0.0.10 Documentation checkpoint.

The vast majority of the Maple-specific values have been pulled out of
the higher-level overview pages and replaced with refs into documents
under /docs/source/hardware/.

Much of the work that's left to be done in this regard is labeled with
versioned TODO and FIXME comments.

Suggestions from StephenFromNYC and gbulmer were incorporated from
this forum thread:

      http://forums.leaflabs.com/topic.php?id=703

1 files changed, 31 insertions, 34 deletions

diff --git a/docs/source/adc.rst b/docs/source/adc.rst
index b943808..af613cc 100644
--- a/docs/source/adc.rst
+++ b/docs/source/adc.rst
@@ -6,23 +6,12 @@
 
 Analog-Digital Conversion is the process of reading a physical voltage
 as a number. The Maple has a large number of pins which are capable of
-taking 12-bit ADC measurements, which means that voltages from ground
-to +3.3v are read as numbers from 0 to 4095; this corresponds to a
+taking 12-bit ADC measurements, which means that voltages from 0 to
+3.3V are read as numbers from 0 to 4095.  This corresponds to a
 theoretical sensitivity of just under 1 millivolt. In reality, a
-number of factors introduce noise and bias into this reading and a
+number of factors introduce noise and bias into this reading, and a
 number of techniques must be used to get good precision and accuracy.
 
-.. compound::
-
-   The header pins with ADC functionality (marked as "AIN" on the
-   silkscreen) are:
-
-     D0, D1, D2, D3, D10, D11, D12, D13, D15, D16, D17, D18, D19, D20, D27, D28
-
-   Note that pins 3, 27, and 28 are not marked AIN on the silkscreen
-   for Maple revisions through Rev 5, however, they **do work** as
-   analog input pins.
-
 .. contents:: Contents
    :local:
 
@@ -31,13 +20,15 @@ number of techniques must be used to get good precision and accuracy.
 Noise and Bias
 --------------
 
+.. FIXME [0.0.10, Maple-specific]
+
 The biggest issues with analog-digital conversion are noise and bias.
 With the Maple, we have tried to isolate the ADC pins and traces from
-strong noise sources but there are always trade--offs between noise,
+strong noise sources, but there are always trade--offs between noise,
 additional functionality, cost, and package size.
 
 The 6 ADC pins in a bank (D15--D20) generally have the least
-noise and should be used for fine measurements.  If the input voltage
+noise, and should be used for fine measurements.  If the input voltage
 changes relatively slowly, a number of samples can be taken in
 succession and averaged together, or the same voltage can even be
 sampled by multiple ADC pins at the same time.
@@ -47,34 +38,40 @@ voltages that the sample is being compared against. In the case of the
 Maple, the high reference is |vcc| and the low reference is ground.
 This means that noise or fluctuations on either |vcc| or ground will
 affect the measurement. It also means that the voltage you are trying
-to sample must be between ground and 3.3V. In the case of a variable
-reading, it is best if the voltage varies over the entire range of
-0--3.3V; otherwise, only a fraction of the sensitivity is being
-leveraged.  Resistor dividers and constant voltage diodes are basic
-tools which can help bring a given voltage signal into the appropriate
-range; opamps and other powered components can also be used.
+to sample must be between ground and 3.3V. 
+
+.. _adc-range:
+
+In the case of a variable reading, it is best if the voltage varies
+over the entire range of 0--3.3V; otherwise, only a fraction of the
+sensitivity is being leveraged.  Some basic tools to accomplish this
+are `resistor dividers
+<http://en.wikipedia.org/wiki/Voltage_divider>`_ and `Zener diodes
+<http://en.wikipedia.org/wiki/Voltage_source#Zener_voltage_source>`_\
+.  However, `operational amplifiers
+<http://en.wikipedia.org/wiki/Operational_amplifier>`_ and other
+powered components can also be used if greater precision is required.
 
 .. _adc-function-reference:
 
 Function Reference
 ------------------
 
-.. doxygenfunction:: analogRead
-
-.. doxygenfunction:: pinMode
-
-.. doxygenenum:: WiringPinMode
+* :ref:`lang-analogread`
+* :ref:`lang-pinmode`
 
 .. _adc-recommended-reading:
 
 Recommended Reading
 -------------------
 
-* `Wikipedia article on Analog-to-digital converter <http://en.wikipedia.org/wiki/Analog-to-digital_converter>`_
-
-* `Arduino Analog Input Tutorial <http://arduino.cc/en/Tutorial/AnalogInputPins>`_
-
-* STMicro documentation:
+* `Wikipedia: Analog-to-Digital Converter
+  <http://en.wikipedia.org/wiki/Analog-to-digital_converter>`_
+* `Arduino Analog Input Tutorial
+  <http://arduino.cc/en/Tutorial/AnalogInputPins>`_
+* ST documentation:
 
-  * `Application Note on ADC Modes (pdf) <http://www.st.com/stonline/products/literature/an/16840.pdf>`_
-  * `Application Note on ADC Oversampling (pdf) <http://www.st.com/stonline/products/literature/an/14183.pdf>`_
+  * `Application Note on ADC Modes
+    <http://www.st.com/stonline/products/literature/an/16840.pdf>`_ (PDF)
+  * `Application Note on ADC Oversampling
+    <http://www.st.com/stonline/products/literature/an/14183.pdf>`_ (PDF)