Looking for a Tutor Near You?

Post Learning Requirement »
x

Choose Country Code

x

Direction

x

Ask a Question

x

x
x
x
Hire a Tutor

IoT Interview Question

Loading...

Published in: Electronics | Robotics
1,738 Views

This pdf will help college students to get a job in the internet of things (IoT) and in their exam viva. It contains some basics and commonly asked question and answers of IoT.

Bhushan N / Pune

5 years of teaching experience

Qualification: M.Sc (Ferguson college pune - 2014)

Teaches: IT & Computer Subjects, Physics, B.Sc Tuition, Electronics, M.Sc Tuition

Contact this Tutor
  1. Internet Internet SHome Network Android Device Light Sensor Motion Sensor 0T Development Board ESP-8266 dev. Kit Arduino nano Arduino uno ESP-32 dev. Kit Arduino mega Arduino Due Raspberry pi 3 0T protoco Communication protocol For device to device Wired Internal communication: Wired External communication: RS-485, (UART, USART) Wireless communication: Wi-Fi, Bluetooth Internet Home Network co.•..a u • Y Router O Web Browser 5 Android Board 0T Development Tool Arduino IDE Language Arduino C/C++ programming Raspbian 10T IDE Language Python Relay Board 0T platform Platforms Adafruit.io Thinger.io ThingSpeak Kaa The things 10T Gecko AWS Microsoft-Azure Google cloud Blynk MQTT Broker Hive MQ Mosquito Eclipse lo.Adafruit SPI, 12C, CAN USB, RS-232, Messaging protocol For device to server MQTT, HTTP, REST, COAP, KAFKA
  2. (BLE) , Zigbee, sigfox Overview on Electronic wired Communication Protocols Protocol: A set of rules and regulations is called a protocol. Communication: Exchange of information from one system to another system with a medium is called a communication. Communication Protocol: A set of rules and regulations that allow two electronic devices to connect to exchange the data with one and another. Types of Electronic Communication Protocols: There are two types of communication protocols which are classified below: 1 . Inter System Protocol 2. Intra System Protocol 1. Inter System Protocol: The inter system protocol using to communicate the two different devices. Like communication between computer to microcontroller kit. The communication is done through a inter bus system. Different categories of Inter system protocol: UART Protocol USART Protocol USB Protocol
  3. I-TART 1- UART stands fcr Univasal Asynchronous transmitta- and receiva, 2. It is a tin vireprotocol and TX, 3. It is and pockets of The data ute 'by byte 'Mthout classes pul s es 4. It is a cornrnuru cati on S. It is slow compare *Mth USART USART 1. USAR T Sands fr unversal ynthronous and ast,mthronous Data tranxnitterand recei'utr 2. Itis a wireprotocol Ryand TX, 3. It is send and recaves a block of data along with classes pulses. 4. It is a filll duplex 5. Itis slow comparet,qth USB USB I. USB stands for universal saial bus. 2. Itis a vire protocol D+ and D-, 3. Send and recaves a data al ong *ith clock pulses 4, It is also fiall. cornrnum cation 5. Iti$ fast comparevhth USART and US 2. Intra System Protocol: The Intra system protocol is used to communicate the two devices within the circuit board. While using this intra system protocols, with out going to intra system protocols we will expand the peripherals of the microcontroller. The circuit complexity and power consumption will be increases by using intra system protocol. Using intra system protocols circuit complexity and power consumption, cost is decrease and it is very secure to accessing the data. Different categories of Inter system protocol 12C Protocol SPI Protocol CAN Protocol
  4. 12C 1. 12C standsfor inter circu it. 2. It is dateloped by the Phil 3. It is a H elf Duplet protocol 4, Syncronization S, It is twowire protocols SCLand 6. It is multi master protocol With in the circuit board SPI 1. SPI stands for serial peripheral Interface 2. It is deæloped by the Motorola, 3.1t is a full duplet protocol Synchronization S. It is a four wire protocol SCL and SS 6. It is single master rxotocol With in th e circuit board SPI -1. CAN *ands for controller Area network. 2. It is deweloped by the R Bosch, 3. It is a full protocol S ynchronitation 5. It is a twowire protocol CAN H+ and CAN H-, 6. It is multi master protocol 7, With in two circuit board. 12C Specifications Number of Bus lines data rate Run current Preferable application Device addressing Acknowledgement (ACK) mechanism Four ( SCLK, CS, MISO, MOSI) Higher, about 10 MHz or more Lower, about 200 WA at 4 Mbps, hence less power consumption Perform well in single master and single slave configuration Does not support Does not have mechanism to support receipt of the data Two ( SDA, SCL) Lower, about 100 KHz or 400 KHz Higher, about 400 WA at 400 Kbps, hence more power consumption Perform well in multi-master and multi-slave configuration Support It has mechanism to support receipt of the data using ACK
