The SEM controller IP is available in six modes:
- Mitigation and Testing
- Mitigation only
- Detect and Testing
- Detect only
- Emulation
- Monitoring
Pick the mode based on your usage and application of the IP. A comparison table is provided at the bottom of the Vivado IDE to help you understand the feature differences between each mode.
If error correction capability is desired, select either the Mitigation and Testing or Mitigation only modes. In these modes, the controller monitors the error detection circuits and reports error conditions. Additionally, it attempts to correct errors that are detected. In general most errors are correctable, and after successful correction, the controller signals that a correctable error has occurred and was corrected. For errors that are not correctable, the controller signals that an uncorrectable error has occurred and goes to Idle state.
The error correction method uses the ECC syndrome to identify the exact location of the error in a frame. The frame containing the error is read, the relevant bit inverted, and the frame is written back. This is signaled as correctable.
If the built-in error correction capability is not desired, select either the Detect, Emulation, or Monitoring modes. In the Detect mode, the IP is in the Detect only state after initialization completes and it continuously scans the configuration memory for SEU errors. After an error is detected, it reports the error and transition to the Idle state without performing any corrections.
In Emulation and Monitoring modes, the IP is in the Idle state after initialization completes and you are not able to enable continuous scan of the configuration memory to detect and correct SEU errors (cannot transition to Observation state).
Independent of the modes, there are error detection and reporting features available from the Idle state that you can command the controller to perform: Detect only and Diagnostic Scan.
Error injection is a design verification function that provides a mechanism for you to create errors in Configuration Memory that model a soft error event. This is useful during integration or system-level testing to verify that the controller has been properly interfaced with system supervisory logic and that the system responds as desired when a soft error event occurs. The error injection feature is not available in the Mitigation only, Detect only, or Monitoring modes.
For a summary of features available in each mode, see Table 1.