Personal Computer User Manual

Preparation

http://www.motorola.com/computer/literature 1-7

Whether the MVME5100 operates as a VMEbus master or as a VMEbus

slave, it is configured for 32 bits of address and 32 bits of data (A32/D32).

However, it handles A16 or A24 devices in the appropriate address ranges.

D8 and/or D16 devices in the system must be handled by the processor

software.

If the MVME5100 tries to access off-board resources in a nonexistent

location and if the system does not have a global bus time-out, the

MVME5100 waits indefinately for the VMEbus cycle to complete. This

will cause the system to lock up. There is only one situation in which the

system might lack this global bus time-out; that is when the MVME5100

is not the system controller and there is no global bus time-out elsewhere

in the system.

Note Software can also disable the bus timer by setting the appropriate

bits in the Universe II VMEbus interface.

Multiple MVME5100 boards may be installed in a single VME chassis;

however, each must have a unique VMEbus address. Other MPUs on the

VMEbus can interrupt, disable, communicate with, and determine the

operational status of the processor(s).