trying to send data to my arduino without success (to rx input- 0 )

Projects Programming
1

Hello every one,

i am sending data 8 bit to my arduino and i want my data to get into the rx ( by rf module 434A receiver).

So, i tried to send data but he always gets the data as "-1" .

i did a check by shorting the rx and the tx of the arduino to where is the problem but it works ( the data from the tx of the arduino gets into the rx of the arduino pretty good)',

i also checked my transmitter and my receiver they works good too ,

anybody thinks he knows where the problem can come from?

here is my simple code:

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

}

void loop() {
Serial.write(255);
delay(100);
int x=Serial.read();
Serial.print(x);
delay(100);

}

thanks alot,

gidi

2

We need the exact ref of your rf module, the datasheet of it would help.

May the rf module works à 4800 bauds and not 9600.

So from there is mistake in your code.

If you get -1 it's NORMAL because :

Serial.read() will return a byte. or you are using an int. So from 255 is 0xFF that can be interpeted à -1 !

So from use a byte or char insteed of an int

You don't also check if serial datas are available, you could do a program like :

char x;

void loop()
{

Serial.write(65, BYTE);
delay(100);

if (Serial.available()
{
x =Serial.read();
Serial.print(x);
delay(100);
}
}

You must get more results

3

hi greg,

thanks for the answer i did what you wrote but its cannot comiled

it write me an eror : "cannot convrert from int to cont_units"

and i tried to write the program with byte and with char and now it givs me someting like y in Gibrish so i rhort with wireseally dont know what to do ' i tried to connect other microconroller in serial( srhort with wires the tx of the microcontroller -pic18f8520 to the rx of the arduinothwy both works at ttl level 0-5 volt) and desame ;

when i am writeing :
if( serial.available())
{
}
nothings happenes, the program seems to be stucked in a loop ....

so i really dont know what to do,

thanks alot,

gidi

4

Gibberish, ah yes.

Can you copy and paste the whole sketch please? And put "code" tags around it by selecting it and hitting the "#" button?

5

try with :

if (Serial.available()
{
x =Serial.read();
Serial.print(x, DEC);
Serial.proint(' ');
delay(100);
}
else
print('.');

if you see continuous dot ............ it's because no serial datas are coming to your arduino !

6

@grag38:
You're pushing towards 100 posts.
Don't you think it is about time you started posting code properly?

if (Serial.available()) {
   int x =Serial.read();
   Serial.print(x, HEX);  // Does anyone remember ASCII codes in decimal?
   Serial.print(' ');
   delay(10);
 } else Serial.print('.');