraries */
/* End include libraries */
// Bunch of constants in the form of definitions
// 1 = output debug to serial port, 0 = no debug
#define debug 1
// define the buffer size...
#define serialbufferSize 50
#define commandDelimeters "|,.- "
// Define some Digital pins
// Dont use the PWM capable ones
#define D0 0
#define D1 1
#define D2 2
#define D3 4
#define D4 7
#define D5 8
#define D6 12
#define D7 13
// define the PWM Pins
#define PWM0 3
#define PWM1 5
#define PWM2 6
#define PWM3 9
#define PWM4 10
#define PWM5 11
#define MAXPWM 1023
#define MINPWM 0
#define analogToVolts 5/1023 // Volts per step in ADC
// End of Constants
// Now the real varibles
char inputBuffer[serialbufferSize] ;
int serialIndex = 0; // keep track of where we are in the buffer
// End of real variables
void setup()
{
// initialise all the digital outputs
pinMode(D0, OUTPUT);
pinMode(D1, OUTPUT);
pinMode(D2, OUTPUT);
pinMode(D3, OUTPUT);
pinMode(D4, OUTPUT);
pinMode(D5, OUTPUT);
pinMode(D6, OUTPUT);
pinMode(D7, OUTPUT);
// initialise all the PWM outputs
pinMode(PWM0, OUTPUT);
pinMode(PWM1, OUTPUT);
pinMode(PWM2, OUTPUT);
pinMode(PWM3, OUTPUT);
pinMode(PWM4, OUTPUT);
pinMode(PWM5, OUTPUT);
// initialize serial:
Serial.begin(9600);
// do other setup here as needed
// Print some pretty instructions
Serial.println(" Hello, please ask me something");
Serial.println("type \"Hello\", \"Goodby\", \"web\" or \"dosomething\"" );
Serial.println("or \"pwmx where x is from 0 to 5\"" );
Serial.println("or \"analogx where x is from 0 to 5\"" );
Serial.println("or \"digitalx where x is from 0 to 7\"" );
Serial.println("or make up your own command");
Serial.println();
}
void loop()
{
// Notice how the main loop is very simple and the functions
// seperate the logic into easily manageable parts
if (CheckSerial()) DoCommand(inputBuffer);
// Do other stuff
}
// Enhanced Command Processor using strtok to strip out command from multi parameter string
boolean DoCommand(char * commandBuffer)
{
char* Command; // Command Parameter
char* Parameter; // Additional Parameter
int analogVal = 0; // additional parameter converted to analog if possible
// Get the command from the input string
Command = strtok(commandBuffer,commandDelimeters); // get the command
Parameter = strtok(NULL, commandDelimeters); // get the parameter if any
//if there are more than one parameter they will be ignored for now
// Make sure we have an analog value if we are to allow PWM output
int outparameter = isNumeric (Parameter);
//if it is a number then convert it
if (outparameter)
{
analogVal = atoi(Parameter);
// check the analog value is in the correct range
if (analogVal < MINPWM || analogVal > MAXPWM) outparameter = false;
}
// Standard way to handle commands
if (strcmp(Command,"Hello")==0){
Serial.println("Hello back at you ");
// Do some other work here
// and here
// and here
}
else if (strcmp(Command,"Goodby")==0){
Serial.println("Goodby back at you ");
// Do some other work here
// and here
// and here
}
else if (strcmp(Command, "dosomething")==0){
Serial.println("Like what ?? ");
// Do some other work here
// and here
// and here
}
else if (strcmp(Command ,"web1")==0){
Serial.println("HTTP/1.1 200 OK");
Serial.println("Content-Type: text/html");
Serial.println("Connection: close");
Serial.println();
Serial.println("<!DOCTYPE html>");
Serial.println("<html><head><title>Hello from www.thebreadboard.ca</title></head>");
Serial.println("<body><h1>test 1</h1></body>");
Serial.println("</html>");
// Do some other work here
// and here
// and here
}
else if (strcmp(Command, "web2")==0){
Serial.println("HTTP/1.1 200 OK");
Serial.println("Content-Type: text/html");
Serial.println("Connection: close");
Serial.println();
Serial.println("<!DOCTYPE html>");
Serial.println("<html><head><title>Hello from www.thebreadboard.ca</title></head>");
