01 Intro

What happens when we switch on computer¶

1. BIOS(Basic Input Output System) loaded from the ROM(Read-Only Memory)
2. BIOS loads OS into the RAM RAM should atleast be the size of the OS
3. OS loads programs from disk to RAM Program: set of instructions executed by \(\mu p\)

What is an instruction?¶

Tells the MP what actions to perform

• operations
  • logic
  • arithmetic
• read data from input device
• write to memory
• reset
• stop

Assembly program gives these instructions. Each microprocessor understands these instructions in different ways.

High-level program use statements which get compiled/interpreted into machine language. Allows programmer focus on the logic, rather than worrying about how it will understood by the MP.

Microprocessor¶

has both sequential and combinational circuits

• Control unit has sequential circuits
• ALU has combinational circuits

Size of the processor = size of ALU

Instruction-Handling¶

Instructions is a set of command, used by the mp to perform to certain taks

1. Fetch Instruction Instruction taken from the memory and stored in instruction register
2. Decode Instruction
3. Fetch Operand(s)
4. Execute Cycle actions are performed
5. Store result

Make this into block diagram

• BIU - Bus Interface Unit
• ALU - Arithmetic Logic Unit
• Execution Unit

Overview¶

Microcontrollers like Arduino have the memory also embedded to the processor

Detailed¶

Architectures¶

Instruction Set Architecture¶

This is the design/theory

1. Execution Model
2. Processor Register
3. Address and Data Formats

Microarchitecture¶

This is the hardware components

1. Interconnections between elements
2. ALU
3. Data Path
4. Control Path

MPU vs MCU¶

	MPU MicroProcessor Unit	MCU MicroController Unit
CPU Clock rate	> 1 GHz	1 MHz - 0.4 GHz
Memory location	External	Internal
Memory capacity	> 0.5 GB	2 KB - 512 KB
Storage location	External	Internal
Storage capacity	> 64 GB	32 KB - 2 MB
I/O	External	Internal
Peripherals	External	Internal
No glue logic/software needed	❌	✅
Power Consumption	Higher > 30W	Lower \(\rm{150 \micro W - 23.5 mW}\)
Size	Large	Small
Design flexibility	✅	❌
Use	Computer system	Embedded system
Other names		SOC (System on a chip) Embedded controller Computer on a chip

Types of Microprocessors¶

x86 Family¶

• CISC
• Instructions are broken into \(\micro\) operations

8086 has 1MB capacity

8086 (Tut)¶

Byte-organised

We represent the address of each location in 5bit hex \(00000H \to FFFFFH\)

If we need to store 16bits of data

• we need 2 bytes
• so we will require 2 contigious memory locations

Memory Addressing¶

Each range of addresses is allocated for different **segments **of registers

• Code segment
• Data segment
• Stack segment
• Extra segment
• Instruction pointer

If CS = 10000 and offet = 0002, then DS = 10002

Internal Cache¶

a small and fast SRAM memory attached to the processor, for pre-fetching data

Registers¶

IDK¶

The reason we're left-shifting by 1 digit is because

• Address is to be 20 bits (5hex digits)
• Pointer we want to hold 16bits (4 hex digits) because the blocks in x86 architecture

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