Career in Embedded Systems

Hi Folks, This is Murugan, today i post "Career in Embedded system " ..let be COOL.!!
Many students are not aware of the lucrative opportunities available in the field of Embedded Systems. Most graduates go after the popular “IT” industry to seek a good career. I think there are 2 reasons for this1)lack of awareness 2) entry barrier. While studying most students may come across the name “Embedded Systems”. Apart from that they may not be aware of -”what is an embedded system”, how do they work, what knowledge and skills should be acquired to build a great career in the field of embedded systems, which companies are working in this field etc etc. If it is in the case of computer science – the industry is readily known – the lucrative IT industry. The leading companies are Microsoft,Google,Adobe (product based) and there are many smaller and medium ones. There are service based IT firms like Wipro, Infosys, Accenture,Cognizant etc. Knowledge and skills required is mainly about programming languages and technologies – like Java, Asp.net, C & C++, Python, Php etc etc.. the list goes on. Entry barrier to the IT industry is very low. Any fresher with a basic skill and knowledge can get a job in this IT industry and that too with a decent entry level salary (well, that’s not the case always!!)

When it comes to Embedded systems – do you know who all are the leading players in this industry? Let’s have a look.

Samsung – They make mobile phones and gadgets, consumer electronics like washing machine, microwave oven, television, air conditioners etc. You must know that there are “n” number of competitors for Samsung who make similar products. All these products has embedded systems – with its own hardware and software. For example:- In an air conditioner functions like – ‘intelligent room temperature control’ will be controlled by the embedded device inside the air conditioner. This embedded device will be made of a microcontroller, its associated hardware and software for intelligent temperature sensing

Siemens – They make products in the field of medical electronics and automation industry.The products will be scanner, doppler , cardiograph machines, radiology machines etc etc.. its a big list. 

Bosch – They make products for automotive industry.

I just mentioned 3 companies serving 3 different industries. There are thousands of other companies in the field of embedded systems – offering various kinds of services, consultation and product building.

Now we got an idea of companies that can offer a job in embedded systems. Now lets take a look at who all can opt for a career in embedded systems. The basic requirements will be a graduation/post graduation in electronics. There are many such courses offered by various kinds of universities. I will say, easy entry is for engineering degree holders in different streams of Electronics engineering – like Electrical and electronics, Electronics and communication, Electronics and instrumentation etc.  Other degree holders in electronics like Bachelor of Science (Electronics as main), Master of Science (Electronics) as main can also opt for a career in Embedded systems. 

Knowledge and skills  required in these areas are-  Good knowledge in theory and practical of one or two micro controllers like PIC, 8051, or AVR etc. Deep and sound knowledge in programming language C – especially embedded C. Knowledge in these 2 areas will help you to get an entry level job in the field of embedded systems. The real “learning curve” will only start at your first job – where you will deal with real issues and problem solving methods.  After gaining much experience from the first job (may be a 2 years) you can always switch to big companies.

The trend we see here in India is, freshers will boost their knowledge in these areas – especially in controllers and C programming by taking a good training after their graduation. The reason is an “outdated” and inefficient curriculum used by many universities in India. Even in an engineering course, there is only a single paper about microcontrollers. Most fresh graduates are unemployable in Embedded systems (unless some mavericks build their own way up learning all themselves).  To supplement this, fresh graduates take 3 or 6 months additional training. This will help them to land at an entry level job, usually in a medium level company. They gain more knowledge at this job and later switch  to bigger ones like Bosch, Samsung etc.

The first job you take will have a very high influence on your career. Example:- An employee working with a “Consulting type” company is likely to work his career in that direction. Where as a “Product based” company is a little different and they function in an entirely different way than a “Consulting company”. So be aware of your first job – what you learn there will decide the way your career is headed!

By- CircuitsToday

Where to buy electronics components online in India?

If you are a student and doing your academic projects on your own, then here are a few Embedded related component vendors who can provide you with almost any sensor, microcontrollers , interface boards, Embedded development kits etc.

1) NSK Electronics, Bangalore: NSK electronics,S.P Road, Bangalore is the most famous and most heard among the circle, They provide almost all components needed for doing a project, even i order most of my project components from them. They also have their website www.nskelectronics.in if you are interested.

