peripherals/doc; Added Documentation to Peripherals

firmware/peripherals/doc.txt

@@ -2,16 +2,35 @@
 @defgroup peripherals Peripherals
 @ingroup  m4a-firmware
 
-### What goes here?
+### Peripherals
 Specific documentation for our reference peripherals;
 In the next module you can find:
 
-### ds18_sensor
+### Kconfig Setup
 
-Module to get temperature data.
+The peripherals has an effect in each board. a property of the board is periph_conf where is all
+specifications of each communication protocol used, converters analog to digital, and PWM parameters.
+So, peripherals actually provides support to manage de VREF of ADC channels, This will give more precision
+with the measurements.
 
-### moisture_sensor
+ | Macro of the periph_conf        | Voltage Referenced                   | type            |
+ |:-------------------------------:|:------------------------------------:|:---------------:|
+ |   CONFIG_ADC_VREF_DEFAULT       |      1.0V                            |     Internal    |
+ |   CONFIG_ADC_VREF_INTVCC0       |      1/1.48 VDDANA                   |     Internal    |
+ |   CONFIG_ADC_VREF_INTVCC1       |  1/2 VDDANA (only for VDDANA > 2.0V) |     Internal    |
+ |   CONFIG_ADC_VREF_EXT1          |      External reference  #1          |     External    |
+ |   CONFIG_ADC_VREF_EXT2          |      External reference  #2          |     External    |
 
-Module to get moisture data.
+### Ds18_sensor
+
+This is a soil temperature sensor that could provide the current measurement
+in degrees centigrades "°C". this works with any digital pin, but needs to use the
+one wire protocol to obtain the data from itself.
+
+### Moisture_sensor
+
+A peripheral that could read through adc pins, getting an analog measurement, this works with a
+10-bit resolution, and it's adjustable to work with 3.3V (in low consumption) and 5V for more
+information about the peripheral see @ref moisture_sensor module
 
 */

firmware/peripherals/ds18_sensor/doc.txt

@@ -2,10 +2,29 @@
 @defgroup ds18_sensor Ds18 sensor
 @ingroup  peripherals
 
-### What goes here?
+### Ds18 soil sensor
 
-This module is used to get the data of the temperature sensor. The function
-``` init_temperature_sensor ```initialize the sensor and the function
-``` get_temperature_value ``` gets the values.
+The ds18b20 is a temperature sensor with a range between -55 °C and 125 °C, its operative
+voltage is 3V or 5V respectively, only needs a data pin to transfer data an a MCU using one-wire communication.
+Has an acurracy of 0.5 °C. The output resolution is programmable between 9 - 12 bits, conversion time of 750 ms
+at 12-bit resolution.
+
+### Pinout scheme
+
+\image html DS18B20-Sensor-Pinout.jpg Ds18b20 Pinout scheme width=40%
+
+This module works with the ds18b20 peripheral, this implement two steps,
+`init_temperature_sensor()` and `get_temperature_value()`. the first function checks
+if the peripheral is connected to a designed pin. when the initialization it's successfully returns `DS18_OK`
+in case that the peripheral was not found returns a `DS18_ERROR`.
+
+To the function `get_temperature_value()` needs receive a int16_t variable as parameter (Signed Integer variable), because the
+peripheral could operates with positive and negative values. when you are reading the received data it could be observed
+in this way:
+
+ | Value read  |Integer part       | Decimal part      | Temp read in °C |
+ |:-----------:|:-----------------:|:-----------------:|:---------------:|
+ |    1517     |      15           |         17        |  15.17 °C       |
+ |    -1517    |      -15          |         17        | -15.17 °C       |
 
 */

firmware/peripherals/moisture_sensor/doc.txt

@@ -2,11 +2,23 @@
 @defgroup moisture_sensor Moisture sensor
 @ingroup  peripherals
 
-### What goes here?
+### Analog Capacitive Moisture sensor V1.2
 
-This module gets the data of the moisture sensor.
+This module contains all about the manage the read data from the Moisture sensor. It's an Analog
+sensor that operates betwwen 3.3V and 5.0V, has three pins VCC (Red wire), GND (Black wire), DATA (Yellow Wire),
+There is a fixed frequency oscillator that is built with a 555 Timer IC. The square wave generated is then fed
+to the sensor like a capacitor. To a square wave signal that capacitor, however, has a certain reactance, or
+for argument’s sake a resistance that forms a voltage divider with a pure ohm type resistor (the 10k one on pin 3).
+The greater is the soil moisture, the higher the capacitance of the sensor. Consequently, there is a smaller reactance
+to the square wave, thus lowering the voltage on the signal line. The voltage on the Analog signalpin can be measured by
+an analog pin of a MCU.
 
-Note:  This is an adc device, for the correct functioning of this module you have to use 3.3V
-and 10bits resolution.
+@image html Electronic-sheme-analog_moisture_sensor.png Fig. 1.1 Electronical scheme of the Analog Capacitive Moisture Sensor V1.2 width=40%
 
+@note The resolution supported is 10 bit.
+
+@warning There a line drawn on the analog sensor, this represent the operating zone to get the humidity from the soil and
+the circuit zone of the device (This limits could affect the sensor and its functionality).
+
+@image html Analog_moisture_sensor_001.jpeg Fig. 1.2 Representation of limits to use the moisture sensor. width=20%
 */