Mikroprosesor

INTRODUCTION

Background

Almost in every place we can find a device that includes tersapat electronic equipment, ranging from PDAs, computers, televisions, radios, cars, until the coffee maker. What is interesting is that from these devices have a variety of functions and complexity, which is actually constructed by the basic components (devices) are similar. On computers and PDA devices require the millions of electrical components that have been organized into components that komleks.



The processor is an example of a complex devices, which baisanya modeled in the box that represents a particular system. Another example of complex devices are black boxes which can be found in devices such as calculators and mobile phones. Basically these complex devices also contain simple devices such as transistors, resistors, capacitors, and inductors. Current leading edge technology has made it possible to pack millions of discrete components such as transistors in a single complex devices. Devices such complex known as the IC.


Microprocessor is a circuit designed with VLSI technology (Very Large Scale Integration) in such a way with very small dimensions and are made in sati "Chip" IC (integrated circuit), works to solve a problem digital phenomena with functions that have been controlled through appropriate programs with expectations


Classically, it is known there are three major companies that compete with each other microprocessor-mikroprosesornya popularization, namely Zilog, MOTOROLA and INTEL. Zilog is famous for starting the Z80 microprocessor (8-bit), Z8000 (16-bit) and Z80000 (32-bit) and pheripheralnya. MOTOROLA popular with microprocessors starting from MC6800 (8-bit), MC6809 (8-bit), MC68000 (16-bit), MC68010 (16/32-bit), MC68020 (16/32-bit), MC68030 (32-bit ) until the final version along with pheripheralnya. The famous INTEL mikroprosesornya starting from 8080 (8-bit), 8085 (8-bit), 8086 (16-bit), 8088 (8/16-bit), the 80286 (32-bit), 80 386 (32-bit) , 80 486 (32-bit), known as the i486 only, until the latest Pentium family and pheripheralnya.


The discussion in this paper I focus on the Z80 CPU, because almost every person in this world who do research work in the field familiar with the Z80 microprocessor and CPU are generally used as the first time that I learned.


Goal Writing
The purpose of the preparation of the paper are:
By default compiler can know and understand the process of the performance of a microprocessor.
To increase the knowledge and insight, particularly in the field of Data Communications and Electronics digitally. As the task of Data Communications courses.


Systematics Writing
Authors manggunakan systematics writing as follows:

CHAPTER I. Introduction: Contains background issues, purpose of writing, and systematics of writing.

CHAPTER II. Discussion: The discussion contains about Z80 architecture, the registers in the Z80, Z80 Interrupt, timing Z80, and Z80 instruction execution time.

DISCUSSION

Z80 CPU Architecture
Z80 CPU was first made by Zilog Corporation circa 1975-1976. Because of the properties and ease of design work systemnya Z80 became very popular. Already many software and hardware perankat that have been made to reflect from Zilog-80. Z80 accepted not only among education, but also the industrial world. Many control equipment in industries known to use microprocessor-based CPU Z80. Z80 CPU architecture designed by applying the method of standard buses, which classifies pathways in three kinds of buses: address bus that serves as an output that can be had 3 conditions (high, low, and tri-state), the data bus that serves as both input and output and also has 3 conditions (high, low, and tri-state) and the control bus. Architecture basically followed the Intel 8085 CPU architecture as well. Therefore, the Z80 and 8080 machine code similar. Bial 8080 have 78 instructions, Z80 has a 158.
Type Z80 is an early type which has a capacity of only 2MHz work, then renew its type denagn Z80A performing up to 4 MHz.Pada mid 1980, the Z80 has been developed using CMOS technology type Z84C00. This type is the last production that is able to work with frequencies up to 16 MHz.
Z80 to work on a single voltage +5 V. He has a 208-bit internal registers, including 6 units general-purpose registers that can be used separately (each 8-bit) or which is used to multiply accumulatore or general-purpose register to another. This exchange facilities can be used fatherly show a fast interrupt response function. Z80 also has a register stack pointer, program counters, two index registers, a Refresh Register and an interrupt register.
Register - registers Z80 CPU
Z80 CPU has a Read / Write memory called registers or 208 bits (26x8) bits. The memory of the CPU is very useful for programmers in the manufacture of a program.

