HY[B/E]18L256160B[C/F]X-7.5
256-Mbit Mobile-RAM
Functional Description
1. At first, device core power (VDD) and device IO power (VDDQ) must be brought up simultaneously. Typically
VDD and VDDQ are driven from a single power converter output.
Assert and hold CKE and DQM to a HIGH level.
2. After VDD and VDDQ are stable and CKE is HIGH, apply stable clocks.
3. Wait for 200µs while issuing NOP or DESELECT commands.
4. Issue a PRECHARGE ALL command, followed by NOP or DESELECT commands for at least tRP period.
5. Issue two AUTO REFRESH commands, each followed by NOP or DESELECT commands for at least tRC
period.
6. Issue two MODE REGISTER SET commands for programming the Mode Register and Extended Mode
Register, each followed by NOP or DESELECT commands for at least tMRD period; the order in which both
registers are programmed is not important. Programming of the Extended Mode Register may be omitted when
default values (half drive strength, 4 bank refresh) will be used.
Following these steps, the Mobile-RAM is ready for normal operation.
2.2
Register Definition
Mode Register
2.2.1
The Mode Register is used to define the specific mode of operation of the Mobile-RAM. This definition includes
the selection of a burst length (bits A0-A2), a burst type (bit A3), a CAS latency (bits A4-A6), and a write burst
mode (bit A9). The Mode Register is programmed via the MODE REGISTER SET command (with BA0 = 0 and
BA1 = 0) and will retain the stored information until it is programmed again or the device loses power.
The Mode Register must be loaded when all banks are idle, and the controller must wait the specified time before
initiating any subsequent operation. Violating either of these requirements results in unspecified operation.
Reserved states should not be used, as unknown operation or incompatibility with future versions may result.
MR
Mode Register Definition
(BA[1:0] = 00B)
BA1
BA0
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
0
0
0
0
0
WB
0
0
CL
BT
BL
Field Bits Type Description
WB
9
w
Write Burst Mode
0
1
Burst Write
Single Write
CL
[6:4]
w
CAS Latency
010 2
011 3
Note:All other bit combinations are RESERVED.
BT
3
w
Burst Type
0
1
Sequential
Interleaved
Data Sheet
8
Rev. 1.11, 2007-01
07142005-CR47-RB2E
QIMONDA [ QIMONDA AG ]
