The document describes the basic functions and components of a computer. It discusses the processor, memory, input/output modules, and how they interact. It also covers the fetch-execute cycle, how interrupts work, and how the computer handles multiple interrupts.

1. COMPUTER FUNCTION
T S PRADEEP KUMAR
Assistant Professor (SG)
VIT University – Chennai Campus
http://www.pradeepkumar.org
tspembedded@gmail.com

2. Computer Specifications
Processor Core i3
Variant 370M
Clock Speed 2.4GHz
Cache 3MB L2 Cache
System Memory 2GB DDR3
Graphics Processor Intel HD Graphics
Hard Disk 500GB SATA Disk
Ports RJ45, HDMI, USB, COM, ThunderBolt
Network Wi-Fi 802.11, Bluetooth

3. Random Access Memory (RAM)

4. Processor

5. Cache Memory

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Computer Function

7. Computer Function
• Program Counter
• Contains the address of the next Instruction
• Instruction Register
• Contains the address of the current instruction
• Memory Buffer Register (MBR)
• contains the data to be written into memory or receives the data
read from memory.
• Memory Address Register (MAR)
• specifies the address in memory for the next read or write

8. Computer Function
• I/O Address register
• specifies a particular I/O device
• IO Buffer register
• is used for the exchange of data between an I/O module and the
CPU.
• Memory Module
• consists of a set of locations, defined by sequentially numbered
addresses.
• IO Module
• An I/O module transfers data from external devices to CPU and
memory, and vice versa. It contains internal buffers for temporarily
holding these data until they can be sent on..

9. Computer Function
• Processor-memory
• Data may be transferred from processor to memory or from memory to
processor.
• Processor-I/O
• Data may be transferred to or from a peripheral device by transferring
between the processor and an I/O module.
• Data processing
• The processor may perform some arithmetic or logic operation on
data.
• Control
• An instruction may specify that the sequence of execution be altered.
For example, the processor may fetch an instruction from location 149,
which specifies that the next instruction be from location 182. The
processor will remember this fact by setting the program counter to
182.Thus, on the next fetch cycle, the instruction will be fetched from
location 182 rather than 150.

10. Computer Function

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Instruction Fetch and Execute

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Instruction Fetch and Execute

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Interrupts and their effects
• Classes of Interrupts
• Program
• Generated by some condition that occurs as a result of an instruction
execution, such as arithmetic overflow, division by zero, attempt to
execute an illegal machine instruction,
• Timer
Interrupts generated by the OS to take some special actions
• I/O
• Generated by the I/O Controllers like signals, errors, etc
• Hardware Failure
• Power failure or memory parity error

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Interrupts and Instruction Cycle

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Interrupts and Instruction Cycle

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Interrupts and Instruction Cycle

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Sequential Interrupts

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Nested Interrupts

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Time Sequence of Multiple Interrupts

20. CONTINUED…..