RPU Configuration Options - 2025.1 English - UG1304

Versal Adaptive SoC System Software Developers Guide (Versal AI Edge Series Gen 2 and Versal Prime Series Gen 2) (UG1304)
Document ID
UG1304
Release Date
2025-06-23
Version
2025.1 English

The following table and figure describe the six configuration options of the RPU.

Table 1. RPU Configuration Options
Configuration Option Description Core Running
Option 1: Split mode High-performance mode.

In this configuration, all the four real-time cores work independently, each using separate TCMs.

 RPU Cluster 0: RPU core 0 and RPU core 1

RPU Cluster 1: RPU core 0 and RPU core 1
Option 2: Split mode, only one core used High-performance mode.

In this configuration, RPU core 0 can be held in reset, while RPU core 1 runs independently in both the clusters using all 256 KB of TCM.

 Only RPU core 1 in both RPU clusters 0 and 1
Option 3: Lock-step mode Safety mode.
Note: The lock-step mode is typically used for safety-critical deterministic applications.

In this configuration, both cores in each cluster run in parallel with each other, with integrated comparator logic. The RPU core 0 initiates the transaction and core 1 is the checker.

In both clusters 0 and 1, RPU core 1 operates as redundant copies RPU core 0.

The TCM is combined to give RPU core 0 a larger TCM.

Each core executes the same code. The inputs and outputs of the two cores are compared. If they do not match, the comparator detects an error.

While two cores are used, the performance is of one core.

 Only RPU core 0 in both clusters 0 and 1
Option 4: Lock-step mode and split mode only core used Safety mode
In this configuration, each cluster can independently be set to split or lockstep mode.
Note: Changing of the lockstep/split mode only necessitates the cluster that is involved to be reset.

RPU cluster 0 in lockstep mode, and RPU cluster 1 in split mode with either single core and dual cores used.

 RPU cluster 0: RPU core 0

RPU cluster 1: RPU core 0 and RPU core 1 (in dual cores), or RPU core 1 only.
Option 5: Split mode only one core used and Lock-step mode Safety mode
In this configuration, each cluster can independently be set to split or lockstep mode
Note: Changing the lockstep/split mode requires that the cluster that is involved to be reset.

RPU cluster 0 in split mode with either single core or dual cores used, and RPU cluster 1 in lockstep mode.

 RPU cluster 0: RPU core 0 and RPU core 1 (in Dual cores), or RPU core 1 only.

RPU cluster 1: RPU core 0
Option 6: None RPU is not used. None
  1. RPU core 0 TCM is the tightly coupled memory associated with Cortex-R52 core 0 core in split mode; RPU core 1 TCM is the tightly-coupled memory associated with the RPU_0 core in split mode.
  2. RPU core 1 TCM is located slightly farther from the cores than RPU core 0 TCM, so there might be a slightly longer delay when cores access RPU core 1 TCM versus RPU core 0 TCM.

RPU cores can use the system watchdog timer (SWDT) to monitor functionality and check performance through a periodic write to a timer register.

Note: For Versal Prime Series Gen 2 and Versal AI Edge Series Gen 2 devices RPU configuration is same for all 5 clusters. Refer to Figure 1 for possible configuration in each R52 cluster.

Refer to RPU Subsystem Interconnect Diagram in Versal AI Edge Series Gen 2 and Prime Series Gen 2 Technical Reference Manual (AM026)