bitbank2/fastio

A fast substitute for Arduino digital pin functions on AVR MCUs

FastIO
Project started 1/9/2019
Copyright (c) 2019 BitBank Software, Inc.
Written by Larry Bank
[email protected]

Faster replacement for accessing digital pins on Arduino AVR MCUs The digital I/O functions provided by the Arduino core library are much slower than they can be due to pin number translation, boundary checking and ensuring that ports are accessed while interrupts are disabled. For most projects, all of these precautions are not necessary and this allows code which calls the FastIO functions to generate much faster signals. The standard digital pin numbers of each Arduino board map to different port addresses depending on the chipset in use. FastIO changes the pin numbering to be based on the AVR port and not the virtual I/O pin. The pin numbers are specified as port (B/C/D/E/F/G) plus bit. For example, on the ATmega32u4 (Leonardo / Pro Micro), digital pin 2 is actually bit 1 of port D. To access that pin with the FastIO library you would specify pin number 0xD1.

Features:
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• Supports fast access to digital ports on all AVR microcontrollers
  
• pinMode, digitalRead and digitalWrite work the same as the originals
  
• Repeated accesses to the same pin number only require a few clock cycles