Add content Functions/Arduino Due only

Author: Akshay Sharma

Language/Functions/Arduino DUE only/analogReadResolution.adoc

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+:source-highlighter: pygments
+:pygments-style: arduino
+:ext-relative: adoc
+
+= analogReadResolution()
+
+
+// OVERVIEW SECTION STARTS
+[#overview]
+--
+
+[float]
+=== Description
+analogReadResolution() is an extension of the Analog API for the Arduino Due.
+
+Sets the size (in bits) of the value returned by analogRead(). It defaults to 10 bits (returns values between 0-1023) for backward compatibility with AVR based boards.
+
+The *Due has 12-bit ADC capabilities* that can be accessed by changing the resolution to 12. This will return values from analogRead() between 0 and 4095.
+[%hardbreaks]
+
+
+[float]
+=== Syntax
+`analogReadResolution(bits)`
+
+
+[float]
+=== Parameters
+`bits`: determines the resolution (in bits) of the value returned by `analogRead()` function. You can set this 1 and 32. You can set resolutions higher than 12 but values returned by `analogRead()` will suffer approximation. See the note below for details.
+
+[float]
+=== Returns
+Nothing
+
+--
+// OVERVIEW SECTION ENDS
+
+
+
+
+// HOW TO USE SECTION STARTS
+[#howtouse]
+--
+
+[float]
+=== Example Code
+// Describe what the example code is all about and add relevant code   ►►►►► THIS SECTION IS MANDATORY ◄◄◄◄◄
+The code shows how to use ADC with different resolutions.
+
+[source,arduino]
+----
+void setup() {
+  // open a serial connection
+  Serial.begin(9600);
+}
+
+void loop() {
+  // read the input on A0 at default resolution (10 bits)
+  // and send it out the serial connection
+  analogReadResolution(10);
+  Serial.print("ADC 10-bit (default) : ");
+  Serial.print(analogRead(A0));
+
+  // change the resolution to 12 bits and read A0
+  analogReadResolution(12);
+  Serial.print(", 12-bit : ");
+  Serial.print(analogRead(A0));
+
+  // change the resolution to 16 bits and read A0
+  analogReadResolution(16);
+  Serial.print(", 16-bit : ");
+  Serial.print(analogRead(A0));
+
+  // change the resolution to 8 bits and read A0
+  analogReadResolution(8);
+  Serial.print(", 8-bit : ");
+  Serial.println(analogRead(A0));
+
+  // a little delay to not hog serial monitor
+  delay(100);
+}
+----
+[%hardbreaks]
+
+[float]
+=== Notes and Warnings
+If you set the `analogReadResolution()` value to a value higher than your board's capabilities, the Arduino will only report back at its highest resolution padding the extra bits with zeros.
+
+For example: using the Due with `analogReadResolution(16)` will give you an approximated 16-bit number with the first 12 bits containing the real ADC reading and the last 4 bits *padded with zeros*.
+
+If you set the `analogReadResolution()` value to a value lower than your board's capabilities, the extra least significant bits read from the ADC will be *discarded*.
+
+Using a 16 bit resolution (or any resolution *higher* than actual hardware capabilities) allows you to write sketches that automatically handle devices with a higher resolution ADC when these become available on future boards without changing a line of code.
+[%hardbreaks]
+
+[float]
+=== See also
+// Link relevant content by category, such as other Reference terms (please add the tag #LANGUAGE#),
+// definitions (please add the tag #DEFINITION#), and examples of Projects and Tutorials
+// (please add the tag #EXAMPLE#)  ►►►►► THIS SECTION IS MANDATORY ◄◄◄◄◄
+
+[role="example"]
+* #EXAMPLE# http://arduino.cc/en/Tutorial/AnalogInputPins[Description of the analog input pins]
+
+[role="language"]
+* #LANGUAGE# link:analofRead{ext-relative}[analogRead()]
+
+
+--
+// HOW TO USE SECTION ENDS

