Asynchronous Serial Communication Baud Rate Adjustment
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Solution Overview
Problem
Existing asynchronous serial communication methods face issues with accurate data transmission and reception due to clock rate deviations, leading to incorrect reading of data parts and stop parts, especially when the baud rate is not precisely matched between transmitting and receiving devices, and require costly fine-tuning of clocks and external transistors to improve frequency precision.
Innovation Solution
A communication device and system that utilize a receiving unit, measuring unit, and transmitting unit to measure and adjust pulse widths of low and high data output intervals, allowing for correct data transmission and reception by synchronizing the baud rate based on these measurements, even with clock deviations, and simplifying the configuration by using a 1-bit low data output interval for the start part and a 1-bit high data output interval for the stop part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional asynchronous serial communication is used with fixed baud rate, then the communication protocol is simple, but data transmission accuracy deteriorates when clock rate deviations occur
Solution Approach 1:
The patent implements dynamic baud rate adjustment by measuring the actual pulse width of received data and calculating a correction value. The receiving unit dynamically adjusts the baud rate based on the measured pulse width difference from the expected value, allowing the system to adapt to clock rate deviations and maintain accurate data transmission without requiring complex fixed-rate synchronization mechanisms.
2Reliability
If clock fine-tuning and external transistors are used to improve frequency precision, then data transmission accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements self-service by having the receiving unit automatically measure the actual pulse width of received data, calculate the baud rate correction value, and adjust the reading timing accordingly. This eliminates the need for external clock fine-tuning mechanisms or additional transistors, as the system self-corrects frequency deviations through software-based pulse width measurement and adjustment.
Solution Approach 2:
The patent replaces mechanical clock tuning mechanisms with an electronic/software-based solution. Instead of using physical clock adjustment circuits or external transistors to fine-tune frequency, the system uses digital pulse width measurement and mathematical calculation to determine and adjust the baud rate, substituting hardware complexity with software-based correction.
3Device complexity
If 1-bit start part with low data output interval is used, then the communication protocol is simplified, but synchronization becomes more difficult with clock deviations
Solution Approach 1:
The patent implements feedback by having the receiving unit measure the actual pulse width of the received data, compare it with the expected pulse width, calculate a correction value, and use this feedback to adjust the reading timing. This feedback mechanism allows the system to maintain synchronization accuracy even with the simplified 1-bit start part structure, as the actual timing information from the received data is used to correct any deviations.
Data Source
AI summary
The present disclosure provides a communication device configured to perform serial communication using an asynchronous serial communication. The communication device includes: a receiving unit, configured to receive a received data comprising an order of a start part including a 1-bit low data output interval, a data part started with a rising and a stop part; a measuring unit, configured to measure a pulse width in an interval including the low data output interval; and a transmitting unit, configured to transmit a transmission data at a baud rate based on a pulse width measured by the measuring unit.