PWM Continuous Clock SPI Interface With Synchronized Clocking

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Solution Overview

Problem

Existing serial communication interfaces, such as SPI, operate synchronously and require a separate clock signal, which can limit flexibility and efficiency in data transmission.

Innovation Solution

A PWM-based continuous clock serial interface is implemented using a microcontroller with an SPI circuit and a PWM generator, where the PWM signal is synchronized with the SPI clock signal to provide a continuous clock and data communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate clock signal is used for SPI communication, then synchronous data transmission is achieved, but device complexity and wiring requirements increase

Engineering Contradiction:

Improvesynchronous data transmissionVSAvoidseparate clock signal requirement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the clock signal generation and data transmission functions into a single PWM output channel. The PWM signal's duty cycle variations encode both clock timing and data information, eliminating the need for separate clock and data lines that would otherwise be required in traditional SPI communication.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The PWM output channel is made multi-functional by using it to carry both clock synchronization and data transmission responsibilities. By modulating the duty cycle of the PWM signal, the same output pin serves dual purposes: providing timing reference and conveying data, thereby reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If traditional SPI interface is used, then reliable data communication is achieved, but CPU bandwidth consumption increases

Engineering Contradiction:

Improvedata communicationVSAvoidCPU bandwidth consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system implements self-service by using the PWM peripheral's built-in capabilities to handle both clock generation and data encoding. The PWM module autonomously manages timing and data output through duty cycle modulation, reducing the need for CPU intervention and lowering CPU bandwidth consumption while maintaining reliable communication.

Inventive Principle:

Principle #25Self-service

3Duration of action of stationary object

If PWM signal is used for clock output, then continuous clock is provided, but synchronization with SPI clock signal becomes challenging

Engineering Contradiction:

Improvecontinuous clockVSAvoidsynchronization requirement

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The system employs feedback mechanisms where the PWM generator is configured to operate in synchronization mode with the SPI clock source. The PWM module monitors the SPI clock signal and adjusts its output accordingly, ensuring that the continuous PWM clock remains synchronized with the SPI timing requirements through automatic phase and frequency alignment.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250119132A1PWM-based continuous clock serial interface

Publication Date: 2025.04.10 TEXAS INSTRUMENTS INC

AI summary

A circuit includes a microcontroller having a clock output and a data output. The microcontroller includes a serial-peripheral interface (SPI) circuit, a pulse-width modulation (PWM) generator, and a central processing unit (CPU). The SPI circuit is configured to provide an SPI clock signal and an SPI data signal to the data output. The PWM generator is configured to provide a continuous PWM signal to the clock output. The CPU is coupled to the SPI circuit and the PWM generator, and the CPU has executable instructions configured to synchronize the PWM signal to the SPI clock signal.