Microcontrollers In Wireless Sensor Networks

Microcontrollers In Wireless Sensor NetworksABSTRACT Now a days piano tuner demodulator profitss moderate been gaining act with physical in world. Whereas these can be utilise in unalike applications in medical, military, roadside, industrial etc .In the radio sensor network reducing spring is the main importance. In radio set sensor network, which ar use outpouring operated sensors need downhearted-power component de delinquencys to increase the life time of the sensors and as well gives rise for receiving set sensor networks which prolongs the life time for sensor nodes. In this we explore about the three different microcontrollers in wireless sensor and also we discussed about the characteristics of the typical wireless sensor network application. They argon Microchip, AVR and MSP430 series. By canvass this we conclude which is trump for the wireless sensor network. Now a days these microcontrollers ar commercially exploitation in sensor nodes.1. INTRODUCTIONA sensor node is a node which is able for playing some processing, collecting sensor informations and communicating with other connected nodes in a sensor network and it is also called as mode. These sensor nodes usually have very humble computers and storage capability comp ard to backcloth computers. This can be attributed to their use of very low power microcontrollers.Microcontrollers perform the main labour in the sensor nodes i.e. processing the data and controlling the functions of the other components. These are some of the controllers using as digital Signal Processors, Field Programmable Gate Array and applications. So microcontrollers are more(prenominal) suitable for sensor nodes. The best choice for embedded systems is to use microcontrollers because of the services providing by them, like it can connect to other devices more flexible and the power consumption is less.Digital Signal Processing is commandeering for broadband wireless conference, but fit in to wirel ess sensor networks the communication should be simple and easy to process. Field Programmable Gate Array are not apply in wireless sensor network because it should required more time and zippo for the reprogrammabling and reconfiguring to their usage. Application-specific Integrated circuits are performing as ironware where as microcontrollers are providing as softwares.So a wireless sensor network mostly uses microcontrollers. In this wireless sensor network we uses so many microcontrollers with different companies they are Microchip, Atmel etc.There are three different typical micro controllers which are use in wireless sensor network applications .they are Microchips, AVR series MSP430 series.2. TY celluloidAL MICROCONTROLLERS USED IN WSN APPLICATIONS2.1. Microchips pictorial matter microcontrollers are made by microchip technologies limited. These are mainly used in industrial reading referable to their low cost and it has serial programming capability. The features for m icrochip are explained below.2.1.1. dissipate structureIn the PIC microcontroller interrupt structure is very simple but powerful, we can set the priority levels to the interrupts i.e., tall or low and also these are useful for real time interrupts.2.1.2. pedagogy setFor the disgrace end PICs it varies about 35 directions and for higher end PICs it varies about 80 knowledges.pic micro controllers called as 8bit micro controllers because we have different PIC series for example PIC12 series size varies from 12bit and 30bits in the PIC30.in this single oscillation effectuation with single delay cycle.2.1.3. Memory architecturePIC microcontrollers follow Harvard architecture zero but separate code and data space. This microcontroller have number of register files which works as command purpose ram some of special purpose control registers for on chip researches. In this retrospection is divided in to banks.2.1.4. Input and output featuresFor every microcontroller we have I/O ports, which are used for transceiver and analog to digital conversion interfacing. save for some of the PIC series microcontrollers have on-chip ADC, due to this we used direct for analogy data from the transducer.PIC series also having the hardware which can carry SPI out.2.1.5. applicability of low power techniquesThese microcontrollers are able to operate over a wide frequency and voltage drift which makes frequency marking possible. Some of PIC series dont support frequency scaling but due to the external hardware they can support they are PIC12 and PIC16.but some PIC series supports the frequency scaling because of having the internal RC oscillator which can be used as clock. Due to this clock switching it takes time for result.2.1.6. pitiful power sleep modeBy comparing the microcontrollers the PIC series microcontrollers are simplistic. Due to this inflict end PICs doesnt have sleep modes. But for PIC16 microcontrollers it has only one sleep mode which was placed on mainframe computer core, for PIC18 series have two sleep modes if the peripherals are running then the core is shut-off and it is vice versa for second sleep mode.2.1.7. PipeliningPIC study takes one machine to execute i.e. 4 clock cycles. For execution it takes two phases fetch and execute. This is a two stage pipeline.2.1.8. ShortcomingPIC microcontrollers have a small set of direction set but these are best comparing to reduced instruction set computing devices. But PIC architecture doesnt have more advantages compared to RISC.They are, it doesnt have load-store architecture, due to this the memory direction refers in arithmetic and perspicuous instructions. By comparing to RISC processor, this PIC has only a