This repository contains code which communicates with a host PC from an Arduino (or other ATmega 328 device) using the USART.
I have been experimenting with programming the Arduino using assembly
language of late and found it interesting. When writing C/C++ code for
the arduino, a debugging technique I have used is to write information
back to the PC using the Serial library of the Arduino/Wiring platform.
Three programs in this repo implement serial communications of different types:
Repeatedly write the alphabet to the USART.
Write a message to the serial port which is stored in the code segment. In this case, the message is "Hello World". (original, huh?)
Both of the above programs use blocking mode, polling on the UDRE0 (USART
Data Register Empty 0) bit of the UCSR0A register (USART Control and Status
Register 0 A) to determine when UDR (the USART Data Register) is empty and
ready for a new byte to be sent. The serial-interrupt.asm program enables
the UDRE0 interrupt and has an interrupt handler to send the next byte
of the message.
- For a great introduction to AVR Assembly programming see Command Line Assembly Language AVR Tutorials on Instructables.