/oEncoder

Primary LanguageC

Optical Encoder Project

Overview

This project is an optical encoder designed to encode 62 numerical characters (0-9, a-z, A-Z) from a keyboard over a serial channel and output these encoded characters to 6 LEDs. The project is written in embedded C and designed to run on an ATMEGA328 MCU interfaced with an FT232RL USB to Serial adapter.

Project Structure

Include Files

  • delay.h: Defines functions for millisecond and microsecond delays.
  • led.h: Contains function prototypes for LED control and initialization.
  • reg_map.h: Defines the registers in the ATMega328/P microcontroller.
  • usart.h: Defines functions for serial communication with a terminal emulator.
  • util.h: Contains utility function prototypes, such as division modulus.

Source Files

  • led.c: Implements the LED control and initialization functions.
  • interrupt.c: Contains code to handle interrupts.
  • util.c: Implements utility functions.
  • usart.c: Defines functions used for communication with the terminal emulator.
  • oencoder.c: The main file implementing the optical encoder logic.
  • Makefile: Contains the build instructions for the project.

Detailed Functionality

LED Control and Initialization

  • init_led(): Initializes the LEDs. This function must be called before using the LED ON and OFF functions.
  • LED ON/OFF Functions: Implemented in led.c and the prototypes are defined in led.h.

Delays

  • delay_ms(): Introduces a delay in milliseconds.
  • delay_us(): Introduces a delay in microseconds.

Register Definitions

  • reg_map.h: Contains definitions for the registers in the ATMega328/P microcontroller.

Interrupt Handling

  • interrupt.c: Contains the code required to handle interrupts appropriately.

Utility Functions

  • util.c: Implements various utility functions such as division modulus operations.
  • util.h: Contains the corresponding function prototypes.

Serial Communication

  • usart.c & usart.h: Define functions for communicating with a terminal emulator running on the development PC.
  • sscanc(): Reads a character from the terminal emulator.
  • init_usart(): Initializes the serial communication channel.
  • Error Handling: sscanc() may return errors which should be handled accordingly in the implementation.

Configuration for Serial Terminal

Use the following configuration for Tera Term or Screen:

  • Speed: 9600
  • Data: 8-bit
  • Parity: None
  • Stop bits: 1 bit
  • Flow control: None

Building and Running the Project

Prerequisites

  • ATMEGA328 MCU
  • FT232RL USB to Serial adapter
  • 6 LEDs
  • Development PC with terminal emulator (e.g., Tera Term, Screen)

Steps

  1. Initialize the LEDs by calling init_led().
  2. Set up the serial communication by calling init_usart() with the correct configuration.
  3. Compile the project using the provided Makefile.
  4. Upload the compiled code to the ATMEGA328 MCU.
  5. Run the terminal emulator with the specified configuration to start encoding characters and observe the LED outputs.