Memory Requirements; Ppcbug Implementation; Mpu, Hardware, And Firmware Initialization - Motorola MVME2301 Installation And Use Manual

Memory Requirements

PPCBug requires a maximum of512KB of read/write memory (i.e.,
DRAM). The debugger allocates this space from the top of memory.
For example, a system containing 64MB ($04000000) of read/write
memory will place the PPCBug memory page at locations
$03F80000 to $03FFFFFF.

PPCBug Implementation

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. No mixed-language modules are used.
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,
and the result (which includes a precalculated checksum contained
in the Flash devices), is verified against the expected checksum.

MPU, Hardware, and Firmware Initialization

The debugger performs the MPU, hardware, and firmware
initialization process. This process occurs each time the MVME230x
is reset or powered up. The steps below are a high-level outline; not
all of the detailed steps are listed.
1. Sets MPU.MSR to known value.
2. Invalidates the MPU's data/instruction caches.
3. Clears all segment registers of the MPU.
4. Clears all block address translation registers of the MPU.
5. Initializes the MPU-bus-to-PCI-bus bridge device.
6. Initializes the PCI-bus-to-ISA-bus bridge device.
PPCBug
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