Multiplexer for APIX to CSI Tx Bridge
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Solution Overview
Problem
Current systems face challenges in efficiently transmitting multiple video streams from an Automotive Pixel Link (APIX) interface to a Camera Serial Interface (CSI) Tx, particularly due to differences in data packetization and clocking, leading to increased pin-count and electromagnetic interference (EMI) issues.
Innovation Solution
A system comprising a multiplexer and control logic that reads data from buffers at a fixed frequency clock, combining data streams into a single input stream for CSI Tx, allowing operation in high-speed mode for video transmission and low-power mode for data intervals, reducing the need for multiple CSI Tx interfaces and minimizing EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple CSI Tx interfaces are used to transmit multiple video streams, then transmission capability is improved, but pin-count increases and EMI issues worsen
Solution Approach 1:
The patent combines multiple video stream transmissions into a single CSI Tx interface by implementing a multiplexer that time-division multiplexes multiple data streams. This merging approach maintains the transmission capability for multiple video streams while reducing the number of physical interfaces and pins required, directly resolving the contradiction between productivity and device complexity.
Solution Approach 2:
The patent employs periodic time-division multiplexing where different video streams are transmitted in alternating time slots through the single CSI Tx interface. The multiplexer periodically switches between different data streams based on timing signals, enabling multiple streams to share the same interface without interference, thus maintaining transmission capability while reducing pin-count.
2Productivity
If multiple CSI Tx interfaces are used to transmit multiple video streams, then transmission capability is improved, but electromagnetic interference worsens
Solution Approach 1:
By merging multiple video stream transmissions into a single CSI Tx interface through time-division multiplexing, the patent reduces the number of high-speed serial interfaces operating simultaneously. This consolidation decreases the overall electromagnetic radiation and interference in the system, resolving the contradiction between transmission capability and EMI.
Solution Approach 2:
The periodic time-division multiplexing scheme ensures that only one data stream is actively transmitted at any given time through the single CSI Tx interface. This temporal separation prevents simultaneous signal transmissions that would cause electromagnetic interference, while still enabling multiple video streams to be transmitted over the same interface at different time intervals.
3Adaptability or versatility
If data is read from buffers at varying clock frequencies, then data transfer flexibility is improved, but synchronization complexity increases
Solution Approach 1:
The patent changes the clock frequency parameter to a fixed value for reading data from all buffers. By using a uniform fixed-frequency clock signal for all buffer read operations, the system maintains data transfer flexibility through the multiplexer while eliminating the synchronization complexity that would arise from coordinating multiple varying clock frequencies across different buffers and interfaces.
Data Source
AI summary
A system for receiving at least two data streams and providing a single input data stream to a MIPI's CSI Tx is disclosed. The two received data streams are written into respective data buffers. The system includes a control logic configured to control reading of data stored in the buffers to a multiplexer, the read-side clock being a multiple of a frequency of a fixed frequency clock. The control logic is further configured to control the multiplexer to combine data read from each buffer that corresponds to a complete unit of data into a separate portion and multiplex the separate portions into the input data stream. In this manner, two data streams may be transmitted using a single CSI Tx. When the two data streams are received by the system from an APIX interface, the system provides a bridge between the APIX interface and MIPI's CSI Tx.