Payment methods:

• Direct deposit to their bank account
• Direct purchase from their shop in SP road, Bangalore

---

2) Element14 India : Element14 India which was previosly known as Farnell, is an international component distributor. Similar to Digikey and Mouser electronics, This website provides a way to order almost any component. This website asks for a SalesTax number at the time of checkout, So if you are a student or hobbyist then you can order the components from www.kitsnspares.com a website owned by EFY(Electronics for you magazine). All you need is to do is copy the part number of the component you want to order from www.element14.com website and search for that part number in www.kitsnspares.com website. When you find the component you can place an order by checking out. The advantage of this site is that, you can make payment through almost any banks net banking facility. The courier charges are also affordable. I have heard complaints about this site is that the components ordered dont arrive soon. So if you have urgent requirements this is not the site i recommend.

Payment methods for Kitsnspares:

• Netbanking
• Credit/Debit cards

---

3) Sunrom Technologies: This is a well known website similar to element14/kitsnspares and provides the same payment methods and they ship worldwide. Explore more by visting the website.

Payment methods:

• Netbanking
• Credit card
• Paypal
• Western union money transfer
• Wire transfer

---

4) RS Components: Found this site on search. it is similar to element14 website with slightly higher prices than element14. But most of the semiconductor parts are showing Out of Stock. 

Payment options:

• Cash/DD against delivery
• Credit card

---

5) Rhydolabz.com: One more good site for ordering compoents online. i would also like to add they have a very good customer support. 

Payment methods: 

• Netbanking
• Credit cards
• Cash deposit
• Cheque/DD

---

 6) Tenet Technotronics: Tenet technotronics provides major parts like Development boards and sensors and modules needed to develop your project but discrete semiconductors are not available.

Payment Methods:

• Credit cards (VISA/MASTER) 
• Debit cards
• Netbanking

7) Robokits India: One more good site for ordering parts related to robotics online. 

Payment methods: 

• Netbanking
• Credit cards
• Cash deposit
• Cheque/DD
• Paypal 

---

8) Vega robo kit: Limited number of parts available not recommended as only Credit cards and Paypal are accepted for payment.

Payment Methods:

• Credit cards (VISA/MASTER) 
• Paypal

---

9) Mouser Electronics: Mouser electronics is one of the global electronics components supplier. The whole world buys their parts from here. Not recommended for students as the parts are shipped from outside India and courier charges will be around 2000Rs. If you want to order parts from mouser without courier charges then get them from Aqtronics technologies, Bangalore. You can send your mouser part enquiry tosupreeth@aqtronics.com. They will reply you with the costing for each part. You can then confirm the order, so that they get the parts from Mouser Electronics and ship to you. 

Payment methods for Aqtronics Technologies:

• Cash on delivery

 Payment methods for Mouser electronics:

• Credit cards (VISA/MASTER) 

---

10) Digikey.com: Digikey is the default global electronics components supplier for everyone worldwide. Even the part numbers of this site are incorporated in various PCB design tools. Not recommended for students as the parts are shipped from outside India and courier charges will be around 2000Rs. 

 Payment methods for Digikey:

• Credit cards (VISA/MASTER)

---

11) RK Electro: One more site claiming to provide online purchase of components, but i was not succesful to find any part from this site.

---

 12) Probots: Provides most of the components needed for embedded systems. The site offers modules, programmers and development kits attractive prices. The prices mentioned on this site are less compared to other online purchase sites.

Payment Methods : 

• Direct Cash deposit to HDF bank account
• NEFT amount transfer to bank account 

---

13) Digibay:

Payment Methods : 

• Direct Cash deposit or DD payment to bank account
• Net banking or NEFT/RTGS amount transfer to bank account
• Credit Card/ Debit card support coming soon.

Shipping Options : 

• Bluedart
• DTDC

visit:1. https://www.facebook.com/ElectronicAndCommunication?ref=hl

        2. http://electrocommtech.blogspot.in/

#Murugan

Audio amplifier circuit using IC LM386

                                                  Audio Amplifier using IC LM386

Amplifiers are used to boost the strength of the input signal and give an amplified version of the signal in the output. Audio amplifiers are widely used in Stereo or Home theater systems, Mini speakers etc. There are numerous ways to build a Audio amplifier but nothing is efficient as building using a dedicated Audio amplifier IC. The above circuit diagram shows the connections and components used to build a Audio amplifier.

