Slave Device Serial Bus Communication Reset Handling
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Solution Overview
Problem
Existing communication establishment protocols over serial buses, such as USB, can be disrupted by false reset signals from dumb chargers, leading to resource depletion and disruption of user applications in slave devices.
Innovation Solution
A slave device processes a reset signal and checks for additional information like synchronization signals before entering a communication state, avoiding false reset interpretations by verifying the presence of signals like chirp K, start of frame, and descriptor packets to differentiate between host device and dumb charger connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the slave device enters communication state upon receiving a reset signal, then communication establishment is initiated, but false reset signals from dumb chargers cause resource depletion and application disruption
Solution Approach 1:
The slave device performs preliminary verification actions by checking for the presence of specific synchronization signals (chirp K, start of frame, descriptor packets) before fully entering the communication state. This preliminary check distinguishes between valid host devices and dumb chargers, preventing unnecessary state changes and resource expenditure on false reset signals while still initiating communication with legitimate hosts.
2Reliability
If the slave device checks for additional information before entering communication state, then false reset signals are differentiated from valid host connections, but the communication establishment process becomes more complex
Solution Approach 1:
The slave device applies local quality checks by verifying specific synchronization signals (chirp K, start of frame, descriptor packets) at particular stages of the communication establishment process. Rather than implementing a completely complex verification system, the patent introduces targeted checks at critical decision points to differentiate between valid and false reset signals, balancing accuracy with implementation complexity.
Data Source
AI summary
In accordance with an aspect of the present invention, a slave device enters a state suitable for establishing communication with a host device only if additional information is received on a serial bus after receiving a reset signal on the same bus. Such a feature may avoid or reduce disruption to applications executing on a slave device when false reset signals are received, for example, when the slave device is connected to a dumb charger on a USB interface for charging.