3.125 MHz (8085A)

 

5 MHz (8085A-2)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(ns)

 

 

(ns)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Parameter

Min

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Max

Cycle Dependencies

Min

Max

 

Cycle Dependencies

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tcyc

320

 

 

2000

 

 

 

200

2000

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

t1

80

 

 

 

 

 

1/2T-80

40

 

 

 

1/2T-70

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

t2

120

 

 

 

 

 

1/2T-40

70

 

 

 

1/2T-50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tr

 

 

 

30

 

 

 

 

30

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tf

 

 

 

30

 

 

 

 

30

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tAL

115

 

 

 

 

 

1/2T-45

50

 

 

 

1/2T-50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tlA

100

 

 

 

 

 

1/2T-60

50

 

 

 

1/2T-50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tll

140

 

 

 

 

 

1/2T-20

80

 

 

 

1/2T-20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tlCK

100

 

 

 

 

 

1/2T-60

50

 

 

 

1/2T-50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tlC

130

 

 

 

 

 

1/2T-30

60

 

 

 

1/2T-40

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tAFR

 

 

 

0

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tAD

 

 

 

575

 

 

(5/2+N)T -225

 

350

 

 

(5/2+N)T -150

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tRD

 

 

 

300

 

 

(3/2+N)T -180

 

150

 

 

(3/2+ N)T-150

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tRDH

0

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tRAE

150

 

 

 

 

 

1/2T-10

90

 

 

 

1/2T-10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tCA

120

 

 

 

 

 

1/2T-40

60

 

 

 

1/2T-40

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tDW

420

 

 

 

 

 

(3/2+N)T -60

230

 

 

 

(3/2+N)T -70

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tWD

100

 

 

 

 

 

1/2T-60

60

 

 

 

1/2T-40

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tCC

400

 

 

 

 

 

(3/2+N)T-80

230

 

 

 

(3/2+N)T -70

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tCl

50

 

 

 

 

 

1/2T-110

25

 

 

 

1/2T-75

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tARY

 

 

 

220

 

 

3/2T-260

 

100

 

 

3/2T-200

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tRYS

110

 

 

 

 

 

 

100

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tRYH

0

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tHACK

110

 

 

 

 

 

1/2T-50

40

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tHABE

 

 

210

 

 

1/2T+50

 

150

 

 

1/2T+50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tRV

400

 

 

 

 

 

3/2T-80

220

 

 

 

3/2T-80

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tAC

270

 

 

 

 

 

T-50

115

 

 

 

T-85

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tHDS

170

 

 

 

 

 

 

120

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tHDH

0

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tiNS

360

 

 

 

 

 

1/2T+200

150

 

 

 

1/2T+50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tlNH

0

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tlDR

 

 

460

 

 

2T -180

 

270

 

 

4/2T-130

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Where T = tcyc and N = th'enumber of wait states that are incorporated.

All mathematical operations in Table 2 are performed from left to right. except where qualified with parenthesis.

Table 2. 808SA and 8085A-2 Cycle Dependencies

A1-19

Page 160
Image 160
Intel MCS-80/85 manual 2T-80

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.