IC LM386:

                                                       Pin diagram of LM386

LM386 is a simple low power audio amplifier used in most of the Audio circuits for its less power consumption. This IC is capable of giving a output gain of about 200 when external components are used along with it. But when you use it without adding external components its capable of delivering amplification of 20. 

The pin 1 & 8 are meant for altering the gain level by tying up a capacitor or RC pair in between them. Audio input was fed through the Non inverting input pin while inverting input tied to the ground usually. 

WORKING OF CIRCUIT:

The IC is initially powered by means of Vcc, Resistor R1 and Capacitor C2 was used to prevent oscillations in the circuit. The Resistors R2 and Capacitor C3 plays a major role in this above circuit as it alters the output gain obtained in the output. Adding a single capacitor of 10uF will help us to obtain max gain. While using along with resistor will help you obtain a gain of about 50db. The positive terminal of C3 should be connected to pin 1 and negative to pin 8 of the IC LM386.

Capacitor C3 was used to couple the output to the speaker and POT can also be used to tailor the gain of the obtained output signal. The increase gain is only used when a very low input signal is to be amplified. You can feed any Audio signals to this circuit and this works just fine to do its purpose.

Like this circuit? Share this with others through social site and don't forget to follow us there for more of these tutorials and circuits. 

#Murugan

what is RS232 Communication??

        RS232 is Based on serial communication which means it can send or receive one bit at a time RS232 is a Standard (1987) to make a communication sophisticated RS232 connect a peripheral devices like printer,scanner,modem and mouse with computer RS232 can provide p2p communication some time called point to point-communication the speed of RS232 is not too much fast we can achieve a maximum speed of 920 Kbps during a data communication by using RS232.

           we can connect a peripheral device with computer at a maximum distance of 50 ft RS232 styles is different it,s shape is just like D so people called it a D style so it comes in two shape the one is D9 ( total 9 pins connector ) and second one is D25 ( total 25 pins connector ) but mostly three pins are using such as Tx,RX,CT

1) TXD ( Pin NO 3 ) : The function of this pin is to send or transmit data serially to a connected devices with computer

2) RXD ( Pin NO 2 ) : The function of this pin is to Receive a data serially from connected devices with computer

3) CTS&RTS ( Pin NO 7,8 ) : Clear to send and Ready to send Just to check that the channel is busy or free for the communication

4) DSR ( Pin NO 6 ) : it,s stand for Data set ready it works with device like modem to tell to computer that now i m ready to take a new data

5) DTR ( Pin NO 4 ) : The function of 

this pin is to connect or disconnect a peripheral device from computer

6) DCD: ( Pin NO 1 ) : To check that Devices is disconnected or still connected with the pc

7) RI: ( Pin NO 9 ) : it,s stand for Ring indicator the function of this pin is to inform the computer that modem is ringing 

8) SG: ( Pin NO 5 ) : it,s stand for Signal ground in a simple words a reference point of the circuitry 

How to set up your own Electronics Lab at home

Every Electronic hobbyists have a dream of setting up his own lab at home to learn, explore, widen the knowledge and of course have fun with Electronics. But most of us don't how to start setting up one and even if we did it will end up in a complete mess. So after going through several forums and asking the suggestions of pros i have prepared this article on setting up your own lab, i hope this will be helpful for all budding Electronic Engineers and Hobbyist.

WORKSPACE:

This is the first thing you need to set for your homemade lab. The workspace should consist a large wooden work bench, desk or table that fits the components and tools while you are working. Ensure that work area is well lit and comfortable to work even for long time. Your work area should be accessible to household electrical power (220V AC)

Also install a Desktop or Laptop computer in your work area which will be helpful to refer datasheets of components or IC's. Also it will come handy when you are working with Microcontrollers and makes your work a lot easier.

POWER SUPPLIES:

This comes next in the list as Power supplies hold the next priority in your Electronics Lab. When coming to power supplies you have lot of options to consider but it all depends on how much you are about to invest. Bench power supply is usually preferred but it was insanely expensive and you have to spend 40% of your budget in it.

As i said you do have options, so its best to buy some DC power supply adapters which suits your need such as 12v, 5v or 9v. You can also construct power supply for your needs, it takes bit of work but believe me it will come handy.