Language/Functions/Arduino DUE only/analogWriteResolution.adoc

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+:source-highlighter: pygments
+:pygments-style: arduino
+:ext-relative: adoc
+
+= analogWriteResolution()
+
+
+// OVERVIEW SECTION STARTS
+[#overview]
+--
+
+[float]
+=== Description
+`analogWriteResolution()` is an extension of the Analog API for the Arduino Due.
+
+`analogWriteResolution()` sets the resolution of the `analogWrite()` function. It defaults to 8 bits (values between 0-255) for backward compatibility with AVR based boards.
+
+The Due has the following hardare capabilities
+* 12 pins which default to 8-bit PWM, like the AVR-based boards. These can be changed to 12-bit resolution.
+* Pns with 12-bit DAC (Digital-to-Analog Converter).
+
+By setting the write resolution to 12, you can use `analogWrite()` with values between 0 and 4095 to exploit the full DAC resolution or to set the PWM signal without rolling over.
+[%hardbreaks]
+
+
+[float]
+=== Syntax
+`analogWriteResolution(bits)`
+
+
+[float]
+=== Parameters
+`bits`: determines the resolution (in bits) of the values used in the `analogWrite()` function. The value can range from 1 to 32. If you choose a resolution higher or lower than your board's hardware capabilities, the value used in `analogWrite()` will be either truncated if it's too high or padded with zeros if it's too low. See the note below for details.
+
+[float]
+=== Returns
+Nothing
+
+--
+// OVERVIEW SECTION ENDS
+
+
+
+
+// HOW TO USE SECTION STARTS
+[#howtouse]
+--
+
+[float]
+=== Example Code
+// Describe what the example code is all about and add relevant code   ►►►►► THIS SECTION IS MANDATORY ◄◄◄◄◄
+Explain Code
+
+[source,arduino]
+----
+void setup(){
+  // open a serial connection
+  Serial.begin(9600);
+  // make our digital pin an output
+  pinMode(11, OUTPUT);
+  pinMode(12, OUTPUT);
+  pinMode(13, OUTPUT);
+}
+
+void loop(){
+  // read the input on A0 and map it to a PWM pin
+  // with an attached LED
+  int sensorVal = analogRead(A0);
+  Serial.print("Analog Read) : ");
+  Serial.print(sensorVal);
+
+  // the default PWM resolution
+  analogWriteResolution(8);
+  analogWrite(11, map(sensorVal, 0, 1023, 0 ,255));
+  Serial.print(" , 8-bit PWM value : ");
+  Serial.print(map(sensorVal, 0, 1023, 0 ,255));
+
+  // change the PWM resolution to 12 bits
+  // the full 12 bit resolution is only supported
+  // on the Due
+  analogWriteResolution(12);
+  analogWrite(12, map(sensorVal, 0, 1023, 0, 4095));
+  Serial.print(" , 12-bit PWM value : ");
+  Serial.print(map(sensorVal, 0, 1023, 0, 4095));
+
+  // change the PWM resolution to 4 bits
+  analogWriteResolution(4);
+  analogWrite(13, map(sensorVal, 0, 1023, 0, 127));
+  Serial.print(", 4-bit PWM value : ");
+  Serial.println(map(sensorVal, 0, 1023, 0, 127));
+
+  delay(5);
+}
+----
+[%hardbreaks]
+
+[float]
+=== Notes and Warnings
+If you set the `analogWriteResolution()` value to a value higher than your board's capabilities, the Arduino will discard the extra bits. For example: using the Due with `analogWriteResolution(16)` on a 12-bit DAC pin, only the first 12 bits of the values passed to `analogWrite()` will be used and the last 4 bits will be discarded.
+
+If you set the `analogWriteResolution()` value to a value lower than your board's capabilities, the missing bits will be *padded with zeros* to fill the hardware required size. For example: using the Due with analogWriteResolution(8) on a 12-bit DAC pin, the Arduino will add 4 zero bits to the 8-bit value used in `analogWrite()` to obtain the 12 bits required.
+[%hardbreaks]
+
+[float]
+=== See also
+// Link relevant content by category, such as other Reference terms (please add the tag #LANGUAGE#),
+// definitions (please add the tag #DEFINITION#), and examples of Projects and Tutorials
+// (please add the tag #EXAMPLE#)  ►►►►► THIS SECTION IS MANDATORY ◄◄◄◄◄
+
+[role="example"]
+* #EXAMPLE# http://arduino.cc/en/Tutorial/AnalogInputPins[Description of the analog input pins]
+
+[role="language"]
+* #LANGUAGE# link:analogWrite{ext-relative}[analogWrite()] +
+* #LANGUAGE# link:analogRead{ext-relative}[analogRead()] +
+* #LANGUAGE# link:map{ext-relative}[map()]
+
+
+--
+// HOW TO USE SECTION ENDS