sameeksha-embedded-system presentation1
TRANSCRIPT
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Presentation
OnSummer Training Project Report
titled asEMBEDDED SYSTEMS
BySAMEEKSHA RUSTAGI
O7-ECE-197
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EMBEDDED SYSTEMS
Embedded systems are combination of computerH/W and S/W, and perhaps additional mechanicalor other parts, which are designed usingmicroprocessor or microcontroller but for a specifictask to perform a dedicated function.
In some cases, ES may be part of a larger system
One of the critical needs of embedded system is todecrease power consumptions and space whichcan be done by integrating more functions on theCPU chip
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EMBEDDED SYSTEMS
ES generally use microcontroller thatcontains many functions of computer ona single device
Motorola and Intel make some of themost popular microcontrollers
Contrast this with a Pentium based PC
which cannot be regarded as anembedded system as it is used toperform multiple tasks
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EMBEDDED SYSTEM
DEVICES PLANT CONTROL
Robots
Industrial Process controlAirplane control System
Missile Guidance System
AUTOMOTIVE
Engine Controller
Anti-brake lock controller
CONSUMER ELECTRONICS
Microwave Ovens
Digital Cameras
DVD Player
Washing Machine
TELECOMMUNICATIONSwitches
Cellular Phones
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Percentage share of various verticals inEmbedded Software market
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VARIOUS MICROCONTROLLERS
1) 8031 MICROCONTROLLER
It is an Intel product
It is an 8 bit microcontroller
Internally no ROM is provided
2)8051 MICROCONTROLLER
It is the 1st complete 8 bit microcontroller It has the same instruction set, pin configuration and
architecture, only the memory storage capacity is different
Internally PROM is provided so it is called one timeprogrammable (OTP)
3)AT89C51 MICROCONTROLLER
It is an Atmel product
It is an 8 bit microcontroller.
Internally EPROM is provided
It is multiple time programmable (MTP) i.e app 1000 times
Hence it is better than 8051 microcontroller
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Some features that make 8051 popular
8-bit data bus
16-bit address bus
34 general purpose registers each of8 bits
16 bit timers (usually 2, but may have more, orless).
3 internal and 2 external interrupts.
Bit as well as byte addressable RAM area of16 bytes.
Four8-bit ports, (short models have two 8-bitports).
16-bit program counter and data pointer
Internal RAM of 128 bytes
Internal ROM of 4Kb
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PIN DIAGRAM OF 8051
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On chip memory
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It has four parts on which it can be explained :
Register banks- R0,R1,R2 and R4are basically used to manipulate data from one memory to another memory
place.
BIT MEMORY
gives the user the ability to access a number ofbit variables.
There are 128 bit variables available to the user, numbered 00h through 7Fh
GENERAL PURPOSE REGISTERSuse to store memory addresses and data
SPECIAL FUNCTION REGISTER(SFR)
Special Function Registers (SFRs) are areas of memory that control specificfunctionality of the 8051 processor . Four SFRs permit access to the 8051s 32
input/output lines .
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SFR
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VARIOUS REGISTERS
1) A Register (Accumulator)
Its a general purpose register used for
storing intermediate results during operation
2) B Register
It is used in multiply and divide operations which areperformed only upon nos stored in A & B registers. All other
instructions use it as a spare accumulator3) R Registers (R0 to R7)
its a common name for 8 general purpose registers whichare stored in 4 banks in the scope of RAM
4) PSW Registers (program status word)
It is one of the most imp SFR which contains several statusbits that reflect the current state of the CPU. It contains carry bit,auxiliary carry, 2 register bank select bits, overflow flag, paritybit and status flag
4) DPTR Register ( data pointer)
Its used for storing data and results that have nothing to dowith memory locations
5) SP Register
It is used to point to a valid RAM address and permits stackavailability
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TIMER
The 8051 comes equipped with two timers, both of
which may be controlled, set, read,
and configured individually. The 8051 timers havethree general functions:
1) Keeping time and/or calculating the amount of time
between events,
2) Counting the events themselves,
3) Generating baud rates for the serial port.
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Timer SFRs
The805
1 has two timers which each function essentiallythe same way. One timer is TIMER0 and the other is
TIMER1.
The two timers share two SFRs
(TMOD and TCON) which control the timers.
Each timer also has two SFRs, dedicated solely to itself
(TH0/TL0 and TH1/TL1).
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Timer SFRS
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TIMER MODES
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TMOD SFRS
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TCON SFRS
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Interrupt
An interrupt is some event which interrupts normal
program execution
Interrupts give us a mechanism to put on hold the
normal program flow, execute a subroutine, and thenresume normal program flow as if we had never left it
Subroutine called an interrupt handler, is only
executed when a certain even occurs.
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8051 Microcontroller Interrupts
There are five interrupt sources for the805
1, whichmeans that they can recognize 5 different event that can
interrupt regular program execution.
Event may be one of the timersoverflowing,receiving a
character via the serial port,trasmitting a character via
the serial port or one of the two external events
Each interrupt can be enabled or disabled by setting bits
in the IE register. Also, as seen from the picture below
the whole interrupt system can be disabled by clearing
bit EA from the same register.
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IE SFR
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INTERRUPT HANDLING
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SERIAL INPUT/OUTPUT PORT
One of the 8051s many powerful features is its integrated UART,otherwise known as a serial port. The fact that the 8051 has anintegrated serial port means that you may very easily read and writevalues to the serial port. If it were not for the integrated serial port,writing a byte to a serial line would be a rather tedious processrequiring turning on and off one of the I/O lines in rapid succession
to properly "clock out" each individual bit ,including start bits, stopbits, and parity bits. However, we do not have to do this. Instead, wesimply need to configure the serial ports operation mode and baudrate. Once configured, all we have to do is write to an SFR to write avalue to the serial port or read the same SFR to read a value fromthe serial port.
The 8051 will automatically let us know when it has finished sending
the character we wrote and will also let us know whenever it hasreceived a byte so that we can process it. We do not have to worryabout transmission at the bit level--which saves us quite a bit ofcoding and processing time.
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SCON SFR
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THANK YOU
BY SAMEEKSHA RUSTAGI