The Raspberry Pi is also
They had released several generations of Raspberry Pi.
- Raspberry Pi Model B (First generation) – February 2012
- Raspberry Pi Model A – February 2013
- Raspberry Pi Compute Model- April 2014
- Raspberry Pi Model B+ – July 2014
- Raspberry Pi 2 – February 2015
- Raspberry Pi Zero- November 2015
- Raspberry Pi 3 Model B – February 2016
- Raspberry Pi Zero W – February 2017
- Raspberry Pi 3 Model B+ – March 2018
The Raspberry Pi was first released on 29 February 2012 with an introductory price of US$35. The System On Chip (SoC) used is Broadcom BCM2837B0 and compatible with plenty of Operating Systems such as Linux, FreeBSD, NetBSD, OpenBSD, Plan 9, RiscOS and Windows 10 IoT Core. The Raspberry Pi 3+ uses a Broadcom BCM2837B0 SoC with a 1.4 GHz 64-bit quad-core ARM Cortex-A53 processor, with 512 KB shared L2 cache. Besides, it comes with a 40 pin General Purpose Input Output (GPIO) connector. The Keyboard and mouse can be connected with the USB, and other components such as sensors can be connected with the GPIO pins. The RPi has no built-in real-time clock, so it cannot track the time of the day. It comes with lots of accessories like Camera, SenseHat ( has lots of built-in sensors), Gertboard, Official Display and so on.
Anatomy of Raspberry Pi 3 B+ model
HARDWARE SPECIFICATIONS
The Raspberry Pi 3B+ model was launched in March 2018, comes with a CPU, GPU, USB ports, 40 pin header (GPIO pins), WiFi, Bluetooth, POE (Power over Ethernet). The CPU has an Arithmetic Logic Unit (ALU) and a control unit and the primary storage is the Memory. A GPU (Graphics Processing Unit) is nothing but a specialized circuit that is very efficient at processing images and computer graphics, better than a CPU. This kind of design that packs all the components required to power a computer onto a single chip is called System on Chip (SoC). Nowadays, SoCs are implemented into Smartphones and Tablets. The System on Chip has both CPU and GPU combined together in this model to give enormous speed compared to the previous versions. At the back side of the Raspberry Pi, there is a slot allocated for the Secondary Storage, where you will be installing your OS.
CPU and GPU
A CPU is always considered to be a brain of a computer, and it works same for Raspberry Pi too. It has a 64-bit capacity and is responsible for arithmetic and logical units. It also comes with a control unit. The GPU ie, the Graphics Processing Unit is very efficient in image calculation and processing. The Broadcom video core cable is included in the device for video games.
Clock Speed and Memory
The Raspberry Pi comes with a quad-core ARM Cortex A53 and a RAM memory (Primary) of 1 GB. It consists of a clock speed of 1.4 GHz Broadcom BCM2837B0. At the back side of the Raspberry Pi, there is an additional slot is given for the secondary memory, this takes in a micro SD card, similar to which all the cameras and smartphones use for their additional storage. You will be installing the OS in the SD card. It’s better if you use 16 GB or 32 GB
LEDs
There are two LEDs in the device, one is red and another one is green. The red LED indicates the on/off of the Pi whereas, the green LED reads the software in the SD card. So, when you have the OS installed in secondary memory ie, in the given slot, the green LED blinks, if not then there is a fault in your SD card. You can simply replace the card with new OS installed in that.
Micro USB 2.0 Power source Connector
The RPi consists of a micro USB for power source, which you use for smartphones. It provides 5 V power to the board and it draws 170 to 200 mA which is more power than the previous version of the model.
Other specifications
- The Raspberry Pi consists of an Ethernet, through which you can connect with LAN cable to your modem/ computer/ laptop.
- There are 4 USB ports in this model to provide a connection to the peripherals such as
mouse , keyboard, etc - An HDMI output port in the RPi is used for the display when connected to monitor or screen.
- Audio output socket and video composite reside in a single 4 pole 3.5 mm near the HDMI output.
- It also has a Camera Serial Interface where you can connect the Raspberry Pi Camera into that via cable. It is available in the market for $20- $35.
- PoE (power over Ethernet) is an additional feature incorporated in this device that lacks in B model.
- The Raspberry Pi 3 B+ measures 85mm length and 56mm width same as in the B model.
What is a GPIO Pin?
Building “things” (Systems) that can respond to the world around them is called physical computing. The idea behind this physical computing is to make the “things” to communicate is to use the Sensors. These sensors cannot be directly communicated with the computer/laptops that we use
The Raspberry Pi 3B+ model has 40 GPIO pins, unlike the Arduino the Pi has digital I/O pins. In the earlier models there were only 26 pins.
Physical Computing of GPIO Pins
Before we go in detail with each of the pin, we first understand how the physical computing is setup in Raspberry Pi using these GPIO pins.
- First thing, you should figure out what kind of input and output devices you need to compute. A light sensor or a pressure sensor can be input and whereas you need an output device to implement the results. So the output device
maybe a seven-segment display or just an LED to indicate the results. - Understand the interface of the device like how it gives output and how it receives the input. Each pin has
specific purpose, some need to be a certain voltage, etc. - Then connect it to the computer, say Raspberry Pi in our case and understand which GPIO pin you had to use based on the interface whether input or output.
- Finally, write the code- configure the pin number in the code which you have chosen, when it should look for the input and at what time it should give the output. You can choose any language to write the code.
Roles of the GPIO pins
There are two numbering schemes of these GPIO pins. They are 1. BOARD and 2. BCM. The difference between these schemes is, BOARD signifies using the physical pin numbers on the Raspberry Pi P1 connector and the BCM signifies the Broadcom SoC channel designation. We will use the BOARD numbering scheme.
This is how the pins are numbered on the Raspberry Pi board. If you notice that one side of the pins, numbered even, in which some of the pins are ground pins. These are the negative terminal of the battery ie, Raspberry Pi, which will act as the 0 V or the neutral end of the circuit. There are 26 bi-directional pins that are configured as input or output which take two states HIGH (3.3 V) or LOW (0 V).
There two kind of power pins ie, it will act as positive terminal
- Pin number 2 and 4 – draw 5 V from the Pi’s micro USB, it can draw up to 300 mA
- Pin number 1 and 17- draw 3.3 V and can draw only up to 50 mA
There are some pins allocated for serial
SPI (Serial Peripheral Interface)- 5 pins ( 19,21,23,24,26)
- GPIO10- MOSI (Master Out Slave In)
- GPIO9- MISO (Master In Slave Out)
- GPIO11 – CLK
- GPIO7 and GPIO8- CHIP select
UART (Universal Asynchronous Receiver/Transmitter)- pin number 8 and 10 – to convert parallel interface and serial interface
- GPIO14 – UART transmitter
- GPIO15- UART receiver
I2C Inter Integrated Circuit – there are two pins for data and clock.
- GPIO2 – SDA (for data)
- GPIO3- SCLK- clock
Pin number 27 and 28 can be used to connect to other hardware boards and configure the GPIO as per that need.
Pin number 12 can be used for Pulse Width Modulation functionality.
Where to buy?
You can find good piece of a Raspberry Pi board in this link! The product is by Element14 from Amazon.
Thank you for reading my article! If you have any questions or suggestions, feel free to comment below or contact me using the form.
