Academic Session 2025-26
ODD Semester Jul-Dec 2025
UNIVERSITY INSTITUTE OF ENGINEERING
DEPARTMENT OF COMPUTER SCIENCE &
ENGINEERING
BACHELOR OF ENGINEERING
CSE/IT/ THIRD SEMESTER
COMPUTER ORGANIZATION & ARCHITECTURE
(24CST-201/24ITT-201)
Unit No. 3 Chapter No. 3.1 Lecture No. 3.1.3
Topic : Modes of Transfer-Programmed I/O
Er. Shikha Atwal (E11186) Assistant Professor
, Learning Objectives
1
1. To understand the working of Programmed I/O, where
the CPU actively checks device status and controls data
transfer.
2. To learn how data is transferred between I/O devices and
CPU using polling techniques without interrupt or DMA
support.
3. To analyze the limitations of Programmed I/O in terms of
CPU efficiency and its suitable use cases in simple
embedded systems.
, Content
2
1. Modes of Transfer
2. Programmed I/O
3. Programmed I/O Mode Input Data Transfer
4. Programmed I/O Mode Output Data Transfer
5. I/O Commands
6. I/O Instruction
7. Isolated and Memory Mapped I/O
ODD Semester Jul-Dec 2025
UNIVERSITY INSTITUTE OF ENGINEERING
DEPARTMENT OF COMPUTER SCIENCE &
ENGINEERING
BACHELOR OF ENGINEERING
CSE/IT/ THIRD SEMESTER
COMPUTER ORGANIZATION & ARCHITECTURE
(24CST-201/24ITT-201)
Unit No. 3 Chapter No. 3.1 Lecture No. 3.1.3
Topic : Modes of Transfer-Programmed I/O
Er. Shikha Atwal (E11186) Assistant Professor
, Learning Objectives
1
1. To understand the working of Programmed I/O, where
the CPU actively checks device status and controls data
transfer.
2. To learn how data is transferred between I/O devices and
CPU using polling techniques without interrupt or DMA
support.
3. To analyze the limitations of Programmed I/O in terms of
CPU efficiency and its suitable use cases in simple
embedded systems.
, Content
2
1. Modes of Transfer
2. Programmed I/O
3. Programmed I/O Mode Input Data Transfer
4. Programmed I/O Mode Output Data Transfer
5. I/O Commands
6. I/O Instruction
7. Isolated and Memory Mapped I/O
