MSM5412222 Datasheet, PDF (1/15 Pages) OKI electronic componets – 262,214-Word x 12-Bit Field Memory

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MSM5412222
262,214-Word ¥ 12-Bit Field Memory
This versio_Mn:_SMJan₅.₄1₁9₂9₂8₂₂
Previous version: Dec. 1996
DESCRIPTION
The OKI MSM5412222 is a high performance 3-Mbit, 256K ¥ 12-bit, Field Memory. It is especially
designed for high-speed serial access applications such as HDTVs, conventional NTSC TVs,
VTRs, digital movies and Multi-media systems. MSM5412222 is a FRAM for wide or low end use
in general commodity TVs and VTRs exclusively. MSM5412222 is not designed for high end use
in medical systems, professional graphics systems which require long term picture storage, data
storage systems and others. Two or more MSM5412222s can be cascaded directly without any
delay devices between them. (Cascading provides larger storage depth or a longer delay).
Each of the 12-bit planes has separate serial write and read ports. These employ independent
control clocks to support asynchronous read and write operations. Different clock rates are also
supported, which allow alternate data rates between write and read data streams.
The MSM5412222 provides high speed FIFO, First-In First-Out, operation without external
refreshing: MSM5412222 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 the 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 MSM5412222’s function is simple, and similar to a digital delay device whose delay-bit-
length is easily set by reset timing. The delay length, and the 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 ¥ 12-bit enable high
speed first-bit-access with no clock delay just after the write or read reset timings.
Additionally, the MSM5412222 has a 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 cannot stop the increment,
when write/read clocking is continuously applied to MSM5412222. 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 facilitates data processing to display a “picture in picture”
on a TV screen.
The MSM5412222 is similar in operation and functionality to OKI 1-Mbit Field Memory
MSM514222B and 2-Mbit Field Memory MSM518222. Three MSM514222Bs or one MSM514222B
plus one MSM518222 can be replaced simply by one MSM5412222.
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