Hybrid Memory Cube Controller IP Core User Guide - Intel Stratix 10 Beta Version

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ID 683854
Date 8/08/2016
Public
Document Table of Contents
Document Table of Contents x
1. About the Hybrid Memory Cube Controller IP Core 2. Getting Started with the HMC Controller IP Core 3. Functional Description 4. HMC Controller IP Core Signals 5. HMC Controller IP Core Register Map 6. HMC Controller IP Core Stratix 10 Design Example A. HMC Controller IP Core User Guide Archives B. Additional Information
1. About the Hybrid Memory Cube Controller IP Core x
1.1. HMC Controller IP Core Supported Features 1.2. HMC Controller IP Core Supported HMC Transaction Types 1.3. Device Family Support 1.4. IP Core Verification 1.5. Performance and Resource Utilization 1.6. Device Speed Grade Support 1.7. Release Information
1.4. IP Core Verification x
1.4.1. Simulation
2. Getting Started with the HMC Controller IP Core x
2.1. Installing and Licensing Intel® FPGA IP Cores 2.2. Specifying IP Core Parameters and Options 2.3. HMC Controller IP Core Parameters 2.4. Files Generated for Intel FPGA IP Cores 2.5. Integrating Your IP Core in Your Design 2.6. Simulating Intel FPGA IP Cores
2.1. Installing and Licensing Intel® FPGA IP Cores x
2.1.1. Intel® FPGA IP Evaluation Mode
2.3. HMC Controller IP Core Parameters x
2.3.1. RX Mapping and TX Mapping Parameters
2.5. Integrating Your IP Core in Your Design x
2.5.1. Pin Constraints 2.5.2. Required External Blocks
2.5.2. Required External Blocks x
2.5.2.1. Adding the External PLL 2.5.2.2. Adding the External I2C Master Module
3. Functional Description x
3.1. High Level Block Diagram 3.2. Interfaces Overview 3.3. Clocking Structure 3.4. Initialization and Reset 3.5. M20K ECC Support 3.6. Flow Control 3.7. Error Detection and Management 3.8. Testing Features
3.2. Interfaces Overview x
3.2.1. Application Interfaces 3.2.2. HMC Interface 3.2.3. Interface to External I2C Master 3.2.4. Control and Status Register Interface 3.2.5. Status and Debug Interface 3.2.6. Transceiver Control Interfaces
3.2.6. Transceiver Control Interfaces x
3.2.6.1. External PLL Interface 3.2.6.2. Transceiver Reconfiguration Interface
4. HMC Controller IP Core Signals x
4.1. Application Interface Signals 4.2. HMC Interface Signals 4.3. Signals on the Interface to the I2C Master 4.4. Control and Status Register Interface Signals 4.5. Status and Debug Signals 4.6. Clock and Reset Signals 4.7. Transceiver Reconfiguration Signals 4.8. Signals on the Interface to the External PLL
4.1. Application Interface Signals x
4.1.1. Application Request Interface 4.1.2. Application Response Interface 4.1.3. HMC Controller IP Core Data Path Example
5. HMC Controller IP Core Register Map x
5.1. CONTROL Register 5.2. XCVR_STATUS Register 5.3. LANE_STATUS Register 5.4. LINK_STATUS Register 5.5. ERROR_RESPONSE Register 5.6. LIMIT_OUTSTANDING_PACKETS Register 5.7. Interrupt Related Registers 5.8. Error and Retry Statistics Registers
B. Additional Information x
B.1. HMC Controller IP Core User Guide Revision History
1. About the Hybrid Memory Cube Controller IP Core
2. Getting Started with the HMC Controller IP Core
3. Functional Description
4. HMC Controller IP Core Signals
5. HMC Controller IP Core Register Map
6. HMC Controller IP Core Stratix 10 Design Example
A. HMC Controller IP Core User Guide Archives
B. Additional Information

5.6. LIMIT_OUTSTANDING_PACKETS Register

Table 27.  HMC Controller IP Core LIMIT_OUTSTANDING_PACKETS Register at Offset 0x1C
Bits Field Name Type Value on Reset Description
31 Enable RW 0x0 Writing the value of 1 to this register field turns on the Limit Outstanding FLITs feature. When this feature is turned on, the IP core limits the number of FLITs in outstanding response packets, to the threshold specified by the MaxRspPktFlit field. The effect of turning on this feature is that the IP core does not send requests to the HMC if the expected responses would exceed the threshold.

Whether the feature is on or off, the IP core sends request packets to the HMC only if retry buffer space and tokens are available. The client is responsible to send requests on the data path request interface only if the client is able to receive the expected response at any time. The IP core can backpressure a data path request interface by deasserting the dp<n>_req_ready signal. If the Limit Outstanding FLITs feature or the Response Open Loop Mode feature prevents the IP core from sending request packets to the HMC, the IP core deasserts the dp<n>_req_ready signal.

30:10 Reserved RO 0x000000
9:2 MaxRspPktFlit RW 0x00 Specifies the maximum number of FLITs if the Limit Outstanding FLITs feature is turned on. The threshold value is four times the value of this register field.

The typical value for this register is 150. However, given your design's traffic pattern and system configuration, you may want to adjust this value for better throughput or latency. A lower value reduces the latency but can degrade the RX throughput. Use the lowest value that results in acceptable throughput.

1:0 Reserved RO 0x0
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