single register but for RISC typically includes 16.2.2. AVR seriesThe AVR series microcontroller is also fallows the Harvard architecture.ATMega128L microcontroller is widely used in sensor nodes. The features for AVR are explained below.2.2.1. Interrupt structureAVR micr ocontroller is a powerful interrupt structure for AVR interrupt execution is enabled for four clock cycle minimum. Then the program is executed.2.2.2. Instruction setThe AVR ISA is more suitable than 8-bit microcontroller. The ATMEGA128 offer 133 powerful instructions. Each instruction takes one or two 16bit words. In this instruction set arithmetic operations work ob register R0-R32, but not directly on push back.2.2.3. Memory architectureThe Harvard architecture type AVR is ground with programs and is stores data separately for performing and parallelism. Flash, EEPROM, SRAM are single integrated chip. The register file, foreplay out registers, and SRAM are data address space.2.2.4. I/O featuresGeneral purpose I/O ports are bi-directional. These AVRs has a built in ADC and Analog comparators. In AVR on Chip Debugging (OCD) support through JTAG.The flexible communication in AVR is serial peripheral interface and a two-wire serial interface and these are analog comparators.2.2.5. Applicability of low power techniquesIn this the low voltage is operating down to 1.8v.in this voltage is available and also frequency scaling also provided.2.2.6. menial power sleeps modesIt also fix power sleep modes they are Idle, ADC noise reduction, power-save, power-down, stand by and extended stand by.2.2.7. PipeliningIn this microcontroller each instruction occupies one or two cycles and it also consists of fetch and the execute cycle. It also has single level pipeline design.2.3. MSP430These types of microcontrollers are by Texas instruments. It is one of the lowest power consuming processor in the market at present. It is ideal for wireless applications and embedded systems. The features for MSP430 are explained below.2.3.1. Interrupt structureIn the MSP430 microcontroller interrupt structure provides two timers and a guard dog timer. It is also a power interrupt structure. In this interrupts have fixed priority by ordering.2.3.2. Instruction setThe MSP430 is a 16-bit RI SC processor and it has common RISC features in ISA. in this controller it has 27 core instructions and 7 addressing modes are present. These are having three core instructions format they are operand, operands or a jamp.In this both dedicated stack and stack are available.2.3.3. Memory architectureThese microcontrollers are also uses same space and data as per above discussed controllers. In this the entire ROM and RAM a single 16-bit pointer is used. This processor contains 16-bit register.R0 is a program counter,R1 is a stack pointer,R2 is a stance register and R3 is a special register i.e. nothing but a constant generation.R4 to R15 is for public use.2.3.4. I/O featuresThe host of I/O features are built in msp430.for interfacing devices like radio and transducers it has 10 I/O ports. UART and SPL support are available on the type of models.2.3.5. Applicability of low power techniqueFor low power applications the msp430 is neutral. With the help of its supply voltage supervisor it can sample input voltage and at each time it can set below a software programmable threshold.2.3.6. Low powers sleep modesSix different power modes are available for msp430. Wakeup time is 6micro sec with the use of digital oscillator.2.3.7. PipeliningIt is not a pipelining architecture. There is no pipeline because they have different number of cycles in instruction but the positive is the most instructions run in one cycle which doesnt make the processor too down. The maximum clock frequency is slower when compared to other because of it lack of pipeline and division of instruction cycle.2.4. Comparison between PIC and AVR microcontrollersIn PIC microcontroller the memory architecture requires bank register to approaching 256 bytes of memory but for AVR no need of bank to access the data memory.PIC has only one general purpose register but AVR has 32 general purpose registers.PIC doesnt have SRAM where as AVR has SRAM that the stack is contained at bottom SRAM in order to bu ild the hardware stack.PIC18F and AT Mega having hardware multipliers where as AT Tiny and PIC16F dont having hardware multipliers.PIC is having high clock speed but it is divided by four to give the actual instruction rate. By comparing ATMega128L and MSP430 have rich instruction set and also it has a wide wind of arithmetic instructions sets, many addressing modes. But in PIC18 and 8051 microcontrollers are limited. But PIC16 has add with carry instructions. The MSP430 has 40 digital pins, ATMega128L has 53 pins, PIC18 has 36, and PIC16 33 and 8051 has 37.3. CONCLUSIONThese microcontrollers are the central parts of any kind of sensors nodes. We have different types of microcontrollers in the present market which have almost same feature with the life of battery we can know the lifetime of the node. With the kind of memory access, instructions we known, how the execution of code is performed. The processing task can be done with more complex instructions, allowing more sleeping ti me to the system. It has the ability for self-importance programming which is a useful feature. The efficient code will be generated with a well optimised version. But it doesnt deal well with the accumulator.Finally by comparing these three different microcontrollers MSP family series microcontrollers are snap off than the others. Because, its work better than the older microcontrollers and it completely dominates or rectifies the problem and works.