IMPORTANT THINGS TO BUY:

• Needle Nose Pliers
• Wire Strippers
• Tweezers
• Screwdrivers
• Knife
• Drill
• Connecting Wires
• Breadboard
• Gator Clips
• Helping Hands
• Solder Iron/Gun
• Solder
• Flux
• Multimeter
• Protoboards

These are the things which are very essential and should be in your lab if you wanna be a better worker. And many would have noticed i missed "Oscilloscope" in the above list. A decent Oscilloscope will cost around $50 and am not sure that how many of you would like to spend that much for your lab. Usage of Oscilloscope might suit certain applications but always remember Oscilloscope is not the first thing to buy.

COMPONENTS TO BUY:

When coming to the components there is not much help others can do as you need to identify your needs. The usage of components varies based on the things you are working in your lab. Here are some of the basic components you must have in your lab.

• Resistors ( 100,330,470,1k,10k,100k,1M)
• Capacitors ( 0.1uF, 22pF, 100uF, 1000uF)
• NPN & NPN Transistors (2N222,2N3906)
• Diodes (1N4001,1N4148)
• Voltage Regulators (7805,7812)
• IC's ( 555,4017)
• LED (red, Blue, white)
• Male and Female Header
• Battery
• Push Buttons

The above list is to provide a general idea about the components to buy for your lab. Also do not forget to analyze your needs and buy the components which fit your need.

IF YOU ARE WORKING WITH MICROCONTROLLERS:

You need to spend some extra bucks if you are the one who loves to play with the Microcontrollers. A Development board is the best choice for all the programmers who wants to learn and have fun with the Controllers. There are number of Development boards in the market for 8051, PIC ,AVR or ARM Controllers.

• Arduino
• Raspberry Pi
• Easy PIC
• 
  

FINAL WORDS:

I Hope the above lists and suggestions would have given you a clear idea about setting up your lab. Setting up a perfect lab at the beginning itself is quite a difficult task, so don't get disheartened keep on expanding your lab by experimenting and adding many stuffs to it. Undoubtedly you will learn a hell lot of things and   gradually it will make you a pro.

Like this article? Share this with others through social sites and don't forget to follow us there for more of these contents.

regards,

 Murugan

I2C Protocol

Introduction

Usually embedded systems are complex design which include multiple peripherals interconnected like LED, LCD, RTC, other microcontroller, Memory card, etc with main computer or master to expand its capabilities. All these peripheral’s interfacing is done by standard rules which is called protocol. Protocol is a set of rules that defines how communication between systems and devices are done which include bit ordering, bit pattern meanings, creating data frames, error checking, etc. UART, SPI, I2C, USB and Ethernet are some of the protocols widely used in embedded systems for serial data communication. Here we are bound to I2C Protocol.

                 The Inter-integrated Circuit (I2C) Protocol was originally developed in 1982 by Philips(now known as NXP) used to connect multiple devices with only two wire. Its is also called two wire interface protocol.

Why I2C Protocol ?

Comparing I2C with UART

In UART, separate clock line is not used with data transmission so both device should agree on same Baud-rate. If differences occur between Baud-rate on either end will cause garbled data while in I2C separate clock line is used.

• UART uses hardware overheads like start bit, stop bit, partiy bit or CRC bit in each frame of transmission which will lead to increase in transmission time while I2C use only acknowledgement bit(ACK) or no acknowledgement bit.
• Another drawback of UART is that they are suited to communications between two, and only two, devices while I2C can used with multiple devices and different modes like multi-master or single master, etc.
• Data transfer speed is also an issue for UART, they are limited to some extent and maximum baud-rate is around 230400 bps.

Comparing I2C with SPI

• The first drawback of SPI is pin used to connect multiple devices. If we connect two device with SPI standard it will use four pins MISO, MOSI, SCK, CS.
• In SPI protocol, there is only single master but it can support arbitrary number of slaves. While in I2C, multiple master can be possible.
• If we compare data transmission speed of SPI and I2C, then SPI will win definitely. SPI support speed upto 10MHz (10 Mbps).

What’s good in I2C ?

• I2C requires only two line(two wire), but those two wires can support up to 1008 slave devices.
• Unlike SPI, I2C can support a multi-master system, allowing more than one master to communicate with all devices on the bus (although the master devices can’t talk to each other over the bus and must take turns using the bus lines).
• Data rates of I2C devices can communicate at the rate of 100kHz to 400kHz.

How I2C Protocol Works ?

