1/15

¡ Semiconductor

MSM514221B

DESCRIRTION

The OKI MSM514221B 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 MSM514221B 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.

Each of the 4-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 MSM514221B 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 the 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 MSM514221B'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 MSM514221B is similar in operation and functionality to OKI 2-Mbit Field Memory

MSM518221.

¡ Semiconductor

MSM514221B

262,263-Word

¥ 4-Bit Field Memory

This version: Jan. 1998

Previous version: Dec. 1996

E2L0029-17-Y1