The low-power RF Core (LRF) implements a high-performance and highly flexible RF subsystem containing RF and baseband circuitry in addition to a software-defined digital radio (LRFD). LRFD provides a high-level, command-based API to a host CPU and handles all of the timing-critical and low-level details of many different radio PHYs. Several signals are also available to control external circuitry, such as RF switches or range extenders, autonomously. The modem is highly configurable and has the flexibility to support future standards. It is not programmable by customers but is instead loaded with precompiled images provided in the radio driver in the SimpleLink™ software development kit (SDK). This mechanism allows the radio platform to be updated for support of future versions of standards with over-the-air (OTA) updates while still using the same silicon. LRFD stores the code images in the RF SRAM and does not make use of any ROM memory; thus, image loading from flash only occurs once after boot, and no patching is required when exiting power modes.