Implementation And Memory Requirements; Using Ppcbug - Motorola MVME5100 Manual

3 PPCBug Firmware
Because PPCBug is command-driven, it performs its various operations in response to user
commands entered at the keyboard. When you enter a command, PPCBug executes the
command and the prompt reappears. However, if you enter a command that causes execution
of user target code (for example, GO), then control may or may not return to PPCBug,
depending on the outcome of the user program.

Implementation and Memory Requirements

PPCBug is written largely in the C programming language, providing benefits of portability and
maintainability. Where necessary, assembly language has been used in the form of separately
compiled program modules containing only assembler code.
Physically, PPCBug is contained in two socketed 32-pin PLCC Flash devices that together
provide 1MB of storage. The executable code is checksummed at every power-on or reset
firmware entry. The result (which includes a precalculated checksum contained in the flash
devices), is verified against the expected checksum.
PPCBug requires a maximum of 768KB of read/write memory. The debugger allocates this
space from the top of memory. For example, a system containing 64MB (0x04000000) of
read/write memory will place the PPCBug memory locations 0x03F40000 to 0x3FFFFFF.
Additionally, the first 1MB of DRAM is reserved for the exception vector table and stack.

Using PPCBug

PPCBug is command-driven; it performs its various operations in response to commands that
you enter at the keyboard. When the
is ready to accept debugger commands. When the
the debugger is ready to accept diagnostics commands. To switch from one mode to the other,
enter SD.
What you enter is stored in an internal buffer. Execution begins only after you press the Return
or Enter key. This allows you to correct entry errors, if necessary, with the control characters
described in the PPCBug Firmware Package User's Manual, listed in
Documentation.
After the debugger executes the command, the prompt reappears. However, depending on
what the user program does, if the command causes execution of a user target code (that is,
GO), then control may or may not return to the debugger.
18
MVME5100 Installation and Use (V5100A/IH5)
If you are in the debugger directory, the debugger prompt PPC6-Bug> is
displayed and you have all of the debugger commands at your disposal.
If you are in the diagnostic directory, the diagnostic prompt PPC6-Diag> is
displayed and you have all of the diagnostic commands at your disposal as well
as all of the debugger commands.
prompt appears on the screen, the debugger
PPC6-Bug>
PPC6-Diag>
prompt appears on the screen,
Appendix D, Related