Motorola MVME177 manual Hardware Preparation and Installation

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Hardware Preparation and Installation

firmware. This may be changed, by software, to any other base address. Refer to the Single Board Computers Programmer's Reference Guide for details.

If the MVME177 attempts to access offboard resources in a nonexistent location, and is not system controller, and if the system does not have a global bus time-out, the MVME177 waits forever for the VMEbus cycle to complete. This causes the system to hang up. There is only one situation in which the system might lack this global bus time-out:

❏The MVME177 is not the system controller, and

❏There is no global bus time-out elsewhere in the system

Multiple MVME177 modules may be configured into a single VME card cage. In general, hardware multiprocessor features are supported.

Other MPUs on the VMEbus can:

❏Interrupt

❏Disable

❏Communicate with, and

❏Determine the operational status of

the processor(s). One register of the GCSR set includes four bits which function as location monitors to allow one MVME177 processor to broadcast a signal to other MVME177 processors, if any. All eight registers are accessible from any local processor as well as from the VMEbus.

The MVME177 provides +12 Vdc power to the Ethernet LAN transceiver interface through a 1 amp polyswitch F2 located on the MVME177 module. The +12V LED lights when +12 Vdc is available. The polyswitch is located near diode CR1. Polyswitches act like circuit breakers that reset automatically when the excessive load is removed. If the Ethernet transceiver fails to operate, check

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