This document provides an overview of basic computer organization and design. It discusses memory reference instructions, input/output and interrupts, and the design of a basic computer. The computer consists of a memory unit, nine registers, flags, decoders, buses, and control logic. It describes the control functions for memory reading and writing, register selection, flag manipulation, and arithmetic operations using an adder and logic circuit. The document aims to provide a complete description of the basic components and design of a computer system.

1. BASIC COMPUTER ORGANISATION AND DESIGN
Presented by,
R.RAMADEVI,
I-M.SC(CS&IT)
Nadar Saraswathi College Of Arts And Science, Theni.

2. BASIC COMPUTER ORGANIZATION AND
DESIGN
 MEMORY REFERENCEIN INSTRUCTION
 INPUT OUTPUT AND INTERRUPT COMPLETE COMPUTER DESCRIPTION
 DESIGN OF A BASIC COMPUTER
 DESIGN OF ACCUMULATOR LOGIC

3. MEMORY REFERENCE INSTRUCTIONS
 D7:Register or I/O=1
 D6-D0=7
 Instruction:
 AND TO AC
 ADD TO AC
 LDA : Memory read
STU : Memory write
BUN : branch unconditionally
BSA : branch and save return address
Return address : save return address(13521)

4. SUBROUTINE CALL
0 BSA L35
PC=20
PC=21 NEXT INSTRUCTION
135 21 (return address)
pc=136 subroutine
1 Bun 135

5.  ISZ : increment and skip if zero control flow chart
 flow chart for the 7mmemory reference instruction
 the longest instruction : ISZ(76)
 3 bit sequence counter
INPUT-OUTPUT ANT INTERRUPT
Input-output configuration:
Input register (INPR) output register(OUTR)
 There two register communicate with a communication interface serially and with the AC in
parallel
 Each quantity of information has eight bits of an alphanumeric code
 Input flag(FGI),output flag(FGO)
 FGI : set when INPR is ready clear when INPR is empty
 FGO: set when operation is completed clear when output device is in the process of
printing
INPUT-OUTPUT INSTRUCTION
P=D7IT3,IR(I)=Bi IR(6-11),B6-B11=6 I/O Instruction

6. PROGRAM INTERRUPT
 INPUT-OUTPUT TRANSFER MODE
 Programmed I/O
 Interrupt-initiated I/O
 DMA
 IOP
INTERRUPT CYCLE:
During the executed phare , IEN is checked by the control
IEN=0 the programmer does not want to use the interrupt so control continues
with the next instruction cycle
IEN=1 the control circuit checks the flags bit if (FGI/FGO) FLAG SET TO I,R F/F
Set to 1

7.  At the end of the executed phare control check the value of r
 R=0 instruction cycle *R=1 instruction interrupt cycle
 Demonstration of the interrupt cycle
 The memory location at address 0 as the place for storing the return address
 Interrupt branch to memory location
 Interrupt cycle
Complete computer description:
The final flow chat of the instruction cycle
The control function and microperation
DESIGN OF BASIC COMPUTER
The basic computer consists of the following hardware components
1.A memory unit with 40% word of 16bits
2.Nine register : AR,PC,DR,AC,IR,TR,OUTR,INTR,SC
3. sever F/FS:I,S,E,R,IEN,FGL AND FGO

8. 4.Two decoder in control unit : 3*8 operation decode 4*16 timing decode
5.A 16 bit common bus
6.Control logic gates
7.Address and logic circuit connected to the AC input
control logic gates
 Signal to control the I/O of the nine register
 Signal to control the create write I/O of memory
 Signal to set ,clear or complement the FIFS
 Signal for s2 s1 s0 to select a register for the bus
 Signal to control the AC adder and logic circuit
 Register control :AR

9.  Control Input of AR :LD,INR,CLK
 Control FUNCTION
MEMORY CONTROL :READ
 Control input of memory : READ,WRITE
 Find all the statement that specify a read operation
 control function
F/F CONTROL: IEN
 CONTROL FUNCTION
BUS CONTROL
 Encode for bus selection
s0=x1+x3+x5+x7
s1=x2+x3+x6+x7
s2=x4+x5+x6+x7

10.  control function
 same as memory read
 control function
 memory write

11. ADDER AND LOGIC CIRCUIT

12. THANKYOU!!!