Micro

Text Editor

is used to develop a program using a computer. A text editor allows the user to type, modify, and save the program source code in a text file.

Computer

is made up of hardware and software.

Processor

serves as the computer’s “brain”. also known as "central processing unit"

Registers

is a storage location in the CPU. It is used to hold

data and/or a memory address during execution of an instruction.

arithmetic logic unit

is the computer’s numerical calculator and logical operation evaluator.

control unit

contains the hardware instruction logic. It decodes and monitors the execution of instructions.

program counter

which controls the memory address of the next instruction to be executed

status register

During the execution of an instruction, the presence of overflow, an addition carry, a subtraction borrow, and so forth, are flagged by the system and stored in here

resultant flags

used by the programmers for program control and decision-making.

clock cycles

CPU activities are measured and synchronized by this. modern microprocessors have more than 800 MHz

input unit

which programs and data can be entered into the computer

output unit

which computational results can be displayed

memory

which the computer software

programs and data are stored. Its types may contain semiconductor, magnetic, and/or optical

bus

a set of signal lines

data bus

address bus

control bus

Types of bus

microprocessor

is a processor packaged in a single integrated circuit.

microcomputer

is a computer that uses a microprocessor as its CPU.

cache memory

To enhance the CPU performance, many 32-bit and 64-bit microprocessors contain on-chip high-speed. has a copy of the most recently accessed instructions and data. It is much smaller than the main memory.

Glue logic

is needed to interconnect external memory and peripheral interface chips to the microprocessor

Microcontroller

is a computer implemented on a single very large scale integration (VLSI) chip

Motorola 68HC11

is an 8-bit microcontroller family developed in 1985. This family has more than fifty members, and the number is still increasing

RAM

is volatile in the sense that it cannot retain data in the absence of power. It is also called read/write memory because it allows the processor to read from and write into it.

Static RAM

uses from four to six transistors to store one bit of information. As long as power is stable, the information stored will not be degraded

Dynamic RAM

uses one transistor and one capacitor to store one bit of information. The information is stored in the capacitor in the form of an electric charge. The charge stored in the capacitor will leak away over time, so a periodic refresh operation is needed to maintain the contents.

ROM

is nonvolatile. If power is removed from it and then reapplied, the original data will still be there.

Masked-programmed read-only memory (MROM)

is a type of ROM that is programmed when it is manufactured. The semiconductor manufacturer places binary data in the memory according to the request of the customer.

Programmable read-only memory (PROM)

is a type of read-only memory that can be programmed in the field (often by the end user) using a device called a PROM programmer or a PROM burner.

Erasable programmable read-only memory (EPROM)

is a type of read-only memory that can be erased by subjecting it to strong ultraviolet light. The circuit design of EPROM requires us to erase the contents of a location before we can write a new value into it.

Electrically erasable programmable read-only memory (EEPROM)

is a type of nonvolatile memory that can be erased by electrical signals and reprogrammed. Like EPROM, the circuit design of it also requires us to erase the contents of a memory location before we can write a new value into it.

Flash Memory

was invented to incorporate the advantages and avoid the drawbacks of both EPROM and EEPROM technologies. It can be erased and reprogrammed in the system without using a dedicated programmer.

Program writing

The programmer will need to memorize the binary pattern of each machine instruction

Program debugging

Whenever there are errors, it is extremely difficult to trace the program because the program consists of only sequences of 0s and 1s.

Program maintenance

Most programs will need to be maintained in the long run. A programmer who did not write the program will have a hard time reading the program and following the program logic.

Assembly instruction

is the mnemonic representation of a machine instruction.

Assembly language

was invented to simplify the programming job.

Source program or Source code.

the assembly program that the programmer enters

Program

is a set of instructions that the computer hardware can execute.

Machine instructions

computer’s memory in the form of binary numbers

Assembler

is invoked to translate the program written in assembly language into machine instructions.

Object code

The output of the assembly process

Cross assembler

is an assembler that runs on one computer but generates machine instructions that will be executed by another computer that has a different instruction set.

Native assembler

runs on a computer and generates machine instructions to be executed by machines that have the same instruction set.

Memory Addressing

is referred to as an information unit.

Nibble

4-bit quantity

Immediate Addressing Mode (IMM)

the actual argument is contained in the byte or bytes immediately following the instruction opcode. The number of bytes matches the size of the register.

Direct Mode (DIR)

the least significant byte of the effective address of the instruction operand appears in the byte following the opcode. The high-order byte of the effective address is assumed to be $00 and is not included in the instruction.

Extended Mode (EXT)

the effective address of the operand appears explicitly in the two bytes following the opcode

Indexed Mode (INDX, INDY)

one of the index registers (X or Y) is used in calculating the effective address.

Inherent Mode (INH)

everything needed to execute the instruction is encoded in the opcode.

Relative Mode (REL)

is used only for branch instructions.

Read Cycle

The process of accessing a memory location