by Bryon Moyer
July 23, 2014 at 12:14 PM
This year’s DAC included a discussion with Arrow Devices. They’re a company exclusively focused on protocol VIP. They’re not a tool company (other than, as we’ll see, their debug assistant); their VIP plugs into any of your standard tools.
There are three distinct angles they play: verification (making sure your design works in the abstract, before committing to silicon), validation (making sure the silicon works; they also include emulation models in this as well), and debug.
Their focus is on protocol abstraction: allowing verification to proceed at a high level so that designers can execute their tests and review the results at the level of the protocol rather than at the signal level. This enhanced semantic intelligence is how they claim to distinguish themselves from their VIP competition, saying that verification can be completed two to three times faster as compared to competitive VIP.
The verification suites consist of bus-functional models (BFMs) and suites of tests, coverage, and assertions. These work in virtual space. The validation suites, by contrast, have to be synthesizable – hence usable in emulators. They include software APIs and features like error injection. Their debugger is also protocol-aware, although it’s independent of the VIP: it works with anyone’s VIP based on modules that give the debugger the protocol semantics.
One of the effects of digging deep into a protocol is that you occasionally uncover ambiguities in the standards. When they find these, they take them in a couple of directions. On the one hand, they may need to build option selections into the VIP so that the customer can choose the intended interpretation. On the other hand, they can take the ambiguities to the standards bodies for clarification.
On the debug side of things, the protocol awareness ends up being more than just aggregating signals into higher-level entities. When testing a given protocol, the specific timing of signals may vary; a correct implementation might have some cycle-level variations as compared to a fixed golden version. So they had to build in higher-level metadata, assigning semantics to various events so that the events can be recognized and reported. This tool works at the transaction level, not at the waveform level; they’re looking at connecting it to a waveform viewer in the future.
Their protocol coverage varies.
- For verification, they cover the JEDEC UFS (Universal Flash Standard) protocol, MIPI’s M-PHY, UniPro, and CSI-3 protocols, and USB power delivery and 2.0 host/device protocols.
- For validation, they cover only USB 3.0 – but they also claim to be the only ones offering VIP for USB 3.0.
- Finally, the debugger has modules supporting USB 3.0 and 2.0; JEDEC UFS; PCIe/M-PCIe, MIPI UniPro, CSI-3 and -2, and DIS; and AMBA/ACE/AXI/AHB/APB.
You can find out more on their site.