Heimdall-Slave is a product consisting of a PIR (Pyroelectric Infra-Red) sensor, a highly integrated 433MHz ISM band radio transmitter together with a 32-bit general purpose ARM M0-based microcontroller.

Heimdall-Slave integrates 160kB of flash RAM and 8kB of SRAM on die. It integrates multiple clocking options including use of an external low cost 30MHz XTAL and integrated low power (<1uA) 10kHz auxiliary clock, for high performance, low power designs.

The integrated wireless transmitter operates in the 433 MHz ISM band with capability from 310MHz – 450 MHz covered by a single crystal and a fractional-N PLL. FSK, PSK and ASK modulation are all fully supported.

The PIR interface consists of two extremely low-power uncommitted operational amplifiers, which may be configured as bandpass filters to condition the PIR sensor’s output; plus a window comparator, which may be used in combination with a digital state machine, to determine the validity of motion events.