Update README.md

updated to show the use of the new readPercent(...) functions.

README.md

@@ -7,29 +7,51 @@ NO external parts necessary!
 
 [see this Microchip application note to learn more about the internal features used and supported to implement this feature](https://ww1.microchip.com/downloads/en/Appnotes/00002447A.pdf)
 
+Update: Now includes support for reading the voltage as a percentage of total charge. 
+You can also optionally supply the voltage level that is considered to be 0% and the voltage level considered to be 100%. 
+This is really useful for battery-based projects! You can now specify the lower voltage level you would like to use to
+indicate when the system needs charging and when it is fully charged.
+
 Example use:
 
 #
 ```
+    /*
+     * CPUVolt.ino
+     * 
+     * Example Arduino sketch showing the use of the CPUVolt library.
+     * Updated to show the use of the new readPercent(...) methods.
+     * 
+     */
     #include <CPUVolt.h>
     
-    // We don't need a setup and a loop function so we just use a single main:
-    int main() {
+    void setup() {
         Serial.begin(115200);
     
-        // Measure the processor's Vcc voltage:
-        double volts = readVcc();
+        // Read the current voltage level and convert it
+        // to an easier to read floating point value
+        float mv = readVcc() / 1000.0;
     
-        // Format it as a string to 2 decimal places:
-        char fstr[8];
-        dtostrf(volts, 5, 2, fstr);
+        // Show the voltage with 2 decimal places
+        Serial.print("Voltage: ");
+        Serial.println(mv, 2);
     
-        // Display it:
-        Serial.print("voltage: ");
-        Serial.println(fstr);
+        // Get the voltage level as a percentage of total charge.
+        // You can optionally specify the voltage level to be considered
+        // as 100%. The default voltage is 5V if not supplied.
+        float pct = readPercent(/*5000*/);
+        Serial.print("Percent: ");
+        Serial.println(pct, 2);
     
-        return 0;
+        // You can also specify both the lower and upper voltage
+        // ranges to be considered what is 0% and what is 100%.
+        // This is really useful for battery powered projects!
+        pct = readPercent(2900, 4700);
+        Serial.print("Percent: ");
+        Serial.println(pct, 2);
     }
+    
+    void loop() { }
 ```
 
 Output: