CAN Delay Module for Long-Distance Bit Reconstruction
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Solution Overview
Problem
In large CAN systems, bit corruption occurs due to overlapping frame transmissions between distant nodes, leading to distorted RXD signals and errors in bit reconstruction, especially with high data rates.
Innovation Solution
A delay module is introduced with a delay unit that detects idle states and delays specific signal changes in the RXD signal to align with reference times, preventing errors in bit reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If nodes are connected over long distances in a CAN system, then system coverage is improved, but bit corruption occurs due to overlapping frame transmissions
Solution Approach 1:
The delay module performs preliminary action by detecting idle states before frame transmissions occur and pre-calculating the required delay time. This allows the system to proactively align signal changes from distant nodes before they reach the receiver, preventing bit corruption rather than correcting it after occurrence
Solution Approach 2:
The delay module acts as an intermediary component between the CAN bus and the receiving node. It intercepts the RXD signal, applies the calculated delay to specific signal changes, and outputs the corrected signal to the CAN controller, thereby mediating the timing conflict caused by long transmission distances
2Speed
If high data rates are used in CAN communication, then transmission speed is improved, but bit corruption increases due to overlapping frames
Solution Approach 1:
The delay module implements dynamic timing adjustment by continuously monitoring idle states and calculating delay times based on actual transmission conditions. The delay value is not fixed but adapts to the specific timing requirements of each frame transmission, allowing the system to maintain high data rates while dynamically preventing bit corruption
Solution Approach 2:
The system changes the timing parameter of the RXD signal by applying a calculated delay to specific signal changes. This parameter modification aligns the timing of frames from distant nodes with the sampling clock, ensuring that high data rate transmissions are reconstructed accurately at the receiver
3Measurement precision
If delay is applied to align signal changes, then bit reconstruction accuracy is improved, but transmission delay increases
Solution Approach 1:
The delay module applies local quality by selectively delaying only specific signal changes (those occurring during idle states) rather than applying a uniform delay to the entire signal. This localized timing adjustment achieves bit alignment precision without introducing unnecessary overall delay to the transmission
Data Source
AI summary
The present disclosure relates to a delay module for a CAN device. The delay module is configured to delay only a single signal change of an RXD signal, wherein the single signal change forms the end of an idle state. Use of the delay module allows a second RXD signal to be generated. The present disclosure further relates to a CAN device comprising two CAN controllers. Each of the two CAN controllers may be provided with one of the two RXD signals. The CAN device may further be configured to detect possible errors based on the decoded bits of the RXD signals. As a result, the CAN device can communicate error-free with both distantly located further CAN devices and closely located further CAN devices, while ensuring a high data rate. The present disclosure also relates to a method for the delay module.