W632GU6NB
Publication Release Date: Aug. 20, 2018
Revision: A01
- 23 -
8.3.3
Mode Register MR2
The Mode Register MR2 stores the data for controlling refresh related features, Rtt_WR impedance,
and CAS write latency. The Mode Register 2 is written by asserting low on CS#, RAS#, CAS#, WE#,
high on BA1 and low on BA0 and BA2, while controlling the states of address pins according to the
Figure 7 below.
BA1
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
Rtt_WR
ASR
Address Field
Mode Register 2
BA1
BA0
0
0
0
0
1
1
1
1
MR0
MR1
MR2
MR3
5 (t
CK(avg)
≥ 2.5nS)
8 (1.5nS > t
CK(avg)
≥ 1.25nS)
9 (1.25nS > t
CK(avg)
≥ 1.07nS)
6 (2.5nS > t
CK(avg)
≥ 1.875nS)
7 (1.875nS > t
CK(avg)
≥ 1.5nS)
A5
A4
A3
1
0
0
0
0
0
0
1
1
0
0
1
0
1
0
A7
1
0
Normal operating temperature range
Extended operating temperature range
ASR enable
Manual SR Reference (SRT)
BA0
A13
1
0
0
*
1
Reserved
Reserved
1
1
1
1
0
0
1
1
1
A10
0
0
1
1
A9
0
1
0
1
Dynamic ODT off
(Write does not affect Rtt value)
Reserved
RZQ/4
RZQ/2
A2
0
0
0
0
1
1
1
1
A1
0
0
1
1
0
0
1
1
A0
0
1
0
1
0
1
1
0
Full array
1/8th Array (BA[2:0]=000)
3/4 Array (BA[2:0]=010,011,100,101,110 & 111)
1/8th Array (BA[2:0]=111)
Quarter Array (BA[2:0]=110 & 111)
Half Array (BA[2:0]=000,001,010 & 011)
Quarter Array (BA[2:0]=000 & 001)
Half Array (BA[2:0]=100,101,110 & 111)
0
*
1
SRT
CWL
PASR
BA2
0
*
1
MR Select
A6
1
0
Auto Self Refresh (ASR)
Self Refresh Temperature (SRT) Range
Rtt_WR*
2
Partial Array Self Refresh for 8 Banks
CAS write Latency (CWL)
10 (1.07nS > t
CK(avg)
≥ 0.938nS)
Notes:
1. BA2, A8, A11~A13 are reserved for future use and must be programmed to
“0” during MRS.
2. The Rtt_WR value can be applied during writes even when Rtt_Nom is disabled. During write leveling, Dynamic ODT is not
available.
Figure 7
– MR2 Definition