posted by Bryon Moyer
Everyone seems to be in on the sensor fusion game. After all, it’s only software; how hard could it be?
You’ve got the sensor makers with their lower-level fusion kits. Then you’ve got the sensor-agnostic folks like Movea, Hillcrest Labs, and Sensor Platforms. And now a microcontroller maker. (OK, they did provide one of the sensors… but I’m getting ahead of myself…)
But for an engineer just starting to use sensors, having ready-to-go software can make an enormous difference in the learning curve, wiping out huge chunks of study that might otherwise be necessary. So access to software can be a big win.
Besides, the software helps sell sensors, and it runs on microcontrollers being used as sensor hubs, so it can help sell them as well. If you happen to make both, like ST and Freescale, then double bonus; you can even integrate them.
In this case, TI has announced their Sensor Hub BoosterPack. It’s more than just software; it’s a daughter card for their Tiva C Series TM4C123G LaunchPad eval board. It has seven sensors, including acceleration, orientation, compass, pressure, humidity, ambient/infrared light, and temperature. It includes a sensor driver library, a fusion API, and several example applications. Good for getting a sense of how this stuff works.
It appears to be something of a community effort, since the sensors on the card come from a variety of players:
- InvenSense provides the 9-axis IMU
- Bosch Sensortec provides the pressure sensor
- Sensirion provides the humidity and ambient temperature sensors
- Intersil provides the light sensor
- TI itself has contributed its non-contact infrared temperature sensor
You can find more information in their release.
posted by Bryon Moyer
Early this year we took a look at MEMS standards (or the need therefor), and one of the active efforts involved unifying sensor parameters and data sheets so that users could compare and combine different sensors from different companies – a challenging task at present.
Well, that effort has now yielded some results. The “Sensor Performance Parameter Definitions” document has been released under the auspices of the MEMS Industry Group (MIG). The effort itself was led by Intel and Qualcomm, with input from a number of different sensor players.
While many such standards documents start with a limited scope and just can’t stop, a quick look at the table of contents suggests that hasn’t happened here. The bulk of the document is simply a set of definitions for parameters for different sensors. It is augmented by helpful lists of terms and acronyms, symbols and equations, and measurement conversions.
The sensors covered by the document are:
- Pressure Sensors
- Humidity Sensors
- Temperature Sensors
- Ambient Light Sensors
- Proximity Sensors
This seems to cover all of the Windows HID-required sensors (since inclinometers and orientation sensors are typically fused versions of the above) except for GPS.
Each sensor type has its own parameters. For example, the following parameters are defined for accelerometers:
- Full Scale Range
- Digital Bit Depth
- Zero-g Offset
- Zero-g Offset Temperature Coefficient
- Sensitivity Temperature Coefficient
- Current Consumption
- Output Data Rate (ODR)
- Filter -3dB Cutoff
- Internal Oscillator Tolerance
- Cross-Axis Sensitivity
- Integral Non-Linearity
- Transition Time
- Data Ready Delay
For each parameter, the following information is provided:
- Any aliases or other names for the parameter
- A definition
- Conditions under which the parameter is specified (typically more than one)
- Distribution (e.g., minimum/typical/maximum)
Various timing diagrams and other graphs are used to illustrate the parameters.
And that’s pretty much all there is to it. A modest 60 pages (with lots of whitespace, easy to read). As promised, no more, no less.
posted by Bryon Moyer
I’m getting a sense that we’re back into the small-company-friendly phase of the EDA company cycle. A number of newcomers (which means they’ve been around working quietly for several years and are now launching) are knocking on doors.
Invarian is one such company, and they’ve launched two analysis platforms: their “InVar Pioneer Power Platform”, with power, IR-drop/EM, and thermal analysis, and their “InVar 3D Frontier Platform” for thermal analysis of 3D ICs.
Their claim to fame is that they’re the only tool that can handle true full-chip sign-off analysis at 28 nm and below, with SPICE accuracy and fast run times (“fast” being a relative term). In particular, for digital designs, they do concurrent analysis of timing, thermal, EM/IR, and power. Yeah, they have a timing engine – and they say it’s really good, too. But trying to displace PrimeTime as the gold standard is a tough call; that’s not their goal. So the timing engine serves the other pieces.
The whole concurrent thing means that, instead of running one analysis to completion and then handing those results to the next engine for different analysis, they run the engines together. As they iterate towards convergence, they update a common database on each cycle, so each engine is using a slightly-more-converged value from the other engines on every new cycle. They say that this speeds overall convergence, taking analysis that used to require several days to run and managing it in a few hours instead, with no loss of accuracy.
Of course, having a new tool also means that you can build in parallelism from the get-go, leveraging multicore and multi-machine computing resources.
For analog sign-off, they can do co-simulation with the usual SPICE suspects. And for 3D analysis for packages with multiple dice, they boast models that are more accurate and realistic than the standard JEDEC models. And they claim greater ease of use, making rules (which are constantly evolving) more manageable in particular.
You can find more in their release.