各位老大,我今天直接调了个DDR2控制器IP核作为顶层,综合能过,加上DQ和DQS管脚约束,fitter时就报
Error: The I/O standard LVDS cannot be used on the Bidir pin mem_clk[0].双向信号不能用差分。
(使用stx3,直接用IP核作为顶层综合,未修改任何内容,只加了DQ和DQS管脚约束)
DDR2 IP核用户手册又说:
The "mem_clk" signals are output only signals from the FPGA. However,
in the Quartus II software they must be defined as bidirectional (INOUT) I/Os to support
the mimic path structure that the altmemphy megafunction uses.