Dram Mapping; Sizing - Performance Computer PT-VME161 User Manual

DRAM Mapping

DRAM Size Address Range
4 MBytes 20000000-203FFFFFh
20400000-20FFFFFFh
21000000-213FFFFFh
21400000-21FFFFFFh
The pattern of (4M Normal) - (12M Blank) - (4M Normal) - (12M Blank) repeats
throughout the range of 20000000-2FFFFFFFh. Thus address 20000000h may be read
or written at 21000000h, 22000000h, etc.
8 MBytes 20000000-207FFFFFh
20800000-20FFFFFFh
21000000-217FFFFFh
21800000-21FFFFFFh
The pattern of (8M Normal) - (8M Blank) - (8M Normal) - (8M Blank) repeats
throughout the range of 20000000-2FFFFFFFh. Thus address 20000000h may be read
or written at 21000000h, 22000000h, etc.
16 MBytes 20000000-20FFFFFFh
21000000-21FFFFFFh
The pattern of (16M Normal) - (16M Normal) repeats throughout the range of
20000000-2FFFFFFFh. Thus address 20000000h may be read or written at
21000000h, 22000000h, etc.
32 MBytes 20000000-21FFFFFFh
22000000-23FFFFFFh
24000000-25FFFFFFh
26000000-27FFFFFFh
The pattern of (32M Normal) - (32M Blank) - (32M Normal) - (32M Blank) repeats
throughout the range of 20000000-2FFFFFFFh. Thus address 20000000h may be read
or written at 24000000h, 28000000h, etc.
64 MBytes 20000000-23FFFFFFh
24000000-27FFFFFFh
The pattern of (64M Normal) - (64M Normal) repeats throughout the range of
20000000-2FFFFFFFh. Thus address 20000000h may be read or written at
24000000h, 28000000h, etc.

Sizing

To size DRAM perform the following steps:
Step 1 Write location 20000000h with AA55AA55h.
Step 2 Set Memory pointer to 20400000h
Response
Normal
Blank
Normal - repeat of 20000000-203FFFFF
Blank
Normal
Blank
Normal - repeat of 20000000-207FFFFF
Blank
Normal
Normal - repeat of 20000000-20FFFFFF
Normal
Blank
Normal - repeat of 20000000-21FFFFFF
Blank
Normal
Normal - repeat of 20000000-23FFFFFF
Extensible Single Board Computer/Controller User's Manual 29
Performance Computer