xSPI Data Strobe Signal for Continuous Read Latency
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Solution Overview
Problem
The Expanded Serial Peripheral Interface (xSPI) bus does not support continuous data reading operations when a slave device is busy, leading to bottlenecks and increased latency in memory device systems, particularly in non-volatile memory devices like NAND flash memory.
Innovation Solution
A device and system configuration that utilizes a data strobe signal to indicate the readiness or busy status of a slave device, allowing the master device to pause or resume data reading operations based on the signal, ensuring efficient data transmission by edge-aligning data packets with the strobe signal and center-aligning them with the clock signal, and using a multiplexer to output the strobe signal accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the xSPI bus is used for data reading operations, then data throughput is improved, but continuous reading operations cannot be supported when slave device is busy
Solution Approach 1:
The slave device provides feedback through the data strobe signal to indicate its readiness status. When the slave device is ready for continuous reading, it outputs an alternating data strobe signal; when busy, it outputs a constant signal. This feedback mechanism allows the master device to adapt its reading operations accordingly, resolving the contradiction between high throughput and continuous operation support.
Solution Approach 2:
The data strobe signal transitions from a static constant level to a dynamic alternating signal to indicate the slave device's operational state. This dynamic signaling enables the master device to detect readiness changes and adjust its reading operations in real-time, supporting continuous reading when the slave is ready while maintaining high throughput.
2Reliability
If data reading operations are paused when slave device is busy, then data transmission errors are avoided, but latency increases
Solution Approach 1:
The slave device prepares data in advance and signals readiness through the alternating data strobe signal before the master device initiates reading operations. This preliminary preparation allows the master device to continuously read data without pausing, as data is already ready in the slave device's buffer, thus avoiding latency while maintaining transmission accuracy.
Solution Approach 2:
By using the alternating data strobe signal to indicate readiness, the system enables continuous data reading operations without interruption. The master device can maintain continuous read operations as long as the slave device outputs the alternating signal, eliminating pauses and reducing latency while ensuring data transmission accuracy through proper synchronization.
3Productivity
If a data strobe signal is used to indicate slave device status, then data transmission efficiency is improved, but signal synchronization complexity increases
Solution Approach 1:
The data strobe signal serves multiple functions: it acts as a clock signal for data sampling, a readiness indicator for continuous reading operations, and a synchronization reference for edge-aligning data packets. This multi-functionality improves transmission efficiency without requiring additional dedicated signals, thereby limiting the increase in synchronization complexity.
Solution Approach 2:
The patent combines the readiness indication function with the existing data strobe signal used for data transmission synchronization. By merging these functions into a single signal mechanism, the system achieves improved transmission efficiency while avoiding the complexity of adding separate readiness signals or synchronization mechanisms.
Data Source
AI summary
Method and apparatus for improving continuous read operations with expanded serial interface are provided. In one aspect, a device comprises: a memory configured to store data; a buffer configured to receive data from outside of the device and transfer the received data to the memory; a plurality of input pins configured to be coupled to an expanded serial peripheral interface (xSPI); and a processor configured to: select a slave device, through the xSPI, from a plurality of slave devices, send instruction data to the slave device for data reading, receive data, through the xSPI, from the selected slave device, and receive a signal on a data strobe line of the xSPI and determine data reading operations based on the received signal.