The integrated circuit sensor may come in a variety of interfaces — analogue or digital; for digital, these could be Serial Peripheral Interface, SMBus/I2C or 1-Wire.
In OpenBSD, many of the I2C temperature sensors from the below list have been supported and are accessible through the generalised hardware sensors framework[3] since OpenBSD 3.9 (2006),[4][5]: §6.1 which has also included an ad-hoc method of automatically scanning the I2C bus by default during system boot since 2006 as well.
[6][5]: §5
In NetBSD, many of these I2C sensors are also supported and are accessible through the envsys framework,[7] although none are enabled by default outside of Open Firmware architectures like macppc,[8] and a manual configuration is required before first use on i386 or amd64.
[5]: §7.1 Remote uncooled IR thermal radiometer sensors are also commonly used in integrated circuits.