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| author | Marti Bolivar <mbolivar@mit.edu> | 2010-10-25 21:15:28 -0400 |
|---|---|---|
| committer | Marti Bolivar <mbolivar@mit.edu> | 2010-11-17 12:44:28 -0500 |
| commit | 2d429e75ce69e77f8c95490ac03881ec9aa0354a (patch) | |
| tree | a3b810a6c75625b07a4b976e5d1e319c60e19a6b /source/arduino/analogreference.rst | |
| parent | 30ac55d80c18e93f9c39a6dd850c10f9e7fd92ac (diff) | |
| download | librambutan-2d429e75ce69e77f8c95490ac03881ec9aa0354a.tar.gz librambutan-2d429e75ce69e77f8c95490ac03881ec9aa0354a.zip | |
arduino language reference nearing completion, properly CC-BY-SA 3.0 attributed
Diffstat (limited to 'source/arduino/analogreference.rst')
| -rw-r--r-- | source/arduino/analogreference.rst | 66 |
1 files changed, 0 insertions, 66 deletions
diff --git a/source/arduino/analogreference.rst b/source/arduino/analogreference.rst deleted file mode 100644 index 9a25169..0000000 --- a/source/arduino/analogreference.rst +++ /dev/null @@ -1,66 +0,0 @@ -.. _arduino-analogreference: - -analogReference(type) -===================== - -Description ------------ - -Configures the reference voltage used for analog input (i.e. the -value used as the top of the input range). The options are: - - - - -- DEFAULT: the default analog reference of 5 volts (on 5V Arduino - boards) or 3.3 volts (on 3.3V Arduino boards) -- INTERNAL: an built-in reference, equal to 1.1 volts on the - ATmega168 or ATmega328 and 2.56 volts on the ATmega8. -- EXTERNAL: the voltage applied to the AREF pin is used as the - reference. - - - -Parameters ----------- - -type: which type of reference to use (DEFAULT, INTERNAL, or -EXTERNAL). - - - -Returns -------- - -None. - - - -Warning -------- - -**If you're using an external reference voltage (applied to the AREF pin), you must set the analog reference to EXTERNAL before calling analogRead().** -Otherwise, you will short together the active reference voltage -(internally generated) and the AREF pin, possibly damaging the -microcontroller on your Arduino board. - - - -Alternatively, you can connect the external reference voltage to -the AREF pin through a 5K resistor, allowing you to switch between -external and internal reference voltages. Note that the resistor -will alter the voltage that gets used as the reference because -there is an internal 32K resistor on the AREF pin. The two act as a -voltage divider, so, for example, 2.5V applied through the resistor -will yield 2.5 \* 32 / (32 + 5) = ~2.2V at the AREF pin. - - - -See also --------- - - -- `Description of the analog input pins <http://arduino.cc/en/Tutorial/AnalogInputPins>`_ -- `analogRead <http://arduino.cc/en/Reference/AnalogRead>`_\ () - - |