What are the control methods for information transfer between the host and peripheral devices?

The control methods for information transmission between the host and peripheral devices are: 1. Unconditional transmission, suitable for peripherals that are always in a ready state; 2. Query mode transmission; 3. Interrupt mode transmission; 4. Direct memory access.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

There are four control methods for data transmission between the host and peripherals:

• Unconditional transmission

• Query transfer

• Interrupt mode transfer

• Direct memory access (DMA, Direct Memory Access)

1. Unconditional transmission method

Suitable for peripherals that are always in a ready state

Advantages: Simple software and interface hardware

Disadvantages: Only applicable to simple peripherals, narrow scope of application

2. Query mode transmission

Applicable to peripherals and not always ready , and the requirements for transmission rate and transmission efficiency are not high.

Requirements for peripherals: device status information should be provided

Requirements for interfaces: status ports need to be provided

Advantages: The software is relatively simple

Disadvantages: The CPU efficiency is low, the real-time performance of data transmission is poor, and the speed is slow

3. Interrupt mode transmission

The CPU efficiency is high, the real-time performance is good, and the speed is fast; programming is relatively complex complex.

4. Direct memory access

Data transmission is controlled by DMA hardware. Data is directly exchanged between memory and peripherals, which can reach very high transfer rate (up to several MB/second).

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