What is the primary function of the DAA instruction in the 8085?

Decimal Adjust Accumulator for BCD addition

8085 & 8051 Microprocessor & Microcontroller Cheat Sheet

This cheat sheet summarizes the core architecture, instruction sets, addressing modes, memory interfacing, and peripheral control of the 8085 microprocessor and 8051 microcontroller.

Core Principles

The 8085 is an 8-bit microprocessor with key components like ALU, Accumulator, Flag Register, and various general-purpose registers for data processing.
The 8051 is an 8-bit microcontroller integrating CPU, memory (ROM/RAM), timers, I/O ports, and serial communication on a single chip.
Addressing modes (Immediate, Register, Direct, Indirect, Implied, Indexed) define how instructions access operands, impacting program flexibility and efficiency.
Memory interfacing involves connecting ROM (for programs) and RAM (for data) using address lines, control signals (RD, WR, PSEN), and address decoding.
Peripherals like LEDs, Seven-Segment Displays, Stepper Motors, and ADCs/DACs are interfaced using I/O ports and dedicated controller ICs (e.g., 8255 PPI).
Interrupts allow microprocessors/microcontrollers to respond to external events efficiently by pausing current execution and running service routines.

Key Terms

Microprocessor: A central processing unit (CPU) on a single integrated circuit (IC) that performs arithmetic and logic operations.
Microcontroller: An integrated circuit that contains a CPU, memory, and programmable input/output peripherals on a single chip.
ALU: Arithmetic Logic Unit; performs arithmetic and logical operations.
Register: A small, fast storage location within a CPU used to hold data temporarily.
Addressing Mode: The method by which an operand is specified in an instruction.
Memory Interfacing: Connecting memory chips (ROM/RAM) to the microprocessor/microcontroller.
Interrupt: A signal that temporarily halts the normal execution of a program to handle an urgent event.
PPI: Programmable Peripheral Interface (e.g., 8255); used for flexible I/O operations.
UART: Universal Asynchronous Receiver/Transmitter; hardware for serial communication.
Baud Rate: The rate at which data is transmitted over a serial communication channel.

Quiz

Which register in the 8085 stores the address of the next instruction to be executed?: Program Counter
What is the primary function of the DAA instruction in the 8085?: Decimal Adjust Accumulator for BCD addition
In the 8051, which register pair is typically used for accessing external memory?: DPTR