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Can CTS stop tracing on hierarchical module ports?

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Dear community,

my clock signal is connected to the clock network on the one hand. On the other hand it is connected to a module's input. Within this module the signal is always used as a data signal (chip is switched to different mode of operation for this).

This module contains logic, therefore CTS traces through the input ports. AFAIK tracing can only stop at top level ports or leaf cell pins.

Is there any way to make CTS stop tracing at the module's input port (like ExcludedPin/ExcludedPort - which don't work)?

Many thanks in advance for your suggestions!


Originally posted in cdnusers.org by agruebl
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  • archive

    This is an interesting thread- thanks for raising the question!

    Here's some thought I have on what's been discussed:

    (1) It looks like CTS doesn't offer an ability to stop on hierarchical module ports.  In some ways, that's not surprising because a hierarchical module port doesn't necessarily have a physical location.  If we're asking the tool to build a tree *to* the module port and it doesn't have a location, how should CTS know where to place the buffers?  The intent may be to treat elements downstream from the hierarchical module port as a leaf (which sounds like what you're seeking to do), but it's not clear to me that everyone would expect this behavior every time.

    (2) The leafPort option offers a way to specify a stop point based on the master cell name rather than the instance name (ie, "BUFX1/A" instead of "DTMF_INST/RESUTLS_CONV_INST/i0/A").  With a leafPort, you can therefore be more concise in the way you instruct the tool to stop based on cell-type rather than having to find and list every instance pin.  Hope that makes sense.

    (3)  You might want to consider specifying these pins as "ExcludePin" rather than "LeafPin"- the difference being whether CTS balances to the elements inside the module or merely omits them from being sink targets.

    (4)  Regarding coming up with a scripted solution to the challenge of "how to find the instance pins driven by a hierarchical module port"- there are 3 options for db access in this area that I'll include examples of below.

    Hope this helps

    #FE-TCL style (available in all FE releases)
    #userHTermSinks DTMF_INST/RESULTS_CONV_INST/clk
    proc userHTermSinks {htermName} {
    set returnList {}
    set hterm [dbGetHTermByInstTermName $htermNam! e]
    set net [dbHTermNet $hterm]
    dbForEachNetInputTerm $net te rm {
    set instName [dbTermInstName $term]
    set instHInstName [file dirname $instName]
    set termName [dbTermName $term]
    set instTermName $instName/$termName
    set hinstName [dbHInstName [dbHTermHInst $hterm]]
    if {[string match $hinstName $instHInstName]} {
    Puts "$instTermName"
    lappend returnList $term
    }
    }
    return $returnList
    }

    #CTE-TCL style:
    #user_get_pin_sinks DTMF_INST/RESULTS_CONV_INST/clk
    proc user_get_pin_sinks {hterm_name} {
    set hinst_name [file dirname $hterm_name]
    set sinks [all_connected [all_connected [get_pins -hierarchical $hterm_name]]]
    foreach_in_collection sink $sinks {
    if {[get_property $sink object_type] == "pin"} {
    set sink_instterm_name [get_property $sink hierarchical_name]
    set sink_inst_name [file dirname $sink_instterm_name]
    set sink_hinst_name [file dirname $sink_inst_name]
    if {[string match $sink_hinst_name $! hinst_name]} {
    append_to_collection return_sinks $sink
    }
    }
    }
    query_objects $return_sinks
    return $return_sinks
    }

    #dbGet style (available in SOC7.1.RTM):


    Originally posted in cdnusers.org by BobD
Reply
  • archive

    This is an interesting thread- thanks for raising the question!

    Here's some thought I have on what's been discussed:

    (1) It looks like CTS doesn't offer an ability to stop on hierarchical module ports.  In some ways, that's not surprising because a hierarchical module port doesn't necessarily have a physical location.  If we're asking the tool to build a tree *to* the module port and it doesn't have a location, how should CTS know where to place the buffers?  The intent may be to treat elements downstream from the hierarchical module port as a leaf (which sounds like what you're seeking to do), but it's not clear to me that everyone would expect this behavior every time.

    (2) The leafPort option offers a way to specify a stop point based on the master cell name rather than the instance name (ie, "BUFX1/A" instead of "DTMF_INST/RESUTLS_CONV_INST/i0/A").  With a leafPort, you can therefore be more concise in the way you instruct the tool to stop based on cell-type rather than having to find and list every instance pin.  Hope that makes sense.

    (3)  You might want to consider specifying these pins as "ExcludePin" rather than "LeafPin"- the difference being whether CTS balances to the elements inside the module or merely omits them from being sink targets.

    (4)  Regarding coming up with a scripted solution to the challenge of "how to find the instance pins driven by a hierarchical module port"- there are 3 options for db access in this area that I'll include examples of below.

    Hope this helps

    #FE-TCL style (available in all FE releases)
    #userHTermSinks DTMF_INST/RESULTS_CONV_INST/clk
    proc userHTermSinks {htermName} {
    set returnList {}
    set hterm [dbGetHTermByInstTermName $htermNam! e]
    set net [dbHTermNet $hterm]
    dbForEachNetInputTerm $net te rm {
    set instName [dbTermInstName $term]
    set instHInstName [file dirname $instName]
    set termName [dbTermName $term]
    set instTermName $instName/$termName
    set hinstName [dbHInstName [dbHTermHInst $hterm]]
    if {[string match $hinstName $instHInstName]} {
    Puts "$instTermName"
    lappend returnList $term
    }
    }
    return $returnList
    }

    #CTE-TCL style:
    #user_get_pin_sinks DTMF_INST/RESULTS_CONV_INST/clk
    proc user_get_pin_sinks {hterm_name} {
    set hinst_name [file dirname $hterm_name]
    set sinks [all_connected [all_connected [get_pins -hierarchical $hterm_name]]]
    foreach_in_collection sink $sinks {
    if {[get_property $sink object_type] == "pin"} {
    set sink_instterm_name [get_property $sink hierarchical_name]
    set sink_inst_name [file dirname $sink_instterm_name]
    set sink_hinst_name [file dirname $sink_inst_name]
    if {[string match $sink_hinst_name $! hinst_name]} {
    append_to_collection return_sinks $sink
    }
    }
    }
    query_objects $return_sinks
    return $return_sinks
    }

    #dbGet style (available in SOC7.1.RTM):


    Originally posted in cdnusers.org by BobD
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