6.4 Sensor Controller
The Sensor Controller contains circuitry that can be selectively enabled in standby mode. The peripherals in this domain may be controlled by the Sensor Controller Engine, which is a proprietary power-optimized CPU. This CPU can read and monitor sensors or perform other tasks autonomously; thereby significantly reducing power consumption and offloading the main CM3 CPU.
A PC-based development tool called Sensor Controller Studio is used to write, test, and debug code for the Sensor Controller. The tool produces C driver source code, which the System CPU application uses to control and exchange data with the Sensor Controller. Typical use cases may be (but are not limited to) the following:
- Analog sensors using integrated ADC
- Digital sensors using GPIOs with bit-banged I2C or SPI
- Capacitive sensing
- Waveform generation
- Pulse counting
- Key scan
- Quadrature decoder for polling rotational sensors
The peripherals in the Sensor Controller include the following:
- The low-power clocked comparator can be used to wake the device from any state in which the comparator is active. A configurable internal reference can be used with the comparator. The output of the comparator can also be used to trigger an interrupt or the ADC.
- Capacitive sensing functionality is implemented through the use of a constant current source, a time-to-digital converter, and a comparator. The continuous time comparator in this block can also be used as a higher-accuracy alternative to the low-power clocked comparator. The Sensor Controller takes care of baseline tracking, hysteresis, filtering, and other related functions.
- The ADC is a 12-bit, 200-ksamples/s ADC with 8 inputs and a built-in voltage reference. The ADC can be triggered by many different sources, including timers, I/O pins, software, the analog comparator, and the RTC.
- The analog modules can be connected to up to eight different GPIOs (see Table 6-1).
The peripherals in the Sensor Controller can also be controlled from the main application processor.
Table 6-1 GPIOs Connected to the Sensor Controller(1)
| ANALOG CAPABLE |
CC13x0 |
7 × 7 RGZ
DIO NUMBER |
5 × 5 RHB
DIO NUMBER |
4 × 4 RSM
DIO NUMBER |
| Y |
30 |
14 |
|
| Y |
29 |
13 |
|
| Y |
28 |
12 |
|
| Y |
27 |
11 |
9 |
| Y |
26 |
9 |
8 |
| Y |
25 |
10 |
7 |
| Y |
24 |
8 |
6 |
| Y |
23 |
7 |
5 |
| N |
7 |
4 |
2 |
| N |
6 |
3 |
1 |
| N |
5 |
2 |
0 |
| N |
4 |
1 |
|
| N |
3 |
0 |
|
| N |
2 |
|
|
| N |
1 |
|
|
| N |
0 |
|
|
(1) Depending on the package size, up to 15 pins can be connected to the Sensor Controller. Up to eight of these pins can be connected to analog modules.