Visible to Intel only — GUID: lxi1507219182891
Ixiasoft
Visible to Intel only — GUID: lxi1507219182891
Ixiasoft
3.6. User-requested Reset in Intel® Stratix® 10 EMIF IP
Description | |
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Reset-related signals | local_reset_req (input) local_reset_done (output) |
When can user logic request a reset? | local_reset_req has effect only when local_reset_done is high. After device power-on, the local_reset_done signal transitions high after the completion of the first calibration, whether the calibration is successful or not. In subsequent calibration in user mode, the local_reset_done signal transitions high once the calibration is completed. The local_reset_done signal takes more time to transition high in first calibration after device power-on as more operations are required put the PHY into working state. |
Is user-requested reset a requirement? | A user-requested reset is optional. The I/O SSM automatically ensures that the memory interface begins from a known state as part of the device power-on sequence. A user-requested reset is necessarily only if the user logic must explicitly reset a memory interface after the device power-on sequence. |
When does a user-requested reset actually happen? | A reset request is handled by the I/O SSM. If the I/O SSM receives a reset request from multiple interfaces within the same I/O column, it must serialize the reset sequence of the individual interfaces. You should not make assumptions about when the reset sequence will begin after a request is issued. |
Timing requirement and triggering mechanism. | Reset request is sent by transitioning the local_reset_req signal from low to high, then keeping the signal at the high state for a minimum of 2 EMIF core clock cycles, then transitioning the signal from high to low. local_reset_req is asynchronous in that there is no setup/hold timing to meet, but it must meet the minimum pulse width requirement of 2 EMIF core clock cycles. |
How long can an external memory interface be kept in reset? | It is not possible to keep an external memory interface in reset indefinitely. Asserting local_reset_req high continuously has no effect as a reset request is completed by a full 0->1->0 pulse. |
Delaying initial calibration. | Initial calibration cannot be skipped. The local_reset_done signal is driven high only after initial calibration has completed. |
Reset scope (within an external memory interface). | Only circuits that are required to restore EMIF to power-up state are reset. Excluded from the reset sequence are the IOSSM, the IOPLL(s), the DLL(s), and the CPA. |
Reset scope (within an I/O column). | local_reset_req is a per-interface reset. |
Method for Initiating a User-requested Reset
Step 1 - Precondition
Before asserting local_reset_req, user logic must ensure that the local_reset_done signal is high.
As part of the device power-on sequence, the local_reset_done<