a) Accumulator (A) and Flag Register (F)
Z80 has two free registers memory with a special name that is accumulator and flag registers, each consisting of 8-bit. Accumulator (A) is a register that has specialized in opersi Traffic arithmetic and logic. Bial seen from the instructions of assembly Language Z80 then arithmetic operations and logic always melibtkan accumulator A. Bial compared with the other registers, the accumulator is most commonly used by programmers. Flag register is used to indicate special conditions on operations data 8-bit or 16-bit accumulator A produces zero (zero) or not. Accumulator and flag registers is register pairs are often diguanakan together to aritmatikadan logic operations.

b) General Purpose Registers
Z80 have registers that can at times be used to store the memory in the program, so regiater regiser Z80-versatile (General Purpose Register). Register-reregister it is B, C, D, E, H and L each have a specific complement registers. Each register has an 8-bit structure. When required, 16-bit register it can be arranged as registers BC, DE and HL. Adadlah complement BC ', DE' and HL '.

c) The Special Purpose Registers
Program Counter (PC) in charge of 'hold' 16-bit address at all times when the CPU is melakujan process fetch data from memory. Secarar PC will automatically be increased by 1 if a data fetch process is complete. PCs will also change bial program jump to a specific location. PCs will follow the address where the jump towards.
Stack Pointer (SP) in charge of holding the 16-bit address most ats from external memory (system RAM) at all times when the program is running. External Memory Stack is made sengan sisem LIFO (Last-In-First-Out). Data on-push-ups from a CPU register to the stack or in-pop from the stack into a register.
Two Index Registers (IX & IY) in charge of holding a 16-bit alamata used in the indexed addressing modes in programming. In this case the contents of index register is used as a basic point of connection to a CPU specific memory region where data is stored or retrieved.
Interrrupt Page Address Register (I). Z80 can be operated in a certain mode where an indirect relationship to memory can be achieved by providing an interrupt response. In this operation I used fatherly registers store the high order 8-bits of address that will be addressed, while the low-order 8-bits will be provided by a device which did interrupt it. With that advantage, an interrupt subroutine can be placed anywhere in accordance with the desired form of a program with a minimal time.
Memory Rfresh Register (R) on the Z80 has a memory refresh counter to allow for the Z80 to put together with dynamic memory together with the static memory.

d) Aritmatic and Logic Unit (ALU)
Z80 Assembly Language has the facilities to megnolah opersi data in arithmetic and logic. These operations are performed in the ALU (arithmetic & Logic Unit), which is a part of a series on special duty in the CPU process data in opersi arimatika and logic. Each opersi arithmetic and logic instructions are given on the CPU, the ALU will be active to process the data. Operations in the ALU is expressed in the form of Z80 Assembly Language instructions. Data as opersi objects can be placed in the registers according to the registers used by the instruction to be given.

e) Register Instruction and CPU Control
Any instructions that diambila from memory is always placed in the instruction register and then decoded (translated means in accordance with Z80 assembly language.) Once decoded, the control CPU will run the command in accordance with the task of producing control signals read / write, control signals to set the ALU and other control signals to adjust the outer circuits.

f) Indicator Status Flags Register
On the Z80 has a Status Indicators in the form of Flag Register. F and F 'or Flag Register can provide information to programmers about the status of Z80 CPU at all times when the CPU is working.

Bit positions of each flag is as follows:
D7 S
D6 Z
D5 x
H D4
D3 x
D2 P / V
D1 N
C D0

Description:
C = Carry Flag
N = Add / Subtruct Flag
P / V = Parity / Overflow Flag
H = Half-Carry Flag
Z = Zero Flag
S = Sign Flag
x = Not used

Flag register mangandung 6-bit Z80 CPU status information that can be tested and set or is reset through the instructions in the program. Bit 3 and bit 5 is not diguanakan. 4 and 6 bits used to be testable. With a conditional jump, call or return, 4 bits (C, P / V, Z and S) can be known status. The two remaining bits are not sestable and only used in BCD arithmetic operations.

