The Differences Between The Pt-Vme151A And The Vme151; Renamed Registers; New Devices; Dram Sizing - Performance Computer PT-VME161 User Manual

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Section APPENDICES
APPENDIX G: The differences between the PT-VME151A and the VME151
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NOTE: The following Appendix has been provided for customers that are upgrading from a PT-
VME151 to the PT-VME161. Information in this Appendix must be used to change native PT-
VME151 code to PT-VME151A code before applying changes needed for the PT-VME161.
It may be desirable to run software written for the PT-VME151 on a PT-VME151A. Most of the new
features on the 161 are disabled after reset, making them transparent to existing software. This appendix
is an overview of the programming issues that must be considered when porting code from the PT-
VME151/151E to the PT-VME151A.

Renamed Registers

The PT-VME151 System Control Register and the System Status Register have been renamed on the PT-
VME151A to System Control Register 1 and System Status Register 1, respectively. All fields in these
registers remain consistent with those defined by the PT-VME151.

New Devices

The "UNASSIGNED" addresses of the PT-VME151 would return Bus Errors when accessed. Several of
these address have been assigned to the new devices on the PT-VME151A. Any PT-VME151 code that
purposely accessed these locations to produce a Bus Error, may produce unwanted results on the PT-
VME151A.
Software may determine whether it is running on a PT-VME151 or a PT-VME151A by reading one of
the new device registers. If a no Bus Error occurs then the code is running on a PT-VME151A. A
summary of the new register assignment follows:

DRAM Sizing

The PT-VME151 could be configured with 1, 2, 4, or 8 MBytes of DRAM (Main Memory). The PT-
VME151A can be configured with 4, 8, 16, 32, or 64 Mbytes of DRAM. The installed DRAM repeats
throughout the address range 20000000h - 2FFFFFFFh. The pattern of repeatability differs from the 151
to the 151A. Software that takes advantage of the repeat pattern to size memory will have to be modified..
92 Extensible Single Board Computer/Controller User's Manual

Table 23: 151 to 161 Register Map DIfferences

ADDRESS RANGE
0D000000h-0DFFFFFFh
50000000h-5FFFFFFFh
0C000000h-0CFFFFFFh
60000000h-67FFFFFFh
68000000h-6FFFFFFFh
70000000h-7FFFFFFFh
PT-VME151
System Control Register
UNASSIGNED
System Status Register
UNASSIGNED
UNASSIGNED
UNASSIGNED
PT-VME161
System Control Register 1
System Control Register 2
System Status Register 1
System Status Register 2
System Status Register 3
82C54 Interval Timer