  5. Overhead in point to point connection Less applications requiring continuous data stream transmission UART More communication between devices which does not require continuous transmission i.e. requiring occasional communication Application Features Full Form Interface Diagram Pin Designations Data rate Universal Asynchronous Receiver/Transmitter SPI Serial Peripheral Interface 12C Inter-Integrated Circuit TxD RxD (Device-I) RxD TxD (Device-2) MISO MOSI SCK CSI CS2 (Master) (Slave-I) MISO MOSI SCK cs MISO MOSI SCK cs SDA SCL (Master-I) SDA SCL (Master-2) SDA SCL (slave—I) SDA SCL (Slave-2) UART Interface Diagram TxD: Transmit Data RxD: Receive Data As this is is asynchronous communication, data rate between two devices wanting to communicate should be set to equal value. Maximum data rate supported is about 230 Kbps to 460kbps. SPI Interface Diagram SCLK: Serial Clock MOSI: Master Output, Slave Input MISO: Master Input, Slave Output SS: Slave Select Maximum data rate limit is not specified in SPI interface. Usually supports about 10 Mbps to 20 Mbps 12C Interface Diagram SDA: Serial Data SCL: Serial Clock 12C supports 100 kbps, 400 kbps, 3.4 Mbps. Some variants also supports 10 Kbps and 1 Mbps.
  6. Distance Type of communication Number of masters Clock Hardware complexity Protocol Software addressing Lower about 50 feet Asynchronous Not Application No Common Clock signal is used. Both the devices will use there independent clocks. lesser For 8 bits of data one start bit and one stop bit is used. As this is one to one connection between two devices, addressing is not needed. highest Synchronous One There is one common serial clock signal between master and slave devices. less Each company or manufacturers have got their own specific protocols to communicate with peripherals. Hence one needs to read datasheet to know read/write protocol for SPI communication to be established. For example we would like SPI communication between microcontroller and EPROM. Here one need to go through read/write operational diagram in the EPROM data sheet. Slave select lines are used to address any particular slave connected with the master. There will be 'n' Higher Synchronous One or more than One There is common clock signal between multiple masters and multiple slaves. more It uses start and stop bits. It uses ACK bit for each 8 bits of data which indicates whether data has been received or not. Figure depicts the data communication protocol. 8bts.enc 8bbgv•te There will be multiple slaves and multiple masters and all masters can communicate with all the slaves. Upto 27 slave
  7. Advantages Disadvantages • It is simple communication and most popular which is available due to IJART support in almost all the devices with 9 pin connector. It is also referred as RS232 interface. • They are suitable for communication between only two devices. • It supports fixed data rate agreed upon between devices initially before communication otherwise data will be garbled. slave select lines on master device for 'n' slaves. •It is simple protocol and hence so not require processing overheads. •Supports full duplex communication. •Due to separate use of CS lines, same kind of multiple chips can be used in the circuit design. •SPI uses push-pull and hence higher data rates and longer ranges are possible. •SPI uses less power compare to 12C • As number of slave increases, number of CS lines increases, this results in hardware complexity as number of pins required will increase. • To add a device in SPI requires one to add extra CS line and changes in software for particular device addressing is concerned. devices can be connected/addressed in the 12C interface circuit. •Due to open collector design, limited slew rates can be achieved. •More than one masters can be used in the electronic circuit design. •Needs fewer i.e. only 2 wires for communication. •12C addressing is simple which does not require any CS lines used in SPI and it is easy to add extra devices on the bus. •It uses open collector bus concept. Hence there is bus voltage flexibity on the interface bus. •Uses flow control. •Increases complexity of the circuit when number of slaves and masters increases. •12C interface is half duplex. •Requires software stack to control the protocol and hence it needs some processing overheads on microcontroller/microprocessor.
  8. •Master and slave relationship can not be changed as usually done in 12C interface. •No flow control available in SPI. ComparingMith-Othen Technology Beyond Tne Dreams Bus RS232 RS485 PC SPI CAN USB Transfer Type Point to point Network Master-Save Master-Save Network Master-Save Transfer Rate (NS) 20k 35k 100k 110k 1M 480M t%x. Length (m) 15 1200 1 1 5 No. Of Nodes 1 32 128 any 2032 126