1. Open Education Resource-OER on Microprocessor 8085 Instruction Set By Dr. S. N. Sampat, Team leader Ms. R. P. Merchant, Member Mr. A. K. Bilakhia, Member RC-1093 , Group-004, Domain-Electrical and Allied branches Team for OER creation IDP in Educational Technology, IIT Bombay
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

2. Links of OER
Different links of various resources like Video, Quiz, Evaluation strategy, Contact through are available on following URL developed by us*
* Frequent updating activity is being carried out on above URL
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

3. Learning Objectives Define Machine language.
Define Assembly Language and need of assembler.
Define categories of 8085 instructions.
Identify Op Code and Operand of instruction.
Identify Registers used in 8085 instructions.
Identify valid pairs of 8085 registers used in instructions.
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

4. Evaluation Strategy Sr Question Type Mark 1
Multiple Choice Question -MCQ 2
True / False 3
Fill in the gaps
0.5 to 1 4
Brief Subjective
2 to 3 5
Detailed Subjective
4 to 6
Above questions would be placed on URL shown in slide 2
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

5. Introduction
A microprocessor/ microcontroller / DSP executes instructions given by the user’s program.
Instructions should be in a language known to the microprocessor
Microprocessor understands the language of 0’s and 1’s only
This language is called Machine Language.
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

6. Assembler
Microprocessor cannot understand a program written in Assembly language
An Assembler is used to convert Assembly language program to machine language
Assembly
Language
Program
Assembler
Machine
Code
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

7. Instruction
An instruction is a group of binary bits with special meaning and designed as per architecture of microprocessor / microcontroller / DSP to perform a specific function or operation.
8085 has 246 instructions.
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

8. Instruction Instruction consists of op-code and operand.
Op-code is operational code or command by which microprocessor decides which operation should be done.
Operand is either data or an address on which operation is performed . The length of the data or an address is of either 8 or 16 bit.
Example: MOV A,B
MVI A,32H
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

9. 8085 Instruction Category
According to number of bytes occupied in memory
One byte instruction
- includes the op-code and operand in the same byte.
Two byte instruction
- First byte specifies the op-code and second byte specifies operand as either data or an address of 8-bit
Three byte instruction
- First byte specifies the op-code and other two bytes specifies operand as either data or an address of 16-bit
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

10. Register structure and Memory
Microprocessor register structure
Program memory
Data Memory
A (8-bit)
F (8-bit)
B (8-bit)
C (8-bit)
D (8-bit)
E (8-bit)
H (8-bit)
L (8-bit)
PC (16-bit) H
SP (16- bit) FFFE
Address (16-bit)
Data (8-bit)
2000 XX
2001
2002
XXXX
FFFD
FFFE
FFFF
Address (16-bit)
Data (8-bit)
3000 YY
3001
3002
3003
3004
3005
3006
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

11. Instruction Format (One Byte)
Task type
Task
Op-code
Operand
Data transfer
Copy the contents of the source register to destination register
MOV
Rd, Rs
(Rd)=(Rs)
Arithmetic
Add the content of any register to the content of an accumulator and save the result in accumulator
ADD Rs
(A)=(A)+(Rs)
Logical
Complement content of the accumulator
CMA
(A)=(A)’
Here Rd, Rs or A is an address of particular register and ( ) indicates the data of that register
Rs= Source register
Rd= Destination register
R may be A, B, C, D, E, H, L
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

12. Instruction Format (Two Byte)
Task type
Task
Op-code
Operand
Data transfer
Load an 8-bit data in to destination register
MVI
Rd, 8-bit data
(Rd)= 8- bit data
Content of input port can be copied in to an accumulator IN
8-bit port address
(A)=( #port)
Content of an accumulator can be copied to an output port
OUT
( #port) =(A)
Arithmetic
Add 8-bit data to an accumulator
ADI
8-bit data
(A)=(A)+8-bit data
Here Rd or A is an address of particular register as well as #port is an 8-bit address of the port and ( ) indicates the data of that register of port
Rd= Destination register
R may be A, B, C, D, E, H, L
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

13. Instruction Format (Three Byte)
Task type
Task
Op-code
Operand
Data transfer
Load register pair with 16-bit data
LXI
Rp, 16-bit data
(Rp)= 16- bit data
Date transfer
Transfer the program sequence to the 16-bit memory address
JMP
16-bit data address
(PC)= 16-bit data address
Transfer the program sequence to the 16-bit memory address to call subroutine
CALL
(PC)= 16-bit data address (SP)=(SP)-2 ((SP)-1)=(PCh)
((SP)-2)=(PCl)
Here Rp is address of particular register pair as well as ( ) indicates the data of that register pair
Rp = Destination register pair
Rp may be AF, BC, DE, HL
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

14. Classification Of Instruction Set
It can be classified as
Data Transfer Instructions
Arithmetic Instructions
Logical Instructions
Branching Instructions
Control Instructions
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning

15. Thank you all
Four-Week ISTE STTP on Use of ICT in Education for Online and Blended Learning