Knowledge Base Article
Error (18108): Can't place multiple pins assigned to pin location <CLKUSR pin number> (IOPAD_<CLKUSR pin location address>)
Description
Due to a problem in the Intel® Quartus® Prime Software version 15.1 and later, you might see the following error message when compiling designs targeting Intel® Arria® 10 devices.
Error (18108): Can't place multiple pins assigned to pin location <CLKUSR pin number> (IOPAD_<CLKUSR pin location address>)
Info (18109): Pin ~ALTERA_CLKUSR~ is assigned to pin location <CLKUSR pin number> (IOPAD_<CLKUSR pin location address>)
Info (18109): Pin <a differential pin name>(n) is assigned to pin location <CLKUSR pin number> (IOPAD_<CLKUSR pin location address>)
Although you can use CLKUSR pin as a user I/O pin when CLKUSR is not optionally used for device configuration, initialization, transceiver calibration or/and EMIF HMC calibration, this error might occur if an n-channel of a differential pin pair is assigned to the dual purpose CLKUSR pin.
Resolution
To avoid this error, use the following assignment:
set_global_assignment -name AUTO_RESERVE_CLKUSR_FOR_CALIBRATION OFF