CAN Module Stuff Bit Correction for False Error Detection
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Solution Overview
Problem
Existing CAN bus systems face challenges in preventing false positive error detections due to disturbances on the CAN bus, particularly during the transmission of stuff bits, which can lead to incorrect interpretation of CAN frames.
Innovation Solution
A CAN module is introduced that includes a processing logic capable of identifying bit sequences and stuff bits within the RXD stream. This module manipulates the bit sequences to generate corrected stuff bits that are complementary to their preceding bits, thereby preventing false error detections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stuff bits are transmitted on the CAN bus, then data transmission follows the CAN protocol standard, but disturbances during stuff bit transmission cause false positive error detections
Solution Approach 1:
The system performs preliminary identification of stuff bits before error detection. The processing logic identifies the position of stuff bits in advance based on the bit sequence pattern (five consecutive identical bits followed by a stuff bit), and prepares to correct them before they can cause false error detections. This preliminary action prevents the harmful effect of bus disturbances during stuff bit transmission.
Solution Approach 2:
The system converts the potentially harmful stuff bits into a beneficial feature by using their predictable position and pattern. Instead of treating stuff bits as error sources, the system identifies them by their characteristic pattern (five identical bits + stuff bit) and actively corrects them. This transforms what could be a source of false errors into a known quantity that can be reliably corrected, improving overall transmission reliability.
2Reliability
If the CAN module corrects stuff bits by making them complementary to preceding bits, then false positive error detections are prevented, but additional processing complexity is introduced
Solution Approach 1:
The system changes the state parameter of stuff bits by inverting them (making them complementary to the preceding bit). Instead of complex error detection and correction algorithms, the system applies a simple parameter change - bit inversion - at the identified stuff bit positions. This straightforward parameter transformation effectively prevents false positive errors while maintaining relatively simple processing logic.
Solution Approach 2:
The system creates a corrected copy of the bit sequence with modified stuff bits. Rather than attempting to detect and correct errors in the original sequence through complex analysis, the system generates a corrected version where stuff bits are inverted based on their identified positions. This copying approach simplifies the processing logic while ensuring reliability.
Data Source
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AI summary
The present disclosure relates to a Controller Area Network, CAN, module that can be integrated between a CAN controller and a CAN transceiver. The CAN module comprises a receive data, RXD, input interface for receiving a first bit sequence through a RXD stream and a RXD output interface for sending a manipulated receive data, MRXD, stream including a second bit sequence. A processing logic of the CAN module is configured to manipulate the first bit sequence to generate a second bit sequence comprising a second stuff bit at a second position in the second bit sequence corresponding to a first position of a first stuff bit in the first bit sequence such that the second stuff bit is complementary to a preceding bit of the second stuff bit in the second bit sequence. The present disclosure also relates to a method for the CAN module.