Technical data

Functional Description
http://www.mcg.mot.com/literature 4-5
4
Functional Description
This section contains a functional description of the major blocks on the
MVME172LX.
Data Bus Structure
The local bus on the MVME172LX is a 32-bit synchronous bus that is
based on the MC68060 bus, and which supports burst transfers and
snooping. The various local bus master and slave devices use the local bus
to communicate. The local bus is arbitrated by priority type; the priority of
the local bus masters from highest to lowest is: 82596CA LAN, 53C710
SCSI, VMEbus, and MPU. As a general rule, any master can access any
slave; not all combinations pass the common sense test, however. Refer to
the MVME172 VME Embedded Controller Programmer’s Reference
Guide and to the user’s guide for each device to determine its port size, data
bus connection, and any restrictions that apply when accessing the device.
Microprocessor
The MVME172LX may be ordered with an MC68060 or MC68LC060
microprocessor.
The MC68060 has on-chip instruction and data caches and a floating point
processor. (The floating point coprocessor is the major difference between
the MC68060 and MC68LC060.) Refer to the M68060 user’s manual for
more information.
MC68
xx 060 Cache
The MVME172LX local bus masters (VMEchip2,
MC68060/MC68LC060, 53C710 SCSI controller, and 82596CA Ethernet
controller) have programmable control of the snoop/caching mode. The
MVME172LX local bus slaves which support MC68060/MC68LC060
bus snooping are defined in the “Local Bus Memory Map” in the
MVME172 VME Embedded Controller Programmer’s Reference Guide.
The Industry Pack DMA has jumpers to control the state of the snoop
control signals.