Merge pull request #933 from arduino/karlsoderby/bit-rw

bitRead & bitWrite Improvements

Author: karlsoderby

Language/Functions/Bits and Bytes/bitRead.adoc

@@ -17,7 +17,7 @@ subCategories: [ "Bits and Bytes" ]
 
 [float]
 === Description
-Reads a bit of a number.
+Reads a bit of a variable, e.g. `bool`, `int`. Note that `float` & `double` are not supported. You can read the bit of variables up to an `unsigned long long` (64 bits / 8 bytes).
 [%hardbreaks]
 
 
@@ -36,6 +36,54 @@ Reads a bit of a number.
 === Returns
 The value of the bit (0 or 1).
 
+=== Example Code
+
+This example code demonstrates how to read two variables, one increasing counter, one decreasing counter, and print out both the binary and decimal values of the variables.
+
+The `readBit()` function loops through each bit of the variable (starting from the rightmost bit), and prints it out.
+
+[source,arduino]
+----
+long negative_var = -0;  //
+unsigned long long positive_var = 0;
+
+//predefined sizes when looping through bits
+//e.g. long_size is 32 bit (which is 0-31). Therefore, we subtract "1".
+const int bool_size = (1 - 1);
+const int int_size = (8 - 1);
+const int long_size = (32 - 1);
+
+void setup() {
+  Serial.begin(9600);
+}
+
+void loop() {
+  //run readBit function, passing the pos/neg variables
+  readBit("Positive ", positive_var);
+  readBit("Negative ", negative_var);
+  Serial.println();
+
+  //increase and decrease the variables
+  negative_var--;
+  positive_var++;
+
+  delay(1000);
+}
+
+/*this function takes a variable, prints it out bit by bit (starting from the right)
+then prints the decimal number for comparison.*/
+void readBit(String direction, long counter) {
+  Serial.print(direction + "Binary Number: ");
+  //loop through each bit
+  for (int b = long_size; b >= 0; b--) {
+    byte bit = bitRead(counter, b);
+    Serial.print(bit);
+  }
+  Serial.print(" Decimal Number: ");
+  Serial.println(counter);
+}
+----
+
 --
 // OVERVIEW SECTION ENDS
 

Language/Functions/Bits and Bytes/bitWrite.adoc

@@ -17,7 +17,7 @@ subCategories: [ "Bits and Bytes" ]
 
 [float]
 === Description
-Writes a bit of a numeric variable.
+Writes to a bit of a variable, e.g. `bool`, `int`, `long`. Note that `float` & `double` are not supported. You can write to a bit of variables up to an `unsigned long` (32 bits / 8 bytes).
 [%hardbreaks]