MCS-85™ APPLICATIONS

!

Small System

The schematic in Figure 3 is of a complete microcomputer with only 6 ICs. The system con- tains its own serial 1/0 communication lines, multi-level interrupt, two programmable timers, and power-on reset. System capacity is 512 bytes of RAM, 4K bytes of PROM, and 76 lines of programmable 1/0.

Block Move, Block Search

In a large system application high speed block moves may be necessary. The addition of an 8257 Direct Memory Access (DMA) controller and an 8255 Programmable Peripheral Interface

(PPI) device with some miscellaneous logic removes the task from the'8085 and results in a very high speed capability. The addition of an eight bit comparator also permits block sear- ches. (See Figure 4.)

I

I

I

I

 

 

 

 

 

Vss

Vcc

 

 

 

 

 

RESET IN

~

~

 

 

 

 

 

 

 

 

-----+-

T RAP

 

 

 

 

 

HOLD

_

RST7,5

 

 

 

 

 

HlDA

 

 

 

 

 

 

 

-

RST6,5

 

 

 

 

 

SOD

 

 

 

 

8085A

 

 

SID

-- .. INTR

 

 

 

 

 

S1

 

 

 

 

 

RESET

So

 

 

 

 

ALE AD

WR 101M

OUT

 

 

AD DR

 

ADDR/DATA

ROY elK

181

181

8212 l~

DS1) -

 

 

 

 

 

 

 

 

 

 

 

 

 

 

'~

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I

 

 

3TO 8

 

 

I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DECODER

I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I~

19

 

I~

 

15

 

 

 

 

 

 

 

.....

--

..t --- t --

IREADy

ORO

-------- ,

 

 

.....

 

t-+

I I __+_liOW

o

 

 

 

 

 

 

 

 

 

 

 

 

DACK

 

 

 

 

 

 

 

-- -- -- --

--

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

.. __ / ----

1 ClK

1 ORO I - . ----

t ---------

.

 

 

 

 

 

+ -

t -

 

+ - + - + - + __IMEMW--

DACK ____

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

'

 

-'-'+ + +-- -- --

.-1RESET

ORO I - . ---

 

t --

t -----

,

 

.

-.-

.+--

 

+--

+

--

+-+ 11 1------- --L>ACK -

1 MEMR

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PAt:(8~~P

 

-

.

-.-

.+

--+--

+-__

RESET

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8BIT

 

 

 

 

 

 

 

 

 

 

 

 

 

COMPo

 

 

+-t-+-t

-----+-IWR

 

 

18~ /

 

 

 

 

 

 

 

 

 

 

 

PB

 

B

 

 

 

8255

 

-

V

~~

 

 

+-t-+-+-+-

t-------IAD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FIGURE 4. BLOCK MOVE, BLOCK SEARCH addition of an 8257 Direct Memory Access (DMA) con- troller and an 8255 Programmable Peripheral Interface (PPI) device permits block searches, high speed block moves. (2.5 I1s/word).

A1-6

Page 146 Page 148
Page 147
Image 147
Intel MCS-80/85 manual PAt8~~P
Page 146 Page 148

MCS-80/85 specifications

The Intel MCS-80/85 family, introduced in the late 1970s, is a seminal collection of microprocessors that played a pivotal role in the early days of computing. The MCS-80 series, initially targeting embedded systems and control applications, gained remarkable attention due to its innovative architecture and flexible programming capabilities.

The MCS-80 family is anchored by the 8080 microprocessor, which was one of the first fully integrated 8-bit microprocessors. Released in 1974, the 8080 operated at clock speeds ranging from 2 MHz to 3 MHz and featured a 16-bit address bus capable of addressing up to 64KB of memory. The processor’s instruction set included around 78 instructions, providing extensive capabilities for data manipulation, logic operations, and branching.

Complementing the 8080 was a suite of support chips, forming the MCS-80 platform. The most notable among them was the 8155, which integrated a static RAM, I/O ports, and a timer, tailored for ease of designing systems around the 8080. Other support chips included the 8085, which provided improvements with an integrated clock generator, making it compatible with more modern designs and applications.

The MCS-85 series, on the other hand, revolves around the 8085 microprocessor, which provided a more advanced architecture. The 8085 operated at clock speeds of up to 6 MHz and came with a 16-bit address bus, similar to its predecessor. However, it introduced more sophisticated features, including an enhanced instruction set and support for interrupt-driven programming. These enhancements made the 8085 especially appealing to developers working in real-time processing environments.

The MCS-80/85 family utilized NMOS technology, known for its lower power consumption and higher performance compared to previous technologies like TTL. The family’s architecture allowed for easy interfacing with a variety of peripherals, making it a favorite for educational institutions and hobbyists embarking on computer engineering projects.

With its robustness, versatility, and affordability, the Intel MCS-80/85 microprocessors laid the groundwork for many subsequent microcomputer systems and applications. The legacy of this powerful family continues to influence modern microprocessor design, emphasizing the importance of reliable architecture in a rapidly evolving technology landscape.
Top Page Image Contents