ADC

Or as called "Analog to digital converter", the most important module in Embedded systems field.

As seen in the last article "The difference between analog and digital sensors", most sensors are analog sensors, and all computers cannot understand the analog signals, it understands the boolean values only (1 or 0).

To make it possible for computers to understand the analog signals, we have to make some electronic module works as an intermediary between sensor and computer, or specially, converts analog signals to digital signal, so this module is called (Analog to Digital converter).

Simple way to make the computer understands the read value, is to use a comparator (op-amp as a comparator) to compare the current signal given by the sensor, and some reference value given by the user "see Fig. 1", if the given value is more than or equal to the V-REF, then the output is the VCC value, otherwise, the output is the GND.

Using this method, we can give the computer some order depends on the surrounding environment "depends on some read from a sensor".

But this is not a direct way to convert analog signal to digital signal.

In this case the computer cannot make some relation between this read and the real read (Ex. temperature sensor give 25mv at 25 ْC but here the computer cannot understand That).

So we have to find another method that can convert this signal to some digital signal to make it easy for us to give the computer all information about this value.

Other methods (more in complexity) is to use an ADC module, this module can convert the analog value "output of any sensor" to some digital reading that the computer can read it, then it can have some accurate value about the surrounding environment.

Types of ADC:

ADCs come in various speeds, use different interfaces, and provide differing degrees of accuracy. The most common types of ADCs are:

• Flash method
• Successive approximation method.
• Segma-Delta method.

In next articles, we'll talk about each method separately, Theory of work, advantage, and disadvantage of each.