Virtual GPIO Over TDM Bus Reducing Pin Count

Solution Overview

Problem

Existing methods for transmitting general purpose input/output (GPIO) signals between integrated circuits (ICs) require dedicated pins and additional circuitry, leading to increased costs and area consumption, and existing virtual GPIO solutions incur overhead in packaging and routing.

Innovation Solution

Implementing virtual GPIO over a time division multiplex (TDM) bus, where raw GPIO signals are directly placed into TDM slots without additional overhead, allowing concurrent transmission to all drops on a multi-drop bus with minimal latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated pins and circuitry are used for GPIO signals, then signal transmission reliability is improved, but device area and manufacturing cost increase

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent reuses existing TDM bus infrastructure (designed for audio/data transmission) to carry GPIO signals, allowing the same physical pins and circuitry to serve multiple functions - both their original purpose and GPIO communication, thereby eliminating dedicated GPIO pins and reducing device area

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates a virtual representation of GPIO signals by encoding them within TDM data frames, where the GPIO information is copied into the TDM stream without requiring physical duplication of dedicated GPIO transmission pathways

Inventive Principle:

Principle #26Copying

2Area of stationary object

If virtual GPIO is implemented over existing buses, then device area is reduced, but communication overhead increases

Engineering Contradiction:

Core Design Contradiction:

Area of stationary objectVSQuantity of substance

Solution Approach 1:

The patent merges GPIO signal transmission with the existing TDM bus communication stream by embedding GPIO data within the TDM frame structure, combining multiple communication functions into a single unified protocol without requiring separate overhead channels

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If message packaging is used for VGI transmission, then protocol compatibility is improved, but transmission latency increases

Engineering Contradiction:

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent utilizes the periodic TDM frame structure to transmit GPIO signals at regular intervals synchronized with the audio/data stream, allowing GPIO information to be conveyed rhythmically within the established periodic communication framework without requiring additional packaging delays

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10511397B2Virtual general purpose input/output (GPIO) (VGI) over a time division multiplex (TDM) bus

Publication Date: 2019.12.17

AI summary

Systems and methods for providing virtual general purpose input/output (GPIO) (VGI) over a time division multiplex (TDM) bus are disclosed. While a SOUNDWIRE bus is particularly contemplated, other TDM buses may also be used to provide the benefits outlined herein. In particular, raw GPIO signals are placed into time slots on a TDM bus without requiring additional overhead or packaging. This arrangement allows all drops on a multi-drop bus to receive the GPIO signals substantially concurrently with latency measured in less than a frame period.