Solution to Firmware Engineering Internship Assesment

blink_lcd.ino

// q no 1

const int LED_ONE = 7; 
const int LED_TWO = 12; 

int prev_milli_one = 0; 
int prev_milli_two = 0; 

const int INTERVAL_ONE = 1000; 
const int INTERVAL_TWO = 2000; 

int led_state_one = LOW; 
int led_state_two = LOW;

void setup() {
  pinMode(LED_ONE, OUTPUT);
  pinMode(LED_TWO, OUTPUT);
}

void loop() {
  unsigned long currentMillis = millis();

  if (currentMillis - prev_milli_one >= INTERVAL_ONE) {
    prev_milli_one = currentMillis;

    // Toggle LED 1 state
     if (led_state_one == LOW) {
      led_state_one = HIGH;
      } else {
      led_state_one = LOW;
      }

    digitalWrite(LED_ONE, led_state_one);
  }

  // Toggle LED 2 every 2 seconds
  if (currentMillis - prev_milli_two >= INTERVAL_TWO) {
    prev_milli_two = currentMillis;
    if (led_state_two == LOW) {
      led_state_two = HIGH;
    } else {
      led_state_two = LOW;
    }
    digitalWrite(LED_TWO, led_state_two);
  }
}

blink_using_rtos.ino

// q no 4
#include <Arduino_FreeRTOS.h>

const int LED_ONE = 7;
const int LED_TWO = 12;

void Blink_One_Sec( void *pvParameters );
void Blink_Two_Sec( void *pvParameters );

void setup() {
  
  xTaskCreate(
    Blink_One_Sec,
    "Blink One Sec" ,  
    128,  
    NULL,
    1, 
    NULL 
    );

  xTaskCreate(
    Blink_Two_Sec,
    "Blink Two Sec",
    128,
    NULL,
    1, 
    NULL
    );
}

void loop(){}

void Blink_One_Sec(void *pvParameters){
  
  pinMode(LED_ONE, OUTPUT);

  for (;;) {
    digitalWrite(LED_ONE, HIGH);   
    vTaskDelay( 1000 / portTICK_PERIOD_MS );
    digitalWrite(LED_ONE, LOW);
    vTaskDelay( 1000 / portTICK_PERIOD_MS );
  }
}

void Blink_Two_Sec(void *pvParameters){
    pinMode(LED_TWO, OUTPUT);

  for (;;){
    digitalWrite(LED_TWO, HIGH);
    vTaskDelay( 2000 / portTICK_PERIOD_MS );
    digitalWrite(LED_TWO, LOW); 
    vTaskDelay( 2000 / portTICK_PERIOD_MS ); 
  }
}

gpio.ino

// q no 2

const int PUSH_BTN = 2;
const int LED_ONE  = 12;

volatile bool Btn_ON = false;


void setup()
{
  pinMode(LED_ONE, OUTPUT);
  pinMode(PUSH_BTN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(PUSH_BTN), CheckStatusAndToggle, FALLING);
 
}

void CheckStatusAndToggle(){
  if(digitalRead(PUSH_BTN) == LOW){
    Btn_ON = !Btn_ON;
    digitalWrite(LED_ONE, Btn_ON);
  }
}

void loop()
{
 // delay doesn't matter.
 delay(500); 
}

uart.ino

// q no 3

const int LED_PIN =  13;

volatile bool ledState = LOW;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(9600);
  // Set up Timer 1 for interrupt every 1 second
  TCCR1A = 0;
  TCCR1B = 0;
  TCNT1 = 0;
  OCR1A = 15624;
  TCCR1B |= (1 << WGM12);
  TCCR1B |= (1 << CS12) | (1 << CS10); // 1024 prescalar
  TIMSK1 |= (1 << OCIE1A); 
}

void loop() {
  // Check for commands received through UART
  if (Serial.available() > 0) {
    String command = Serial.readStringUntil('\n');
    if (command.indexOf("{\"command\":\"on\",\"gpio\":18}") != -1) {
      digitalWrite(LED_PIN, HIGH);
    } else if (command.indexOf("{\"command\":\"off\",\"gpio\":18}") != -1) {
      digitalWrite(LED_PIN, LOW);
    }
  }
}

ISR(TIMER1_COMPA_vect) {
  // Transmit character 'A' via UART every 1 second
  Serial.write('A');
}

How can you make sure that the string will have newline character in here?

Pressing an Enter Key after inputting the command would work.

This can be programmed not to send CR or LF on enter. But anyway the overall solution is considerable. Will be updating further by email. Thank you.