DP8422V datasheet(41/60 Pages) NSC

tên linh kiện	DP8422V

Giải thích chi tiết về linh kiện	microCMOS Programmable 256k/1M/4M Dynamic RAM Controller/Drivers

PDF	60 Pages

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nhà sản xuất	NSC [National Semiconductor (TI)]

Trang chủ	http://www.national.com

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100 Dual Accessing (DP8422V DP84T22) (Continued)

1032 LOCK Input

When the LOCK input is asserted the currently granted port

can ‘‘lock out’’ the other port through the insertion of wait

states to that port’s access cycle LOCK does not disable

refreshes it only keeps GRANTB in the same state even if

the other port requests an access as shown in

Figure 35

LOCK can be used by either port

TLF11109 – 61

FIGURE 35 LOCK Function

104 TRI-STATE OUTPUTS (DP84T22V Only)

This version is a metal option on the DP8420V21V22V-33

DRAM controllers It comes in a 84-pin PLCC and imple-

ments TRI-STATE output capabilities It has only one extra

pin OE When OE is asserted the output buffers are enabled

allowing the DRAM controller to interface to the DRAM ar-

ray

If OE is negated the output buffers are at TRI-STATE (high-

Z) making the board level circuit testing easier The time

penalty for the TRI-STATE option has been minimized mak-

ing this option attractive to high performance designs This

part is functionally compatible to the DP8422A-20 -25

TRI-STATE Output Drivers

TLF11109 – 62

DP8422V bảng dữ liệu(PDF) 41 Page - National Semiconductor (TI)