Maximizing Memory Efficiency with User-Controlled Refresh in Intel® Arria® 10 DDR3 External Memory Interfaces
Table of Contents
- Introduction
- Understanding Memory Refresh
- User Control Refresh Option
- Enabling User Control Refresh
- Memory Map Configuration
- User Logic Design
- Initiating User Control Refresh
- Registers for User Control Refresh
- Timing Diagram for Sending Refresh Request
- Conclusion
🖥️ Understanding Memory Refresh
In this article, we will explore the concept of memory refresh and the user control refresh option in the ERA 10 Hack memory controller. Memory refresh is an important operation performed by the memory controller to maintain data integrity. However, with the user control refresh option, we can have more control over when the refresh occurs. This can improve the efficiency of the memory controller by avoiding interruptions during read or write operations.
🔄 User Control Refresh Option
The user control refresh option allows us to determine the timing of memory refresh operations. By having specific knowledge of traffic Patterns, we can strategically schedule the refresh operations to minimize their impact on other operations. This option is not available in the Attend Hot Memory Controller.
⚙️ Enabling User Control Refresh
To enable the user control refresh option, we need to parameterize the memory IP. In the general tab, select the appropriate DDR protocol (DDR3, DDR4, or LPDDR4). Then, in the controller tab and the efficiency section, select the user refresh control option. Enabling this option makes the users responsible for issuing sufficient refresh requests to meet the memory requirements.
📝 Memory Map Configuration
To perform user control refresh, we send a request to the Memory Map Configuration (MMR) interface. The MMR interface is where we create the user logic to communicate with the memory controller. The interface supports both read and write signals for refreshing requests.
💡 User Logic Design
When designing the user logic, we need to ensure that the refresh request is low all the time to support backpressure. It is also crucial to assess the MMR interface only after the clear-to-send signal is successful. This signal indicates that previous operations are complete, allowing us to issue the next refresh request.
📑 Registers for User Control Refresh
The MMR interface exposes registers that we can use to initiate a user control refresh. There are two registers we will utilize:
User Refresh Enable
: Enables or disables the user control refresh. A value of "1" enables the user refresh.
Refresh Request View
: Specifies the refresh request to issue for each rank. The address and bit mappings correspond to specific ranks.
⏱️ Timing Diagram for Sending Refresh Request
To understand the timing of sending a refresh request, we need to follow a specific sequence. First, write to the Conversion User Refresh
register with data 1 0 to initiate a neighbor user refresh. Then, write to the MMR Refresh Request
register with data 1 2 to send a refresh request to the desired rank. We need to wait for 32 clock cycles before checking the MMR Refresh Acknowledge
field. If the refresh operation is in progress, the acknowledge signal will be asserted.
🔚 Conclusion
In conclusion, the user control refresh option in the ERA 10 Hack memory controller allows us to optimize the timing of memory refresh operations based on traffic patterns. By enabling this option and properly configuring the memory IP, we can improve the efficiency of unified base memory controllers. Understanding the MMR interface and following the timing diagram will ensure successful implementation.
Highlights
- Memory refresh is crucial for maintaining data integrity in memory controllers.
- User control refresh option provides more control over the timing of refresh operations.
- Enabling user control refresh improves efficiency by avoiding interruptions during read/write operations.
- Utilizing the Memory Map Configuration (MMR) interface for user logic design.
- Two registers, User Refresh Enable and Refresh Request View, are used to initiate user control refresh.
- Following the timing diagram is essential for sending refresh requests accurately.
FAQ
Q: Which DDR protocols support the user control refresh option?
A: The user control refresh option is supported in DDR3, DDR4, and LPDDR4.
Q: What is the purpose of the Memory Map Configuration (MMR) interface?
A: The MMR interface allows users to create their logic for communicating with the memory controller.
Q: How long should we wait before checking the Refresh Acknowledge field?
A: We should wait for 32 clock cycles before checking the Refresh Acknowledge field.
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