Operation Fundamentals
Debug Commands
MMDS0508OM/D
MOTOROLA
Operation Fundamentals
71
Debug Commands
The MMDS commands that apply to the debugging phase of system
development are described in this section.
Setting CPU
Registers
The contents of the CPU registers and the condition code register are
displayed in the CPU window. These registers – A, H (MMDS08 only),
X, PC, SP, and CCR – contain the environment for execution of an
instruction and, after the instruction has been executed, the results. Any
of these registers, except SP, can be modified by entering the
corresponding register designator command and an appropriate value.
The commands that affect the CPU registers are A, ACC, X, XREG, PC,
CCR, H, I, N, Z, and C. Additional commands to support the M68HC08
MCU are HX, HREG, and V. When <CR> is pressed, the register display
shows the new value. Refer to
Command-Line Commands
for
examples on how to modify CPU register values.
Memory Display
Memory contents are displayed in the memory F3 window. When code
execution is stopped, 32 consecutive bytes of memory are displayed in
both hexadecimal and ASCII format. The memory display (MD)
command specifies the beginning location of the 32 bytes displayed. The
window can be scrolled via the mouse or by selecting the window (F3)
and using page up/down keys to view other memory ranges.
A special use of the memory F3 window is for displaying real-time
memory during code execution. The display real-time memory (RTMEM)
command specifies the beginning location of a 32-byte clock to display
and periodically update during code execution.
The display real-time variable (RTVAR) command and display variable
(VAR) command display the specified address and its contents in the
variables F8 window. Real-time variables are periodically updated
during code execution while normal variables are only displayed when
code execution is stopped.
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