Why do the number of I/O pins listed in the Stratix V, Arria V and Cyclone V handbooks for each device variant, differ from the user I/O value provided in the Quartus II software?

Description

The Stratix® V, Arria® V and Cyclone® V handbooks list the total number of General Purpose I/O (GPIO) available for given device variants. This number does not include the number of Transceiver I/O available.

The Quartus® II design software however includes the Transceiver I/O along with the GPIO, in it's total user I/O count, for each device variant.

These device families are offered in multiple configurations where the general purpose I/O count is the same, but the number of Transceiver I/O differs depending upon the number of Transceivers in that device variant. It is therefore advised to use the Quartus II software to decipher the total number of I/O available in a device, including Transceiver I/O.