CAN Controller DMA Selective Message Transfer
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Solution Overview
Problem
In data processing devices equipped with CAN controllers, the CPU load and system bus traffic increase due to the need to transfer all received messages, including sensor information and diagnostic results, which are not always necessary, leading to inefficiencies in processing and communication.
Innovation Solution
A data processing device with a CAN controller that includes a receive buffer and a DMA controller, which selectively transfers only the latest messages with specific IDs to memory, reducing CPU load and system bus traffic by using a direct memory access mechanism to manage message transfer based on predefined rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all received messages are transferred to memory area, then CPU can access all necessary data, but CPU load and system bus traffic increase
Solution Approach 1:
The patent extracts only the necessary information (latest sensor values with specific IDs) from the complete message set and transfers just those to memory, rather than transferring all messages. This selective extraction reduces the data volume transferred to memory, thereby reducing CPU load and system bus traffic while maintaining access to required data.
Solution Approach 2:
The patent applies partial action by transferring only a subset of messages (those with specific IDs representing latest sensor values) rather than all received messages. This partial transfer approach reduces the burden on CPU and system bus while still providing sufficient data for processing purposes.
2Reliability
If all received messages are transferred to memory area, then CPU can process all data, but system bus traffic increases
Solution Approach 1:
The patent extracts only the necessary information (latest sensor values with specific IDs) from the complete message set and transfers just those to memory, rather than transferring all messages. This selective extraction reduces the data volume transferred to memory, thereby reducing CPU load and system bus traffic while maintaining access to required data.
Solution Approach 2:
The patent applies partial action by transferring only a subset of messages (those with specific IDs representing latest sensor values) rather than all received messages. This partial transfer approach reduces the burden on CPU and system bus while still providing sufficient data for processing purposes.
3Loss of information
If all sensor information is transferred, then CPU has complete data, but unnecessary data transfer occurs
Solution Approach 1:
The patent extracts only the necessary information (latest sensor values with specific IDs) from the complete message set and transfers just those to memory, rather than transferring all messages. This selective extraction reduces the data volume transferred to memory, thereby reducing CPU load and system bus traffic while maintaining access to required data.
Solution Approach 2:
The patent applies partial action by transferring only a subset of messages (those with specific IDs representing latest sensor values) rather than all received messages. This partial transfer approach reduces the burden on CPU and system bus while still providing sufficient data for processing purposes.
Data Source
AI summary
A data processing device includes a first CPU (Central Processing Unit), a first memory, a CAN (Controller Area Network) controller and a system bus coupled to the first CPU, the first memory and the CAN controller, wherein the CAN controller comprises a receive buffer that stores a plurality of messages each of which has a different ID, and a DMA (Direct Memory Access) controller that selects the latest message among messages having a fist ID stored in the receive buffer and transfers the selected latest message to the first memory, wherein the message is one of CAN, CAN FD and CAN XL messages.