Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Cyclone IV pin connection Guide line make confuse

Hi all, I am using document number PCG-01008- 1.3 (pin connection guide line of Cyclone IV) as main reference for board design. In Clock and PLL Pins section, there is Connection Guidelines: "In C...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

In my opinion, the cyclone IV device manual is very clear about the required coupling for the GX transceiver reference clock. It requires AC coupling for all source IO standards, except for PCIe HCSL, that is DC coupled. See e.g. Volume 2, page 1-22, Table 1–5. REFCLK I/O Standard Support.

If the DC coupled clock on the DevKit is not HCSL standard, it would in fact contradict the manual.