The MC9S12DT128 microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit (HCS12 CPU), 128K bytes of Flash EEPROM, 8K bytes of RAM, 2K bytes of EEPROM, two asynchronous serial communications interfaces (SCI), two serial peripheral interfaces (SPI), an 8-channel IC/OC enhanced capture timer, two 8-channel, 10-bit analog-to-digital converters (ADC), an 8-channel pulse-width modulator (PWM), a digital Byte Data Link Controller (BDLC), 29 discrete digital I/O channels (Port A, Port B, Port K and Port E), 20 discrete digital I/O lines with interrupt and wakeup capability, three CAN 2.0 A, B software compatible modules (MSCAN12), a Byteflight module and an Inter-IC Bus. The MC9S12DT128 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 PLL circuit allows power consumption and performance to be adjusted to suit operational requirements.