Structure of Embedded Systems
Updated: Aug 24, 2020
An #embedded system is defined as the integration of computer memory, processor, and input/output peripheral devices designed to perform a particular task in a given time. The Embedded system is a cornerstone of the electronics industry. Almost all the electronic appliances that we use are manufactured only with the help of embedded systems.
The usage of the embedded systems ranges from mobile phones, digital watches to traffic light controllers, and avionics.
At the core level, it is an integrated circuit that has been designed to perform some real-time operations. The complexity of an embedded system depends on the task to which it has been assigned. Now you may get a question, How these are working?
By understanding the basic structure of embedded systems, you will get some ideas. This article provides adequate information on the structure of embedded systems.
Structure of Embedded Systems:
Embedded systems can receive and transmit data to the outside world. It takes the unprocessed or raw data as the input, processes it, and converts into an end product. Basically this is an interactive system and it requires certain components to perform its operation. Let's see those,
A #sensor measures any physical quantity such as pressure, speed and converts them into a measurable electrical signal. It also possesses a separate memory space where the measured quantities can be stored. The #electrical signal can be read by devices such as analog to digital converters. Sensors may exist as many types. Starting from a button, sound signals through a microphone, a video that can be recorded by cameras, and even touch screen in our mobile phones.
The analog signal sent by the sensor is converted into readable #digital signals in this analog to digital converter component.
The converted digital signals are stored in this memory space. The Embedded system has two kinds of memory. They are volatile and non-volatile memory. The volatile #memory is temporary and stores data at a high speed. It gets deleted once the system is turned off. RAM and cache memory are part of this memory. On the other hand, non-volatile memory is permanent and the information stored in it is not lost, even if the system is turned off. ROM is a part of non-volatile memory.
PROCESSOR & ASIC:
The processor is known as the brain of embedded systems. It fetches the stored digital signal from memory and processes the received data and stores the output again in the memory. This component possesses a two-way function. Based on the type of embedded system, this part may differ but they are intended towards the one assigned task. This part also consists of a division named Intellectual Property (IP) core other than the controllers. Mostly they perform the functions as the network controllers (Ethernet, CAN) and audio/video processing (audio codec, VGA controller). This IP core interacts with the processor based on some pre-designed communication protocols.
The digital output signals are converted back into analog signals with the help of a D-A Converter.
This device compares the received output signal with the already existing actual output signal. And then it stores the approved or correct output signal in the memory space. A lot of actuators are existing in the real world. The LED screen which displays the output based on the given signal, even the bulbs, and electric fans in our home that works but taking up the electric current.
In this section, let us see some real-life examples, the presence, and the functions of the above-mentioned components in it. Let's consider a microwave oven.
The microwave oven has several input buttons for deciding the cooking time, to start, and to cancel the heating process.
Besides this, it also has a door sensor to indicate whether the door is in an open/closed state and a weight sensor to detect the presence of any food inside the oven. All the components come under the category of sensors.
The analog signal [button that sends the cooking time] sent by the sensor is converted into a digital signal by the A-D converter and stored in the memory. Then the cooking process gets started and when it gets to the end, a digital signal is generated by the #processor. Then it gets converted into an analog signal and fed into the actuators. In the microwave oven, beeper and LCD display act as actuators.
The beeper indicates the end of the cooking and the LCD screen displays the time of day and time consumed or left in the cooking process.
The same functionality and mechanism are applied for other home appliances such as washing machines, air conditioners, and refrigerators.
In televisions, the dish antenna serves as the sensor which receives the radio waves. It is then converted into respective digital #signals. The processor which is present inside the television processes the signal and allocates audio to the respective video data.
The LCD or LED screen which is the actuator here, displays the processed data as a virtual video to us.