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MSM5412222B Documents
Description The OKI MSM5412222B is a high performance 3-Mbit, 256K x 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.
MSM5412222B is a FRAM for wide or low end use in general commodity TVs and VTRs
exclusively. MSM5412222B is not designed for the other use or high end use in
medical systems, professional graphics systems which require long term picture
storage, data storage systems and others. More than two MSM5412222Bs can be
cascaded directly without any delay devices among the MSM5412222Bs. (Cascading
of MSM5412222B 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 that allow alternate data
rates between write and read data streams.
The MSM5412222B provides high speed FIFO, First-In First-Out, operation
without external refreshing: MSM5412222B 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 MSM5412222B'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 x 12-bit enable high speed first-bit-access with no clock delay just after
the write or read reset timings.
Additionally, the MSM5412222B 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 cannot stop the increment, when
write/read clocking is continuously applied to MSM5412222B. 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 MSM5412222B is similar in operation and functionality to OKI 1-Mbit Field
Memory MSM514222C and 2-Mbit Field Memory MSM518222A. Three MSM514222Cs or one
MSM514222C plus one MSM518222A can be replaced simply by one MSM5412222B.
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