Z80 CPU interrupts
Interrupt the execution of a subroutine insertion process in a program, which was not done in software (not inserted in the form of instruction in the program), but done through a hardware interrupt signals activation.
In practice, the use of an interrupt is to allow a peripheral device input / output port or a circuit system connected to the main system CPU to suspend operations that are executed by the CPU at any time during the process is under way, with the purpose of requesting or ordering CPU to execute programs from pheripheral-pheripheral routine in accordance with the "vector" of the interrupt that has been defined previously.


Z80 CPU Timing
Z80 CPU has 3 basic operations:
· Memory read / write
· I / O Devices read / write
· Interrupt
An instruction that is owned Z80 is actually just the development of the three basic operations. Each opersi requires 3 to 6 clock periods to complete the task, or bias also extended to afford the CPU synchronization with external equipment. In opersi program, the first machine cycle of each instruction is a fetch cycle (taking in decode I. opcode for this cycle requires 4 to 6 cycles, except when control is activated WATTS. The next machine cycle usually is the transfer of data between CPUdengan memory or I / O, although there are also specific instructions on the next machine cycle is the opcode fetch again.

Z80 CPU Instruction Execution Time
Z80 is an 8-bit processor that has 8-bit data bus. The combination of logic which may vary from the data bus until 11111111B 00000000B or 256 possibilities. In the process of data fetch, the CPU interprets any combination of logic that exist in the data bus. Because 8-bit CPUs have 256 possible combinations of logic on the data bus is 8-bit CPU can have up to 256 basic instructions berbeda.Artinya any combination of logic on the data bus can be interpreted as an instruction.
However, generally the designers of microprocessors do not use any logic combination of the data bus is used as a fatherly basic instructions for a basic instruction can be developed into an advanced instruction by adding a role behind them with consideration, among others, will more efficiently utilize sesediit possible programming techniques. Use the instructions that many tend to require programmers to provide greater energy also to memorize and understand the meaning of each instruction.

CLOSING

Based on the work system being studied in the paper that the Z80 CPU is a microprocessor that is used widely not only among education, but also among the industry and known microprocessors that they use to use Z80. In the early produksinyua Z80 has a type that is only capable of 2MHz early and later developed to be 16MHz. Z80 CPU has 208-bit internal registers, including 6 general-purpose registers that can be used separately (each 8-bit) or which is used to multiply accumulatore or general-purpose register to another.
On the Z80 has a 208-bit registers in the form of memory, inisangat very useful for programmers in making their program. In these registers also have functions effectively.
Interrupt Process done not with the method of inserting through the software, but through a hardware interrupt enable signals.
Z80 instructions that actually is the development of a memory operation read / write, I / O devices read / write and interrupt. Each operation takes 3 to 6 clock periods to complete the task, or it could be extended to work for CPU synchronization with external equipment.

Z80 is an 8-bit processor that has 8-bit data bus. The combination of logic which may vary from the data bus until 11111111B 00000000B or 256 possibilities. But usually the designers of microprocessors do not use any logic combination of the data bus is used as a fatherly basic instructions for a basic instruction can be developed into an advanced instruction by adding a role behind them with consideration, among others, will more efficiently utilize sesedit possible programming techniques.

REFERENCES

Pitowarno, Endra.2005. Microprocessors & Interfacing. Yogyakarta: Andi Publisher
Budiharto, Widodo & Firman, Sigit.2005. Digital Electronics and Microprocessors. Yogyakarta: Andi Publisher.
http://id.wikipedia.org/wiki/Prosesor_mikro
www.203.130.205.68garingdosengaringajigaringcomputer_organization/
www.innovativeelectronics.com/innovative_electronics/download_files/artikel/AN32.pdf
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