Microchip Technology MPLAB ICE, User Manual

Page: 181 / 192

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2001 Microchip Technology Inc. DS51159B-page 181
Glossary
Single Step
This command steps though code, one instruction at a time. After each
instruction, MPLAB IDE updates register windows, watch variables and status
displays so you can analyze and debug instruction execution.
You can also single step C compiler source code, but instead of executing
single instructions, MPLAB IDE will execute all assembly level instructions
generated by the line of the high level C statement.
Skew
The information associated with the execution of an instruction appears on
the processor bus at different times. For example, the executed opcode
appears on the bus as a fetch during the execution of the previous instruction,
the source data address and value and the destination data address appear
when the opcode is actually executed, and the destination data value appears
when the next instruction is executed. The trace buffer captures the
information that is on the bus at one instance. Therefore, one trace buffer
entry will contain execution information for three instructions. The number of
captured cycles from one piece of information to another for a single
instruction execution is referred to as the skew.
Skid
When a hardware break point is used to halt the processor, one or more
additional instructions may be executed before the processor halts. The
number of extra instructions executed after the intended break point is
referred to as the skid.
Source Code - Assembly
Source code consists of PICmicro instructions and MPASM directives and
macros that will be translated into machine code by an assembler.
Source Code - C
A program written in the high level language called “C” which will be
converted into PICmicro machine code by a compiler. Machine code is
suitable for use by a PICmicro MCU or Microchip development system
product like MPLAB IDE.
Source File - Assembly
The ASCII text file of PICmicro instructions and MPASM directives and
macros (source code) that will be translated into machine code by an
assembler. It is an ASCII file that can be created using any ASCII text editor.
Source File - C
The ASCII text file containing C source code that will be translated into
machine code by a compiler. It is an ASCII file that can be created using any
ASCII text editor.
Special Function Registers
Registers that control I/O processor functions, I/O status, timers, or other
modes or peripherals.