XM28C040 查看數據表（PDF） - Xicor -> Intersil
零件编号
产品描述 (功能)
生产厂家
XM28C040 Datasheet PDF : 17 Pages
| |||
XM28C040
MultiPlane Architecture
The design of the XM28C040 has implemented a mul-
tiplane architecture. That is, there are four independent
128K x 8 memory spaces or planes, each selected by its
own chip enable input via the on-board decoder chip.
This architecture can be utilized in a number of ways.
Separate Data and Program Memory Spaces
The multiplane concept allows the system to write to one
plane of the module and still be able to read (continue
executing code) from the module, utilizing any plane not
performing a write operation.
This concept of separate data and program spaces can
be expanded by providing a simple off-module circuit
that will disable writes to predetermined portions of
memory. A very basic version is shown in the Functional
Diagram. Whenever A18 is HIGH, the WE input is forced
HIGH, write protecting one half the module. This half
would be reserved for read only program store while the
other half would be available for read and write data
store.
Expanded Sequential Page Lengths
A standard system implementation would be decoding
externally the module's chip enable and then wiring
each address of the module to its corresponding ad-
dress line in the system. This would effectively provide
the system a memory organized as four separate memory
planes with a sequential page address space of 256
bytes.
In an application such as data logging, the most efficient
method of logging the data is in a sequential manner. If
the data come in bursts that exceed 256 bytes in length
a longer page might be desirable. By swapping address
lines externally the effective page length can be ex-
panded to 1024 bytes. Refer to the table below for a
matrix illustrating the various page length options.
TABLE 1. ADDRESS TRANSLATION MATRIX
A0-A7
Module Address Inputs
A8-A16
A17
Effective
A18
Page Size
No. of
Planes
System
A0-A7
A8-A16
A17
A18
256
4
Address
A0-A7
A9-A17
A8
A18
512
2
Lines
A0-A7
A10-A18
A8
A9
1024
1
3873 PGM T09
Note: The user should be aware the overall ICC of the module will increase as more individual components on the module are activated.
15
Share Link: 