emc646sp16ak Emlsi Inc., emc646sp16ak Datasheet - Page 27

• Manufacturer Part Number: emc646sp16ak
• Description: 4mx16 Bit Cellularram
• Manufacturer: Emlsi Inc.

Refresh Configuration Register
The refresh configuration register (RCR) defines how the CellularRAM device performs its transparent self refresh. Altering the refresh
parameters can dramatically reduce current consumption during standby mode. Page mode control is also embedded into the RCR.
Figure 20 describes the control bits used in the RCR. At power-up, the RCR is set to 0010h. The RCR is accessed with CRE HIGH and
A[19:18] = 00b; or through the register access software sequence with DQ = 0000h on the third cycle.
Figure 20: Refresh Configuration Register Mapping
Address Bus
All must be
RCR[19] RCR[18]
set to “0”
A[21:20]
Reserved
21-20
0
1
0
RCR[7]
A[19:18]
0
0
1
0
1
Register
Select
19-18
Select RCR
Select BCR
Select DIDR
Page Mode Disable (default)
Page Mode Enable
Page Mode Enable/Disable
Register Select
All must be
set to “0”
Reserved
A[17:8]
17-8
Page
A7
7
Setting is ignored
A6
6
(Default 00b)
Reserved
RCR[4]
A5
0
1
5
27
DPD Enable
DPD Disable (default)
Deep Power-Down
DPD
A4
4
RCR[2]
Must be set to “0”
0
0
0
0
1
1
1
1
Reserved
A3
3
RCR[1]
0
0
1
1
0
0
1
1
EMC646SP16AK
A2
2
RCR[0]
0
1
1
0
1
0
1
0
4Mx16 CellularRAM
Full array (default)
Bottom 1/2 array
Bottom 1/4 array
Bottom 1/8 array
None of array
Top 1/2 array
Top 1/4 array
Top 1/8 array
PAR
A1
Refresh Coverage
1
A0
0