Updating to version 2.0 - more user-friendly

- Made most functions more user friendly.
- digitalWrite, pinMode, and other standard Arduino function calls are
  used.
- Should remain mostly backwards compatible.
- blink and breathe functions now try to estimate millisecond durations
- Improved clock control

Author: Jim Lindblom

examples/analogWrite/analogWrite.ino

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+/*************************************************************
+analogWrite.ino
+SparkFun SX1509 I/O Expander Example: pwm output (analogWrite)
+Jim Lindblom @ SparkFun Electronics
+Original Creation Date: September 21, 2015
+https://github.com/sparkfun/SparkFun_SX1509_Arduino_Library
+
+This example demonstrates the SX1509's analogWrite function. 
+Connect an LED to the SX1509's pin 15 (or any other pin, they 
+can all PWM!). The SX1509 can either sink or source current, 
+just don't forget your limiting resistor!
+
+Hardware Hookup:
+	SX1509 Breakout ------ Arduino -------- Breadboard
+	      GND -------------- GND
+	      3V3 -------------- 3.3V
+		  SDA ------------ SDA (A4)
+		  SCL ------------ SCL (A5)
+		  15 -------------------------------- LED+
+		                                 LED- -/\/\/\- GND
+                                                330
+
+Development environment specifics:
+	IDE: Arduino 1.6.5
+	Hardware Platform: Arduino Uno
+	SX1509 Breakout Version: v2.0
+
+This code is beerware; if you see me (or any other SparkFun 
+employee) at the local, and you've found our code helpful, 
+please buy us a round!
+
+Distributed as-is; no warranty is given.
+*************************************************************/
+
+#include <Wire.h> // Include the I2C library (required)
+#include <SparkFunSX1509.h> // Include SX1509 library
+
+// SX1509 I2C address (set by ADDR1 and ADDR0 (00 by default):
+const byte SX1509_ADDRESS = 0x3E;  // SX1509 I2C address 
+SX1509 io; // Create an SX1509 object to be used throughout
+
+// SX1509 Pin definition:
+const byte SX1509_LED_PIN = 15; // LED to SX1509's pin 15
+
+void setup() 
+{
+  // Call io.begin(<address>) to initialize the SX1509. If it 
+  // successfully communicates, it'll return 1.
+  if (!io.begin(SX1509_ADDRESS))
+  {
+    while (1) ; // If we fail to communicate, loop forever.
+  }
+  
+  // Use the pinMode(<pin>, <mode>) function to set our led 
+  // pin as an ANALOG_OUTPUT, which is required for PWM output
+  io.pinMode(SX1509_LED_PIN, ANALOG_OUTPUT);
+}
+
+void loop()
+{
+  // Ramp brightness up, from 0-255, delay 2ms in between 
+  // analogWrite's
+  for (int brightness=0; brightness<256; brightness++)
+  {
+    // Call io.analogWrite(<pin>, <0-255>) to configure the 
+    // PWM duty cycle
+    io.analogWrite(SX1509_LED_PIN, brightness);
+    delay(2); // Delay 2 milliseconds
+  }
+  delay(500); // Delay half-a-second
+  
+  // Ramp brightness down, from 255-0, delay 2ms in between 
+  // analogWrite's
+  for (int brightness=255; brightness>=0; brightness--)
+  {
+    io.analogWrite(SX1509_LED_PIN, brightness);
+    delay(2); // Delay 2 milliseconds
+  }
+  delay(500); // Delay half-a-second
+  
+}

