[Partially solved] ISR from SoftwareSerial port

Projects Programming
32

Hello again!
I did some experiments with which I would like to share.

The experiment consisted of comparing libraries and duplexes.

The experiment #1. Library: SoftwareSerial; Checking half-duplex: YES (line 25)

#include <SoftwareSerial.h>
#include <NeoSWSerial.h>

SoftwareSerial mySerial(2,3);   // RX, TX
//NeoSWSerial mySerial(2, 3);
uint32_t button_press = 1;
void setup()
{
  mySerial.begin(9600);		
  Serial.begin(9600);
  Serial.print("\nSoftwareSerial test with half-duplex:\n");
  Serial.print("Ready!\n");
  delay(100);
}

void loop()
{
	if (mySerial.available() > 0)
	{
		Serial.print("\n");
		int data = mySerial.read();
		Serial.print(data, DEC);
		button_press = 1;
	}
	mySerial.print("sdfsf"); //line 25
	if (button_press && !mySerial.available())
	{
		button_press = 0;
		Serial.print("\nNew button press:");
	}
}

Result:

SoftwareSerial test with half-duplex:
Ready!

New button press:
0
3
0
255
255
New button press:
101
0
3
0
255
255
255
New button press:
89
64
64
New button press:

The experiment #2. Library: SoftwareSerial; Checking half-duplex: NO (comment line 25)

#include <SoftwareSerial.h>
#include <NeoSWSerial.h>

SoftwareSerial mySerial(2,3);   // RX, TX
//NeoSWSerial mySerial(2, 3);
uint32_t button_press = 1;
void setup()
{
  mySerial.begin(9600);		
  Serial.begin(9600);
  Serial.print("\nSoftwareSerial test with half-duplex:\n");
  Serial.print("Ready!\n");
  delay(100);
}

void loop()
{
	if (mySerial.available() > 0)
	{
		Serial.print("\n");
		int data = mySerial.read();
		Serial.print(data, DEC);
		button_press = 1;
	}
	//mySerial.print("sdfsf"); //line 25
	if (button_press && !mySerial.available())
	{
		button_press = 0;
		Serial.print("\nNew button press:");
	}
}

Result:

SoftwareSerial test without half-duplex:
Ready!

New button press:
101
0
3
0
255
255
255
New button press:
101
0
3
0
255
255
255
New button press:
101
0
3
0
255
255
255
New button press:

As we can see, the packets are lost during a half duplex test.

The experiment #3. Library: NeoSWSerial; Checking half-duplex: YES (line 25)

#include <SoftwareSerial.h>
#include <NeoSWSerial.h>

//SoftwareSerial mySerial(2,3);   // RX, TX
NeoSWSerial mySerial(2, 3);
uint32_t button_press = 1;
void setup()
{
  mySerial.begin(9600);		
  Serial.begin(9600);
  Serial.print("\nNeoSWSerial test with half-duplex:\n");
  Serial.print("Ready!\n");
  delay(100);
}

void loop()
{
	if (mySerial.available() > 0)
	{
		Serial.print("\n");
		int data = mySerial.read();
		Serial.print(data, DEC);
		button_press = 1;
	}
	mySerial.print("sdfsf");
	if (button_press && !mySerial.available())
	{
		button_press = 0;
		Serial.print("\nNew button press:");
	}
}

Result:

NeoSWSerial test with half-duplex:
Ready!

New button press:
101
0
3
0
-1
-1
-1
New button press:
101
0
3
0
-1
-1
-1
New button press:
101
0
3
0
-1
-1
-1
New button press:
101
0
2
0
-1
-1
-1
New button press:

The library NeoSWSerial works with half-duplex. But the last bytes (0xFF) perceives differently. I think so I didn't work display.

Thank you for attention,
Marat