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Altera_Forum
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15 years ago

Source synchronous constraints for both edges in TimeQuest

I've been working my way through the tutorials and Rysc's document. Unfortunately, the waveforms don't match what I'd expect. I thought I'd see the min-rise output delays from the rising edge of th...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Thanks for the quick response.

I added 


set_false_path -setup -fall_from U_HT_CORE|U_HT_EC|htxtop_inst|ht_link_wrapper_I|CTLCADLO_OUT_SERDES_I|oserdes_altera_inst|altlvds_tx_component|auto_generated|lvds_tx_pll|clk -rise_to l1_rx_clk_0
set_false_path -setup -rise_from U_HT_CORE|U_HT_EC|htxtop_inst|ht_link_wrapper_I|CTLCADLO_OUT_SERDES_I|oserdes_altera_inst|altlvds_tx_component|auto_generated|lvds_tx_pll|clk -fall_to l1_rx_clk_0
set_false_path -hold -fall_from U_HT_CORE|U_HT_EC|htxtop_inst|ht_link_wrapper_I|CTLCADLO_OUT_SERDES_I|oserdes_altera_inst|altlvds_tx_component|auto_generated|lvds_tx_pll|clk -fall_to l1_rx_clk_0
set_false_path -hold -rise_from U_HT_CORE|U_HT_EC|htxtop_inst|ht_link_wrapper_I|CTLCADLO_OUT_SERDES_I|oserdes_altera_inst|altlvds_tx_component|auto_generated|lvds_tx_pll|clk -rise_to l1_rx_clk_0
set_false_path -hold -fall_from

And now I see closer to what I expected. I still see three rising launch edges and only one falling launch edge. I thought it would be symmetrical.

I'll try place and route again to see if it has an easier time. The edges that got cut were all edges with large positive slack, so that might not have helped (except for making the timing analysis clearer).

Thanks,

Myles