Latch Circuit Device for In-Vehicle Microcomputer Port Sampling
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Solution Overview
Problem
In multifunctional in-vehicle devices, the limited number of input ports in microcomputers can lead to issues with inputting all required signals, and there is a problem with signal values changing during the transition from a sleep state to an active state, resulting in inappropriate signal input.
Innovation Solution
A latch circuit device with a detection circuit to identify input signals during the sleep state, a wake-up circuit to transmit a wake-up signal, a sampling circuit to read the signals, a transmission circuit to send the signals to the microcomputer after wake-up, and a release circuit to clear the latch state, allowing for efficient input of multiple signals using serial communication and reducing the number of occupied input ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If parallel-serial conversion is used to input multiple signals, then the number of input ports required is reduced, but signal values may change during the transition from sleep state to active state resulting in inappropriate signal input
Solution Approach 1:
The latch circuit latches the input signal in advance during the sleep state before the microcomputer returns to the active state. This preliminary action ensures that the signal value is captured and held stable, preventing any changes that would occur during the state transition, thus resolving the reliability issue while maintaining reduced port usage
2Use of energy by moving object
If the microcomputer remains in sleep state to save energy, then energy consumption is reduced, but input signals may change during the sleep period causing signal loss
Solution Approach 1:
The latch circuit performs preliminary latching of the input signal during the sleep state, capturing the signal value before the microcomputer wakes up. This ensures the signal is preserved and transferred to the data register upon wake-up, preventing signal loss while maintaining energy savings during sleep
Solution Approach 2:
The latch circuit acts as an intermediary between the input port and the microcomputer during sleep state. It holds the signal value stable and transfers it to the data register when the microcomputer is ready, preventing direct signal changes from affecting the sleeping microcomputer while ensuring no information is lost
Data Source
AI summary
A latch circuit device includes: a latch circuit configured to latch an input signal to a microcomputer; a detection circuit configured to detect that the input signal is input to the latch circuit during a sleep period in which the microcomputer is in a sleep state; a wake-up circuit configured to transmit a wake-up signal to the microcomputer when an input of the input signal is detected during the sleep period; a sampling circuit configured to read the input signal from the latch circuit; a transmission circuit configured to transmit the input signal read by the sampling circuit to the microcomputer returned from the sleep state based on the wake-up signal; and a release circuit configured to release a latch state of the latch circuit after the input signal is read.