Sensors
Sensors usually have an GPIO (digital), SPI, I2C, ADC or UART interface.
Digital sensors
The simplest digital sensors are buttons and sliders which were covered in the built-in hardware chapter above.
BlackSoC support for digital sensors
BlackSoC contains a module, mod_timer, that can be used to generate an interrupt on button presses. It also support mod_pwm that can be used to generate PWM outputs on digital pins, including simple audio output.
Other digital sensors are supported by mod_gpio in BlackSoC, for example mechanical and capacitive button, led and buzzer Grove sensors:
HC-SR04 ping sensor
Other digital sensors measure a pulse. An HC-SR04 ultrasonic ping sensor is such a device. It uses an output (trigger) pin to request a range measurement and then measures the length of the pulse on an input (echo) pin.
This is supported in BlackSoC by mod_ping. See the ping and theremin examples. See also Robotics below, for another use of an HC-SR04 sensor.
Rotary sensor
Other types of sensor use quadrature to count rotations. Two signals with a 90-degree phase difference allow the direction of rotation to be measured.
This is supported by mod_rotary in BlackSoC. See the rotary example. See also the pong VGA output example in the Output devices chapter.
The encoders on encoder motors are also quadrature rotation sensors. See the Actuators and Robotics chapters.
I2C sensors
A lot of sensors use the I2C interface.
Examples are the BME 280 temperature, atmospheric and humidity sensor, and the STM time of flight laser sensor.
These sensors can be driven in BlackSoC by the mod_i2c_master module.
BME 280
The BME 280 example and the Weather example in BlackSoC, use the BME 280 sensor.
12.2.2 STM Time of Flight sensor
The Time of Flight example uses the STM time of flight sensor.
DS 1307 Real Time Clock
The BlackSoC rtc example uses the DS1307 sensor.
SPI sensors
Some sensors, such as the Digilent ACL 2 Pmod acceleration sensor, use the SPI interface.
This is supported by mod_spi in BlackSoC. See the acl2 example.
Another SPI sensor is the Digilent AD 1 12-bit dual 1MSPS ADC sensor. The BlackSoC ad1 example uses that sensor.
UART sensors
Some sensors use a UART interface, such as most of the LEGO Mindstorms EV3 sensors – see the chapter below.
These are supported by mod_rs232 in BlackSoC. Most of the devices in the Communication devices chapter use uart.
Analog sensors
Some sensors use an analog interface, which requires and analog to digital converter (ADC) such as the Digilent AD1 described above. The BlackSoC ad1 example can be used to show the values coming from the joystick.
BlackSoC ad1 example: https://github.com/lawrie/icotools/tree/master/icosoc/examples/ad1
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