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Rev. 00D
06/02/08
IS42S32200E
FUNCTIONAL DESCRIPTION
The 64Mb SDRAMs 512K x 32 x 4 banks) are quad-bank
DRAMs which operate at 3.3V and include a synchronous
interface (all signals are registered on the positive edge of
the clock signal, CLK). Each of the 16,777,216-bit banks
is organized as 2,048 rows by 256 columns by 32bits.
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
sequence. 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-A10
select the row)
. The address bits
(A0-A7)
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
descriptions and device operation.
Initialization
SDRAMs must be powered up and initialized in a
predefined manner.
The 64M SDRAM is initialized after the power is applied
to V
DD and VDDQ (simultaneously) and the clock is stable.
A 100µs delay is required prior to issuing any command
other than a
COMMAND INHIBIT
or a
NOP
. The COMMAND
INHIBIT or NOP may be applied during the 100us period
and continue should at least through the end of the period.
With at least one COMMAND INHIBIT or NOP command
having been applied, a PRECHARGE command should be
applied once the 100µs delay has been satisfied. All
banks must be precharged. This will leave all banks in an
idle idle state where two
AUTO REFRESH
cycles must be
performed. After the
AUTO REFRESH
cycles are complete,
the SRDRAM is then ready for mode register programming.
The mode register should be loaded prior to applying any
operational command because it will power up in an
unknown state.
14
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Rev. 00D
06/02/08
IS42S32200E
REGISTER DEFINITION
Mode Register
The mode register is used to define the specific mode of
operation of the SDRAM. This definition includes the
selection of a burst length, a burst type, a CAS\ latency,
an operating mode and a write burst mode, as shown in
MODE REGISTER DEFINITION.
The mode register is programmed via the LOAD MODE
REGISTER command and will retain the stored information
until it is programmed again or the device loses power.
Mode register bits M0-M2 specify the burst length, M3
specifies 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 and M12 are reserved for future use.
The mode register must be loaded when all banks are idle,
and the controller must wait the specified time before
initiating the subsequent operation. Violating either of
these requirements will result in unspecified operation.
MODE REGISTER DEFINITION
Latency Mode
M6 M5 M4 CAS Latency
0 0 0 Reserved
0 0 1 Reserved
0 1 0 2
0 1 1 3
1 0 0 Reserved
1 0 1 Reserved
1 1 0 Reserved
1 1 1 Reserved
Write Burst Mode
M9 Mode
0 Burst Write
1 Single-Bit Write
MRS
M8 M7 MRS
0 0 Mode Register Set
All Other States Reserved
Burst Type
M3 Type
0 Sequential
1 Interleaved
Burst Length
M2 M1 M0 Sequential Interleave
0 0 0 1 1
0 0 1 2 2
0 1 0 4 4
0 1 1 8 8
1 0 0 Reserved Reserved
1 0 1 Reserved Reserved
1 1 0 Reserved Reserved
1 1 1 Full Page Reserved
Address Bus
BA0,1 A10/AP A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
(1)
00
(1)
Note:
1. Maintain low during Mode Register Set.
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Rev. 00D
06/02/08
IS42S32200E
BURST DEFINITION
Burst Starting Column Order of Accesses Within a Burst
Length Address Type = Sequential Type = Interleaved
A0
2 0 0-1 0-1
1 1-0 1-0
A1 A0
0 0 0-1-2-3 0-1-2-3
4 0 1 1-2-3-0 1-0-3-2
1 0 2-3-0-1 2-3-0-1
1 1 3-0-1-2 3-2-1-0
A2 A1 A0
0 0 0 0-1-2-3-4-5-6-7 0-1-2-3-4-5-6-7
0 0 1 1-2-3-4-5-6-7-0 1-0-3-2-5-4-7-6
0 1 0 2-3-4-5-6-7-0-1 2-3-0-1-6-7-4-5
8 0 1 1 3-4-5-6-7-0-1-2 3-2-1-0-7-6-5-4
1 0 0 4-5-6-7-0-1-2-3 4-5-6-7-0-1-2-3
1 0 1 5-6-7-0-1-2-3-4 5-4-7-6-1-0-3-2
1 1 0 6-7-0-1-2-3-4-5 6-7-4-5-2-3-0-1
1 1 1 7-0-1-2-3-4-5-6 7-6-5-4-3-2-1-0
Full n = A0-A7 Cn, Cn + 1, Cn + 2 Not Supported
Page Cn + 3, Cn + 4...
(y) (location 0-y) …Cn - 1,
Cn…
Burst Length
Read and write accesses to the SDRAM are burst ori-
ented, with the burst length being programmable, as
shown in MODE REGISTER DEFINITION. The burst
length determines the maximum number of column loca-
tions 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 opera-
tion 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-A7 (x32) when the burst length is set to two; by A2-A7
(x32) when the burst length is set to four; and by A3-A7
(x32) 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.
Burst Type
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 BURST DEFINITION table.

IS42S32200E-6BI-TR

Mfr. #:
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Description:
DRAM 64M (2Mx32) 166MHz SDRAM, 3.3v
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