
SYSTEM MANAGER
S3C3410X RISC MICROPROCESSOR
4-16
DRAM/SDRAM SELF REFRESH CONTROL REGISTER (REFCON)
Register
Offset
Address
R/W
Description
Reset
Value
REFCON
0x2020
R/W
DRAM/SDRAM refresh control register
0x1
REFCON
Bit
Description
Initial State
VSMR
[0]
Validity of Special Memory Register (SMR):
Whenever CPU access one of system manager registers(SMR),
VSMR bit will be cleared automatically and all memory bank will
be disabled. To re-activate the memory bank, VSMR bit should
be set to 1 by using STMIA instruction(Data in the CPU registers
can be stored into the memory or memory mapped register by
single instruction). In other word, user should update the
necessary configuration in SMR as well as setting VSMR bit in
REFCON register, simultaneously. To do the simultaneous
updating, user should use the STMIA instruction, which can
transfer the CPU register data into SMR. The last data transfer
from CPU register should be data transfer to REFCON register to
set the VSMR bit.
0 = Not accessible to memory bank
1 = Accessible to memory bank
1
RC
[11:1]
Refresh Interval (Refresh Count): This RC field determine the
DRAM refresh period by below equation.
Refresh Period = (2
11 – refresh count + 1) / MCLK
Ex) If refresh period is 15.6us and MCLK is 33MHz, the refresh
count should be as follows:
Refresh Count = 2
11 + 1 – 33 x 15.6 = 1019 = 1111111011b
00000000000b
REN
[12]
Refresh Enable: If Bank 6 and/or Bank 7 are configured to have
DRAM bank by MT[1:0] field in SYSCFG register, this bit has
following option.
0 = Disable DRAM refresh.
1 = Enable DRAM refresh.
If Bank 6 and/or Bank 7 are configured to have SDRAM bank by
MT[1:0] field in SYSCFG register, this bit has following option.
0 = Disable SDRAM auto-refresh.
1 = Enable SDRAM auto refresh.
0
Tch
[15:13]
CAS Hold Time. Please refer the timing diagram.
000 = 1 Clock
001 = 2 Clock
010 = 3 Clock
011 = 4 Clock
100 = 5 Clock
Other = Not used
000
Tcsr
[16]
CAS Set-up Time. Please refer the timing diagram.
0 = 1 Clock
1 = 2 Clock
0