This paper proposes a standalone, integrated 2.4-GHz Wake-up Radio receiver (WUR), compliant with the IEEE 802.11ba standard. The chip, fabricated in CMOS 40-nm, demonstrates a very low power consumption, and includes a RISC-V microprocessor, with AES encryption engine, to im- plement the MAC layer, communicate with the main Wi-Fi radio, and execute the calibration routines for internal analog circuitry. In addition to the mandatory features required by the standard, the dedicated microprocessor allows to interface external sensors and actuators, to realize smart IoT devices with Wi-Fi communication.