Motorola MVME197LE manual System Considerations

Hardware Preparation and Installation

provided in the MVME197LE, MVME197DP, and MVME197SP Single

2Board Computers Programmer’s Reference Guide). Some cable(s) are not provided with the MVME712X module and therefore, are made or provided by the user. (Motorola recommends using shielded cables for all connections to peripherals to minimize radiation). Connect the peripherals to the cable(s).

g.Install any other required VMEmodules in the system.

h.Replace the chassis cover.

i.Connect the power cable to the ac power source and turn the equipment power ON.

System Considerations

The MVME197LE needs to draw power from both connectors P1 and P2 of the VMEbus backplane. Connector P2 is also used for the upper 16 bits of data for 32-bit transfers, and for the upper 8 address lines for the extended addressing mode. The MVME197LE may not operate properly without its main board connected to connectors P1 and P2 of the VMEbus backplane.

Whether the MVME197LE operates as a VMEbus master or as a VMEbus slave, it is configured for 32 bits of address and for 32 bits of data (A32/D32). However, it handles A16 or A24 devices in certain address ranges. D8 and/or D16 devices in the system must be handled by software. Refer to the memory maps in the MVME197LE, MVME197DP, and MVME197SP Single Board Computers Programmer’s Reference Guide.

The MVME197LE contains shared onboard DRAM whose base address is software-selectable. Both the onboard processor and off-board VMEbus devices see this local DRAM at base physical address $00000000, as programmed by the MVME197Bug firmware. This may be changed, by software, to any other base address. Refer to the MVME197LE, MVME197DP, and MVME197SP Single Board Computers Programmer’s Reference Guide for details.

If the MVME197LE tries to access off-board resources in a non-existent location, and is not the system controller, and if the system does not have a global bus timeout, the MVME197LE waits forever for the VMEbus cycle to complete. This would cause the system to hang up. There is only one situation in which the system might lack this global bus timeout: when the MVME197LE is not the system controller and there is no global bus timeout elsewhere in the system.

2-8 Installation Guide