Hi,
I am using spd_82801.c file to get the SPD values
of the my DDR SDRAM. I have checked the values and it seem to be
correct.
Now I want to program the DRAM registers. When I
was browsing the 440gx code, I could found that these SPD values are not used
directly to
get the DRAM register value.
I could not understand the step used to
calculate the DRAM register values. In the specification I could see only the
description of DRAM register, not the
steps to calculate the value of DRAM register.
Where can I find those steps? How do you get to know for the 440gx ? Is it ok to
hardcode the values ?
I am going for this option because our system is a
embedded system, so the configuration will not change.
Also while browsing the 440gx code, I found
that most of the register are left with default values. Can any one
giving some idea about the set of registers which I need to
program. I have attached the output of the SPD
program. But how to calculate the DRAM register values like DRB, DRT, DRC,FDHC
and etc.,
The Output of the SPD_82801.c file on my DDR
SDRAM:
[root@wipro2 scanspd]# ./spd_82801ba
dev=1f,
fn=3
IO_BASE=5000
After reset status 0x40
SLOT
0
After reset status 0x40
Number of bytes used by module
manufacturer 0x80
After reset status 0x40
Memory Type
0x07 ---------------> DDR SDRAM
After reset status
0x40
Number of Row Address bits 0x0d
After reset status
0x40
Number of Column Address bits 0x0a
After reset
status 0x40
Number of Sides 0x01
After reset status
0x40
DIMM Configuratio type 0x00
After reset status
0x40
Refresh Rate 0x82-------------------------------> refresh
rate is 7.8 micro sec
After reset status 0x40
Number of
Banks 0xa0
After reset status 0x40
Module Bank Density
0x40
After reset status 0x40
SPD Revision Code
0x00
After reset status 0x40
CAS # Latency
0x0c
-----------------------> 2.5
After reset status
0x40
Min Row Precharge 0x50
After reset status
0x40
Min RAS to CAS Delay 0x50 ------------------------------> 20
ns
After reset status 0x40
Min RAS Pulse Width
0x2d
[root@wipro2 scanspd]#
Thanks,
Siva