Slave Device Clock Gating with Pre-Decoded Bus Address Activation
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Solution Overview
Problem
Inefficient clock management in microprocessor systems can lead to system crashes and excessive power consumption due to improper activation of clock signals for slave devices, causing hard faults and resource waste.
Innovation Solution
Implementing a clock gating control circuit and clock gating circuits to selectively enable clock signals for slave devices based on pre-decoded instructions and addresses, ensuring proper activation and deactivation according to operational needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If clock signals are turned off for slave devices not in use to save energy, then power consumption is reduced, but system reliability deteriorates due to potential hard faults and system crashes
Solution Approach 1:
The clock gating control circuit pre-decodes instructions and determines clock activation status before the slave device needs to execute operations. This preliminary action ensures that clocks are activated in advance to prevent hard faults while maintaining energy savings by keeping only necessary clocks active.
Solution Approach 2:
The system continuously monitors the operational status of slave devices and adjusts clock gating accordingly. When a slave device is detected as inactive, its clock is gated off to save energy; when activation is needed, the clock gating control circuit activates the appropriate clock signal, creating a feedback loop that balances power consumption and system reliability.
2Loss of energy
If clock gating circuits are added to control clock signals for each slave device, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The clock gating control circuit serves multiple functions: it decodes instructions, determines which slave devices need clock activation, controls clock gating circuits, and prevents hard faults. This multi-functionality reduces the need for separate dedicated control circuits for each slave device, thereby limiting the increase in overall device complexity while achieving energy savings.
3Device complexity
If clock activation is not properly managed before memory access, then system simplicity is maintained, but reliability deteriorates due to hang status and hard faults
Solution Approach 1:
The clock gating control circuit performs preliminary clock activation before the main CPU attempts to access memory of inactive slave devices. This ensures that the necessary clock signals are already active, preventing the main CPU from entering hang status and avoiding hard faults, while maintaining a simple control flow where the CPU只需 output instructions without additional control signals.
Data Source
AI summary
A clock control method for a slave device and a microprocessor system using the same are disclosed. The clock control method for a slave device comprises connecting a microprocessor and a plurality of slave devices via a bus; controlling a clock signal to enable or disable for one of the plurality of slave devices through a corresponding one of a plurality of clock gating circuits; pre-decoding an instruction output by the microprocessor to the bus to obtain an address of the instruction; finding a specific slave device corresponding to the address from the plurality of slave devices; and when one of the plurality of clock gating circuits corresponding to the specific slave device is not enabled, enabling the one of the plurality of clock gating circuits so that the specific slave device operates normally to receive the instruction.