MC68HC12 Datasheet, PDF (395/478 Pages) Motorola, Inc – The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit

Technical Data — MC68HC912DT128A
Section 20. Development Support
20.1 Contents
20.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
20.3 Instruction Queue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .395
20.4 Background Debug Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . .397
20.5 Breakpoints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
20.6 Instruction Tagging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
20.2 Introduction
Development support involves complex interactions between
MC68HC912DT128A resources and external development systems.
The following section concerns instruction queue and queue tracking
signals, background debug mode, and instruction tagging.
20.3 Instruction Queue
The CPU12 instruction queue provides at least three bytes of program
information to the CPU when instruction execution begins. The CPU12
always completely finishes executing an instruction before beginning to
execute the next instruction. Status signals IPIPE[1:0] provide
information about data movement in the queue and indicate when the
CPU begins to execute instructions. This makes it possible to monitor
CPU activity on a cycle-by-cycle basis for debugging. Information
available on the IPIPE[1:0] pins is time multiplexed. External circuitry
can latch data movement information on rising edges of the E-clock
signal; execution start information can be latched on falling edges. Table
20-1 shows the meaning of data on the pins.
MC68HC912DT128A — Rev 4.0
MOTOROLA
Development Support
Technical Data
395