The MC9S12A512 MCU is a 16-bit device composed of standard on-chip peripherals, including a HCS12 CPU. System resource mapping, clock generation, interrupt control and bus interfacing are managed by the system integration module (SIM). The MC9S12A512 has full 16-bit data paths throughout, however the external bus can operate in an 8-bit narrow mode so single 8-bit wide memory can be interfaced for lower cost systems. The inclusion of a phase-lock loop (PLL) circuit allows power consumption and performance to be adjusted.