1. Readers Suitable For This Article
First of all, this article is suitable for those rookie-level electronic enthusiasts, those who want to use their soldering iron to solder some gadgets or buy some electronic modules to realize their interactive creativity.
This article is not suitable for professional-level readers. In order to make it understandable for enthusiasts, it is inevitable to adjust some contents that do not affect the principles, so don't be so serious if you see some "mistakes".
In addition, the vast majority of Datasheets are in English, so this also requires readers to have a certain level of English reading.
Finally, a complete understanding of a Datasheet is actually a fairly superb skill. This requires not only deep knowledge of electronics, IC manufacturing technology, circuit design, but also a variety of professional knowledge. Here, the author can only make a rough outline introduction, at least let the reader have a basic concept in future applications. I dare not expect readers to be proficient in datasheets after reading this article.
PS: This article is a pragmatist's self-perception, not an academic paper.
2. What is Datasheet?
The datasheet is a detailed description file issued by electronic parts developers or manufacturers for the electronic parts they produce. In the Datasheet, it will describe various key data of this electronic part. The more complicated electronic parts, the more complicated the Datasheet, while some simple electronic parts (such as ordinary resistors) simply do not have datasheets (because its parameters are really understood by most users).
3. Why is there a Datasheet? And the Necessity of Learning to Read the Datasheet
The electronic world is a very complicated world. For example, even if it is an Arduino motherboard, there are three voltage levels of 3.3V, 5V, and 9-15V on it. In fact, at present, in terms of the working voltage level of various electrical appliances in the world, there are various voltage levels ranging from the lowest zero volts to tens of thousands or even millions of kilovolts. Unlike a screw nut, as long as the dimensions are correct, it can be screwed in any way. (Of course, we do not discuss the problem of screwing in special environments).
But for electronic products, if you only care about the function of the electronic parts, regardless of the scope of application of the electronic parts, and thus use these electronic parts blindly, this will be extremely absurd. For example, if you connect an LED directly to a 220V power supply, 100%, you will hear a crackling sound, and then a burst of smoke rises. And you will never see the effect of the LED being lit.
Think about it, just a voltage standard is so overwhelming. It is precisely because of this complexity that manufacturers are also forced to issue standard data sheets to describe their electronic products. Otherwise, no one will dare to use their products and no one will be able to use them.
4. Why Should We Learn to Read the Datasheet?
We learned to read the Datasheet also to solve our problem. When connected to Arduino, the problem is: Can this part be directly connected to the Arduino system and let it work normally? If it can't be connected directly, what method is needed to connect it to the Arduino platform?
5. Several Elements of Datasheet
Datasheet usually contains the following elements:
5.1 Basic introduction
This content is generally mentioned on the home page, and usually contains a lot of one-sentence information. From this section, you can basically determine whether the materials described in this datasheet meet your requirements.
5.2 Function introduction
This content will mark the functions that the part can achieve, as well as the requirements of the physical environment where the functions are normally implemented, or the applicable interval.
Some parts will also mark the prerequisites and subsequent processing of the part when it realizes the function and the maximum processing capacity of the part.
5.3 Pin configuration
This section will introduce the definition of each pin of this part in detail. You will often see a picture first, which will be marked with labels such as VCC, VACC, GND, PA, etc. Then immediately followed by a list, indicating the specific definition of each pin, sometimes, electrical parameters will also be marked here.
5.4 Electrical parameters for part work
In this part, we can understand the normal operating voltage range and the current range of the described parts. Generally, an electronic part has a certain range of "compatible" space. For our enthusiasts, the "typical" value of this part is what we need to pay attention to. Just like an LED lamp, it typically has a typical current of 20mA.
5.5 Setting parameters and setting instructions of parts
For some electronic parts, it needs to make various settings during use, such as a three-axis acceleration sensor, we need to configure its internal registers in advance so that it outputs the data we need. In this section, we can find a complete configuration list and instructions.
5.6 Package size of parts
For parts with the same function, even if the electrical characteristics are exactly the same, due to different application environments, manufacturers will provide different packaging products according to the actual market demand. Just like everyone sees the core ATMEGA328 of Arduino UNO, it has three standard packages (TQFP, PDIP, MLF).
5.7 Other
The Datasheet will also contain some other information, such as errata, version history, typical application circuit, part test curve, and other information. This information is also worth understanding.
6. For Arduino enthusiasts, you need to be clear before reading the Datasheet and what you need to do after reading it
Our purpose in reading the Datasheet is not to read it purely. Instead of saying that the Datasheet is an entertaining novel, it is better to say that it is an extremely boring dictionary. In this dictionary, you can find all the answers you need. And we not only need to confirm whether its function solves your problem, we also need to confirm how to make it connect with Arduino correctly.
For this reason, we must first have a basic understanding of the Arduino motherboard:
6.1 The IO port voltage of Arduino is 5V, and the maximum current that can be supported is 50MA, usually, 20MA is recommended.
Therefore, if we see the Datasheet of an electronic part labeling its IO voltage as 3.3V, then, it is best that we still do not connect them directly, or we use resistor divider, or we use an isolation chip to connect, of course, how to use these techniques is another question.
6.2 The digital ports of Arduino UNO include SPI, TWI (compatible with I2C, SCCB, etc., with different names), TTL UART, and USB SLAVE.
Therefore, if there is a chip or part that exactly meets your needs, but its interface is SATA, you must have to find ways to convert, and this conversion is also another problem.
6.3 The PWM pulse output by Arduino is 500HZ
If a stepper motor controller needs 1K PWM pulses for control, then okay. You can't figure it out with Arduino. It can only be done indirectly by other methods.
As described in 6.1-6.3, after we have a basic concept of Arduino, we can start our road to extended applications.
7 When to use Datasheet?
First of all, we probably look for electronic parts that can achieve our purpose. Before buying, we first get the Datasheet of this part, and then analyze it to fully understand its various parameters, and judge the following problems based on these parameters:
7.1
Whether it can really achieve its purpose.
7.2
Whether it can be directly applied or not directly but can find indirect ways (such as conversion circuit, adaptation circuit, etc.)
After answering the two questions 7.1 and 7.2 and obtaining affirmative answers, we only need to buy this part in the future, and then directly connect the Arduino and use it according to the previous plan.
Test:
After reading this article, you may have mastered some knowledge about reading datasheets, and now you can have a try. Here are two good products' datasheets for you to practice.
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