Memory Card Detection Circuit Using Latch Circuits for Ground Bounce
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Solution Overview
Problem
Conventional memory card detection circuits face inefficiencies due to ground bounce delays and require multiple counters, leading to increased complexity and cost in chip design.
Innovation Solution
A memory card detection circuit utilizing latch circuits to rapidly identify ground bounce and generate query signals for card type recognition, eliminating the need for waiting periods and reducing hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the memory card detection circuit waits for the de-bounce period to resolve ground bounce before measuring voltages, then measurement accuracy is improved, but detection time increases
Solution Approach 1:
The latch circuit captures and stores the voltage state of the query pin during the ground bounce period before the de-bounce period completes. This preliminary action allows the system to record the voltage information early without waiting for the full de-bounce period, thereby reducing detection time while maintaining measurement accuracy through the latch's ability to hold the captured state.
2Measurement precision
If multiple counters are used to calculate specific periods for voltage measurement control, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The invention extracts the period calculation function from the voltage measurement control path by using the latch circuit to capture voltage states independently of the de-bounce period timing. This separation removes the need for multiple counters to coordinate voltage measurement with specific time periods, thereby reducing circuit complexity while maintaining the ability to accurately determine memory card type through the latched voltage states.
3Measurement precision
If multiple counters are implemented for voltage measurement control, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The latch circuit serves as a simple, low-cost alternative to multiple counters. The latch captures the essential voltage information during the ground bounce period and holds it for reading, providing sufficient detection accuracy without the high manufacturing cost of implementing multiple counter circuits. This substitution maintains functional adequacy while significantly reducing component count and production expense.
Data Source
AI summary
The invention provides a memory card detection circuit of a computer. The memory card detection circuit comprises a plurality of query pins through which a memory card is coupled to the computer and a plurality of latch circuits respectively coupled to each of the query pins. The latch circuits generates query signals indicating whether ground bounce occurs in the voltage of the query pins due to a voltage difference between two ends of the query pins shortly after the memory card is coupled to the computer through the query pins. The query signals identify the type of the memory card without waiting until ground bounce is resolved.