MIPI D-PHY Turnaround Time Reduction via Low-Power Command Sequences
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Solution Overview
Problem
The MIPI D-PHY interface's high turnaround time constrains real-time configuration of devices during interpacket gaps, and existing solutions are prone to data transmission errors due to lack of bit error identification in the PHY layer during high-speed transmission.
Innovation Solution
A specified low-power command sequence is used to modify the MIPI D-PHY interface protocol, reducing turnaround command duration by implicitly signaling the turnaround command with a sequence of two low-power signaling states (LP10, LP00) during low-power mode operation, allowing for faster and more reliable mode transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the specified sequence of low-power mode commands (LP10, LP00, LP10, LP00) is used for turnaround procedure, then the turnaround direction can be swapped, but the turnaround time increases to approximately 550ns-650ns which constrains real-time configuration capability
Solution Approach 1:
The patent applies preliminary action by performing the turnaround procedure during interpacket gaps before the next data transmission begins. The slave device sends turnaround data during the gap between master device packets, allowing the turnaround to be completed in advance without extending the overall transmission timeline. This is achieved by utilizing the idle time between master transmissions to perform slave-to-master communication.
Solution Approach 2:
The patent implements dynamics by making the turnaround procedure adaptive to the interpacket gap duration. The slave device dynamically adjusts its turnaround data transmission to fit within the available interpacket gap, and the master device dynamically switches between receiving normal data packets and receiving turnaround data based on detection of turnaround indicators. This dynamic adaptation allows the system to maintain real-time configuration capability while ensuring reliable turnaround execution.
2Loss of time
If turnaround command is sent in high-speed transmission sequence, then the turnaround time is reduced, but data transmission errors occur due to lack of bit error identification in the PHY layer
Solution Approach 1:
The patent uses an intermediary approach by introducing a low-power mode command sequence as a mediator between the high-speed data transmission and the turnaround procedure. Instead of directly embedding turnaround commands in the high-speed stream, the system transitions to low-power mode for the turnaround command sequence, which provides robust error detection capabilities. This intermediary low-power mode acts as a buffer that ensures reliable command transmission while maintaining overall fast turnaround performance.
Solution Approach 2:
The patent applies periodic action by using a specified sequence of low-power mode commands (LP10, LP00, LP10, LP00) for the turnaround procedure. This periodic pattern of voltage transitions provides inherent error detection capability, as any deviation from the expected pattern indicates potential errors. The rhythmic nature of the command sequence allows the receiving device to verify correct reception through pattern matching, ensuring reliability while maintaining fast turnaround.
3Productivity
If the master device transmits continuous high-speed data packets, then data transmission speed is maximized, but the slave device cannot perform real-time configuration updates during transmission
Solution Approach 1:
The patent applies segmentation by dividing the communication timeline into distinct segments: master-to-slave data transmission segments and slave-to-master turnaround configuration segments. These segments are separated by interpacket gaps where the slave device can perform configuration updates. The segmentation allows both high-speed data transmission and real-time configuration to occur without interference, as they are allocated to different time segments within the overall communication cycle.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that the slave device can continuously perform configuration updates during every interpacket gap, while the master device continuously transmits data packets. Neither device experiences idle time - the master is always transmitting data, and the slave is always either receiving data or performing configuration updates during gaps. This continuous utilization of resources maximizes both productivity and adaptability simultaneously.
Data Source
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AI summary
A system, method, and apparatus are provided for operating a device to receive a first signaling state sequence on a multi-wire interface within a first voltage range to cause the device to transition to a high-speed communication mode for receiving high-speed data on the multi-wire interface within a second, smaller voltage range before returning to a low-power communication mode when the device receives on the multi-wire interface a second sequence of two signaling states within the first voltage range to signal a turnaround command without requiring any additional signaling state within the first voltage range, where the turnaround command enables the device to transmit data from the device over the multi-wire interface by transmitting on the multi-wire interface the first sequence of signaling states within the first voltage range to cause the device to transition to a high-speed communication mode for transmitting data from the device over the multi-wire interface.