2-1
CHAPTER 2
USING THE MONITOR/DEBUG FIRMWARE
The SBC5307 Computer Board has a resident firmware package that provides a self-contained
programming and operating environment. The firmware, named dBUG, provides the user with
monitor/debug, disassembly, program download, and I/O control functions. This Chapter is a how-to-use
description of the dBUG package, including the user interface and command structure.
2.1
WHAT IS dBUG?
dBUG is a resident firmware package for the ColdFire® family Computer Boards. The firmware (stored in
two 512Kx8 Flash ROM devices) provides a self-contained programming and operating environment.
dBUG interacts with the user through pre-defined commands that are entered via the terminal.
The user interface to dBUG is the command line. A number of features have been implemented to achieve
an easy and intuitive command line interface.
dBUG assumes that an 80x24 character dumb-terminal is utilized to connect to the debugger. For serial
communications, dBUG requires eight data bits, no parity, and one stop bit, 8N1. The baud rate is 19200
but can be changed after the power-up.
The command line prompt is “dBUG> “. Any dBUG command may be entered from this prompt. dBUG
does not allow command lines to exceed 80 characters. Wherever possible, dBUG displays data in 80
columns or less. dBUG echoes each character as it is typed, eliminating the need for any “local echo” on
the terminal side.
In general, dBUG is not case sensitive. Commands may be entered either in upper or lower case, depending
upon the user’s equipment and preference. Only symbol names require that the exact case be used.
Most commands can be recognized by using an abbreviated name. For instance, entering “h” is the same
as entering “help”. Thus, it is not necessary to type the entire command name.
The commands DI, GO, MD, STEP and TRACE are used repeatedly when debugging. dBUG recognizes
this and allows for repeated execution of these commands with minimal typing. After a command is
entered, simply press <RETURN> or <ENTER> to invoke the command again. The command is executed
as if no command line parameters were provided.
An additional function called the "TRAP 15 handler" allows the user program to utilize various routines
within dBUG. The TRAP 15 handler is discussed at the end of this chapter.
The operational mode of dBUG is demonstrated in
Figure 5
. After the system initialization, the board waits
for a command-line input from the user terminal. When a proper command is entered, the operation
continues in one of the two basic modes. If the command causes execution of the user program, the dBUG
firmware may or may not be re-entered, depending on the discretion of the user. For the alternate case, the
