Datasheet

Mode Register MR3
Table 11. MR3 Definition
BG0
BA1
BA0
RAS#
/A16
CAS#
/A15
WE#/
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
0
1
1
0
0
0
0
*1
MPR Read
Format
Write CMD
Latency
Fine Granularity
Refresh Mode
TS
PDA
Gear
Down
MPR
MPR Page
Selection
*3
Note 1. Reserved for future use and must be programmed to 0 during MRS.
Note 2. Write Command latency when CRC and DM are both enabled:
 At less than or equal to 1600 then 4t
CK
; neither 5t
CK
nor 6t
CK
 At greater than 1600 and less than or equal to 2666 then 5t
CK
; neither 4t
CK
nor 6t
CK
Note 3. Refer to MPR Data Format table.
A12
A11
MPR Read Format
A10
A9
CRC+DM Write Command Latency
*2
A1
A0
MPR Page Selection
0
0
Serial
0
0
4 t
CK
(DDR4-1600)
0
0
Page0
0
1
Parallel
0
1
5 t
CK
(DDR4-1866/2133/2400/2666)
0
1
Page1
1
0
Staggered
1
0
Page2
1
1
Reserved
A3
Geardown Mode
1
1
Page3
0
1/2 Rate
A8
A7
A6
Fine Granularity Refresh
1
1/4 Rate
0
0
0
Normal (Fixed 1x)
A2
MPR Operation
0
0
1
Fixed 2x
A4
Per DRAM Addressability
0
Normal
0
1
0
Fixed 4x
0
Disable
1
Dataflow from/to MPR
0
1
1
Reserved
1
Enable
1
0
0
Reserved
1
0
1
Enable on the fly 2x
A5
Temperature sensor
1
1
0
Enable on the fly 4x
0
Disable
1
1
1
Reserved
1
Enable
AS4C256M16D4
Confidential
- 20 of 201 -
Rev.1.0 Aug.2019