Lecture Notes: Motherboards and Expansion Slots

Key Components of a Motherboard

• CPU
• Memory
• Storage
• Expansion slots

Communication Between Components

• Components communicate via a bus system.
• Bus: A series of communication paths connecting different components.
• Traces on motherboard: Visible paths that show communication connections.

Expansion Slots and Cards

• Purpose: Add additional functionality to the motherboard.
• Cards must communicate with CPU and memory.

Types of Expansion Slots

PCI (Peripheral Component Interconnect)

• Introduced in 1994.
• Used in older computers.
• Bus Sizes: 32-bit and 64-bit.
  • Parallel Communication: All bits sent simultaneously.
  • 64-bit bus is double the size of a 32-bit bus.
• Voltage support: 3.3 volts and 5 volts.
• Physical Characteristics:
  • 64-bit slots are larger.
  • Slots have keys to ensure correct card insertion.
  • Cards have extra contacts for 64-bit width.
  • Install by aligning card with slot and securing with screw.

PCI Express (PCIe)

• Replaces PCI in newer computers.
• Serial Communication: Different from parallel communication.
• PCI Express lanes: Communication paths used for data transfer.
  • Lanes are marked by x1, x2, x4, x8, x16, x32.
  • Pronounced "by" (e.g., x1 is "by 1").
• More lanes mean higher data transfer capacity.
• Installation:
  • Cards have hooks for secure fitting.
  • Insert correctly and ensure proper alignment.

Installing Expansion Cards

• Align card with slot and press down gently.
• Ensure proper fitting by checking alignment.
• Secure with case screw.

Dual Support Motherboards

• Some motherboards support both PCI and PCIe.
• Provides flexibility and compatibility for various expansion cards.