examples/blink/blink.ino

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+/*************************************************************
+blink.ino
+SparkFun SX1509 I/O Expander Example: blink output
+Jim Lindblom @ SparkFun Electronics
+Original Creation Date: September 21, 2015
+https://github.com/sparkfun/SparkFun_SX1509_Arduino_Library
+
+This example demonstrates the SX1509's set-it-and-forget-it
+blink function. We'll set the pin up as an OUTPUT, and call
+io.blink() all in setup(), then watch the LED blink by itself
+in loop().
+
+Hardware Hookup:
+	SX1509 Breakout ------ Arduino -------- Breadboard
+	      GND -------------- GND
+	      3V3 -------------- 3.3V
+		  SDA ------------ SDA (A4)
+		  SCL ------------ SCL (A5)
+		  15 -------------------------------- LED+
+		                                 LED- -/\/\/\- GND
+                                                330
+
+Development environment specifics:
+	IDE: Arduino 1.6.5
+	Hardware Platform: Arduino Uno
+	SX1509 Breakout Version: v2.0
+
+This code is beerware; if you see me (or any other SparkFun 
+employee) at the local, and you've found our code helpful, 
+please buy us a round!
+
+Distributed as-is; no warranty is given.
+*************************************************************/
+
+#include <Wire.h> // Include the I2C library (required)
+#include <SparkFunSX1509.h> // Include SX1509 library
+
+// SX1509 I2C address (set by ADDR1 and ADDR0 (00 by default):
+const byte SX1509_ADDRESS = 0x3E;  // SX1509 I2C address
+SX1509 io; // Create an SX1509 object to be used throughout
+
+// SX1509 Pin definition:
+const byte SX1509_LED_PIN = 15; // LED to SX1509's pin 15
+
+void setup() 
+{
+  // Call io.begin(<address>) to initialize the SX1509. If it 
+  // successfully communicates, it'll return 1.
+  if (!io.begin(SX1509_ADDRESS))
+  {
+    while (1) ; // If we fail to communicate, loop forever.
+  }
+
+  // Set up the SX1509's clock to use the internal 2MHz
+  // oscillator. The second parameter divides the oscillator
+  // clock to generate a slower LED clock. 4 divides the 2MHz
+  // clock by 2 ^ (4-1) (8, ie. 250kHz). The divider parameter
+  // can be anywhere between 1-7.
+  io.clock(INTERNAL_CLOCK_2MHZ, 4);
+  
+  io.pinMode(SX1509_LED_PIN, OUTPUT); // Set LED pin to OUTPUT
+  
+  // Blink the LED pin -- ~1000 ms LOW, ~500 ms HIGH:
+  io.blink(SX1509_LED_PIN, 1000, 500);
+  // The timing parameters are in milliseconds, but they
+  // aren't 100% exact. The library will estimate to try to
+  // get them as close as possible. Play with the clock
+  // divider to maybe get more accurate timing.
+}
+
+void loop()
+{
+  // Relax! The SX1509's got this...
+}

examples/breathe/breathe.ino

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+/*************************************************************
+breathe.ino
+SparkFun SX1509 I/O Expander Example: breathe output
+Jim Lindblom @ SparkFun Electronics
+Original Creation Date: September 21, 2015
+https://github.com/sparkfun/SparkFun_SX1509_Arduino_Library
+
+This example demonstrates the SX1509's set-it-and-forget-it
+breathe function. The SX1509 will pulse an LED, smoothly
+ramping its brightness up-then-down. We'll set the pin up as
+an ANALOG_OUTPUT, and call io.breathe() all in setup(), then
+watch the LED pulse by itself in loop().
+
+Hardware Hookup:
+	SX1509 Breakout ------ Arduino -------- Breadboard
+	      GND -------------- GND
+	      3V3 -------------- 3.3V
+		  SDA ------------ SDA (A4)
+		  SCL ------------ SCL (A5)
+		  15 --------------------------------- LED+
+		                                 LED- -/\/\/\- GND
+                                                330
+
+Development environment specifics:
+	IDE: Arduino 1.6.5
+	Hardware Platform: Arduino Uno
+	SX1509 Breakout Version: v2.0
+
+This code is beerware; if you see me (or any other SparkFun 
+employee) at the local, and you've found our code helpful, 
+please buy us a round!
+
+Distributed as-is; no warranty is given.
+*************************************************************/
+
+#include <Wire.h> // Include the I2C library (required)
+#include <SparkFunSX1509.h> // Include SX1509 library
+
+// SX1509 I2C address (set by ADDR1 and ADDR0 (00 by default):
+const byte SX1509_ADDRESS = 0x3E;  // SX1509 I2C address
+SX1509 io; // Create an SX1509 object to be used throughout
+
+// SX1509 Pin definition:
+const byte SX1509_LED_PIN = 15; // LED to SX1509's pin 15
+
+void setup() 
+{
+  // Call io.begin(<address>) to initialize the SX1509. If it
+  // successfully communicates, it'll return 1.
+  if (!io.begin(SX1509_ADDRESS))
+  {
+    while (1) ; // If we fail to communicate, loop forever.
+  }
+
+  // Use the internal 2MHz oscillator.
+  // Set LED clock to 500kHz (2MHz / (2^(3-1)):
+  io.clock(INTERNAL_CLOCK_2MHZ, 3);
+  
+  // To breathe an LED, make sure you set it as an
+  // ANALOG_OUTPUT, so we can PWM the pin:
+  io.pinMode(SX1509_LED_PIN, ANALOG_OUTPUT);
+  
+  // Breathe an LED: 1000ms LOW, 500ms HIGH,
+  // 500ms to rise from low to high
+  // 250ms to fall from high to low
+  io.breathe(SX1509_LED_PIN, 1000, 500, 500, 250);
+  // The timing parameters are in milliseconds, but they 
+  // aren't 100% exact. The library will estimate to try to 
+  // get them as close as possible. Play with the clock 
+  // divider to maybe get more accurate timing.
+}
+
+void loop()
+{
+  // Enjoy your hypnotically breathing LED!
+}

