ATPG再了解(九)

Empty Boxes Versus Black Boxes

使用下面指令
set build -reset_boxes # clears black & empty box list
set build -empty_box BUS_SWITCH
set build -black RAM32x8 -empty IRQ_CORE


An “empty box” is similar to a black box with the exception that its output pins are floating.
These can be used for an embedded memory with tristate-able outputs.

Specify an Empty Box module only if its outputs are actually at Z state during test. The empty box can be helpful if multiple modules are connected to a bus, but the module outputs are all at Z state.

Using black boxes in this case would result in bus contention.

Two additional ‘box’ models are supported To make TetraMAX treat a module as a library cell, use the –design_box option:

TetraMAX will then add faults to just the ports of this module, but not inside

To maintain the port connections of a level of hierarchy, use the –portfault_box option:
May be used in SoCBIST flow where scan ports of a module need to be maintained in design