GTS Transceiver PHY User Guide: Agilex™ 3 FPGAs and SoCs
2.6.3.1. I/O PLL in HVIO Bank as System PLL
Below the GTS transceiver bank, there are two HVIO banks (5A/5B) that share a common I/O PLL. This I/O PLL can be used as a second system PLL, but it is limited to the PMA Direct mode in the current release of the Quartus® Prime Pro Edition software.
When you configure the GTS transceiver bank to run PCIe* and non- PCIe* protocols, you must use two system PLLs. Since there is only one system PLL in the Agilex™ 3 device, you must use the I/O PLL from the adjacent HVIO bank. As the I/O PLL support is currently limited, it is not possible to run PCIe* concurrently with other non- PCIe* protocols requiring the use the I/O PLL as a second system PLL in the same design. The I/O PLL support is planned to be expanded in a future release of the Quartus® Prime Pro Edition software.
- HVIO bank 5A
- HVIO bank 5B
- PLLREFCLK1 (5A)
- PLLREFCLK2 (5A)
- PLLREFCLK1 (5B)
- PLLREFCLK2 (5B)
You must consider the following when using the I/O PLL. As the I/O PLL is different from the system PLL, you have to instantiate the I/O PLL using the IOPLL IP instead of the GTS System PLL Clocks IP . Refer to the Clocking and PLL User Guide: Agilex® 3 FPGAs and SoCs for more information. The I/O PLL in the slowest device speed grade is not capable of reaching the system PLL's maximum frequency of 1000 MHz. Refer to the device datasheet for the I/O PLL specifications. Additionally, the I/O PLL does not support the fractional mode.