Serial.println("<body><h1>test 2</h1></body>");
Serial.println("</html>");
// Do some other work here
// and here
// and here
}
else if (strcmp(Command , "web3")==0){
Serial.println("HTTP/1.1 200 OK");
Serial.println("Content-Type: text/html");
Serial.println("Connection: close");
Serial.println();
Serial.println("<!DOCTYPE html>");
Serial.println("<html><head><title>Hello from www.thebreadboard.ca</title></head>");
Serial.println("<body><h1>test 3</h1></body>");
Serial.println("</html>");
// Do some other work here
// and here
// and here
}
else if (strcmp(Command ,"web4")==0){
Serial.println("HTTP/1.1 200 OK");
Serial.println("Content-Type: text/html");
Serial.println("Connection: close");
Serial.println();
Serial.println("<!DOCTYPE html>");
Serial.println("<html><head><title>Hello from www.thebreadboard.ca</title></head>");
Serial.println("<body><h1>test 4</h1></body>");
Serial.println("</html>");
// Do some other work here
// and here
// and here
}
else if (strcmp(Command , "web5")==0){
Serial.println("HTTP/1.1 200 OK");
Serial.println("Content-Type: text/html");
Serial.println("Connection: close");
Serial.println();
Serial.println("<!DOCTYPE html>");
Serial.println("<html><head><title>Hello from www.thebreadboard.ca</title></head>");
Serial.println("<body><h1>test 5</h1></body>");
Serial.println("</html>");
// Do some other work here
// and here
// and here
}
// Now some anlog Read Samples
else if (strcmp(Command, "analog0")==0){
Serial.print("Analog Raw = ");
Serial.print(analogRead(A0)); // read the input pin "A0" is already defined
Serial.print(" Volts = ");
Serial.println(double(analogRead(A0))*analogToVolts); // read the input pin "A0" is already defined
}
else if (strcmp(Command, "analog1")==0){
Serial.print("Analog Raw = ");
Serial.print(analogRead(A1)); // read the input pin "A0" is already defined
Serial.print(" Volts = ");
Serial.println(double(analogRead(A1))*analogToVolts); // read the input pin "A0" is already defined
}
else if (strcmp(Command, "analog2")==0){
Serial.print("Analog Raw = ");
Serial.print(analogRead(A2)); // read the input pin "A0" is already defined
Serial.print(" Volts = ");
Serial.println(double(analogRead(A2))*analogToVolts); // read the input pin "A0" is already defined
}
else if (strcmp(Command, "analog3")==0){
Serial.print("Analog Raw = ");
Serial.print(analogRead(A3)); // read the input pin "A0" is already defined
Serial.print(" Volts = ");
Serial.println(double(analogRead(A3))*analogToVolts); // read the input pin "A0" is already defined
}
else if (strcmp(Command, "analog4")==0){
Serial.print("Analog Raw = ");
Serial.print(analogRead(A4)); // read the input pin "A0" is already defined
Serial.print(" Volts = ");
Serial.println(double(analogRead(A4))*analogToVolts); // read the input pin "A0" is already defined
}
else if (strcmp(Command, "analog5")==0){
Serial.print("Analog Raw = ");
Serial.print(analogRead(A5)); // read the input pin "A0" is already defined
Serial.print(" Volts = ");
Serial.println(double(analogRead(A5))*analogToVolts); // read the input pin "A0" is already defined
}
//And a few Digitals
else if (strcmp(Command, "digital0")==0){
if (outparameter) digitalWrite(D0, !digitalRead(D0));
Serial.print("Digital 0 = ");
Serial.println(digitalRead(D0));
}
else if (strcmp(Command, "digital1")==0){
if (outparameter) digitalWrite(D1, !digitalRead(D1));
Serial.print("Digital 1 = ");
Serial.println(digitalRead(D1));
}
else if (strcmp(Command, "digital2")==0){
if (outparameter) digitalWrite(D2, !digitalRead(D2));
Serial.print("Digital 2 = ");
Serial.println(digitalRead(D2));
}
else if (strcmp(Command, "digital3")==0){
if (outparameter) digitalWrite(D3, !digitalRead(D3));
Serial.print("Digital 3 = ");
Serial.println(digitalRead(D3));
}
else if (strcmp(Command, "digital4")==0){
if (outparameter) digitalWrite(D4, !digitalRead(D4));
Serial.print("Digital 4 = ");
Serial.println(digitalRead(D4));
}
else if (strcmp(Command, "digital5")==0){
if (outparameter) digitalWrite(D5, !digitalRead(D5));
Serial.print("Analog 5 = ");
Serial.println(digitalRead(D5));
}
else if (strcmp(Command, "digital6")==0){
if (outparameter) digitalWrite(D6, !digitalRead(D6));
Serial.print("Digital 6 = ");
Serial.println(digitalRead(D6));
}
else if (strcmp(Command, "digital7")==0){
if (outparameter) digitalWrite(D7, !digitalRead(D7));
Serial.print("Digital 7 = ");
Serial.println(digitalRead(D7));
}
// now allow the PWM Outputs if we have a valid analog parameter
else if (strcmp(Command, "pwm0")==0 && outparameter ){
Serial.print("pwm 0 = ");
Serial.println(analogVal); // read the input pin "A1" is already defined
analogWrite(PWM0,analogVal); // Set the PWM 0 output
}
// now the PWM Outputs
else if (strcmp(Command, "pwm1")==0 && outparameter ){
Serial.print("pwm 1 = ");
Serial.println(analogVal); // read the input pin "A1" is already defined
analogWrite(PWM1, analogVal); // Set the PWM 0 output
}
// now the PWM Outputs
else if (strcmp(Command, "pwm2")==0 && outparameter ){
Serial.print("pwm 2 = ");
Serial.println(analogVal); // read the input pin "A1" is already defined
analogWrite(PWM2, analogVal); // Set the PWM 0 output
}
// now the PWM Outputs
else if (strcmp(Command, "pwm3")==0 && outparameter ){
Serial.print("pwm 3 = ");
Serial.println(analogVal); // read the input pin "A1" is already defined
analogWrite(PWM3, analogVal); // Set the PWM 0 output
}
// now the PWM Outputs
else if (strcmp(Command, "pwm4")==0 && outparameter ){
Serial.print("pwm 4 = ");
Serial.println(analogVal); // read the input pin "A1" is already defined
analogWrite(PWM4, analogVal); // Set the PWM 0 output
}
// now the PWM Outputs
else if (strcmp(Command, "pwm5")==0 && outparameter ){
Serial.print("pwm 5 = ");
Serial.println(analogVal); // read the input pin "A1" is already defined
analogWrite(PWM5, analogVal); // Set the PWM 0 output
}
// Catch All
else {
Serial.print("I dont understand you \nYou said: ");
Serial.println(commandBuffer);
// Do some other work here
// and here
// and here
}
// debug code after here
#if debug
if (Parameter != '\0'){
Serial.print((outparameter)? "Remaining Param is numeric and = " : "Remaining Param is none numeric and = " );
Serial.println(Parameter);
}
Serial.print("Free Ram = "); Serial.println(freeRam(), DEC);
#endif
return true;
}
/*
Checks the serial input for a string, returns true once a '\n' is seen
users can always look at the global variable "serialIndex" to see if characters have been received already
*/
boolean CheckSerial()
{
boolean lineFound = false;
// if there's any serial available, read it:
while (Serial.available() > 0) {
//Read a character as it comes in:
//currently this will throw away anything after the buffer is full or the \n is detected
char charBuffer = Serial.read();
if (charBuffer == '\n') {
inputBuffer[serialIndex] = 0; // terminate the string
lineFound = (serialIndex > 0); // only good if we sent more than an empty line
serialIndex=0; // reset for next line of data
}
else if(charBuffer == '\r') {
// Just ignore the Carrage return, were only interested in new line
}
else if(serialIndex < serialbufferSize && lineFound == false) {
/*Place the character in the string buffer:*/
inputBuffer[serialIndex++] = charBuffer; // auto increment index
}
}// End of While
return lineFound;
}// End of CheckSerial()
int isNumeric (const char * s)
{
while(*s)
{
if(!isdigit(*s)) return 0;
s++;
}
return 1;
}
#if debug
// check free ram
int freeRam ()
{
extern int __heap_start, *__brkval;
int v;
return (int) &v - (__brkval == 0 ? (int) &__heap_start : (int) __brkval);
}
#endif
Back to Intro Blog