Intel D425 AU80610006252AA User Manual

Product codes
AU80610006252AA
Page of 153
 
Processor Configuration Registers 
 
 
 
68  
 
Datasheet  
1.6.2 
C0DRB0 - Channel 0 DRAM Rank Boundary Address 0 
B/D/F/Type: 0/0/0/MCHBAR 
Address Offset: 
200-201h 
Default Value: 
0000h 
Access: 
 RW/L; RO; 
Size: 16 
bits 
The DRAM Rank Boundary Registers define the upper boundary address of each DRAM 
rank with a granularity of 64MB. Each rank has its own single-word DRB register. 
These registers are used to determine which chip select will be active for a given 
address. Channel and rank map: 
ch0 rank0:  200h 
ch0 rank1:  202h 
ch0 rank2:  204h 
ch0 rank3:  206h 
Programming guide: 
1.  Non-stacked mode: 
If Channel 0 is empty, all of the C0DRBs are programmed with 00h. 
C0DRB0 = Total memory in ch0 rank0 (in 64MB increments) 
C0DRB1 = Total memory in ch0 rank0 + ch0 rank1 (in 64MB increments) 
and so on. 
2.  Stacked mode: 
CODRBs:  
 Similar to Non-stacked mode. 
 
 
Bit Access Default 
Value 
RST/
PWR 
Description 
15:10 RO 000000b 
Core 
Reserved ():  
9:0 RW/L  000h Core 
Channel 0 Dram Rank Boundary Address 0 
(C0DRBA0):  
This register defines the DRAM rank boundary 
for rank0 of Channel 0 (64 MB granularity) 
=R0 
R0 = Total rank0 memory size/64MB 
R1 = Total rank1 memory size/64MB 
R2 = Total rank2 memory size/64MB 
R3 = Total rank3 memory size/64MB