[FAQ] HDC2080/HDC2010 - When and why should I use the DRDY/INT pin?

The HDC20x0 devices have a firmware behavior selectable pin named DRDY/INT. The purpose of this pin is to provide an interrupt back to an MCU with interrupt capable GPIO (to allow MCU to sleep in between sensor measurement) or polled GPIO (if MCU not sleeping) when the HDC20x0 device is placed in automatic measurement mode, after a measurement has been completed, to wake up the MCU and trigger a read of the registers 0x00 through 0x03 routine. The key advantage of this is low power consumption at a system level, because both the sensor and the MCU can sleep in-between measurements, which is critical in today’s plethora of battery powered devices, where every coulomb counts. When using the DRDY/INT pin feature, the firmware developer should ensure they write register 0x07 with 0x80 and then write register 0x0E for setting the automatic mode of choice. We also recommend reading register 0x04 for 0x80 (data ready) after the interrupt fires, to have a redundant check that new data is ready, before reading out temperature and humidity registers. If a board designer cannot route the DRDY/INT line due to unknown constraints, or design is using one-shot mode, we recommend at least reading register 0x04 for a value of 0x80 before reading out temperature and humidity registers.