UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
Observer zhoushihua
Observer
6,627 Views
Registered: ‎04-24-2008

A problem with ISE 14.5 map.

Jump to solution

 

With Virtex6 LX760 device. I just use the MIG 3.9.2 generate a DDR3 memory controller with dqs implement as,

 

IOBUFDS_DIFF_OUT #
(
.IBUF_LOW_PWR (IBUF_LOW_PWR)
)
u_iobuf_dqs
(
.O (dqs_ibuf_p),
.OB (dqs_ibuf_n),
.IO (ddr_dqs_p),
.IOB (ddr_dqs_n),
.I (dqs_p_iodelay),
.TM (dqs_p_tq),
.TS (dqs_n_tq)
);

 

When I set -global_opt speed in map phase, it will get a wrong impelement. The IOBUFDS_DIFF_OUT will implement as a IOB on the p port and a IOBS on the n port. It will let the route fail.

 

When I set -global_opt off. It will impment as IOBM and IOBS.

 

But I need use -global_opt speed to improve timing of the other path. How could I do?

 

Thanks.

 

 

1.png
2.png
0 Kudos
1 Solution

Accepted Solutions
Community Manager
Community Manager
10,486 Views
Registered: ‎06-14-2012

Re: A problem with ISE 14.5 map.

Jump to solution

This is a known issue. The problem is that the connectivity in the actual IOB site is changing depending on if -global_opt is used or not. 
when running -global_opt OFF (used by MIG) the IO site is of type "IOBM" and contains routes to the N pair (inside the IOB), but if -global_opt Area/Speed/Power is used the type changes to just "IOB" and does not contain any physical routes to the N pair. Hence there becomes an unroutable situation. 
This can be worked around using "S" constraint. 
NET "u_memc_ui_top/u_mem_intfc/phy_top0/u_phy_data_io/gen_dqs[0].u_phy_dqs_iob/u_iobuf_dqs/split_buf_net" S;
NET "u_memc_ui_top/u_mem_intfc/phy_top0/u_phy_data_io/gen_dqs[1].u_phy_dqs_iob/u_iobuf_dqs/split_buf_net" S; 

 

I hope thsi helps.

 

Regards

Sikta

4 Replies
Community Manager
Community Manager
10,487 Views
Registered: ‎06-14-2012

Re: A problem with ISE 14.5 map.

Jump to solution

This is a known issue. The problem is that the connectivity in the actual IOB site is changing depending on if -global_opt is used or not. 
when running -global_opt OFF (used by MIG) the IO site is of type "IOBM" and contains routes to the N pair (inside the IOB), but if -global_opt Area/Speed/Power is used the type changes to just "IOB" and does not contain any physical routes to the N pair. Hence there becomes an unroutable situation. 
This can be worked around using "S" constraint. 
NET "u_memc_ui_top/u_mem_intfc/phy_top0/u_phy_data_io/gen_dqs[0].u_phy_dqs_iob/u_iobuf_dqs/split_buf_net" S;
NET "u_memc_ui_top/u_mem_intfc/phy_top0/u_phy_data_io/gen_dqs[1].u_phy_dqs_iob/u_iobuf_dqs/split_buf_net" S; 

 

I hope thsi helps.

 

Regards

Sikta

Highlighted
Observer zhoushihua
Observer
6,610 Views
Registered: ‎04-24-2008

Re: A problem with ISE 14.5 map.

Jump to solution

Thank, I will try the work around.

 

BR

Shihua

0 Kudos
Community Manager
Community Manager
6,597 Views
Registered: ‎06-14-2012

Re: A problem with ISE 14.5 map.

Jump to solution

Sure.Keep us posted.

0 Kudos
Observer zhoushihua
Observer
6,575 Views
Registered: ‎04-24-2008

Re: A problem with ISE 14.5 map.

Jump to solution

Just try the constraint, it works.

 

Thanks.

 

BR

Shihua

0 Kudos