Impedance-Based Flow Control for Two-Wire Virtual GPIO
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Solution Overview
Problem
Conventional GPIO systems require a large number of pins for inter-processor communication (IPC), which increases manufacturing costs and limits GPIO availability for other system-level peripheral interfaces, and existing flow control methods necessitate additional pins, contributing to higher pin counts and costs.
Innovation Solution
A virtual GPIO architecture that uses a two-pin interface with impedance-based flow control, where virtual GPIO signals are serialized over a UART transmit pin, and flow control is multiplexed over these two pins, eliminating the need for separate Request to Send (RTS) and Clear to Send (CTS) pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional GPIO systems are used for inter-processor communication, then communication functionality is achieved, but the number of pins required increases manufacturing costs and limits GPIO availability for other interfaces
Solution Approach 1:
The patent combines multiple GPIO signals and flow control signals into a single serialized data stream transmitted over one wire. The transmitter merges the GPIO signal with flow control signals (RTS/CTS) into a unified serial communication protocol, eliminating the need for separate dedicated pins for each function.
Solution Approach 2:
The single communication wire serves multiple functions: transmitting GPIO signals, carrying flow control information, and enabling bidirectional communication. The system uses the same physical medium for data transmission and flow control signaling, making the interface more versatile while reducing pin count.
2Reliability
If separate RTS and CTS pins are added for flow control, then flow control capability is improved, but the pin count and manufacturing cost increase
Solution Approach 1:
The patent merges flow control signals (RTS and CTS) with the main data transmission channel. The flow control information is encoded within the serialized data stream itself, allowing the system to achieve reliable flow control without adding separate dedicated pins for RTS and CTS.
Solution Approach 2:
The patent introduces a serial communication interface as an intermediary that handles both data transmission and flow control functions. This intermediary layer processes and manages flow control signals within the serialized stream, eliminating the need for direct separate physical connections for flow control.
3Quantity of substance
If virtual GPIO architecture with two-pin interface is used, then pin count is reduced, but the complexity of signal serialization and flow control multiplexing increases
Solution Approach 1:
The patent replaces the mechanical approach of using separate physical pins for each signal with an electronic/software-based serialization process. The complexity is shifted from physical wiring to digital signal processing, where firmware or software handles the serialization and flow control multiplexing algorithms.
Solution Approach 2:
The patent changes the operational parameters of the communication interface by implementing variable frame lengths and dynamic impedance adjustment. These parameter changes allow the system to optimize the balance between simplicity and functionality, managing complexity through configurable parameters rather than fixed complex hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the number of pins required for IPC communication, lowers manufacturing costs, and allows for efficient communication without the need for additional flow control pins, while maintaining low power consumption and compatibility with existing processors.
Implementation Method 1
the transmit buffer charges a transmit pin to a power supply voltage through a high output impedance
Implementation Method 2
impedance-based flow control, where virtual GPIO signals are serialized over a UART transmit pin
Data Source
AI summary
A two wire interface is disclosed that serializes messaging signals and GPIO signals into frames transmitted over a transmit pin. The two wire interface is configured to perform flow control by monitoring a voltage for the transmit pin.