BMC Multiplexer Reset for Hung I2C Channels
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Solution Overview
Problem
Hung communication channels between a Baseboard Management Controller (BMC) and a multiplexer prevent successful data transmission and reception from connected sensors, as traditional reset methods are ineffective when the communication line is hung.
Innovation Solution
The BMC transmits an I2C command and a stop sequence to an I2C device via a multiplexer, followed by an immediate reset signal to the multiplexer's reset input through the GPIO interface, resetting all registers and deselecting channels to remediate hung channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional reset methods are used to unhanging a hung channel, then the BMC can restore communication capability, but the method is ineffective when the communication line between the BMC and mux is hung
Solution Approach 1:
The patent introduces an intermediary reset mechanism that resets the multiplexer itself rather than attempting to reset individual hung channels through the communication line. By resetting the mux, all channels are simultaneously reset without requiring communication through the hung line, thus resolving the contradiction between reliability and operational effectiveness.
2Productivity
If the BMC transmits I2C commands and stop sequences to I2C devices via the multiplexer, then data communication with sensors is enabled, but hung channels prevent successful transmission and reception
Solution Approach 1:
The patent applies preliminary action by resetting the multiplexer before attempting data transmission. This preliminary reset ensures that all channels are in a known good state before communication begins, preventing hung channel issues from disrupting productivity while maintaining reliable communication.
3Adaptability or versatility
If multiple sensors and devices are connected through a single multiplexer to increase monitoring capacity, then the BMC can monitor more parameters, but a hung channel on one device affects communication with all devices connected to that multiplexer
Solution Approach 1:
The patent segments the communication reset operation by targeting the multiplexer as a separate resettable unit. This allows independent resetting of the mux without affecting the sensors themselves, maintaining adaptability while improving reliability by isolating the communication control function from the sensor devices.
Data Source
AI summary
Technologies are described herein for ensuring remediation of hung multiplexer bus channels between a baseboard management controller (BMC), multiplexer, and I2C device such as a sensor. In particular, a BMC, which is in operative communication with one or more sensors via a multiplexer, comprises an I2C interface and general purpose input/output (GPIO) interface. Upon transmitting an I2C command to the I2C device via the multiplexer and subsequently transmitting a stop sequence to the I2C device via the multiplexer, the BMC then immediately transmits a reset signal to the multiplexer's reset input. When the multiplexer receives the reset signal, it resets all registers and deselects all channels, thereby remediating any hung channels and ensuring the next communication from the BMC is successful.