The document is an introduction to peripheral interfacing in electronics, explaining the role of I/O modules as intermediaries between the CPU and external devices. It discusses the necessity of I/O modules due to differences in data transfer rates, formats, and speed between the CPU and peripherals. Additionally, it outlines the communication process facilitated by I/O modules between the processor and its connected devices.

1. Hello!
I am Tahrimur Rahman
My
Roll: 12102907
Session: 2011-12
3rd year 2nd semester
Dept. of Electronics and Communication Engineering
J.K.K.N.I.U.

2. Peripheral Interfacing

3. Outline:
My process is easy & simple
What?
A intruduction
Why?
Necessary
How?
Mechanism

4. What?
Peripheral
It means various components or devices
those are connected to CPU. Actually these
are input output devices. Thus, it sometimes
calls as I/O devices.
Interface
An interface is a concept that refers to a point of
interaction between objects or components and
is applicable at the level of both hardware and
software.
Thus PHERIPHERAL INTERFACING is a kind of interaction between processor and external or
peripheral devices.
To interface physically, a component or mediator between I/O device and processor is used which is
called I/O module.

5. “
Now a question may arise. Can’t we connect /
interface directly the I/O devices to processor ?
No!

6. ◇ I/O devices are most of case usually electrical/ mechanical/ electronic
devices where processor is an electronic device. Also the data
transfer rates of I/O are often slower than the processor and
memory. So it is significant that the speed and electrical
characteristics of I/O are different from CPU.
◇ There are a variety of peripherals that exist and may need to be
connected to the same system bus. But it may be difficult to
incorporate all the peripheral device logic into CPU. This reduces
flexibility and creates hinderance in new developments.
◇ Peripheral often use different data formats and word lengths that
used by the CPU
Incorporation of I/O module helps to overcome these problems.
Why?
There are several reasons which lead to use I/O module:

7. Thus, we can say that
First
An I/O module is a mediator
between the processor and an I/O
device/devices.
Second
It controls the data exchange
between the external devices and
main memory; or external devices
and CPU registers.
Fourth
The I/O module should not only
communicate the information
from CPU to I/O device, but it
should also coordinate these two.
Fifth
In addition since there are speed differences between CPU and I/O
devices, the I/O module should have facilities like buffer (storage
area) and error detection mechanism.
Third
An I/O module provide an
interface internal to the computer
which connects it to CPU and
main memory and an interface
external to the computer
connecting it to external device or
peripheral.

8. How?
An I/O module at one end is
connected to the system
bus (information
transmission cable) of
processor and at the other
end may be connected with
a number of I/O devices. It
conveys the information
from I/O device (Sometimes
called as peripheral or
external device) to
processor and vice versa.

9. A simplified block diagram of I/O module
An I/O module is not simply a set of mechanical
connectors that wire a device into the system bus.
Rather, the I/O module contains logic for
performing a communication function between the
peripheral and the bus.
Working functions:
1. CPU checks I/O module device status
2. I/O module returns status
3. If ready, CPU requests data transfer
4. I/O module gets data from device
5. I/O module transfers data to CPU

10. “
Same processor
Various flexible structures of I/O devices
New Era

11. Thanks!
Any questions?
You can find me at:
◇ www.facebook.com/tahrimur-rahman
◇ tahrimurrahman@gmail.com