Forum Discussion
Occasional ContributorE-Tile TX/RX out clock constraint
Hi,
I've defined a data rate in my E-Tile IP and I want to switch the data rate using the E-Tile Avalon reconfiguration interface by setting the internal PLL multiplier.
Now I have chosen the highest data rate in E-Tile and want to constraint the lowest data rate.
Do I have to set the constraint to the output clock of the E-Tiles?
Which clock do I have to constraint here?
I already tried a lot of combinations e.g.:
create_clock -period 3.531 -name freq_low [get_ports {u0|e_tile_phy_0|e_tile_phy_0|g_xcvr_native_insts[0].ct3_xcvr_native_inst|inst_ct3_xcvr_channel|out_pld_pcs_rx_clk_out1_dcm}]
This statement won't be recognised but I can see the port in my tech-map.
If I create a clock_group I can use [get_clocks {u0|e_tile_phy_*|e_tile_phy_*|rx_clkout|ch*}] but for create_clock I have to specify a port/pin/etc. instead of using an existing clock.
How can I apply the create_clock constraint to my E-Tile out clocks for the lowest data rate?
Best regards,
Michael
Michael,
Apologize for the late reply on this. You can try to refer to the following UG to find some of the E-Tile hard IP example designs which were validated by engineering.
See if it is helpful.
6 Replies
KennyT_alteraSuper Contributor
What device that you were using?
What you need to do is create clock at the port and use derive_pll_clocks to generate the correct output clocks.
You can also open up timing analyzer to put the derive_pll_clocks inside the tcl command. It will show you a list of generated clock inside.
Btw, if you want to change to different clock unit. Here is the command:
set_time_format -unit ns -decimal_places 3
- KennyT_altera
Also, can you double check the user guide and reference design for the constrain needed?
MichaelBHi Kenny,
I'm using the Stratix 10 SM16BEU2 device.
"What you need to do is create clock at the port and use derive_pll_clocks to generate the correct output clocks."
Which port should have this create_clock constraint?
I already tried a lot ports in the E-Tile native to constraint but without success.
Best regards,
Michael
- MichaelB
Hi,
is there anyone who could help me with this topic?
I'm still not able to assign any create_clock constraint on the E-Tile TX/RX output clock to support different frequencies and data rates.
Best regards,
Michael
SyafieqSHi Michael,
I'm checking for some user guide/sample design for reference how to constraint this. Will keep you posted.
- SyafieqS
Michael,
Apologize for the late reply on this. You can try to refer to the following UG to find some of the E-Tile hard IP example designs which were validated by engineering.
See if it is helpful.
