add gpio pulsing demo, fix some typos

Author: ladyada

Adafruit_PWMServoDriver.cpp

@@ -134,7 +134,7 @@ void Adafruit_PWMServoDriver::setPWM(uint8_t num, uint16_t on, uint16_t off) {
 
 /**************************************************************************/
 /*! 
-    @brief  Helper to set pin PWM output. Sets pin without having to deal with on/off tick placement and properly handles a zero value as completely off.  Optional invert parameter supports inverting the pulse for sinking to ground.
+    @brief  Helper to set pin PWM output. Sets pin without having to deal with on/off tick placement and properly handles a zero value as completely off and 4095 as completely on.  Optional invert parameter supports inverting the pulse for sinking to ground.
     @param  num One of the PWM output pins, from 0 to 15
     @param  val The number of ticks out of 4096 to be active, should be a value from 0 to 4095 inclusive.
     @param  invert If true, inverts the output, defaults to 'false'

examples/gpiotest/gpiotest.ino

@@ -0,0 +1,49 @@
+/*************************************************** 
+  This is an example for our Adafruit 16-channel PWM & Servo driver
+  GPIO test - this will set a pin high/low
+
+  Pick one up today in the adafruit shop!
+  ------> http://www.adafruit.com/products/815
+
+  These drivers use I2C to communicate, 2 pins are required to  
+  interface.
+
+  Adafruit invests time and resources providing this open source code, 
+  please support Adafruit and open-source hardware by purchasing 
+  products from Adafruit!
+
+  Written by Limor Fried/Ladyada for Adafruit Industries.  
+  BSD license, all text above must be included in any redistribution
+ ****************************************************/
+
+#include <Wire.h>
+#include <Adafruit_PWMServoDriver.h>
+
+// called this way, it uses the default address 0x40
+Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver();
+// you can also call it with a different address you want
+//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x41);
+// you can also call it with a different address and I2C interface
+//Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(&Wire, 0x40);
+
+void setup() {
+  Serial.begin(9600);
+  Serial.println("GPIO test!");
+
+  pwm.begin();
+  pwm.setPWMFreq(1000);  // Set to whatever you like, we don't use it in this demo!
+
+  // if you want to really speed stuff up, you can go into 'fast 400khz I2C' mode
+  // some i2c devices dont like this so much so if you're sharing the bus, watch
+  // out for this!
+  Wire.setClock(400000);
+}
+
+void loop() {
+  // Drive each pin in a 'wave'
+  for (uint8_t pin=0; pin<16; pin++) {
+    pwm.setPWM(pin, 4096, 0);       // turns pin fully on
+    delay(100);
+    pwm.setPWM(pin, 0, 4096);       // turns pin fully off
+  }
+}

examples/servo/servo.ino

@@ -1,6 +1,7 @@
 /*************************************************** 
   This is an example for our Adafruit 16-channel PWM & Servo driver
-  Servo test - this will drive 16 servos, one after the other
+  Servo test - this will drive 8 servos, one after the other on the
+  first 8 pins of the PCA9685
 
   Pick one up today in the adafruit shop!
   ------> http://www.adafruit.com/products/815
@@ -38,7 +39,7 @@ uint8_t servonum = 0;
 
 void setup() {
   Serial.begin(9600);
-  Serial.println("16 channel Servo test!");
+  Serial.println("8 channel Servo test!");
 
   pwm.begin();