I'm trying to bring up sdram in 815ep chipset.
I have some progress regarding ram initialization, but have many problems to resolve.
So I hope your comments, advise and help.
I made sdram initialization code for 815ep and tested sdram with "ram/ramtest.inc".
Some part of sdram works. But i can't access whole sdram. here's my output.
---------------------<cut>------------------
Ram1
Ram2
Ram3
Ram Enable 1
Ram Enable 2
Ram Enable 3
Ram Enable 4
Ram Enable 5
Ram4
Ram5
Ram6
Testing SDRAM : 00000000-00003fff
SDRAM fill:
00003fff
SDRAM verify:
00003fff
Done. <--- passed without errors.
Testing SDRAM : 00100000-0010ffff
SDRAM fill:
0010ffff
SDRAM verify:
00100000
<--- system stops while reading from sdram. without any error message.
---------------------<cut>------------------
As you can see above, fill & verify test passed for 0x0 ~ 0x3fff areas. but it fails
for 0x100000 ~ 0x10ffff areas. in detail, the whole system hangs at verification
(memory read & check correctness) period of ramtest routine.
Do you have any experience similar with this?.
Ofcause it's not becuase of faulty sdram.
Currently I does not use SPD to get sdram information. I set those
information manually. For those values that i set manully for my sdram
( 256M single side at DIMM0 ) is like belows.
DRP(0x52) : 0x0E
DRAMT(0x53)
refresh interval : 7.8us (010 normal operation mode)
CAS# latency : 3clk
I attached the code. Initially codes are taken from 440bx's raminit.inc.
I think it is easy to read for you guys played with other chipset's ram
initialization codes.
-
HeeChul Yun,
Researcher, Embedded S/W Team at ETRI
e-mail: [EMAIL PROTECTED]
phone: +82-042-860-1673
raminit.inc