W956D6HB Datasheet, PDF (30/57 Pages) Winbond – Low-power features

W956D6HB
64Mb Async./Burst/Sync./A/D MUX
8.4.4.1 Refresh Configuration Register Mapping
A [max :20] A[19:18] A [17:16], ADQ [15: 7] ADQ 6 ADQ5 ADQ 4 ADQ 3 ADQ 2 ADQ1 ADQ0
max-20 19 - 18 17 - 7
65 4
3
2 10
Reserved
Register
Select
Reserved
Ignored DPD Reserved
PAR
All must be set to“ 0 ” All must be set to“ 0 ” Setting is ignored Must be set to“ 0 ”
RCR[19] RCR[18]Register Select
0
0 Selsect RCR
1
0 Selsect BCR
0
1 Selsect DIDR
RCR [4] Deep Power - Down
0
DPD Enable
1
DPD Disable (default)
RCR[2] RCR[1] RCR[0] Refersh Coverage
0
0
0 Full array(default)
0
0
1 Bottom1/2 array
0
1
0 Bottom1/4 array
0
1
1 Bottom1/ 8 array
1
0
0
None of array
1
0
1
Top 1/2 array
1
1
0
Top 1/4 array
1
1
1
Top 1/8 array
Notes : Reserved bits must be set to zero. Reserved bits not set to zero will affect device functionality. RCR[15:0] will be read back
as written.
8.4.4.2 Partial Array Refresh (RCR[2:0]) Default = Full Array Refresh
The PAR bits restrict refresh operation to a portion of the total memory array. This feature allows the device to reduce
standby current by refreshing only that part of the memory array required by the host system. The refresh options are
full array, one-half array, one-quarter array, one-eighth array, or none of the array. The mapping of these partitions can
start at either the beginning or the end of the address map.
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Publication Release Date : May 29,2013
Revision : A01-003