QUICK REVISION (PART-1) (ARCHITECTURE OF PIC 18F XXXX)

Summary

This video provides a detailed overview of the PIC 18F microcontroller architecture, covering essential components like the MPU, ROM, RAM, ALU, and instruction registers. Key features such as its embedded flash memory, low power modes, input/output ports, and stack memory organization are discussed. The microcontroller’s functionality, including its arithmetic and logic unit (ALU), reset conditions, and various operational modes like run, sleep, and idle modes, are thoroughly explained. The session also outlines important selection criteria for choosing the appropriate PIC 18F microcontroller based on power consumption, data handling, memory, and performance requirements.

Takeaways

• 😀 The P 18F microcontroller architecture consists of key blocks like the MPU (Microprocessor Unit), ROM, RAM, I/O ports, and the ALU (Arithmetic Logic Unit).
• 😀 The microcontroller includes five I/O ports (A, B, C, D, E) and 33 addressable I/O lines for external device interaction.
• 😀 The microcontroller uses a 21-bit program counter to address up to 2MB of program memory, storing instructions and data tables.
• 😀 The ALU performs both arithmetic (addition, subtraction, etc.) and logical operations, interacting with the working register (W register) and general-purpose registers.
• 😀 The P 18F microcontroller features 15 banks of registers and uses the File Select Register (FSR) to select the appropriate bank.
• 😀 Key features of the P 18F microcontroller include embedded flash memory, 8-bit CPU, multiple timers, low power modes, and serial communication support.
• 😀 Program memory is organized with a 31-level stack, while data memory uses 16 banks (0 to 15) for storing program data, with 4096 file registers.
• 😀 The reset function of the microcontroller can be triggered by several conditions, including power-on reset, stack overflow, manual reset, and external interrupts.
• 😀 The microcontroller supports various power modes, such as Run Mode, Sleep Mode, and Idle Mode, each optimizing power consumption and operational efficiency.
• 😀 When selecting a P 18F microcontroller, factors like power consumption, data handling capabilities, memory organization, and I/O requirements should be considered.

Q & A

What are the major components of the architecture of the PIC 18F microcontroller?

The major components include the Microprocessor Unit (MPU), which consists of an accumulator, general-purpose register (GPR), and file select register (FSR); ROM for program memory; RAM for data memory; input/output ports (5 ports, A, B, C, D, E with 33 I/O lines); stack memory; program counter (PC); instruction register (IR); instruction decoder (ID); and an Arithmetic and Logic Unit (ALU).

What is the role of the Arithmetic and Logic Unit (ALU) in the PIC 18F microcontroller?

The ALU performs arithmetic and logical operations such as addition, subtraction, multiplication, and division. It works with the W register (working register) and the file register to perform these operations and stores the result based on the value of the D bit in certain instructions.

What are the main features of the PIC 18F microcontroller?

Key features of the PIC 18F microcontroller include embedded flash technology, an 8-bit CPU with a RISC architecture, 2MB ROM, 4KB RAM, 32KB flash ROM, 1.536KB SRAM, 256 bytes of EEPROM, five I/O ports with 33 addressable lines, four timers, 15 register banks, power-saving modes, external interrupts, and a wide voltage range of 2 to 5.5V.

How is the program memory organized in the PIC 18F microcontroller?

The program memory in the PIC 18F microcontroller is organized as a 2MB address space, with 31 stack levels used to store return addresses. The memory starts with a reset vector, followed by locations allocated for high and low priority interrupts. The program memory is based on 32KB of flash memory, capable of storing single-word instructions.

What is the purpose of the file select register (FSR) in the PIC 18F microcontroller?

The FSR is used to select one of the 15 register banks in the PIC 18F microcontroller. It allows the microcontroller to access different memory banks for storing and retrieving data, ensuring efficient data management.

Explain the different resetting conditions of the PIC 18F microcontroller.

The PIC 18F microcontroller can reset under several conditions, including a stack overflow or underflow, a manual reset (MCLR bar), power-on reset (P), power-up timer (PWRT), oscillator startup timer (OST), brown-out reset (BOR), and watchdog timer (WDT) reset. These conditions ensure stable operation and recovery from faults or power issues.

What are the types of run modes available in the PIC 18F microcontroller?

The PIC 18F microcontroller has three types of run modes: primary run mode (full power execution), secondary run mode (low power, using a timer oscillator), and RC run mode (highly sensitive timing operations using an internal oscillator). These modes help manage power consumption based on application requirements.

What are some key selection criteria when choosing a PIC 18F microcontroller for a project?

The key selection criteria include power consumption, data handling capabilities, operating speed, memory structure and capacity, special function registers, performance, the number of I/O pins, and the type of packaging (e.g., DIP). These factors help ensure that the microcontroller meets the specific needs of an application.

What does the reset vector address in the PIC 18F microcontroller signify?

The reset vector address, typically 0x0000 in hexadecimal, is the location where the microcontroller begins execution after a reset. It stores the address to which the program counter (PC) is set after a reset, initiating the program's execution from this point.

What is the difference between general-purpose registers (GPR) and special function registers (SFR) in the PIC 18F microcontroller?

General-purpose registers (GPR) are used to store data for program variables and applications, while special function registers (SFR) are used to store control data related to device operations. GPRs are located in different banks of memory, while SFRs are used for specific control tasks in the microcontroller.