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Right up there with functional verification, the challenges of low power design and verification present an existential threat to our customers' products, and ultimately their businesses. Clearly both sides of the low power coin -- reducing generated heat and/or increasing efficiency to make the most of every available joule -- are of primary concern. But what happens when external, environmental factors conspire to betray even the best low power electrical design? In the case of the GoPro "Hero2" camera, ironically the device's waterproof housing that has help propel this amazing system to some incredible heights can sometimes undermine its operational performance in certain corner cases.
First, let me describe the system setup. As shown in the image below, the GoPro Hero2 camera is the little cube on the left. In the middle is the (empty) polycarbonate protective housing that's gasketed to keep out water and dirt. On the right the camera is sealed inside the housing.
As per this video I shot exclusively with GoPro Hero2 this summer, I can personally attest that the camera and housing make for a very solid and effective mechanical system. (If the embedded video doesn't play, click here.Overall the camera performed brilliantly. However, there was one issue that emerged: whenever the camera got too hot it would automatically shut down to avoid damaging itself. For example, when the system is in direct sunlight the housing seems to act like a greenhouse and/or it insulates the camera such that the camera heats up significantly faster than when it's out of the housing (especially on an already hot summer day). So while I praise the Hero2's designers for building-in this automatic fail safe, at the same time it's frustrating to wait for the camera to cool down. (FYI, keeping the system submerged in the pool, or putting it in a cooler with the drinks and snacks expedites the turnaround process. But I digress ...)
What are the lessons for EDA here? I see three:
* The need to model "out of band" behaviors in the digital design domain - i.e. consideration of expected environmental factors in addition to the device's specified logic and firmware performance - will need to become more prevalent as our customers develop more devices destined for mobile use.
* Electronic Design Automation (EDA) will need to get even closer to Mechanical Design Automation (MDA). I know my colleagues in PCB design and IC packaging are well down this road, but this GoPro case study suggests that SystemC/RTL design and verification must also consider macro-level physical factors as well. Beyond today's UVM Low Power flows, should there be a "UVM Thermal Behavior" verification flow?
* Last but not least, the general moral of this story is that as far as we've come, collectively the EDA industry has a ways to go before our innovations make low power one of our customers' lower priorities.
Joe Hupcey III
On Twitter: http://twitter.com/jhupcey, @jhupcey
P.S. For fellow parents:Chances are you have probably heard of GoPro cameras before, but might have dismissed them as being only for young adventurers. Certainly GoPro supports such customers and their extreme sports very well. However, I quickly realized that this camera and its ruggedized shell is as effective for capturing my constantly on-the-go daughter's activities as it is for motor sports and outdoor adventures. Since I'm constantly asked about the Hero2 system by other parents, allow me to anticipate the question "Does the GoPro ‘work' for capturing family-style activities?" with a hearty "Yes". In a nutshell, it's a perfect second camera for the many times where you would rather avoid subjecting your "regular" camera (be it a cell phone camera, point&shoot, DSLR, or camcorder) to rigors and risks of family-oriented activities like swimming, bicycling, rainy hikes, and winter sports.