The infrared (IR) emitter is turned on and off by applying PWM pulses to the IR LED pin (P0.24).
The IR receiver is turned on by pulling the IR_REC pin (P0.23) high. The IR signal from the IR receiver is sent to the nRF52 SoC through the node IR SIGNAL pin (P0.21).
Figure 1. Infrared emitter/receiver schematic
