MACRO TESTING:
->Two Important Phases of the Macro Testing
Macro Test uses a data Independent access scheme.
It is done is two major stages
First Phase is MSV
MSV Tool generates the correspondence solutions for all the relevant macros and macro Operations.
The Correspondence solutions will comprise of the necessary pre-conditioning data
and global pattern templates for the actual test data.
Second Phase: MTG Phase
MTG (Macro Test Generation) combines the local macro-level test data with the
Correspondence solution to generate the global test data for the macros.
Basic Design Flow for MTEST:
1. Read the Netlist
2. Read the MIC file
3. Do the MSV
4. Analyze the MSV messages and Debug in case of errors
5. MTG phase will start
6. Read the MPR file
7. Generate the Macro Test Data
Detailed Description of the MSV Phase
- MSV tool will read the netlist and testmode information. It has to find all the Macros that must be processed for the given test-mode.
- Every Macro must be associated with MIC file
- MIC file defines the macro-specific operations and access requirements.
- MSV will try to find pre-conditioning and correspondence solutions for each macro operation
- For each macro data Input/output, the tool will try to find a suitable correspondence point and sensitize a path.
- Path Sensitization will be done by an ATPG tool that justifies the path side inputs back to appropriate pre-conditioning values.
- MIC file describes the Nature of the senitized or allowed path and pre-conditioning constraints for each macro pin.
- Correspondence solutions will be generated in Binary or text formats
Detailed Description of the MTG Phase
MTG tool reads the binary form of the correspondence solution and the associates Macro Patter Rule (MPR) file.
MPR file contains the macro level test data that are to be plugged into the global pattern templates defined by the correspondence solutions.
Resulting Macro test data are then written into the test data file for the chip
MPR file
C programs that use MTG specific commands to assign the data values to the PINGROUPS defines in operations for the Algorithm represented by the MPR
Basic Concept of MTEST
To Provide Test Stimuli to the Macro Inputs, a logic path is sensitized between each relevant macro data input and a corresponding controllable
To receive the test responses from the macro outputs, a logic path is sensitized between each macro outputs; a Logic path is sensitized between each macro output
and corresponding observable Top in the top level design.
Probable Test Sequence
The test sequence:
1. Force PI
2. Apply the clocks
3. Drop LTEST: go into the Functional Mode
4. Do the Required Testing in Functional Mode
5. Raise the LTEST and then Scanned out the Responses
