Memory Bus Initialization Using Lane-Skew Frame Alignment
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Solution Overview
Problem
As memory devices operate at higher speeds, traditional multi-drop and even point-to-point architectures face challenges with timing skew between command, address, and data signals, leading to complex and costly initialization requirements in processor-based systems.
Innovation Solution
A system and method utilizing a dedicated memory channel with a daisy-chain configuration and phase-lock loop (PLL) to synchronize and align frame packets, clock signals, and data across memory devices, allowing for efficient initialization and minimizing complexity in host controllers and memory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If point-to-point configurations are used to achieve high data transfer rates, then data transfer rate is improved, but timing skew between signals increases
Solution Approach 1:
A dedicated memory channel acts as an intermediary between the host controller and memory devices, providing a controlled communication path that manages timing relationships. The channel includes synchronization mechanisms that mediate the timing between command, address, and data signals, reducing skew while maintaining high transfer rates.
Solution Approach 2:
Initialization procedures are performed in advance before normal memory operations begin. The host controller executes initialization sequences that configure timing parameters and establish synchronization protocols, preparing the system to handle high-speed operations with minimized timing skew from the outset.
2Manufacturing precision
If complex initialization circuitry is added to memory devices to handle timing skew, then timing precision is improved, but device complexity increases
Solution Approach 1:
The initialization and timing management functions are segmented between the host controller and memory devices. The host controller handles complex initialization sequences and timing adjustments, while memory devices execute predefined routines. This division reduces the initialization circuitry needed within each memory device while achieving the required timing precision.
Solution Approach 2:
Memory devices are designed to autonomously execute initialization routines and timing calibration procedures without requiring complex external control circuitry. The devices self-configure their timing parameters based on signals from the host controller, reducing the need for additional initialization circuitry within the devices themselves.
3Reliability
If initialization procedures are implemented in both host controller and memory devices, then timing synchronization is improved, but system cost increases
Solution Approach 1:
Initialization and timing management functions are merged into the dedicated memory channel protocol rather than being implemented as separate hardware circuits in both host and devices. The channel protocol encapsulates timing synchronization logic, achieving reliable synchronization while reducing overall system complexity and cost compared to having independent initialization circuitry throughout the system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables cost-effective initialization of memory systems with high-speed buses, reducing complexity and latency by aligning frame boundaries and clock signals, thus improving data transfer rates and system performance.
Implementation Method 1
A system and method utilizing a dedicated memory channel with a daisy-chain configuration and phase-lock loop (PLL) to synchronize and align frame packets, clock signals, and data across memory devices
Data Source
AI summary
Systems, controllers and methods are disclosed, such as an initialization system including a controller that receives patterns of read data coupled from a memory device through a plurality of read data lanes. The controller is operable to detect any lane-to-lane skew in the patterns of read data received through the read data lanes. The controller then adjusts the manner in which the read data received through the read data lanes during normal operation are divided into frames. The controller can also couple patterns of command/address bits to the memory device through a plurality of command/address lanes. The memory device can send the received command/address bits back to the controller through the read data lanes. The controller is operable to detect any lane-to-lane skew in the patterns of command/address bits received through the read data lanes to adjust the manner in which the command/address bits coupled through the command/address lanes during normal operation are divided into frames.