- Published on
KembaraXtra-Computer Science-Bus Communication
Introduction
Introduction
- Explains how the CPU communicates with memory and I/O devices.
- Focuses on the hardware communication system called a "bus."
- A hardware communication system used by computer components.
- Early buses were sets of parallel wires, each carrying an electrical signal (a bit).
- Modern buses can be more complex, but the core principle of data transfer remains.
- Address Bus:
- Selects the specific memory address the CPU wants to access.
- The CPU writes the desired memory address onto the address bus.
- Example: To access address 0x2FE, the CPU writes 0x2FE to the address bus.
- Data Bus:
- Transfers the actual data being read from or written to memory.
- For writing: The CPU writes the data to the data bus.
- For reading: The CPU reads the data from the data bus.
- Example: To write the value 25 to memory, the CPU writes 25 to the data bus.
- Control Bus:
- Manages and coordinates operations across the address and data buses.
- Carries signals indicating the type of operation (read or write).
- Indicates the status of an operation.
- Example: The CPU uses the control bus to signal a "write" operation.
- Scenario: The CPU wants to read the value at memory address 000003F4.
- Steps:
- The CPU writes 000003F4 to the address bus.
- The CPU sets a specific signal on the control bus to indicate a "read" operation.
- The memory controller (circuit managing memory interactions) receives these signals.
- The memory controller retrieves the data stored at address 000003F4 (which is 84 in the example).
- The memory controller writes the value 84 to the data bus.
- The CPU then reads the value 84 from the data bus.
0 Comments