(完整版)3-电气工程及其自动化专业-外文文献-英文文献-外文翻译-plc方面.doc资源-CSDN文库

34 浏览量 2022-11-19 03:09:37 上传评论收藏 61KB DOC 举报

资源推荐

资源详情

资源评论

(完整版)3-电气工程及其自动化专业_外文文献_英文文献_外文翻译_plc 方面

1、外文原文

A: Fundamentals of Single-chip Microcomputer

The single—chip m i c r o c o m p u t e r i s t h e c u l m i n a t i o n o f b oth

the development o f t h e d i g i t a l c o m p u t e r a n d t h e i n t egrated circuit

arguably the to w m o s t s i g n i f i c a n t i n v e n t i o n s o f t h e 20th century

[1]。

These tow types o f a r c h i t e c t u r e a r e f o u n d i n s i n g l e - c hip

microcomputer. S o m e e m p l o y t h e s p l i t p r o g r a m / d a t a m emory of the

Harvard archite c t u r e ， s h o w n i n F i g 。 3 — 5 A - 1 ， o t h e r s f o l l o w t h e

philosophy， widely a d a p t e d f o r g e n e r a l - p u r p o s e c o m p u t e rs and

microprocessors , o f m a k i n g n o l o g i c a l d i s t i n c t i o n b etween program

and data memory a s i n t h e P r i n c e t o n a r c h i t e c t u r e ， s h o w n in

Fig.3-5A—2。

In general terms a s i n g l e - c h i p m i c r o c o m p u t e r i s

characterized b y t h e i n c o r p o r a t i o n o f a l l t h e u n i t s of a computer

into a single d e v i c e , a s s h o w n i n F i g 3 - 5 A — 3 .

Fig。3-5A-1 A Harvard type

Program

memory

Data

memory

CPU

Input&

Output

unit

(完整版)3-电气工程及其自动化专业_外文文献_英文文献_外文翻译_plc 方面

economical manu f a c t u r e o f t h e d e v i c e s r e q u i r e s t h a t the contents

of the program m e m o r y b e c o m m i t t e d p e r m a n e n t l y d u r i ng the

manufacture of c h i p s . C l e a r l y ， t h i s i m p l i e s a r i g o r o u s approach to

ROM code develo p m e n t s i n c e c h a n g e s c a n n o t b e m a d e a fter

manufacture .Th i s d e v e l o p m e n t p r o c e s s m a y i n v o l v e e mulation using

a sophisticated d e v e l o p m e n t s y s t e m w i t h a h a r d w a r e emulation

capability as w e l l a s t h e u s e o f p o w e r f u l s o f t w a r e tools.

Some manufacturer s p r o v i d e a d d i t i o n a l R O M o p t i o n s b y

including in th e i r r a n g e d e v i c e s w i t h （ o r i n t e n d e d f o r use with) user

programmable me m o r y . T h e s i m p l e s t o f t h e s e i s u s u a l ly device which

can operate in a m i c r o p r o c e s s o r m o d e b y u s i n g s o m e of the

input/output li n e s a s a n a d d r e s s a n d d a t a b u s f o r a ccessing

external memory . T h i s t y p e o f d e v i c e c a n b e h a v e f u n ctionally as

the single chip m i c r o c o m p u t e r f r o m w h i c h i t i s d e r i ved albeit with

restricted I/O a n d a m o d i f i e d e x t e r n a l c i r c u i t 。 The use of these d e v i c e s

is common even i n p r o d u c t i o n c i r c u i t s w h e r e t h e v o l ume does not

justify the dev e l o p m e n t c o s t s o f c u s t o m o n — c h i p R O M ［ 2］ ;there can

still be a sign i f i c a n t s a v i n g i n I / O a n d o t h e r c h i p s compared to a

conventional mi c r o p r o c e s s o r b a s e d c i r c u i t . M o r e e x a ct replacement

for ROM devices c a n b e o b t a i n e d i n t h e f o r m o f v a r i ants with

'piggy—back’ EPROM （ E r a s a b l e p r o g r a m m a b l e R O M ) s o c k e t s o r devices

with EPROM inst e a d o f R O M . T h e s e d e v i c e s a r e n a t u r a lly more

expensive than e q u i v a l e n t R O M d e v i c e ， b u t d o p r o v i d e c omplete circuit

equivalents. EP R O M b a s e d d e v i c e s a r e a l s o e x t r e m e l y attractive for

low—volume appl i c a t i o n s w h e r e t h e y p r o v i d e t h e a d v a ntages of a

剩余17页未读，继续阅读

内容反馈

zzzzl333

粉丝: 677
资源: 7万+

最新资源

资源上传下载、课程学习等过程中有任何疑问或建议，欢迎提出宝贵意见哦~我们会及时处理！点击此处反馈

feedback-tip