Introduction
The Ultra-Low Power (ULP) Sense BoosterPack™ kit (BOOSTXL-ULPSENSE) is an easy-to-use plug-in module equipped with low power sensors to be controlled by the CC13x2/CC26x2 Sensor Controller for ultra-low power sensing. Launch your ultra-low power wireless sensor application by combining the BoosterPack with any of the CC13x2/CC26x2 LaunchPads™. The CC13x2/CC26x2 Sensor Controller is a dedicated 16-bit CPU optimized for ultra-low power operation. It runs independently of the main application processor and can perform tasks such as sampling, storing and simple processing of sensor data while the main processor is sleeping. In addition, the Sensor Controller has access to several ultra-low power analog and digital peripherals allowing it to handle both analog and digital sensors with very low power consumption.
Key Features
- Analog Light Sensor
- Capacitive Touch Buttons
- LC Flow Meter
- Potentiometer
- Reed Switch
- SPI Accelerometer
What's Included
- 1x BOOSTXL-ULPSENSE
- 1x Quick Start Guide
Software Examples
Sensor Controller Studio (SCS) is used to write, test and debug code for the CC13xx/CC26xx Sensor Controller. SCS provides example code and documentation to get you up and running with all of the BOOSTXL-ULPSENSE sensors. Also, the Sensor Controller documentation can be found in the SCS Help Viewer.
Requirements
BOOSTXL-ULPSENSE is designed to be used with a CC13x2/CC26x2 LaunchPad, but can be used with any LaunchPads following the BoosterPack™ Module Pinout Standard. However, to achieve ultra-low power consumption a CC13x2/CC26x2 Sensor Controller is required and software examples are available for the following LaunchPads:
In addition, a SCS example for Cap Touch is available for the following LaunchPads:
ADC Select Jumper
This jumper switch selects whether the Analog Light Sensor or the Potentiometer shall be connected to the ADC on BoosterPack pin #26.
Sensor Power Jumpers
The BoosterPack has a row of jumpers which enables each of the on-board sensors to be disconnected from their power source. This is useful for power measurements, either total system power with all jumpers removed except the sensor in use, or to measure the current consumption of the sensor itself. To achieve ultra-low power consumption, most of the sensors are being powered from a DIO (pin #19), which enables powering off the sensor when data is not being captured. Some sensors require more current than a single DIO can deliver, or can achieve the same power savings with internal functionality and are therefore powered directly from the 3V3-net. The table below shows a complete overview of the power distribution.
| Sensor | Power Source |
|---|---|
| LC Flow Meter | 3V3 and DIO (Pin #19) |
| Accelerometer | 3V3 |
| Cap Touch | N/A |
| Analog Light Sensor | DIO (Pin #19) |
| Reed Switch | DIO (Pin #19) |
| Potentiometer | DIO (Pin #19) |
Potentiometer
The on-board Potentiometer is connected as a voltage divider and can be used to test the
on-chip ADC and verify that your code is working as expected. For example, does the
Sensor Controller wake up the main CPU at the correct ADC threshold? The Potentiometer
is powered from a DIO in order to prevent current leakage while not measuring and can be
powered on quickly to save power. Additionally, SCS provides an example where the
internal comparator and DAC of CC13x2/CC26x2 are used as a successive approximation ADC
to achieve even lower power at expense of resolution.
How to use it
Mount a jumper on the Sensor Power header in the POT-position and the ADC Select Jumper in the POT-position. The Potentiometer is then powered from the DIO at pin #19 and the voltage divider can be read on pin #26.
Accelerometer
An ultra-low power Accelerometer enables use of the SPI interface that the Sensor
Controller has access to. The Sensor Controller can then process Accelerometer data and
take decisions whether to wake up the main CPU or not, and then save
power. Accelerometers often come with internal functionalities such as; free fall
detection, tilt detection, tap sensing etc. By using the Sensor Controller, those
functions can be extended with for example additional filters without adding significant
power to the system. SCS provides example code to read the on-board Accelerometer and
perform simple processing of the data.
How to use it
Mount a jumper on the ACC position on the Sensor Power Jumpers. Remove all other jumpers to save power. The power source for the Accelerometer is 3V3.
Reed Switch
The Reed Switch is capable of detecting magnetic fields. Normally, the switch is open,
but when a magnetic field is applied to the switch it closes. The Reed Switch is
connected in series with a pull-up resistor, thus, the REED signal on pin #5 will
be active low. A reed switch can be used in numerous of applications; one example is
flow meter applications where the Read Switch can be used instead of inductive sensing
to measure flow.
