How to write clean efficient code???

Projects Programming
1

Hey guys, rookie here,
I'm developing this serial command line thingy for my arduino. Like, if I type ON then the LED on pin 13 will turn on. Pretty simple stuff.
Currently I'm using an M0 but I want my program to also fit in the limited 32k flash of the uno.
My program right now is about 12k. I'm worried because I will be adding a lot more commands to my program.
So, how can I write clean efficient code so that I won't run out of ram or flash memory?
I'll give you the code and you can take a look at it. Try uploading it on your boards to see if everything's good.

/*

My Code

*/

#include <Arduino.h>

int led = 13;
String WORDS = "";
int inByte;
String COMMAND = "";
bool canBanner = true;
int pinToWrite;
int i;
//const char compileDate[] = __DATE__ " " __TIME__;

String apps[] = {
  "CALC",
  "SERVO"
  "DWRITE"
  "TIME"
  "BANNER"
};

void banner() {
  Serial.println(" _____     _ _      _____");
  Serial.println("|  |  |___| | |_   |     |___ ___ ___ ___ ___");
  Serial.println("|  |  | . | |  _|  |   --| .'|   |   | . |   |");
  Serial.println(" \\___/|___|_|_|    |_____|__,|_|_|_|_|___|_|_|");
  Serial.println("Volt firmware V.1.0 / Copyright <My Name> 2017");
}

void setup() {
// Turn the Serial Protocol ON
  Serial.begin(1200);
  pinMode(led, OUTPUT);
  digitalWrite(led, LOW);
  while (!Serial.available()) {}
    Serial.println();
    banner();
    Serial.flush();
}

void cursorPrompt() {
  if (COMMAND == "") {
    Serial.print("> ");
  }
  else {
  }
}

void getCommandPrintSerial() {
  while (!Serial.available()) {}
  inByte = Serial.read();
  WORDS = (char)inByte;
  Serial.print(WORDS);
  COMMAND = COMMAND + WORDS;
}

void programs() {
  if (COMMAND != "\r") {
    Serial.println("");
  }
  
  if (COMMAND == "ON\r") {
    Serial.println("LED on!");
    digitalWrite(led, HIGH);
  }

  else if (COMMAND == "OFF\r") {
    Serial.println("LED off!");
    digitalWrite(led, LOW);
  }

  else if (COMMAND == "PING\r") {
    Serial.println("PONG!");
  }

  else if (COMMAND == "BANNER\r") {
    canBanner = true;
    banner();
  }

  else if (COMMAND == "FLUSH\r") {
    Serial.println("Serial data cleared!");
    Serial.flush();
  }


  else if (COMMAND == "CALC\r") {
  COMMAND = "";
  Serial.println("---VOLT CALC 1000---");
  Serial.println("1) Addition");
  Serial.println("2) Subtraction");
  Serial.println("3) Multiplication");
  Serial.println("4) Division");
  cursorPrompt();
  while (Serial.available() == 0) {}
    if (inByte == 13) {
      Serial.println("");
      if (COMMAND == "1\r") {
        Serial.println("YAY!");
      }
      else if (COMMAND == "2\r") {
        Serial.println("HEY!");
      }
      else if (COMMAND == "3\r") {
        Serial.println("WOW!");
      }
      else if (COMMAND == "4\r") {
        Serial.println("FART!");
      }
      else {
        Serial.println("ERROR!");
      }
  }
}

  else if (COMMAND == "APPS") {
    for (i=0; i < sizeof(apps - 1); i++) {
      Serial.println(apps[i]);
    }
  }

  else if (COMMAND == "DWRITE " + pinToWrite) {
    digitalWrite(pinToWrite, HIGH);
  }

  else if (COMMAND == "\r") {
    Serial.println("");
  }

/*
  else if (COMMAND == "TIME\r") {
    Serial.println(compileDate);
  }
*/

  else {
    Serial.println("What?");
  }
  COMMAND = "";
}

void loop() {
  cursorPrompt();
  getCommandPrintSerial();
  if (inByte == 13) {
    programs();
  }
}

Any suggestions on reducing vars or writing more concise code?

THANKS!

BTW there are a lot of incomplete stuff in my code such as the APPS command. I also need to work on the DWRITE function and the CALC function. Any help will be greatly appreciated.

2
  • Don't use String, use char arrays.
  • Use the F() macro for constant string in print statements.
  • Use the defined type uint8_t, uint16_t, uint32_t to control the size of variables.
  • Don't use an int when a uint8_t is sufficient.
  • Make your commands single characters - speeds the code, uses less space and computers don't care about words anyway.

Generally, read other people's code and learn from what they do.

3

compile it for Uno if you want to know the size for the Uno. set board Uno and use the Verify button.

Sketch uses 4850 bytes (15%) of program storage space. Maximum is 32256 bytes.
Global variables use 686 bytes (33%) of dynamic memory, leaving 1362 bytes for local variables. Maximum is 2048 bytes.
4

Instead of doing a series of "if (COMMAND == "text")" statements, implement a table of commands and use a case statement off of the index (or via a separate key.) This works whether you use Strings or char arrays...