GMS30C7201 Datasheet, PDF (80/352 Pages) Hynix Semiconductor – 60MHz operation frequency Low power consumption

SDRAM Controller
The SDRAM controller powers-up with E[3:0]=0000 and R=0. This indicates that the memory
interface is IDLE. Next, the software should set at least one E bit to 1 with the R bit 0. This will
cause all four devices to be precharged (if present). The next operation in the initialization
sequence is to auto-refresh the SDRAMs. Note that the number of refresh operations required
is device-dependent. Set the R bit to 1 and all the E bits to 0000 to start the auto-refresh process.
Software will have to ensure that the prescribed number of refresh cycles are completed before
moving on to the next step. The final step in the sequence is to set the R bit to 1 and to set the E
bits corresponding to the populated slots. This will put the SDRAM controller (and the
SDRAMs) in their normal operational mode.
SOFTWARE EXAMPLE OPERATION
Write
E[3:0] = 0000
R=0
MEMORY OPERATION
IDLE
Write
E[3:0] = 0001
R=0
PRECHARGE
Write
E[3:0] = 0000
R=1
AUTO-REFRESH
No, wait
Refresh complete?
Yes
Write
E[3:0] = According to slot
populated
R=1
MEMORY REFRESHING
MEMORY START
NORMAL OPERATION
End of initialization
Figure 8-1: Software example/memory operation diagram
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GMS30C7201 Data Sheet