Embedded System Design PDF

Running head: EMBEDDED SYSTEM DESIGN
Embedded System Design
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EMBEDDED SYSTEM DESIGN1
Table of Contents
Introduction:....................................................................................................................................2
Discussion:.......................................................................................................................................3
PIC16F84A..................................................................................................................................3
Instruction set of PIC16F84A:.................................................................................................5
Pin diagram of PIC16F84A:....................................................................................................6
ATMEGA328P............................................................................................................................7
Instruction set of ATMEGA328P overview:...........................................................................8
BIT assignments of ATMEGA328P......................................................................................12
Pin diagram of ATMEGA328P:............................................................................................14
ATMEL89C51...........................................................................................................................15
Block diagram of ATMEL 89C51.........................................................................................17
Pin diagram of ATMEL89C51:.............................................................................................19
Instruction set of ATMEL 89C51:.........................................................................................19
Summary of comparison:...............................................................................................................26
Conclusion:....................................................................................................................................27
References:....................................................................................................................................29

EMBEDDED SYSTEM DESIGN2
Introduction:
Microcontroller or MCU generally refers to the small computer that present on a small
integrated circuit. According to the modern terminology it can be stated that MCU is almost
similar to a system on a chip but it is less sophisticated (Mouha et al. 2014). MCU can be one of
the components of SoC or System on a Chip. A MCU is divided in several parts and this might
include one or more CPUs, associated with a memory and peripherals for input and output. MCU
are generally designed for the embedded applications in contrast to the microprocessors that are
used in the personal computers and any other general purpose applications which consists of the
various discrete chips (Pöppelmann Oder and Güneysu 2015). This report generally compares
the three microcontroller with respect to their Architecture, Instruction sets, Families, Memory,
Peripherals, Speed, Cost, Development tools and Applications.

EMBEDDED SYSTEM DESIGN3
Discussion:
PIC16F84A
Fig 1: Architecture of PIC16F84A
PIC16F84A is an 18-pin enhanced Flash/EEPROM 8-Bit microcontroller paving an RISC
architecture. The basic block diagram of the PIC16F84 microcontroller is given below:

EMBEDDED SYSTEM DESIGN4
Fig 2: Block diagram of PIC16F84A
Program Memory (FLASH): This is used for the purpose of storing a written program. This is
due to the fact that the memory which is made using the FLASH technology can be cleared as
well as programmed more than once (Liu and Großschädl 2014). This in turn makes this type of
microcontrollers very much suitable for the development of a device.
EEROM: This is generally used for the purpose of storing the vital information so as to protect
the data from getting lost whenever there is a sudden stop in the power supply.
RAM: This is the data memory which is generally used during the process of execution. The
RAM also stores all the inter-results as well as the temporary data generated during run-time
(Arends et al. 2017).
PORT A and PORT B: Both of this port act as the physical connection between the external
world and the microcontroller (Lee Kim and Park 2013). Port A consists of 5 pin whereas the
port B consists of 8 pins.
FREE-RUN TIMER: This is the 8-bit register which is present inside the microcontroller which
works independently irrespective of the program (Adewuyi Okelola and Jemilehin 2013). The

EMBEDDED SYSTEM DESIGN5
value gets incremented after each fourth clock of the oscillator and continue to get incremented
unless and until the maximum value is reached i.e. 255. After reaching the maximum value it
again starts from Zero.
CENTRAL PROCESSING UNIT: This is responsible for connecting the different elements
present at the other blocks of the microcontroller (Bates 2013). It is responsible for coordinating
the works of the different blocks along with executing the user programs.
Instruction set of PIC16F84A:
Mnemonics & Operands Description
ADDWF f,d Add contents of W-register and f and store the contents in the
specified address(d)
ANDWF f,d AND the contents of W-register and f and store the contents in
the specified address(d)
CLRF f Clear the contents of f
CLRW Clear the contents of W-register
COMF f,d Compliments the contents of f and stores the result in
d(destination)
DECF f,d Decrement f and store the result in the destination(d)
DECFSZ f,d Decrement f, skip if zero
INCF f,d Increment f and store the result in destination (d)
INCFSZ f,d Increment f, skip if zero
IORWF f,d Incluse OR contents of W-register with contents of f and store
the result in destination(d)
MOVF f,d move the contents of f to destination(d)
MOVWF f Move the contents of W-register to fM
NOP No operation (remains quiet for one cycle)
RLF f,d Rotate left f through carry
RRF f,d Rotate right f through carry
SUBWF f,d Subtract contents of W-register from f