CDCAM Specification Tab - CDCAM Specification Tab - 2.0 English - PG468

DRAM Semi-Ternary CAM 2.0 LogiCORE IP Product Guide (PG468)
Document_ID
PG468
Release_Date
2026-01-30
Version
2.0 English
CAM Mode
The pull-down menu options are: BCAM and STCAM. Depending on the option selected, the available configuration parameters vary.
BCAM
Selects the Binary Content Addressable Memory. Refer to Cached DRAM Binary CAM LogiCORE IP Product Guide (PG427).
STCAM
Selects the Semi-Ternary Content Addressable Memory. The following figure shows the configuration parameters when STCAM is selected. Refer to this document.
Figure 1. STCAM Configuration Parameters Generated by Your Tool
Number of Entries
The supported number of entries (depth). The number of entries is limited by the number of RAM instances available in the target device.
Note: NUM_ENTRIES represent number of usable entries. When targeting a certain memory depth for a CAM, specify 95% of the target. For example, to get a CAM with memory of depth 4K, specify NUM_ENTRIES = 0.95 × 4096 = 3892.
Important: For LPM Mode, NUM_ENTRIES represents a fixed number of keys. The actual number of keys that fit can be up to eight times higher. It is recommended to set NUM_ENTRIES = keys/2.
Key Width
The width of the lookup key (in bit).
Format String
See Format String section.
Response Width
The width of the lookup response.
Default Response
Specify the Default Response value when Lookup has no match. Valid range is between 1 to 1024 bits specified in Hex. The value is set to zero by default.
Number of Masks

The number of unique masks. The Vivado CAM compiler generates a STCAM supporting both the specified number of unique masks and the specified number of entries at the same time.

Note: This parameter is not available for LPM mode because the number of masks is automatically derived from the width of prefix field.
Automatically Calculated
The Vivado CAM compiler calculates the appropriate value based on Number of Entries.
Priority Width
Note: This parameter is only available for STCAM.
The priority is usually defined wide enough to support one unique priority value per entry. The width can be larger to facilitate easier management or narrower if entries are order independent and guaranteed not to overlap.
Automatically Calculated
When this check box is selected, the Vivado CAM compiler automatically calculates the appropriate value based on Number of Entries. You can override this by deselecting this check box and specifying the appropriate value.