To understand the working of I2C Protocol, Let we take some practical examples

Single Byte Transfer

                                                                 Single Byte Transaction

• Idle condition: As you can see in above figure, at the initial condition SDA and SCL both High because of both line pulled High with pull-up resister.
• Start condition: Data transfer is start when SDA line pulled down mean High to Low when SCL line is High.
• Bit Detect: Slave can understand bit reception when it receives single bit ‘1’ or ‘0’ when SCL line is High. 
• Data allowed to change: Transition of bit from 1 to 0 or 0 to 1 is only allowed when SCL line is Low as seen in pick.
• ACK Bit: Transmitter must release the SDA line after transmitting 8 bit to allow the Receiver to pull SDA line Low to acknowledgement the previous 8 bit data reception.
• Stop condition: is only understood when SDA line goes Low to High while SCL line is High.

Note: In I2C Protocol Byte is transmitted MSB to LSB. And in multi-Byte transmission, every 8 bits has a 9th bit that is an acknowledge.

Write/Read Two Byte  from Master to Slave

Start Condition

Every communication in I2C Protocol is begin with start condition which we already studied above how start condition form. This alerts all slave devices that a transmission is about to start.

Address Frame Byte

The address frame byte include device address which is of 7-bit long and Read(1)/Write(0) bit.  The address frame byte is always sent first when any new communication sequence initiate.

ACK/NACK Bit

The 9th bit of the frame is the NACK/ACK bit(here NA or A). This is the case for all frames (data or address). Once the first 8 bits of the frame are sent, the receiving device is given control over SDA. If the receiving device does not pull the SDA line low before the 9th clock pulse, it can be inferred that the receiving device either did not receive the data or some error occur. 

Data Bytes

After the address frame byte has been sent, data bytes can begin being transmitted. The master will simply continue generating clock pulses at a regular interval, and the data will be placed on SDA by either the master or the slave, depending on whether the R/W bit indicated a read or write operation. The number of data byte is arbitrary, and most slave devices will auto-increment the internal register, meaning that subsequent reads or writes will come from the next register in line.

Stop condition

Every communication in I2C Protocol is end with stop condition which we already studied above. During normal data writing operation, the value on SDA should not change when SCL is high, to avoid false stop conditions.

Speed of I2C Protocol

Common I²C bus speeds are the 100 kbit/s standard mode and the 10 kbit/s low-speed mode, but arbitrarily low clock frequencies are also allowed. Recent revisions of I²C can run at faster speeds typically 400 kbit/s Fast mode, 1 Mbit/s Fast mode plus or Fm+, and 3.4 Mbit/s High Speed mode.

More About I2C Protocol

10-bit Addressing suppor

ts more number of devices

In order to increase device address capability, 10-bit addressing scheme is introduced to I2C Protocol by which we can connect more number of devices by using I2C Protocol.

In a 10-bit addressing system, two frames are required to transmit the slave address. The first frame will consist of the code 11110xyz, where ‘x’ is the MSB of the slave address, y is  8th bit of the slave address, and z is the Read/Write bit as seen above. The first frame’s ACK bit will be asserted by all slaves which match the first two bits of the address. As with a normal 7-bit transfer, another transfer begins immediately, and this transfer contains bit 0 to bit 7 of the address. At this point, the addressed slave should respond with an ACK bit. If it doesn’t, the failure mode is the same as a 7-bit system. 

Clock stretching

• In an I2C communication the master device determines the clock speed. However, there are situations where an I2C slave is not able to co-operate with the clock speed given by the master and needs to slow down a little. This is done by a mechanism referred to as clock stretching.
• An I2C slave is stretching the clock by pull down the SCL if it needs to reduce the bus speed. The master on the other hand is required to read back the clock signal after releasing it to high state and wait until the line has actually gone high.

Repeated Start Conditions

• When we communicate through I2C bus, its obvious in most cases that first you need to send command and then you get response from slave, so each time you dont need to terminate communication by stop condition. You can use start condition reapetedly without terminating previous transaction. The I2C protocol defines a so-called repeated start condition.
• For example, After having sent the address byte (address and read/write bit) the master may send any number of bytes followed by a stop condition. Instead of sending the stop condition it is also allowed to send another start condition again followed by an address (and of course including a read/write bit) and more data. This is defined recursively allowing any number of start conditions to be sent.
• The purpose of this is to allow combined write/read operations to one or more devices without releasing the bus and thus with the guarantee that the operation is not interrupted.