Device Family: Stratix® V GX

Type: Answers

Area: EMIF, Intellectual Property


IP Product: DDR2 SDRAM Controller supporting ALTMEMPHY

Why did I get Fitter error during compilation when I set ALTMEMPHY wrapper as top level project file?

Description

When you set ALTMEMPHY wrapper as top level project file, you will get following error message during compilation.

Error: The following I/O registers are used illegally and must drive delay chains feeding an I/O output buffer or delay chain fed by an I/O input buffer.

Fitter error message is saying that the outputs of the io_config blocks must drive I/O buffers if they're connected.

Since the PHY is set as a top-level entity, the outputs of the io_config blocks drive output pins, therefore,
the fitter requirement is violated.

To get around this error, in wraptop_ddr2_phy.v, replace the following line:

.hc_scan_dout(hc_scan_dout),

with

.hc_scan_dout(),

This action disconnects the io_config outputs from the top-level pins to resolve the illegality.