The MC68HC908QT4CPE is a 8-bit 4.96bytes Microcontroller uses the enhanced M68HC08 central processor unit and is available with a variety of modules, memory sizes and types. In monitor mode, the MCU can execute code downloaded into RAM by a host computer while most MCU pins retain normal operating mode functions. All communication between the host computer and the MCU is through the PTA0 pin. A level-shifting and multiplexing interface is required between PTA0 and the host computer. PTA0 is used in a wired-OR configuration and requires a pull-up resistor. The rising edge of the internal RST signal latches the monitor mode. Once monitor mode is latched, the values on PTA1 and PTA4 pins can be changed. In monitor mode, the MCU uses different vectors for reset, SWI and break interrupt than those for user mode. The alternate vectors are in the $FE page instead of the $FF page and allow code execution from the internal monitor firmware instead of user code.
● Trimmable internal oscillator
● Auto wakeup from STOP capability
● Configuration register for MCU configuration options, including - Low-voltage inhibit trip point
● In-system FLASH programming
● FLASH security
● Six shared with keyboard interrupt function and ADC
● High current sink/source capability on all port pins
● Selectable pull-ups on all ports, selectable on an individual bit basis
● Low-voltage inhibit module - Software selectable trip point in CONFIG register
● Computer operating properly watchdog
● Low-voltage detection with reset
● External asynchronous interrupt pin with internal pull-up shared with general-purpose input pin
● Master asynchronous reset pin shared with general-purpose I/O pin
● Power-on reset
● Internal pull-ups on IRQ and RST to reduce external components
● Memory mapped I/O registers
● Power saving stop and wait modes
● Extensive loop control functions
● Memory-to-memory data transfers
● Fast 8 x 8 Multiply instruction
