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参数资料
| 型号： | WEDPN16M72VR-66BC |
| 厂商： | WHITE ELECTRONIC DESIGNS CORP |
| 元件分类： | DRAM |
| 英文描述： | 16M X 72 SYNCHRONOUS DRAM MODULE, 7.5 ns, PBGA219 |
| 封装： | 32 X 25 MM, PLASTIC, BGA-219 |
| 文件页数： | 8/13页 |
| 文件大小： | 161K |
| 代理商： | WEDPN16M72VR-66BC |
WEDPN16M72VR-XBX
White Electronic Designs Corporation Phoenix AZ (602) 437-1520
4
Read and write accesses to the SDRAM are burst oriented;
accesses start at a selected location and continue for a
programmed number of locations in a programmed se-
quence. Accesses begin with the registration of an ACTIVE
command which is then followed by a READ or WRITE
command. The address bits registered coincident with the
ACTIVE command are used to select the bank and row to be
accessed (BA0 and BA1 select the bank, A0-12 select the
row). The address bits (A0-8) registered coincident with the
READ or WRITE command are used to select the starting
column location for the burst access.
Prior to normal operation, the SDRAM must be initialized. The
following sections provide detailed information covering
device initialization, register definition, command descrip-
tions and device operation.
SDRAMs must be powered up and initialized in a predefined
manner. Operational procedures other than those specified
may result in undefined operation. Once power is applied to
VDD and VDDQ (simultaneously) and the clock is stable
(stable clock is defined as a signal cycling within timing
constraints specified for the clock pin), the SDRAM requires
a 100s delay prior to issuing any command other than a
COMMAND INHIBIT or a NOP. Starting at some point during
this 100s period and continuing at least through the end of
this period, COMMAND INHIBIT or NOP commands should
be applied.
Once the 100s delay has been satisfied with at least one
COMMAND INHIBIT or NOP command having been applied,
a PRECHARGE command should be applied. All banks must
be precharged, thereby placing the device in the all banks idle
state.
Once in the idle state, two AUTO REFRESH cycles must be
performed. After the AUTO REFRESH cycles are complete, the
SDRAM is ready for Mode Register programming. Because the
Mode Register will power up in an unknown state, it should be
loaded prior to applying any operational command.
The Mode Register is used to define the specific mode of
operation of the SDRAM. This definition includes the selec-
tion of a burst length, a burst type, a CAS latency, an operating
mode and a write burst mode, as shown in Figure 3. The Mode
Register is programmed via the LOAD MODE REGISTER com-
mand and will retain the stored information until it is pro-
grammed again or the device loses power.
Mode register bits M0-M2 specify the burst length, M3 speci-
fies the type of burst (sequential or interleaved), M4-M6 specify
the CAS latency, M7 and M8 specify the operating mode, M9
specifies the WRITE burst mode, and M10 and M11 are reserved
for future use. Address A12 (M12) is undefined but should be
driven LOW during loading of the mode register.
The Mode Register must be loaded when all banks are idle,
and the controller must wait the specified time before initiat-
ing the subsequent operation. Violating either of these re-
quirements will result in unspecified operation.
Read and write accesses to the SDRAM are burst oriented,
with the burst length being programmable, as shown in Figure
3. The burst length determines the maximum number of
column locations that can be accessed for a given READ or
WRITE command. Burst lengths of 1, 2, 4 or 8 locations are
available for both the sequential and the interleaved burst
types, and a full-page burst is available for the sequential type.
The full-page burst is used in conjunction with the BURST
TERMINATE command to generate arbitrary burst lengths.
Reserved states should not be used, as unknown operation
or incompatibility with future versions may result.
When a READ or WRITE command is issued, a block of
columns equal to the burst length is effectively selected. All
accesses for that burst take place within this block, meaning
that the burst will wrap within the block if a boundary is
reached. The block is uniquely selected by A1-8 when the
burst length is set to two; by A2-8 when the burst length is set
to four; and by A3-8 when the burst length is set to eight. The
remaining (least significant) address bit(s) is (are) used to
select the starting location within the block. Full-page bursts
wrap within the page if the boundary is reached.
Accesses within a given burst may be programmed to be
either sequential or interleaved; this is referred to as the burst
type and is selected via bit M3.
The ordering of accesses within a burst is determined by the
burst length, the burst type and the starting column address,
as shown in Table 1.
FUNCTIONAL DESCRIPTION
INITIALIZATION
REGISTER DEFINITION
MODE REGISTER
BURST LENGTH
BURST TYPE
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相关代理商/技术参数 |
参数描述 |
|---|---|
| WEDPN16M72VR-66BI | 制造商:Microsemi Corporation 功能描述:16M X 72 SDRAM MODULE W/REGISTERED BUFFERS, 3.3V, 66 MHZ, 21 - Bulk |
| WEDPN16M72VR-66BM | 制造商:Microsemi Corporation 功能描述:16M X 72 SDRAM MODULE W/REGISTERED BUFFERS, 3.3V, 66 MHZ, 21 - Bulk |
| WEDPN16M72VR-XB2X | 制造商:WEDC 制造商全称:White Electronic Designs Corporation 功能描述:16MX72 REGISTERED SYNCHRONOUS DRAM |
| WEDPN16M72VR-XBX | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Registered SDRAM MCP |
| WEDPN16M72V-XB2X | 制造商:WEDC 制造商全称:White Electronic Designs Corporation 功能描述:16Mx72 Synchronous DRAM |
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