HART Modem Interface Using Break Extension Over Fewer UART Lines
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Solution Overview
Problem
HART-enabled devices face challenges with high cost and complexity due to the need for multiple signals to account for UART and SPI interfaces, which is not efficiently addressed by conventional techniques.
Innovation Solution
The implementation of a break extension protocol using a reduced set of UART communication lines (UART TXD and RXD) to support both UART and SPI communications, reducing the number of communication lines required and simplifying the HART-enabled device architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional techniques use multiple signals for UART and SPI interfaces, then communication functionality is complete, but device complexity and cost increase
Solution Approach 1:
The UART communication lines are designed to serve dual purposes: traditional UART communication and SPI communication. The break extension protocol enables the same TXD and RXD lines to carry both UART data and SPI control signals, allowing a single communication interface to perform multiple functions that would traditionally require separate dedicated lines for each protocol.
Solution Approach 2:
The patent merges UART and SPI communication protocols into a single communication channel using the break extension protocol. By combining the protocol handling capabilities into one unified interface, the system eliminates the need for separate physical communication lines for UART and SPI, thereby reducing overall system complexity while maintaining full communication functionality.
2Reliability
If high cost isolation circuits and HART software stack are used, then UART and SPI interface issues are addressed, but device cost increases
Solution Approach 1:
The HART modem is designed with universal communication capability, able to handle both UART and non-UART (SPI) protocols through the break extension protocol. This multi-functional design eliminates the need for separate isolation circuits and software stacks for different protocols, reducing component count and overall device cost while maintaining reliable communication for both interface types.
3Adaptability or versatility
If more than 10 signals are used for MCU interface, then UART and SPI communications are supported, but complexity and cost increase
Solution Approach 1:
The MCU interface is designed with universal signal lines that can operate in multiple modes. The TXD and RXD lines can dynamically switch between UART communication mode and SPI communication mode based on the protocol being used, allowing the same physical signals to support both UART and SPI protocols without requiring additional dedicated signal lines for each protocol.
Solution Approach 2:
The patent merges the signal requirements for UART and SPI protocols into a unified set of communication lines. By combining the protocol handling into a single interface using the break extension protocol, the system reduces the total number of signals from more than 10 to just the essential TXD and RXD lines, thereby significantly reducing interface complexity.
Data Source
AI summary
A current loop includes a receiver assembly and a transmitter assembly. The current loop also includes: a first conductor between the receiver assembly and the transmitter assembly; and a second conductor between the receiver assembly and the transmitter assembly to complete the current loop. The transmitter assembly includes: a Highway Addressable Remote Transducer (HART) modem; a component in communication with the HART modem via a partial set of Universal Asynchronous Receiver-Transmitter (UART) communication lines; and a break extension protocol controller coupled to or included with the HART modem and configured to support UART and non-UART communications between the HART modem and the component using the partial set of UART communication lines.