IS61LPS51236A-250B3LI-TR ISSI, Integrated Silicon Solution Inc, IS61LPS51236A-250B3LI-TR Datasheet - Page 23

• Manufacturer Part Number: IS61LPS51236A-250B3LI-TR
• Description: IC SRAM 18MBIT 250MHZ 165FBGA
• Manufacturer: ISSI, Integrated Silicon Solution Inc

Specifications of IS61LPS51236A-250B3LI-TR

• Format - Memory: RAM
• Memory Type: SRAM - Synchronous
• Memory Size: 18M (512K x 36)
• Speed: 250MHz
• Interface: Parallel
• Voltage - Supply: 3.135 V ~ 3.465 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 165-FBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

IS61VPS25672A, IS61LPS25672A
IS61VPS51236A, IS61LPS51236A, IS61VPS102418A, IS61LPS102418A
TAP INSTRUCTION SET
Eight instructions are possible with the three-bit instruction
register and all combinations are listed in the Instruction Code
table. Three instructions are listed as RESERVED and should
not be used and the other five instructions are described
below. The TAP controller used in this SRAM is not fully
compliant with the 1149.1 convention because some man-
datory instructions are not fully implemented. The TAP
controller cannot be used to load address, data or control
signals and cannot preload the Input or Output buffers. The
SRAM does not implement the 1149.1 commands EXTEST or
INTEST or the PRELOAD portion of SAMPLE/PRELOAD; instead
it performs a capture of the Inputs and Output ring when these
instructions are executed. Instructions are loaded into the
TAP controller during the Shift-IR state when the instruction
register is placed between TDI and TDO. During this state,
instructions are shifted from the instruction register through
the TDI and TDO pins. To execute an instruction once it is
shifted in, the TAP controller must be moved into the
Update-IR state.
EXTEST
EXTEST is a mandatory 1149.1 instruction which is to be
executed whenever the instruction register is loaded with all
0s. Because EXTEST is not implemented in the TAP
controller, this device is not 1149.1 standard compliant. The
TAP controller recognizes an all-0 instruction. When an
EXTEST instruction is loaded into the instruction register,
the SRAM responds as if a SAMPLE/PRELOAD instruction
has been loaded. There is a difference between the instruc-
tions, unlike the SAMPLE/PRELOAD instruction, EXTEST
places the SRAM outputs in a High-Z state.
IDCODE
The IDCODE instruction causes a vendor-specific, 32-bit
code to be loaded into the instruction register. It also places
the instruction register between the TDI and TDO pins and
allows the IDCODE to be shifted out of the device when the
TAP controller enters the Shift-DR state. The IDCODE
instruction is loaded into the instruction register upon power-
up or whenever the TAP controller is given a test logic reset
state.
SAMPLE-Z
The SAMPLE-Z instruction causes the boundary scan
register to be connected between the TDI and TDO pins
when the TAP controller is in a Shift-DR state. It also places
all SRAM outputs into a High-Z state.
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. N
02/12/2010
SAMPLE/PRELOAD
SAMPLE/PRELOAD is a 1149.1 mandatory instruction.
The PRELOAD portion of this instruction is not imple-
mented, so the TAP controller is not fully 1149.1 compliant.
When the SAMPLE/PRELOAD instruction is loaded to the
instruction register and the TAP controller is in the Capture-
DR state, a snapshot of data on the inputs and output pins
is captured in the boundary scan register.
It is important to realize that the TAP controller clock
operates at a frequency up to 10 MHz, while the SRAM
clock runs more than an order of magnitude faster. Because
of the clock frequency differences, it is possible that during
the Capture-DR state, an input or output will under-go a
transition. The TAP may attempt a signal capture while in
transition (metastable state). The device will not be harmed,
but there is no guarantee of the value that will be captured
or repeatable results.
To guarantee that the boundary scan register will capture
the correct signal value, the SRAM signal must be stabi-
lized long enough to meet the TAP controller’s capture set-
up plus hold times (t
clock input is captured correctly, designs need a way to stop
(or slow) the clock during a SAMPLE/PRELOAD instruc-
tion. If this is not an issue, it is possible to capture all other
signals and simply ignore the value of the CLK captured in
the boundary scan register.
Once the data is captured, it is possible to shift out the data
by putting the TAP into the Shift-DR state. This places the
boundary scan register between the TDI and TDO pins.
Note that since the PRELOAD part of the command is not
implemented, putting the TAP into the Update to the Update-DR
state while performing a SAMPLE/PRELOAD instruction will
have the same effect as the Pause-DR command.
BYPASS
When the BYPASS instruction is loaded in the instruction
register and the TAP is placed in a Shift-DR state, the
bypass register is placed between the TDI and TDO pins.
The advantage of the BYPASS instruction is that it shortens
the boundary scan path when multiple devices are con-
nected together on a board.
RESERVED
These instructions are not implemented but are reserved for
future use. Do not use these instructions.
CS
and t
CH
). To insure that the SRAM
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