splitting hexadecimal byte

Using Arduino Programming Questions
6

Well, you said "byte array" rather than "char array". Try this:

void setup ()
{
  Serial.begin (115200);
  byte a, b;

  byte foo = 0xB5;
  a = foo >> 4;
  b = foo & 0xF;
  
  Serial.println (a, HEX);
  Serial.println (b, HEX);

  char bar = 0xB5;
  a = bar >> 4;
  b = bar & 0xF;
  
  Serial.println (a, HEX);
  Serial.println (b, HEX);
}

void loop () {}

Output:

B
5
FB
5

You are right, it sign-extends (the B not the 5). But you could do:

  a = (bar >> 4) & 0xF;

That throws away the extended sign.

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