MCS·S5™ SPECIAL PERIPHERAL

COMPONENTS

The MCS-85 was designed to minimize the amount of components required for most systems. Intel designed several new peripheral components that combine memory, 110 and timer functions to fulfill this requirement. These new peripheral devices directly interface to the multiplexed MCS-85 bus structure and provide new levels in system integration for today's designer.

101;;; ---- 1

 

 

 

 

 

 

 

 

256 X 8

 

 

 

 

 

STATIC

 

 

* ---..,

 

RAM

 

 

 

 

 

 

AlE ---- 1

 

 

 

AD ---....

 

 

 

ViiR ---..'

 

 

 

 

 

 

 

RESET --- ", TIMER

 

 

 

 

 

 

 

 

TIMER IN

 

 

~Vee(+5V)

TIMER OUT-------'

 

Vss (OV)

*: 8155 =CE, 8156 =CE

8155/8156 RAM, 1/0 and Timer

256 bytes RAM Two 8·bit ports

One 6·bit port (programmable)

One 14·bitprogrammable interval timer Single + 5 Volt supply operation

40 pin DIP plastic or cerdip package

~VCCI+5VI

vss IOVI

8355 ROM and 1/0

2K bytes ROM

Two 8·bit ports (direction programmable) Single + 5 Volt supply operation

40 pin DIP plastic or cerdip package

ClK

 

 

 

 

 

 

 

 

 

READY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ADo-7

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

As- lO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CE

 

 

 

 

 

2K x 8

 

 

 

 

 

 

 

 

101M

 

 

 

 

 

EPROM

 

 

 

 

 

 

 

 

 

 

 

ALE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

G

 

 

 

 

 

 

 

AD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

iOW

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RESET

 

 

 

 

 

 

 

 

 

lOR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PROG/CE~

 

 

Vee (+5V)

 

 

Voo

L .. --- Vss (OV)

8755A EPROM and I/O

Socket compatible with 8355 2K bytes EPROM

Two 8·bit ports (direction programmable) Single + 5 Volt supply read operation U.V. Erasable

40 pin DIP package

One of the most important advances made with the MCS-85 is the socket-compatibility of the 8355 and 8755A components. This allows the systems designer to develop and debug in erasable PROM and then, when satisfied, switch over to mask-programmed ROM 8355 with no performance degradation or board relayout. It also allows quick prototype produc- tion for market impact without going to a com- promise solution.

1/0 PORTS

TIMER IN

TIMER OUT

1/0 PORTS

I/O PORTS

SYSTEM EXPANSION

Each of these peripheral components has features that allow a small to medium system to be constructed without the addition of buf- fers and decoders to maintain the lowest possi- ble component count.

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Image 16
Intel MCS-80/85 manual MCS·S5 Special Peripheral Components, 8155 =CE, 8156 =CE

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.