examples/clock/clock.ino

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+/*************************************************************
+clock.ino
+SparkFun SX1509 I/O Expander Example: clock output
+Jim Lindblom @ SparkFun Electronics
+Original Creation Date: September 21, 2015
+https://github.com/sparkfun/SparkFun_SX1509_Arduino_Library
+
+This example demonstrates the SX1509's clock output
+functionality. The OSC pins (OSCIO in the datasheet), can be
+configured as either a clock input, clock output, or an
+extra output!
+
+Hardware Hookup:
+	SX1509 Breakout ------ Arduino
+	      GND -------------- GND
+	      3V3 -------------- 3.3V
+		  SDA ------------ SDA (A4)
+		  SCL ------------ SCL (A5)
+		  OSC ------------- Check with a multimeter or o-scope
+
+Development environment specifics:
+	IDE: Arduino 1.6.5
+	Hardware Platform: Arduino Uno
+	SX1509 Breakout Version: v2.0
+
+This code is beerware; if you see me (or any other SparkFun 
+employee) at the local, and you've found our code helpful, 
+please buy us a round!
+
+Distributed as-is; no warranty is given.
+*************************************************************/
+
+#include <Wire.h> // Include the I2C library (required)
+#include <SparkFunSX1509.h> // Include SX1509 library
+
+// SX1509 I2C address (set by ADDR1 and ADDR0 (00 by default):
+const byte SX1509_ADDRESS = 0x3E;  // SX1509 I2C address
+SX1509 io; // Create an SX1509 object to be used throughout
+
+void setup() 
+{
+  // Call io.begin(<address>) to initialize the SX1509. If it
+  // successfully communicates, it'll return 1.
+  if (!io.begin(SX1509_ADDRESS))
+  {
+    while (1) ; // If we fail to communicate, loop forever.
+  }
+  
+  // Configure clock:
+  // - INTERNAL_CLOCK_2MHZ: Set clock to internal 2MHz
+  // - 2: Set LED clock to divide by 2^(2-1) (2)
+  // - OUTPUT: Configure OSCIO pin as a clock OUTPUT
+  // - outputFreq: Sets the frequncy of output
+  //   - 0: 0Hz LOW
+  //   - 0x1-0xE: fOSCout = Fosc / 2 ^ (outputFreq - 1) Hz
+  //   - 0xF: 0Hz HIGH
+  byte outputFreq = 6; // Set output freq. to 62.5 kHz
+  io.clock(INTERNAL_CLOCK_2MHZ, 2, OUTPUT, outputFreq);
+}
+
+void loop() 
+{
+}