loops in loops ?

Projects General Guidance
1

I have a strange problem, and just want to verify that a for n= 1 to whatever sequence in a separate function ( subroutine) that it doesnt return to the main loop until it has counted through all n operations ?

2

As stated, you are correct, unless you have a return hiding in the looping function somewhere. Post your code though, funky behaviour may be an indication of pointer issues or low memory.

edit: grammar

3

Its a function to read the data from bcd switches, the clock pulse advances a CD4017 whose outputs go to the common of the switches.

Putting the 4 bits together with the OR function is pasted from another sketch that works in many of my sketches, I don't know if there is a simpler bit manipulation way?

void scan ()
{
    for ( int x=2; x<= switchbanks; x++ ) 
    {
    digitalWrite(clock, HIGH);  
     
    add3 = digitalRead(SW3); 
  // shift it left 3 places
  add3 = add3 << 3;
  add2 = digitalRead(SW2);
  // shift it left 2 places
  add2 = add2 << 2;
  add1 = digitalRead(SW1);
  // shift it left 1 place
  add1 = add1 << 1;
  add0 = digitalRead(SW0);
  // now OR it together
  address = address|add3;
  address = address|add2;
  address = address|add1;
  address = address|add0;
  
  digitalWrite(clock, LOW);  
  
  Serial.print("data for switchbank ");  Serial.print(switchbank);  Serial.print(" =    ");
  Serial.println(address, BIN);
  msg [switchbanks]  = address;
    
  } // end of  for ( int x=2; x<= switchbanks; x==) 

}  // end of scan function
4

A bitwise OR is usually the correct method. It is a logical bit-operation, and is one of simplest ones (if neither is false then true). However, you seem to have forgotten to zero the address at the beginning of each loop cycle - if you don't, OR will never set a bit to false, so only the first reading will be valid.

With your code, it seems like you'd be better off with something like this (it's the same, just a little more elegant):

uint8_t sw[4]; // assign your four pins

void scan() {
  for ( int x = 2; x <= switchbanks; x++ ) 
  {
    address = 0;
    digitalWrite(clock, HIGH);  
    
    for (uint8_t i = 0; i < 4; i++) {
      address |= digitalRead(sw[i]) << i;
    }
  
    digitalWrite(clock, LOW);  
  
    Serial.print("data for switchbank ");  
    Serial.print(switchbank);  
    Serial.print(" =    ");
    Serial.println(address, BIN);
    msg [switchbanks]  = address;
  }
}
5

Thanks thats elegant, but what is the address |=

in

for (uint8_t i = 0; i < 4; i++) {
address |= digitalRead(sw*) << i;*

  • }*
6

but what is the address |=

"address |= x;" is is the same as writing "address = address | x;"

Works with binary arithmetic and logical operators,
-=
+=
*=
/=
&=
^=

7

Got it - compound bitwise or
thanks.