Ensure your space remains cozy and balanced with Si7034 and PIC18F57Q43

Temp&Hum 2 Click is based on the Si7034, a digital humidity and temperature sensor IC with I2C interface, from Silicon Labs. It is a digital relative humidity and a temperature sensor that integrates temperature and humidity sensor elements, an analog-to-digital converter, signal processing, calibration, and data correction on the chip. Each chip is factory calibrated, and the calibration data is stored in its non-volatile memory. The maximum accuracy achieved with this sensor is ± 4% RH for the humidity range from 0 to 80%. Besides the humidity sensing element, this sensor includes an accurate thermal sensor, which can achieve up to ±0.4 °C. It is used in conjunction with the humidity measurement, to allow thermal compensation of the relative humidity measurements. This sensor IC also has an integrated heating element that is used to evaporate condensation reducing the effect of the offset accumulation when used in high humidity conditions, or to implement dew-point

measurement when the Si7034 is used with a separate temperature sensor. The heating element current can be adjusted by the appropriate bits in the Humidity Control Register. Due to the nature of the used sensors, a special care should be taken to reduce the sensor contamination to a minimum. Particles, dirt or other artifacts collected on the surface of the exposed polymer film will affect its ability to measure the humidity, and therefore, the manufacturer recommends protecting the sensor against particles. The sensor otherwise has a long aging period with minimal drift. Synthetic long-term stability tests show less than 0.25 %RH per year drift. The data provided by the IC is ready to be used directly. Two measurements are done when a command is received via the I2C. One is the humidity measurement, while the second is temperature measurement, used for the compensation. Si7034 IC operates on 1.8V and therefore, a small LDO has to be used to convert 3.3V from the mikroBUS™

power rail, down to 1.8V. In addition, the I2C signal voltage levels also have to be converted so it can be used with the MCUs operated with 3.3V. For this purpose, the Click board™ utilizes the PCA9306, a level shifting IC, made by Texas Instruments. It uses 1.8V as the first reference voltage and 3,3V from the mikroBUS™ power rail as the second reference voltage, shifting the I2C communication signal levels, allowing this Click board™ to be used with MCUs operated at 3.3V. The sensor IC is physically located away from other components on the Click board™, so the heating influence of the surrounding components or PCB is reduced to a minimum, allowing the accuracy of the Click board™ to stay within the specifications. The i2C lines of the IC are routed to the mikroBUS™ and supplied by the pull-up resistors, allowing this Click board™ to be used right out of the box. Temp&Hum 2 click uses only 3.3V rail from the mikroBUS™.

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.