while(Wire.available () - 1 master many slave arduino

Projects Programming
1

hi
i want to have 3 or 4 slave arduino and one master communicating via i2c

i want my master can read and write to the slaves but also can do and other functions

in most of the examples i have seen are for just one arduino (master) write or read from an other arduino (slave)

So i was wondering.. when i want to read from the slave arduinos can i use something like that and avoid while loop ? :

  Wire.requestFrom(2, 2); // read from  first slave
  if (Wire.available()) {

    char T = Wire.read();
    if  (T == 'M')
    {
      Serial.println("No locks");

    }
    else if (T == 'Y')   {

      Serial.println("ok");
    }

    Wire.requestFrom(3, 2);  // read from  second slave
    if (Wire.available()) {

      char T = Wire.read();
      if  (T == 'M')
      {
        Serial.println("No locks");

      }
      else if (T == 'Y')   {

        Serial.println("ok");
      }
2

can i use something like that and avoid while loop ? :

Avoid what while loop?

Why are you asking for two bytes and then only reading one? What do you think will happen to the other byte?

3

PaulS:
Avoid what while loop?

in most of the exambles they are using this : while (Wire.available()) {

so i was wondering if i could avoid the "while"

PaulS:
Why are you asking for two bytes and then only reading one? What do you think will happen to the other byte?

my mistake... that was from an other code i had.. so lets say that i am asking one only byte and not two

4

If you ask your neighbor for an egg, do you need to use ANY kind of loop to receive the input from your neighbor?

You need some kind of loop to read the data if there is more than one byte to read. One byte == NO LOOP!

5

In order to read 2-byte data from your I2C Slave with address 0x03, you have executed the following instruction:

Wire.requestFrom(0x03, 2);

It is my understanding that the program control will be transferred to the next label of execution when the requested 2-byte data have arrived into the local unseen FIFO buffer of the Master. Therefore, there is really no need to check the status of data availability by executing the instruction Wire.available(); rather, we may go ahead reading the data from the local unseen buffer and saving them into known user buffer/variable. The codes could be:

byte x1 = Wire.read();
byte x2 = Wire.read();

or using loop as per Post#3

for(int i=0; i<2; i++)
{
   dataByte[i] = Wire.read();
}