Operation
D-Bug12 Command Set
M68HC12A4EVB Evaluation Board — Rev. 1
User’s Manual
MOTOROLA
Operation
65
Trace
T
Syntax:
T [<
Count>]
Where:
<
Count>
is an optional 8-bit decimal number in the range
1 to 255.
The TRACE command is used to execute one or more user program instructions
beginning at the current program counter (PC) location. As each program
instruction is executed, the CPU12’s register contents are displayed and the next
instruction to be executed is displayed. A single instruction may be executed by
entering the TRACE command immediately followed by a carriage return.
Restrictions:
Because of the method used to execute a single instruction, branch instructions
(Bcc, LBcc, BRSET, BRCLR, DBEQ/NE, IBEQ/NE, and TBEQ/NE) that
contain an offset that branches back to the instruction opcode do not execute.
The terminal appears to become stuck at the branch instruction and does not
execute the instruction even if the condition for the branch instruction is
satisfied. This limitation can be overcome by using the GT (GO TILL)
command to set a temporary breakpoint at the instruction following the branch
instruction.
When the CPU12 is not operating in background debug mode, there is no
specialized hardware available to execute a single instruction. The TRACE
command makes use of temporary software breakpoints as a means to control
CPU execution. For this reason, only instructions that reside in alterable
memory may be executed with the TRACE command.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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