AS8579 정전식 센서 -SPI
(HOD CAP CLICK)
개요
- 본 제품은 AS8579 정전식 센서 -SPI입니다.
- AS8579 센서 칩을 기반으로 디자인된 제품으로 정전변화를 검출하는 센서입니다.
- 자동차 휠을 손으로 잡고 있는지 등의 어플리케이션에 사용이 가능한 제품입니다.
특징
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HOW DOES IT WORK?
HOD CAP Click is based on the AS8579, a capacitive sensor from ams OSRAM. The AS8579 is a sensor that detects the change of capacity in different applications, as it measures the relative change of the impedance, which can be used for human being detection besides other usages. The sensors' primary function is the transceiver Analog Front-End (AFE) architecture. The AFE function senses the impedance of the output load by using transmitter and receiver blocks. The transmitter block supplies a sine wave across the load, which the receiver blocks capture. The current change is sensed, and the response is converted to a voltage and then demodulated into in-phase (I) and quadrature (Q) components. These I and Q components are later filtered and converted by a 10-bit ADC to digital words.
The HOD CAP Click comes with a 10-pin header for sense outputs labeled SEN0-9. Five of the ten output pins (SEN5-9) are additionally filtered by the SEN Line Filter circuits. You can set the on-chip ADC in a Single or Continuous Conversion depending on the task. The first causes ADC to wait for the system settling time before starting sampling, while the latter causes the ADC to take successive sample accumulations. Using the CLK SEL jumper, you can provide the system clock with a frequency in two ways. The selected option INT uses the internal PWM duty cycle of the host MCU to provide a desired frequency, which can be in the range of 3 up to 50MHz. The other option uses onboard 48MHz crystal.
In addition, the AS8579 comes with parasitic capacitance protection. A header consisting of VAR SEN, FIX SEN, and GND pins can be used for that purpose. The VAR SEN is a cable shielding driver and should be connected to a cable shielding to avoid parasitic capacitance influence from shielding. The FIX SEN should be connected to a PCB shield layer to avoid parasitic capacitance influences from the PCB shield layer. Otherwise, both should be connected to the GND. For the factory testing option, you can short the R5. The HOD CAP Click uses the standard 4-Wire SPI serial interface to communicate with the host MCU with a clock frequency of up to 8MHz.
This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VIO SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.
SPECIFICATIONS
Type Capacitive Applications Can be used for the development of autonomous driving applications such as hands-on steering wheel detection and detection of any human presence inside a vehicle or outside of the vehicle, e.g., for automatic trunk opener and more On-board modules AS8579 - capacitive sensor from ams OSRAM Key Features Accurate capacitive measurements, higher durability, and lower system costs, an enabler for safety-critical applications, suitable for automotive applications, 10 sense outputs from which five come with line sense filters, the possibility to set a system CLK frequency, and more Interface SPI Compatibility mikroBUS Click board size L (57.15 x 25.4 mm) Input Voltage 3.3V or 5V