Partial Wrappers...

Grady, Theresa, Dwayne, Francisco, Karim and Yervant,

While this e-mail is directly addressed to a smaller set of people, everyone is on the CC list.

Our job is to look at Partial Wrappers. This means many things based upon the "degree-of-partiality" (Oxford dictionary people did not consult me about english). To begin with let us understand the most important partial-wrapper implementation which is the boundary register inside the core and everything else is outside.

The information would look somewhat like the following .... text afterwards will describe constructs and the information they carry to support the tasks.

Signals {
   // boundary definition
}

ScanStructures {
   Length, ScanIn, ScanOut, Clk,
   ScanEnable, ScanCells
}

Timing {
   // some timing used by Macro
}

MacroDefs {
  // operate the chain
}

Environment { CTL etm {
    TestMode ExternalTest;
    Internal {
    // Datatypes of signals
    // IsConnecteds
    // ScanDataType
    // Wrapper PinIDs
    // DriveRequirements
    }
    PatternInformation {
        p1{Purpose EstablishMode}
        m1{Purpose, ScanChain}
    }
    External {
        ConnectTo xxx;
    }
}}

Explanation of constructs:

1. ScanStructures: Defines the scan chains.
2. Internal-DataType: defines the characteristics of the signal to fall in categories such as ScanIn, ScanOut, ScanEnable, clocks.
3. Internal-DataType-ActiveState or AssumedInitialState: defines the stable or active values of the signals.
4. Internal-ScanDataType Boundary: Identifies the boundary scan chains.
5. Internal-IsConnected: Defines the broadside connection to the wrapper cells.
6. Internal-IsConnected-Wrapper IEEE1500 CellID: defines the implementation of the cell behind the connection.
7. Internal-Wrapper IEEE1500 PinID (UpdateWR, ShiftWR, CaptureWR, and TransferWR) define the signals that perform the associated operation with respect to any 1500 partial or complete implementation inside.
8. Internal-DriveRequirements: Defines the special timing flexibility and relationships of the associated signals.
9. PatternInformation-Macro: Defines the macro used to get values into and out of the scan chain. This macro is also linked in to IsConnected to represent the access for the connection.
10. External-ConnectTo: defines the instructions to the integrator to connect to the Instruction register, WIP terminals.

Note: Other syntax could be used to say that scan-chain need to be kept seperate at the next level of integration. Not shown here.

TASKS TO INTEGRATE A CORE WITH A PARTIAL WRAPPER:

1. Are there any boundary scan chains?
   Look for the answer in d.

2. What is the definition of the boundary scan chain?
   Look for the answer in a.

3. Is the boundary chain constructed with IEEE1500 cells?
   Look for the answer in f on a signal by signal basis.

4. Is there a Bypass register or Instruction Register? Since there is no Wrapper IEEE1500 statement on the test mode the wrapper is non-compliant or partial.
   Look for answer with d.

5. Since question 3 says that the wrapper cells are IEEE1500 cells are there any and what are the special terminal to perform the operations of the Wrapper chain?
   Since there is a partial wrapper as answered in 4 I am expecting UpdateWR, ShiftWR, CaptureWR and TransferWR to be there.
   Look for the answer in g.

6. Do I need to implement a WART externally? Assuming that the wart is used to collapse multiple signals to a single signal.
   Look for answer in g.

7. Can I collapse the scan chains?
   Not sure this is needed, but look for answer in Note.

8. Can I collapse the many boundary signals to the WIP signals?
   Look for answer in h.

I believe the above questions 1 to 8 would be needed to be answered to complete the wrapping of a partial wrapper that is a boundary scan chain.

So collectively we need to discuss (e-mail) the following:

• Do we need to ask more questions to successfully integrate the partial boundary scan chain?
• Is the information there to answer all the questions.

regards,
Rohit