Figure 1: An Example for bottom-up architecture
In Figure 1, there are 3 modules, design1, design2 and design 4 need to be hardened. In this case, it has to execute twice bottom-up flows. In addition, the BIST circuit in design 3 module need to be inserted while executing design 1 BFL flow.
To utilize EZ-BIST executing bottom-up flow, user should push the inserted BIST circuit to top module. For example, in Figure 1, user should insert BIST circuit into design 2 and design 4.
Then, user insert BIST circuit into the design 1 module. Meanwhile, BIST also needs to be inserted into designe 3. And then insert the BIST circuit into the top level of chip_top. Finally, integrate all BIST circuits and use a standard JTAG interface as the unique control interface.
Since design 2 and design 4 modules are in the lowest level, the settings of these 2 modules should define following 2 assignments.
- set bist_interface = ieee1500
- set integrator_mode = no
Integrator_mode assign to “no”, EZ-BSIT will generate *.blockinfo text file.
In the design 1 module, one more option “block_path” should be added. The settings as below:
- set bist_interface = ieee1500
- set integrator_mode = no
- set block_path = ./mbist_design2/EZBIST_design2.blockinfo | ./mbist_design4/EZBIST_ design4.blockinfo
After design 1 module settings done, user could insert design 2 and design 4 with BIST into design1.f. Please refer to Figure 2.
Figure 2: An Example to insert design 2 & 4 into design 1
To insert BIST into TOP module, it is similar to design 1, except integrator_mode should assign to yes. The assignments of other options are the same as the previous steps. Please notice the following assignments:
- set bist_interface = ieee1500
- set integrator_mode = yes
- set block_path = ./mbist_design1/EZBIST_design1.blockinfo
The file-list of design 1 with BIST put into chip_top.f as figure 3:
Figure 3: Insert design 1 module to chip top
User can integrate all BIST circuits through EZ-BIST integration flow. And it should be assigned
*.postfixinfo file as below. EZ-BIST will insert BIST circuit into chip_top and then generate
*.postfixinfo file.
- set postfixinfo = ./mbist_chip_top/EZBIST_chip_top.postfixinfo
Figure 6-7 shows the architecture after executing these integration flow in this chapter.
Figure 6-7 Bottom-up flow complete architecture