Specifications

D
evice Driver Programming
7-8
VME Address Ranges 7
The following text explains the address ranges used by VME devices on the (H)VME
primary I/O bus when they are bus masters or bus slaves. These ranges are detailed in the
sections that follow.
Unlike PowerMAXION (Night Hawk) systems, on Power Hawk systems the processor
address and VME address are not always the same. The various busses and bridge chips
between the processor and the VMEbus provide mappings and translations. These are
summarized below.
VME Devices as VME Bus Slaves 7
When a processor acts as bus master on the VME bus and addresses VME devices on the
VME I/O bus, the VME device is a slave device. The Power Hawk 620/640 systems
provide a highly configurable addressing arrangement for VME slave accesses. Any
processor address range from 0xA0000000 to 0xFB00000 can be mapped to the
corresponding VME address with minor exceptions. Mappings are done in 64KB sections.
This mapping is provided as part of the PowerMAX OS (operating system.)
Details on the hardware map registers are provided in either the Motorola MVME 2600
Single Board Computer Programmer’s Reference Guide or the Motorola MVME 4600
Single Board Computer Programmer’s Reference Guide. Details on the configuration of
the VME mappings in PowerMAX OS are explained in the config(1m) command. The
default address ranges for VME slave access are shown in Table 7-1. The A32 address
range can be altered with the config(1m) command.
VME Devices as Bus Masters 7
When an VME device addresses memory (or other VME sources), the VME device is the
bus master. The address ranges for VME bus master accesses are shown in Table 7-2.
Table 7-1. Default VME Bus Slave Access
Mode Processor VME Size
A32: Start
End
0xC0000000
0xFAFFFFFF
0xC0000000
0xFAFFFFFF
944MB
A24: Start
End
0xFCC00000
0xFCFEFFFF
0xFFC00000
0xFFFEFFFF
4MB-64KB
A16: Start
End
0xFCFF0000
0xFCFFFFFF
0xFFFF0000
0xFFFFFFFF
64KB