What is Arduino UNO Pins ,importance of Clock , Power supply Requirement.

Hello, In this article i am going to explain about Arduino UNO pins, Power supply, Clock used in arduino uno in details. If you don't know how much power supply to use while operating arduino uno then you must read this article before you getting start or might you will blown up your arduino uno along with that i you will get to know about GPIO pins and why clock important in arduino uno.

Hardware :

Arduino UNO Headers
Fig 1.1 Arduino UNO Headers

Notice that the two headers have got numbers for each one of the pins. We're not going to get into the specifics I will write another Article that explains what the different types of pins. I'll give you some more details on that but I just wanted you to be aware at this point that each one of those pins does something different on the board.

A few pins for example are dedicated to power or providing power to your shield or to whatever else you have connected. 

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There's a few pins here that deal with analog or so-called analog signals and allow you to measure an analog signal from the outside world I'm going to explain what these are in a different Article. 

Then the other side you've got pins that a digital they can understand values of high or low in an external signal and they can detect the state of a signal from the outside world or they can generate such signal and send them to other connected devices. 

Again, don't worry too much about the details if you don't quite fully understand what I'm talking about because I've got upcoming Articles in this section that specifically discuss those issues. 

Also, You can see digital pins side called SCL and SDA there's RF and down here and TX and RX. These are especially the 1(TX) and 0(RX) and then the SDA and SCL these are communication pins so we can use these pins to allow the atmega 328p microcontroller to communicate with external devices such as for example sensors or even your computer or other Arduinos film.

You can actually build ways by which your Arduino Uno can communicate and send for example numbers or larger text messages to other connected devices. To do that we use mechanisms or as called protocols such as this one here these two pins together implement a very popular such protocol is a serial protocol called I²C protocol. 

On the other side we can use this 1(TX) and 0(RX) pins to communicate a classic serial communications protocol. I'm going to come back to these later in another Article.


USB A to USB B cable
Fig1.2 USB A to USB B cable

Let's move on to the front of the board where we've got a couple of large sockets. What this socket here does is the USB socket it is the socket that is connected to this microcontroller and it allows you to program your Arduino Uno by connecting it via USB to your computer.

You have USB A to USB B cable this one you plug it in USB Socket that you plug the other side to your computer and then that provides both power to your board and also connectivity so that you can use your Arduino IDE for example to send a program to your Arduino Uno.


External Power Adapter
Fig1.3 External Power Adapter

I'm going to demonstrate in detail how to do this in an upcoming Article. Apart from the USB port you can also power your Arduino through barrel connector so you can have an external power Adapter you connect it to the wall power and you can use a compatible millimeter connector to provide power to your Arduino.

This way you don't have to keep your Arduino connected to your computer for power it can use an external power supply and connect it somewhere else where your gadget is supposed to be installed.


Arduino Battery Powering
Fig1.4 Arduino Battery Powering

You can also use an external battery power supply. Just fill it up with easy to get cheap AA batteries and using the same connector it can provide battery power to your Arduino so then now you don't need a power circuit at a wall. 

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It's a good easy way to gain some independence of your gadgets from power sources through a battery. It Really Helps while making portable projects.

Speaking of power requirements your Arduino Uno is capable of dealing with a wide range of power supplies in terms of voltage.

It's got a voltage regulator that makes it possible for you to connect power sources that range from say 5 to 12 volts. You can go above that as well but then if you have a voltage supply that say is 15 or 16 volts then you are going to have a lot of wasted power on voltage regulator.

If you use an external power Adapter I recommend that it's something I'd say 9 volts or no more than 12 volts in order to reduce the heat that is produced on the voltage regulator.

Similarly especially if you use a battery pack then the more batteries you put in the more waste you will have at the voltage regulator.

Again, don't go more than have 9 volts to 12 volts you have a lot of heat produced on voltage regulator. Which sometime damage voltage regulator.

Almost finished just a couple of other things that I wanted to mention here that often cause confusion to especially new Arduino makers.

A lot of people are asking what are ICSP headers two sets of pins. Through the ICSP header you can use a special attached hardware it's called a hardware programmer that allows you to directly program your microcontroller. You have two sets of ICSPs because there are two microcontrollers on this board. One ICSP header is used to program microcontroller atmega 328p and Another set of ICSP is used to program the USB controller.

Of course, You don't need to program it when you buy it you will get already programmed. I explained here just that you know what this is for it's for programming the microcontroller using a dedicated external hardware device called the ICSP programmer so that's one thing. 

There's a couple of other components that I want to mention there's button a reset button. When you press it you reset the board and start executing whichever program is on the microcontroller from the beginning so that's the reset button. 

Then you've got this shiny device this is a crystal clock it is calibrated to beat at 16 million times per second so that's  megahertz and it's the clock that makes the whole board tick.

Every microcontroller just like a microprocessor needs a clock in order for it to operate.

Every time that the clock ticks the processor will execute the next instruction. If there is no clock here or if the clock is not functioning properly then the microcontroller will not operate as well.

It is like time stops if there is no clock. To wrap it up and for this Article I'd like to explain what these two large also silver devices are you can see that these are very close to the barrel connector and also very close to the voltage regulators. 

These two devices are capacitors they are used to clean up the voltage that is coming through the barrel connector from an external source. The idea here is that the microcontroller needs a nice steady power supply in order for it to operate properly.

It wants for example its voltage to be a nice steady 5 volts. It doesn't like it when the voltage fluctuates say for example from 5 volts down to 5 or up to 5.1 and so on. What these two capacitors do is to try and take an unclean power source that is coming through the barrel connector perhaps from a power Adapter from the wall which could contain a lot of interference and noise from other nearby devices and then these capacitors will also contribute towards cleaning that voltage before it reaches the atmega 328p.

I'm going to leave at this and I hope that this Article gave you a good overview of what is on the Arduino Uno board and what are its main components. 

In the next Article I will explain a little bit about the digital and analog ports before moving forward and talking about communications.

Conclusion, in this article i have explain you Arduino power supply requirements, Why Clock important, Arduino uno different pins, Some power supply related pre cautions and different way we can power arduino uno.

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