os32u4

A Kernel for use on 32u4 AVR chips.

This project exists to provide a low-level hardware library to help me program ATmega32u4-based μControllers. Currently, library features include:

• Digital GPIO
• Precise & fuzzy timekeeping
• Timeshare-based multithreading with up to 10 threads
  • Capibilities for IPC, task management, and freezing threads
  • Easy-to-use interface
  • Low resource usage
• Support for interacting with 8-bit shift registers
• Hardware USART with support for redirecting stdio over USART
• A single-digit 7-segment display driver

All code except vendor code has been written by me, by hand. I am using this project to help me learn my way arount the AVR ISA.

Testbed

I am currently developing this library / kernel with the following:

• Arduino Pro Micro (16mhz 5V)
• Generic USB-FTDI converter
• 8bit shift register
• 7 segment display
• A few LEDs

Timers

The following timers are used by os32u4:

Timer	Resolution	Usage
TCCR0	8bit	Timekeeping
TCCR3	8bit	PWM

Documentation

• AVRASM2
• 32u4 datasheet
• Interrupts guide
• avr-libc
• 32u4 timers
• Arduino Core
• MCUdude