热度 2| |
1. Verification methodology验证方法学
(1) Dynamic Simulation(rtl simulation(for function) + pre-layout simulation(for timing) + post-layout simulation(for timing))
Pros: fundamental & useful, straightforward, must-have.
cons: long time, poor coverage.
(2) Formal verification (for example. LEC ) (一般用于验证rtl与netlist的功能一致性。)
Pros: complete coverage, fast, a good helper for dynamic simulation.
Cons: not easy to debug, limited usage.
2. unmapped points (LEC)
(1) Extra: key point that exists in only the Golden design or in only in Revised design, but does not affect the circuit functionality. For example, scan port: scan_in, scan_out。(为了DFT,可能会加入一些test logic,但不会影响功能的一致性。)
(2) Unreachable: key points that is not propagated to any observable point. For example: spare flops (dummy cells).(netlist与rtl相比有些dummy logic在synthesis会被拿掉,另外,因为timing需要,有些逻辑(如buffer)会加上,但不影响功能的一致性。另外,为了芯片后续的ECO,会在芯片中撒入dummy cell。)
(3) Not-mapped: key point that has no correspondence on the other side. May be resolved with renaming rules. (真正有不匹配的数字逻辑)
3. Equivalence checking (LEC)什么时候做?! --> no test bench & no simulation vectors & full coverage
(1) synthesis之后
(2) optimize之后
(3)DFT insertion之后
(4)I/O insertion之后
(5)Placement之后
(6)clock tree insertion之后
(7)route之后