16 8085, 18, 1 0 | Intel MCS-80/85 instruction

THE INSTRUCTION SET

POP PSW (Pop processor status word)

(CY) - «SP))o

(P)- «SP))2 (AC)- «SP))4

(Z)- «S P))6

(S)- «SP))7

(A)- «SP) + 1) (SP) - (SP) + 2

The content of the memory location whose address is specified by the content of register SP is used to restore the condition flags. The content of the memory location whose address is one more than the con- tent of register SP is moved to register A. The content of register SP is incremented by 2.

1 o o o

Cycles: 3

States: 10

Addressing: reg. indirect

Flags: Z,S,P,CY,AC

XTHL(Exchange stack top with H and L)

(L)- «SP))

(H)- «SP) + 1)

The content of the L register is exchanged with the content of the memory location whose address is specified by the content of register SP. The content of the H register is exchanged with the content of the memory location whose address is one more than the content of register SP.

1 1o o o 1 1

Cycles:	5
States:	16 (8085), 18 (8080)
Addressing:	reg. indirect
Flags:	none

SPH L		(Move HL to SP)
	(SP) -	(H) (L)
	The contents of registers Hand L (16 bits)
	are moved to register SP.

1				o	o	1

		Cycles:		1
		States:		6 (8085), 5 (8080)
	Addressing:			register
		Flags:		none
IN port		(Input)
	(A)-(data)
	The data placed on the eight bit bi-
	directional data bus by the specified port is
	moved to register A.

1		o	1	o	1

			port

		Cycles:		3
		States:		10
		Addressing:		direct
		Flags:		none

OUT port (Output) (data) - (A)

The content of register A is placed on the eight bit bi-directional data bus for transmission to the specified port.

1 0 1 0 0

port

Cycles: 3

States: 10

Addressing: direct

Flags: none

5-16

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.

Intel MCS-80/85 manual 16 8085, 18, 1 0

Models: MCS-80/85

THE INSTRUCTION SET

1 o o o

16 (8085), 18 (8080)

SPH L

6 (8085), 5 (8080)

IN port

1 0 1 0 0

MCS-80/85 specifications