Get all register related to ONE clock? > Forums

Unanswered

Active Topics

Forums

Forums > Digital IC > Floorplanning, Place and route

Subject: Get all register related to ONE clock?

Posting to forums is available to community members only.
Login or Register

Rate this topic:

Author

Messages

aidans
Posts: 35
Online: User is Offline

5/17/2007 7:47 PM
we have ECLK and MCLK in my design, I now want to list all the registers related each of the clock. Here is the porblem I met. Approach One: dbForEachCellInst [dbgTopCell] instPtr { set cellPtr [dbInstCell $instPtr] if {[dbIsCellStdCell $cellPtr]} { if {[dbIsCellSequential $cellPtr]} { dbForEachInstTerm $instPtr termPtr { dbIsTermClk $termPtr ...... But I can know which clock this term is connect to Approach Two: dbForEachHeadClock [dbgHead] clockPtr { set sel [dbIsClockSel $clockPtr] set name [dbClockName $clockPtr] puts "$name" } setClockDomains -sClk ECLK -dClk ECLK -fromType register -toType register e I now want to use this command, dbForEachClockDomainInst, but I don't know the syntax since the Encounter Database Access Command Reference did tell use how to used it. Any suggestion and feedback is welcome! Thanks

aidans
Posts: 35
Online: User is Offline

5/17/2007 7:52 PM
I sorry that there is one typo, In the approach one: "But I can know which clock this term is connect to " should be "But I can NOT know which clock this term is connect to "

eminemshow
Posts: 75
Online: User is Offline

5/18/2007 12:06 AM
Dear aidans: Seem that there is a method, it's a makeup to your approach 1. After 'dbIsTermClk $termPtr ', you can add 'dbTermNet' to get the net connected to this clock pin. Then you can trace through this net (across all the buffers & inverters) to get the root clock net, or get the generated clock net, if the net is your MCLK or ECLK, I think it is OK. But this needs a lot of work. Yours EminemShow

aidans
Posts: 35
Online: User is Offline

5/18/2007 1:10 AM
Yes, we can trace all the clock net in theory, since there are limited clock nets in the database. But I think this kind of appoach is to difficult to handle more complex clock tree. Is there a smart way to do this ? In PrimeTime, we can get this register list easily. And now we try to do all the thing inside SOC Encounter, since we our backend team use Encounter flow.

BobD
Posts: 80
Online: User is Offline

5/18/2007 7:14 AM
Great question- I'm glad you asked it. In FE, there's a couple of different ways to probe the db. The long-standing mechanism I call "FE-TCL"- commands like "dbIsTermClk" and "dbForEachClockDomainInst" are FE-TCL commands. They've been around forever and are great for probing things in the physical realm. However, for information that falls in the timing realm there's CTE-TCL (Common Timing Engine-TCL) commands. These are relatively new within the FE environment (within the 6.1/6.2 timeframe), but what's nice about the CTE-TCL commands is that they provide the ability to query timing efficiently. The example task you're asking about here fits better within the CTE-TCL commands. FE-TCL and CTE-TCL commands are all available at the regular encounter prompt- they're complimentary sets of functionality. So, with a netlist like this: module testcase (clk1, clk2); input clk1; input clk2; wire net1; wire net2; wire net3; DFFX1 i0(.CK(clk1), .Q(net1)); DFFX1 i1(.CK(clk1), .D(net1)); DFFX1 i2(.CK(clk2), .Q(net2)); DFFX1 i3(.CK(clk2), .D(net2), .Q(net3)); DFFX1 i4(.CK(clk2), .D(net3)); endmodule ...and a SDC like this: create_clock -period 1 -name clk1 [get_ports clk1] create_clock -period 1 -name clk2 [get_ports clk2] You could get the registers associated with each like this: encounter1> report_timing encounter 6> all_registers -clock clk1 i0 i1 0x8 encounter 7> all_registers -clock clk2 i2 i3 i4 0x9 Have a look at the "Timing Constraint Commands" section in "fetxtcmdref.pdf" for more information on commands like this. Let me know what you think of this and whether it would be OK with you to operate with these CTE-TCL commands instead of FE-TCL for probing timing-related information like this. Hope this helps, Bob

aidans
Posts: 35
Online: User is Offline

5/18/2007 8:22 PM
Thanks Bob, I get the job done by CTE-TCL command. The result I got in SOC E is the same with that from PrimeTime. One remider is that, In SOC Encounter, all_register -clock CLKNAME command should be used after we build timing graph. (report_timing )

Posting to forums is available to community members only.
Login or Register

Forums > Digital IC > Floorplanning, Place and route > Get all register related to ONE clock?

ActiveForums 3.6