AS4C128M16D3A-12BIN
z 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 table below.
Table 8. Extended Mode Register EMR (2) Bitmap
BA2 BA1 BA0 A13 A12 A11 A10 A9
A8
A7
A6
A5
A4
A3
A2
A1
A0 Address Field
Mode Register (2)
0*1 0*1
1
0
Rtt_WR
0*1 SRT ASR
CWL
PASR
BA1 BA0 MRS mode
A6
Auto Self-Refresh (ASR)
0
0
1
1
0
1
0
1
MR0
MR1
MR2
MR3
0
1
Manual SR Reference (SRT)
ASR enable (Optional)
A10 A9
RTT_WR *2
A2 A1 A0 Partial Array Self-Refresh (Optional)
Dynamic ODT off (Write does not affect Rtt value)
0
0
1
1
0
1
0
1
RZQ/4
RZQ/2
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Full Array
HalfArray (BA[2:0]=000,001,010,&011)
Quarter Array (BA[2:0]=000,&001)
1/8th Array (BA[2:0]=000)
Reserved
3/4 Array (BA[2:0]=010,011,100.101,110,&111)
HalfArray (BA[2:0]=100,101,110,&111)
Quarter Array (BA[2:0]=110,&111)
1/8th Array (BA[2:0]=111)
Self-Refresh Temperature (SRT) Range
A7
A5 A4 A3
CAS write Latency (CWL)
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
5 (tCK(avg)≧2.5ns)
Normal operating temperature range
0
1
Extended (optional) operating temperature range
6 (2.5ns＞tCK(avg)≧1.875ns)
7 (1.875ns＞tCK(avg)≧1.5ns)
8 (1.5ns＞tCK(avg)≧1.25ns)
9 (1.25ns＞tCK(avg)≧1.07ns)
Reserved
Reserved
Reserved
Note 1: BA2 and A8, A11~ A13 are RFU and must be programmed to 0 during MRS.
Note 2: The Rtt_WR value can be applied during writes even when Rtt_Nom is disabled.
During write leveling, Dynamic ODT is not available.
Confidential
-18／83-
Rev. 1.0 May 2016
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
