ESP32 and UNO UART protocole

Projects General Guidance
1

I am making a joystick and I am tryin to to get analog joystick module values and button values from uno and send it to esp32 with uart. But the values are not coming as expected. Normally it should be between 0-1023. Right now it is like in 13000. I am going to put my code here.

UNO's code
#define X1 A0
#define Y1 A1
#define X2 A2
#define Y2 A3
#define b1 7
#define b2 8

struct analog
{
unsigned long Xaxis;
unsigned long Yaxis;
};

analog state;

void setup()
{
Serial.begin(9600);
}

void loop()
{

state.Xaxis=analogRead(X1);
state.Yaxis=analogRead(Y1);

byte ptr;
ptr = (byte)&state;
byte counter = sizeof(state);
Serial.print('<');
do
{
byte m = (byte*)*ptr;
Serial.write(m);
Serial.print(m,HEX);
ptr++;
counter--;
}
while(counter != 0);
Serial.write('>'); //end of strauct data
Serial.println();
delay(2000);
}

ESP32's code

#define Rxpin 16
#define Txpin 17

struct analog
{
unsigned long Xaxis;
unsigned long Yaxis;
unsigned long button1;
int button2;
};
analog state;

byte myData[8];
bool flag = false;

void setup()
{
Serial.begin(115200);
Serial2.begin(9600, SERIAL_8N1, Rxpin, Txpin);
}

void loop()
{
byte n = Serial2.available();
if (n != 0 )
{
if (flag == false)
{
char x = Serial2.read();
if (x == '<')
{
flag = true;
}
}
else
{
Serial2.readBytesUntil('>', myData, 8);
//--- recreate structure-------
state.Xaxis = (myData[3]<<8)|myData[0];
state.Yaxis = (myData[7]<<8)|myData[4];
Serial.println(state.Xaxis,HEX);
Serial.println(state.Xaxis,DEC);
flag = false;
}
}
}
I approximately got the code from here Sending structs through serial. - Using Arduino / Programming Questions - Arduino Forum

2

Have used the following level shifter (Fig-1) between UNO and ESP32?

levelsifterBreakout
levelsifterBreakout691×302 137 KB

Figure-1:

3

No, but when ı like print the values in UNO ı mean not esp32's port before sending the values to it. It still gives the scale around 13000 and 12000

4

Then disconnect the ESP32 Board from UNO.
Use a jumper and short 3.3V-point of UNO with A0-pin of UNO.
Upload the following sketch in UNO and check that the display shows approximately 3.3 on the OutputBox of the Serial Monitor of UNO at 1-sec interval.

void setup()
{
     Serial.begin(9600);
}

void loop()
{
      int y = ananlogRead(A0);
      float volt = (5.0/1023.0)*y;
      Serial.println(volt, 1);
      dealy(1000);
}
5

Yes it does it shows 3.2

6

I mean it is like this when ı do like Serial. println(state.Xaxis)
Normally without the usage of struct or uart it gives correct value between 0-1023

7

Why would you send the byte and its HEX value?

8

It was like a test normally it is not like this ı just send the byte value. I forgot to erase

9

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