Et r on Tech
EM6A9320
4Mx32 DDR SDRAM
Mode Register Set (MRS)
The mode register is divided into various fields depending on functionality.
Burst Length Field (A2, A1, A0)
This field specifies the data length of column access and selects the Burst Length.
Addressing Mode Select Field (A3)
•
•
The Addressing Mode can be Interleave Mode or Sequential Mode. Both Sequential Mode and
Interleave Mode support burst length of 2, 4 and 8. Full page burst length is only for Sequential mode.
CAS# Latency Field (A6, A5, A4)
•
This field specifies the number of clock cycles from the assertion of the Read command to the first read
data. The minimum whole value of CAS# Latency depends on the frequency of CK. The minimum whole
value satisfying the following formula must be programmed into this field.
tCAC(min)
CAS# Latency X tCK
Test Mode field :A7; DLL Reset Mode field : A8
These two bits must be programmed to "00" in normal operation.
( BA0, BA1)
•
•
Mode Resistor Bitmap
BA1
0
BA0
A11
A10
A9
A8
A7
TM
A6
A5
A4
A3
BT
A2
A1
A0
Mode RFU must be set to “0” DLL
CAS Latency
Burst Lenght
BA0 Register Mode
A8
0
1
A7
0
0
Mode
Normal
Reset DLL
Test Mode
A3
0
1
Type
Sequential
Interleave
0
1
MRS
EMRS
0
1
A6
0
0
1
1
A5
1
1
0
0
A4
CAS Latency
Reserved
3 clocks
A2
A1
0
1
1
1
A0
1
0
1
1
Burst Length
0
1
0
1
0
0
0
1
2
4
8
4 clocks
5 clocks
Full Page (Sequential)
All other Reserved
All other Reserved
Burst Definition, Addressing Sequence of Sequential and Interleave Mode
Start Address
Burst Length
2
Sequential
Interleave
A2
X
X
X
X
X
X
0
A1
X
X
0
0
1
A0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0, 1
1, 0
0, 1, 2, 3
1, 2, 3, 0
2, 3, 0, 1
3, 0, 1, 2
0, 1
1, 0
0, 1, 2, 3
1, 0, 3, 2
2, 3, 0, 1
3, 2, 1, 0
4
1
0
0, 1, 2, 3, 4, 5, 6, 7
1, 2, 3, 4, 5, 6, 7, 0
2, 3, 4, 5, 6, 7, 0, 1
3, 4, 5, 6, 7, 0, 1, 2
4, 5, 6, 7, 0, 1, 2, 3
5, 6, 7, 0, 1, 2, 3, 4
6, 7, 0, 1, 2, 3, 4, 5
7, 0, 1, 2, 3, 4, 5, 6
0, 1, 2, 3, 4, 5, 6, 7
1, 0, 3, 2, 5, 4, 7, 6
2, 3, 0, 1, 6, 7, 4, 5
3, 2, 1, 0, 7, 6, 5, 4
4, 5, 6, 7, 0, 1, 2, 3
5, 4, 7, 6, 1, 0, 3, 2
6, 7, 4, 5, 2, 3, 0, 1
7, 6, 5, 4, 3, 2, 1, 0
0
0
0
1
0
1
8
1
0
1
0
1
1
1
1
Etron Confidential
6
Rev 0.3
July. 2002
ETRON [ ETRON TECHNOLOGY, INC. ]
