send hex values to serial port

hi.. i have a question here. how i'm gonna send hexadecimal value to serial devices. the hex value can be send by using serial write like example below.

//Serial.write(0x55); <----right (HEX)

i wan using hex code to turn the led ....pls help gv an example.....thx

Hex is just a representation. An Arduino doesn't know the difference between '0', 0x30, and 40.

What are these "serial devices"? Are they other Arduinos?

haoyee12:
hi.. i have a question here. how i'm gonna send hexadecimal value to serial devices. the hex value can be send by using serial write like example below.

//Serial.write(0x55); <----right (HEX)

i wan using hex code to turn the led ....pls help gv an example.....thx

1. Build the following network (Fig-1) using UNO and NANO (or UNO and UNO ) to send 0x55 to NANO using soft UART Port.

unonanox.png
Figure-1:

2. Upload the following sketch in UNO (untested)

#include<SoftwareSerial.h>  //you need to include this file in the IDE
SoftwareSerial SUART(2, 3); //SRX =2, STX = 3 ; this called object creation and intialization

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

void loop()
{
    SUART.write(0x55);   //send 0x55 to NANO
    while(1);                 //wait for ever
}

3. Upload the following sketch in NANO (untested)

#include<SoftwareSerial.h>
SoftwareSerial SUART(2, 3); //SRX =2, STX = 3

void setup()
{
   Serial.begin(9600);
   SUART.begin(9600);
   pinMode(13, OUTPUT);   //bulit-in L (LED) of NANO
   digitalWrite(13, LOW); //L is OFF
}

void loop()
{
    if(SUART.available() >0)  //check id a data byte has come from UNO
   {
        byte x = SUART.read();
        if(x == 0x55)   //check if the arrived data byte is 0x55
        {
            digitalWrite(13, HIGH);  //L is ON; because, 0x55 has arrived from Transmitter
        }
    }
}

unonanox.png