CAN Node Addressing Circuit Using GPIO Level Differentiation
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Solution Overview
Problem
In conventional energy storage systems, two micro-controller units (MCUs) in a cell monitor unit (CMU) cannot independently address each other in the 0.5C project due to identical GPIO pin levels when powered on simultaneously, necessitating the use of two CMU boards to maintain Bill of Materials (BOM) consistency.
Innovation Solution
A circuit and method involving a fuse adapter board with a short-circuited circuit connected to the MCUs, allowing independent addressing by controlling GPIO pin levels through short-circuiting after power-on, enabling each MCU to set distinct CAN addresses based on its GPIO pin level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two MCU1 parts are connected in two CMUs to maintain BOM consistency, then device compatibility is improved, but independent addressing capability deteriorates because GPIO pins both have high level
Solution Approach 1:
The patent applies local quality by making one CMU different from the other through the short-circuited circuit connection. Specifically, the first CMU has its GPIO pin connected to ground through the short-circuited circuit, creating a low level, while the second CMU maintains high level on its GPIO pin. This local differentiation enables independent addressing while keeping the BOM consistent across both CMUs.
Solution Approach 2:
The patent implements asymmetry by creating an asymmetric configuration between the two CMUs through the short-circuited circuit. The first CMU is asymmetrically modified with the short-circuited circuit connection to ground, while the second CMU remains in its standard configuration. This asymmetric design allows the system to distinguish between the two identical MCU1 parts and achieve independent addressing.
2Ease of operation
If pull-down resistor is added to each MCU for separate addressing, then independent addressing is achieved, but device complexity increases
Solution Approach 1:
The patent merges the addressing function into the existing power-on circuitry by using the short-circuited circuit that is already present in the system. Instead of adding separate pull-down resistors to each MCU, the solution combines the addressing differentiation with the power-on connection structure, thereby achieving independent addressing without significantly increasing device complexity.
Solution Approach 2:
The patent uses the existing short-circuited circuit structure and replicates/adapts it for addressing purposes. The short-circuited circuit, originally designed for power-on functionality, is copied and utilized to create the level differentiation needed for addressing, avoiding the need to introduce entirely new circuit elements like additional resistors.
Data Source
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AI summary
A circuit, method and device for addressing CAN nodes are provided. The circuit includes: a fuse adapter board including a short-circuited circuit; a first CMU including a first MCU and a first CAN identification circuit; and a second CMU including a second MCU and a second CAN identification circuit. A first terminal of the first MCU is connected to the fuse adapter board. A second terminal of the first MCU is connected to the first CAN identification circuit. A first terminal of the second MCU is connected to the fuse adapter board. A second terminal of the second MCU is connected to the second CAN identification circuit. The fuse adapter board is connected to the first MCU or the second MCU through the short-circuited circuit, and is configured to control the short-circuited circuit to be shorted to enable a level on a GPIO pin of the first MCU or the second MCU connected to the short-circuited circuit to be a low level, so that the first MCU and the second MCU set their respective CAN addressing based on the respective levels of the respective GPIO pins.