Shared ACK Link for Variable-Latency Memory Writes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing non-volatile memory systems face challenges in ensuring successful write operations with variable latency and high performance, particularly in reducing system cost and power consumption while maintaining low latency and high throughput for write status acknowledgments.
Innovation Solution
The Advanced Random Access Memory (ARAM) interface architecture introduces a high-performance, low-latency, low-power interface that uses Very Low Swing-Near Ground (VLS-NG) signaling and FlexPhase architecture to minimize power consumption and pin count, enabling efficient communication between the ARAM controller and non-volatile memory devices through scalable CA and DQ lanes, and a sideband ACK link for status reporting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If asynchronous ACK per device is used, then write status acknowledgment is achieved, but system cost increases due to increased pin count
Solution Approach 1:
Multiple ACK signals from different memory devices are merged into a single shared ACK line using wired-OR logic. This allows multiple devices to share one physical pin, reducing the pin count from N separate pins to just 1 shared pin while maintaining the ability to acknowledge writes from all devices.
Solution Approach 2:
The shared ACK line serves multiple functions: it carries acknowledgment signals from multiple different memory devices simultaneously, and can be used by any device that needs to signal write completion. This multi-functional use of a single line reduces overall system complexity.
2Reliability
If polling status bit is used, then write status acknowledgment is achieved, but performance penalty occurs due to increased latency
Solution Approach 1:
The system implements active feedback where memory devices automatically send ACK signals to the controller as soon as write operations complete. This eliminates the need for the controller to continuously poll status bits, providing real-time write status information and reducing the time the controller spends waiting for write completion.
Solution Approach 2:
The ACK signaling mechanism is prepared and available in advance, allowing immediate notification of write completion without requiring proactive polling. The devices are pre-configured to send acknowledgments automatically, so the controller receives status information as soon as it becomes available rather than waiting for poll requests.
3Ease of operation
If traditional signaling is used, then communication is achieved, but power consumption is high
Solution Approach 1:
The signaling system transitions from traditional full-swing voltage levels to very low swing voltage levels near ground potential. This parameter change in voltage amplitude dramatically reduces the energy required for signal transitions while maintaining signal integrity and communication functionality.
Solution Approach 2:
The patent replaces traditional high-power electrical signaling mechanisms with a low-power alternative using wired-OR logic and minimal voltage swings. This substitution eliminates the need for high-current drivers and reduces overall power consumption of the communication interface.
Data Source
AI summary
A memory controller comprises a command interface to transmit a memory command to a plurality of memory devices associated with the memory controller. The memory controller also comprises an acknowledgement interface to receive an acknowledgment status packet from the plurality of memory devices over a shared acknowledgement link coupled between the memory controller and the plurality of memory devices, the acknowledgement status packet indicating whether the command was received by the plurality of memory devices. In addition, the memory controller comprises a memory controller core to decode the acknowledgment status packet to identify a portion of the acknowledgement status packet corresponding to each of the plurality of memory devices.