USART Collision Detection by Comparing Input and Output Signals
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Solution Overview
Problem
Existing microcontrollers with USART peripherals face challenges in detecting serial communication collisions, particularly in full-duplex mode, due to increased complexity and power consumption from dedicated receiver circuits.
Innovation Solution
A serial communication apparatus with a transmitter and collision detection circuitry that compares output and input signals to detect collisions, allowing full-duplex operation by using a port peripheral register or input buffer to obtain input signals and assert a collision indication based on signal differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated receiver circuits are used for collision detection in USART communication, then collision detection capability is improved, but device complexity and power consumption increase
Solution Approach 1:
The input buffer associated with the transmit pad is made multi-functional by using it for both receiving external input signals and providing signals for collision detection comparison. This eliminates the need for a dedicated receiver circuit while maintaining collision detection capability, directly resolving the contradiction between reliability and device complexity
Solution Approach 2:
The system uses its own existing components (transmitter, input buffer, port peripheral register) to perform collision detection without requiring external dedicated receiver circuits. The transmitter's output signal and the input buffer's signal are compared to detect collisions, allowing the system to serve its own detection needs and reducing overall device complexity
2Reliability
If dedicated receiver circuits are used for collision detection in USART communication, then collision detection capability is improved, but power consumption increases
Solution Approach 1:
The input buffer is utilized for dual purposes: receiving external input signals and providing signals for collision detection comparison. This eliminates the need for power-hungry dedicated receiver circuits while maintaining collision detection functionality, directly addressing the power consumption issue
Solution Approach 2:
The collision detection function is achieved by repurposing existing circuit components rather than activating additional power-consuming dedicated receiver circuits. The system uses its own transmitter output and input buffer signals for comparison, reducing overall power consumption while maintaining detection capability
3Device complexity
If collision detection is implemented in half-duplex mode only, then device complexity is reduced, but adaptability to full-duplex mode is limited
Solution Approach 1:
The collision detection mechanism is designed to work with the existing input buffer that is already part of the full-duplex USART structure. By using the input buffer associated with the transmit pad for collision detection, the system maintains compatibility with full-duplex operation without requiring separate half-duplex-specific circuits, thus improving adaptability without significantly increasing complexity
Solution Approach 2:
The collision detection system is designed to be dynamically adaptable to different operating modes. The same comparison mechanism between transmitter output signal and input buffer signal works for both half-duplex and full-duplex modes, allowing the system to transition between modes without hardware changes, thereby improving versatility while keeping device complexity manageable
Data Source
AI summary
A serial communication apparatus is provided. The serial communication apparatus may include a transmitter to transmit data by outputting an output signal, and a collision detection circuitry operatively coupled to the transmitter to receive the output signal. The collision detection circuitry is to receive an input signal from an input buffer, compare the input signal and output signal, and provide a collision indication signal in response to a difference between the output signal and the input signal.