MSM514223B Datasheet, PDF (1/14 Pages) OKI electronic componets – 262,263-Word x 4-Bit Field Memory

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MSM514223B
262,263-Word ¥ 4-Bit Field Memory
This versio_Mn_S: _MJa₅n₁. ₄1₂99₂8_3B
Previous version: Dec. 1996
DESCRIRTION
The OKI MSM514223B is a high performance 1-Mbit, 256K ¥ 4-bit, Field Memory. It is designed
for high-speed serial access applications such as HDTVs, conventional NTSC TVs, VTRs, digital
movies and Multi-media systems. It is a FRAM for wide or low end use as general commodity
TVs and VTRs, exclusively. The MSM514223B is not designed for the other use or high end use
in medical systems, professional graphics systems which require long term picture, and data
storage systems and others. The 1-Mbit capacity fits one field of a conventional NTSC TV screen
and cascaded two MSM514223Bs make one frame of the screen: more than two MSM514223Bs
can be cascaded directly without any delay devices among the MSM514223Bs. (Cascading of
MSM514223B provides larger storage depth or a longer delay).
Each of the 4-bit planes has separate serial write and read ports that employ independent control
clocks to support asynchronous read and write operations. Different clock rates are also
supported that allow alternate data rates between write and read data streams.
The MSM514223B provides high speed FIFO, First-In First-Out, operation without external
refreshing: it refreshes its DRAM storage cells automatically, so that it appears fully static to the
users.
Moreover, fully static type memory cells and decoders for serial access enable refresh free serial
access operation, so that serial read and/or write control clock can be halted high or low for any
duration as long as the power is on. Internal conflicts of memory access and refreshing
operations are prevented by special arbitration logic.
The MSM514223B's function is simple, and similar to a digital delay device whose delay-bit-
length is easily set by reset timing. The delay length, number of read delay clocks between write
and read, is determined by externally controlled write and read reset timings.
Additional SRAM serial registers, or line buffers for the initial access of 256 ¥ 4-bit enable high
speed first-bit-access with no clock delay just after the write or read reset timings.
The MSM514223B is similar in operation and functionality to OKI 1-Mbit Field Memory
MSM514221B besides direct cascade capability. (As for MSM514221B operation compatible 2-
Mbit Field Memory, OKI has MSM518221 as a sister device of MSM518222).
Additionally, the MSM514223B has write mask function or input enable function (IE), and read-
data skipping function or output enable function (OE). The differences between write enable
(WE) and input enable (IE), and between read enable (RE) and output enable (OE) are that WE
and RE can stop serial write/read address increments but IE and OE can not stop the increment
when write/read clocking is continuously applied to MSM514223B. The input enable (IE)
function allows the user to write into selected locations of the memory only, leaving the rest of
the memory contents unchanged. This facilitate data processing to display a "picture in picture"
on a TV screen.
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