Visible to Intel only — GUID: lsu1513706130945
Ixiasoft
Visible to Intel only — GUID: lsu1513706130945
Ixiasoft
6.2.1. Clock Signals
Signal | Direction | Description |
---|---|---|
ext_core_clk | Input | Core clock. Output of user-instantiated I/O PLL. The HBM2 IP does not instantiate the I/O PLL required to generate the ext_core_clk. When the core clock frequency is one-half of the HBM2 interface frequency, the reference clock that drives the core I/O PLL must come from the same oscillator as that supplying the UIB PLL reference clock on the board for a given HBM2 interface. Failure to follow this guideline can result in calibration not completing successfully or the AXI bus locking up. Although you can set the core clock frequency to a maximum of one-half of the memory clock, Intel® recommends not exceeding the recommended core clock limits presented in Table 9 to avoid potential timing closure problems. |
ext_core_clk_locked | Input | LOCKED status of I/O PLL driving ext_core_clk, indicating the ext_core_clk is stable. This I/O PLL should achieve LOCKED status within 1ms of device configuration for calibration to be successful. The I/O PLL driving the ext_core_clk cannot be reset after calibration is completed. |
pll_ref_clk | Input | LVDS reference clock input for UIB PLL. This reference clock must be provided through dedicated UIB_PLL_REF_CLK_p/n pins available in Stratix® 10 devices and cannot be provided through an internal I/O PLL. The pll_ref_clk must be stable and free-running at device power-up for successful configuration. Refer to Stratix® 10 pin connection guidelines for information on how to supply these clocks. |
wmc_clk_x_clk | Output | Core clock output feedback from UIB, based on ext_core_clk provided, one per HBM2 Channel (represented by x). Intel® recommends that the user interface drive the AXI interface for the corresponding channels with this clock. |
phy_clk_x_clk | Output | UIB PHY clk output. Not supported. Leave unconnected. This signal appears as phy_clk_x conduit in the Platform Designer. |
Clocking recommendations for Reliable Calibration of the HBM2 Interface
Observe the following clock guidelines for reliable calibration of the HBM2 interface:
- The UIB PLL reference clocks (one per HBM2 interface) must be provided through an external clock source and must be stable and free running prior to configuration and stable thereafter.
- The I/O PLL driving the core clock (ext_core_clk) should achieve a LOCKED condition within one millisecond of device configuration. This I/O PLL cannot be reset once the interface is calibrated.
- For a given HBM2 interface, Intel® recommends that the same clock source provide the reference clocks for both the I/O PLL and the UIB PLL.