The MC9S12D is a 16-bit MCU composed of standard on-chip peripherals, including: * Two asynchronous serial communications interfaces * 8-channel IC/OC enhanced capture timer * Two 8-channel, 10-bit analog-to-digital converters (ADC) * 8-channel pulse-width modulator (PWM) * 20 discrete digital I/O lines * Inter-IC Bus System resource mapping, clock generation, interrupt control and bus interfacing are managed by the System Integration Module (SIM). The MC9S12D 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. A PLL circuit allows power consumption and performance to be adjusted.