Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 4/01/2024
Public

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A.4.4. SDM Gated Signals

The HPS-to-FPGA signals are “gated” and “ungated” by the SDM during FPGA configuration events. The SDM gated signals can asynchronously release with respect to each other, which causes an asynchronous relationship with how these are received into the FPGA logic.

As you can see in the diagrams below, sometimes:
  • The h2f_userX_clock is active before the h2f_reset signal (a->b->c)
  • The h2f_userX_clock is active at the same time as the h2f_reset signal (d->e->f)
  • The h2f_userX_clock is active after the h2f_reset signal (g->h->i)

However, in all cases, you can mitigate this issue by using the h2f_gp_out[31:0] signals to release any specific FPGA logic at the appropriate time.

Figure 335. SDM Gated Signals