
108
PRELIMINARY
82453KX/GX, 82452KX/GX, 82451KX/GX (MC)
A
2.3.8
CDNUM—CONTROLLER DEVICE NUMBER REGISTER
Address Offset:
49h
Default:
00010100 (450KX)
Attribute:
Read Only
This register contains the MC device number. This value is hard coded in the 450KX.
2.3.9
CMD—COMMAND REGISTER
Address Offset:
4C–4Fh
Default:
0000 0000 0000 0000 x000 1000 0000 1011b
(x=captured from address bus on reset).
Attribute:
Read/Write
This register controls DRAM configuration, various memory controller operations, and reports the in-order
queue depth.
Bits
Description
7:5
Reserved.
4:1
Fixed value. The upper four bits of the MC Device Number are always 1010 for the MC.
0
450KX: Fixed value. The lower bit of the MC Device Number is always 0.
450GX: MC Device Number. The lower bit of the MC device number is encoded as follows:
Bits[1:0]
Function
0MC #0
1MC #1
Bits
Description
31:16
Reserved.
15
In-order Queue Depth 1 Select. 1=Depth of 1. 0=Depth of 8. Value captured from A7#.
14:11
Active Interleaves. 1=Active. 0=Inactive. Each bit enables/disables a single interleave. For
example, bits[14:11]=0101 defines a 2-way interleaved system with interleaves 2 and 0 active.
Default is Bits[14:11]=0001.
0001010x (x=loaded at reset)
This number is loaded from the OMCNUM pin. This pin must be strapped (VCC3 or GND) appropriately. MC
Number 0 defaults to responding to DOS accesses (0–512 Kbytes). MC Number 1 defaults to this range
disabled (ignore these accesses).
Bit
Active Interleave
(450KX)
14
Reserved
13
Reserved
12
1
11
0
Active Interleave
(450GX)
3
2
1
0
For a 4-way interleaved system that is functionally reduced to a non-interleaved or 2-way inter-
leaved system, these bits define the currently active interleaves out of the four possible inter-
leaves. For a 4-way interleave, all bits must be set to 1.