Can I temporarily disable Arduino Serial data receive? - arduino

Question

I am working on a project and I encountered some problems.
I am using a DHT11 temperature sensor, an Arduino Uno and a TFT LCD display 2.2-inch model ITDB02-2.2.
What I want my project to do is to use 2 functioning modes for the sensor that I can select from the keyboard at the beginning of the program(one which is normal and one which will be used on special occasions)(so I need serial communication).
I noticed that the screen does not function if I start a serial communication at any rate so I used Arduino Serial.begin(9600) and Serial.end() for the mode selecting part of the program.
THE PROBLEM: My Arduino is still sending data through serial port even if I ended the serial communication and is looking like this:
I found out that Serial.end() function does not shut off serial communication but just the rate of communication. I am curious if you have any idea that I can use in order to get rid of the extra data, to neglect it before the computer receives it.
I`m stuck. I thought that interruptions would be a solution but they are not as far as I researched on the internet.
My ARDUINO CODE:
#include <SimpleDHT.h>
#include <UTFT.h>
UTFT myGLCD(ITDB22,A5,A4,A3,A2);
SimpleDHT11 dht11;
// Declare which fonts we will be using
extern uint8_t BigFont[];
//dht sensor data pin
int dataPinSensor1 = 12;
char mode;
int del;
void setup()
{
Serial.begin(9600);
Serial.print("Select functioning mode");
mode=SensorModeSelect(mode);
Serial.end();
pinMode(12, INPUT);
}
void loop()
{
if(mode=='1') {
FirstFuncMode(dataPinSensor1);
}
if(mode=='2') {
SecondFuncMode(dataPinSensor1,del);
}
delay(10);
}
char SensorModeSelect(char in)
{
char mode='0';
while(mode=='0') {
if(Serial.available() > 0) {
mode=Serial.read();
}
}
if (mode == '1') {
Serial.print("\nMOD1 SELECTED: press t key to aquire data \n");
}
if (mode == '2') {
Serial.print("\nMOD2 SELECTED: press q if you want to quit auto mode \n");
Serial.print("Select the data aquisition period(not smaller than 1 second) \n");
}
return mode;
}
int DataAqPeriod()
{
int del=0;
while(del==0) {
while(Serial.available() > 0) {
//Get char and convert to int
char a = Serial.read();
int c = a-48;
del *= 10;
del += c;
delay(10);
}
}
del*=1000;
return del;
}
void FirstFuncMode(int dataPinSensor1)
{
byte temperature = 0;
byte humidity = 0;
int err = SimpleDHTErrSuccess;
bool DispCond=false;
Serial.begin(9600);
delay(1500);
if (Serial.read() == 't' ) {
DispCond=true;
//read temperature and compare it with an error value
if((err = dht11.read(dataPinSensor1, &temperature, &humidity, NULL)) != SimpleDHTErrSuccess) {
Serial.print("unreliable measurement or unselected functioning mode");
}
byte f = temperature * 1.8 + 32;
Serial.print((int)temperature);
Serial.print(" *C, ");
Serial.print((int)f);
Serial.print(" *F, ");
Serial.print((int)humidity);
Serial.println(" H humidity");
delay(1500);
}
Serial.end();
if(DispCond==true) {
//Setup the LCD
myGLCD.InitLCD();
myGLCD.setFont(BigFont);
//print value on LCD
displayNoInit((int)temperature,(int)humidity);
}
}
void SecondFuncMode(int dataPinSensor1,int del)
{
bool q=false;
byte temperature = 0;
byte humidity = 0;
int err = SimpleDHTErrSuccess;
Serial.begin(9600);
del=DataAqPeriod();
Serial.end();
//Setup the LCD
myGLCD.InitLCD();
myGLCD.setFont(BigFont);
while(q==false) {
Serial.begin(9600);
//read temperature and compare it with an error value
if((err = dht11.read(dataPinSensor1, &temperature, &humidity, NULL)) != SimpleDHTErrSuccess) {
Serial.print("unreliable measurement or unselected functioning mode \n");
}
float f = temperature * 1.8 + 32;
Serial.print((int)temperature);
Serial.print(" *C, ");
Serial.print((int)f);
Serial.print(" *F, ");
Serial.print((int)humidity);
Serial.println(" H humidity");
delay(del);
if(Serial.read() == 'q')
q=true;
Serial.end();
displayNoInit((int)temperature,(int)humidity);
delay(10);
}
}
void displayNoInit(int temperature,int humidity)
{
//effective data display
myGLCD.clrScr();
myGLCD.setColor(255, 255, 0);
myGLCD.setBackColor(10,10,10);
myGLCD.print(" Temperature ", CENTER, 10);
myGLCD.setColor(254, 254, 254);
myGLCD.printNumI(temperature, CENTER, 45);
myGLCD.setColor(255, 255, 0);
myGLCD.print("C ", RIGHT, 45);
myGLCD.print("Relative Hum.", CENTER, 90);
myGLCD.setColor(204, 245, 250);
myGLCD.printNumI(humidity, CENTER, 120);
myGLCD.print("%", RIGHT, 120);
}

Answer 1

You are correct in the definition that Serial.end() does not disable the serial monitor, only the interrupts. After calling Serial.end() you can disable the serial monitor like so.
#include <avr/io.h>
// Save status register, disable interrupts
uint8_t oldSREG = SREG;
cli();
// Disable TX and RX
cbi(UCSRB, RXEN);
cbi(UCSRB, TXEN);
// Disable RX ISR
cbi(UCSRB, RXCIE);
// Flush the internal buffer
Serial.flush();
// Restore status register
SREG = oldSREG;