How to use it
Mount a jumper on the REED position on the Sensor Power Jumpers. Remove all other jumpers to save power. The power source for the Reed Switch is pin #19 and the switch can be read on pin #5. A magnet is required to use the Reed Switch. Place the magnet in close proximity to the Reed Switch to close it.
Light Sensor
The Light Sensor outputs a current dependent on the amount of light the Sensor is
exposed to. The current is fed into a resistor creating a voltage which can be captured
by the ADC. To save power, the Light Sensor is powered from a DIO which allows it to be
on for short time periods.
How to use it
Mount a jumper on the LIGHT position on the Sensor Power Header. Leave the other jumpers unmounted to save power. The ADC Select Jumper must be in the LIGHT position. To test the sensor, cover it with your finger to reduce the exposure and remove it to increase the exposure.
Cap Touch
Two Capacitive Touch buttons are available to demonstrate a low-cost and low-power user
interface solution. The solution requires only a discrete resistor and some PCB area. A
capacitive button is created by a small circular copper area on the top layer of the PCB
and a hatched ground plane on the bottom layer of the PCB, while the layers in between
are non-conductive. This creates a small capacitance (Ct) which will change
when touched with a finger tip. The circular layer on top is connected to an analog port
of CC13x2/CC26x2 and by using an internal Current Source (ISRC) and Time-to-Digital
Converter (TDC), the Sensor Controller is able to measure Ct and detect
whether the button is touched or not. The external bias resistor is used as a reference
and the internal Multiplier and Accumulator (only available on CC13x2/CC26x2) can be
used to filter the data from the TDC for improved operation in noisy environments.
How to use it
None of the Sensor Power Jumpers are required, just make sure the plexiglass is mounted properly and touch the area marked BTN1 or BTN2 on the board.
LC Flow Meter
The Flow Meter sensor is based on inductive sensing where two pairs of on-board
inductors and capacitors keeps track of a rotating disc to measure the actual flow
volume of water, heat or gas. One half of the disc is covered by metal and the other
half is nonmetal. The LC sensors are able to detect if there are metal in close
proximity, thus with two LC sensors it is able to detect rotation of the disc, and in
which direction the disc is rotating. In addition to the LC-components, the BoosterPack
contains external circuitry to create trigger pulses much narrower than the Sensor
Controller is able to produce when running at 2 MHz, which enables ultra-low power
consumption.
How to use it
A disc that is half covered by metal and half by nonmetal is required for the Flow Meter sensor. Place the disc a few millimeters above the inductors marked FLOW 1 and FLOW 2 with its center above the mounting hole on the PCB. The mounting hole can be used to mount the disc onto the PCB. Mount the jumpers marked FLOW VDD and BIAS on the Sensor Power Jumper header, and remove the other jumpers. On the LaunchPad, make sure the TDI and TDO jumpers are removed and the 0-ohms resistors connecting the TDI/TDO signals from CC13x2/CC26x2 to the BoosterPack header are mounted. Then the trigger and readout circuitry is powered from pin #19, while the inductors are being charged directly from 3V3. The LC sensors triggers at pin #31 and pin #32 and can be read at pin #2 and pin #6.
Requirements
Power supply
The BoosterPack is designed to be powered from the 3V3 supply of a compatible LaunchPad through the BoosterPack connector.
Temperature range
The BoosterPack is designed for operation from -40°C to +85°C. Note that other BoosterPack accessories and LaunchPads may have different temperature ranges, and when combined, the combination will be set by the most restrictive combined range.
Good to know
- The LC Flow Meter has multiple footprints to fit different inductors, or to place the inductors closer to each other for smaller disc sizes.
- If you don't have access to a disc, the Flow Meter sensor can be tested with other metal objects. Place the object in close proximity to one of the sensing inductors and use the example in SCS to see if the object has been detected.
- Some LaunchPads comes with the 0-Ohm resistors routing the TDI and TDO signals to the 40-pin BoosterPack connector unmounted. Please make sure that those are mounted and that the TDI and TDO jumpers are unmounted when using the LC Flow Meter Sensors. Refer to the design files for your LaunchPad to see the respective location of the resistors.
To learn more about the Sensor Controller, please visit the SimpleLink Academy which provides a comprehensive set of trainings for the SimpleLink MCU family.
| Lab | Description |
|---|---|
| Introduction to the CC13xx/CC26xx Sensor Controller | Describes what the Sensor Controller programmable CPU is, how it works, and how to use it. |
| Fundamentals | Entry level guide on how to use the Sensor Controller with the GUI tool and Sensor Controller Studio (SCS). You will generate, download and debug code on the sensor controller processor (16-bit custom low power RISC processor). |
| Project from Scratch | Create a new Sensor Controller Studio project, generate the sensor controller driver and integrate with a TI-RTOS application. |
Sensor Controller application notes: