This library aims to abstract away the hardware modules on an AVR microcontroller in an efficient and straightforward manner. Please be aware that at this time the library was only tested on an ATMega2560.
More comprehensive tests will follow, this includes showing the generated assembly as well as timing measurements with an oscilloscope.
At the time there is only one module available which is demonstrated below:
#include <AVRUtils/IO/IO.h>
/*!
* Target: ATMega2560
*/
#define LED io__sfr(C, 3) // PC3
#define SW io__sfr(K, 4) // PK4
int main(void) {
// Configure I/O
// LED as an OUTPUT
io__setDirection(LED, IO__OUTPUT);
// SW as an INPUT
io__setDirection(SW, IO__INPUT);
for (;;) {
// Continuously write the state of `SW`
// to `LED`.
// This code is independent of the physical
// locations of LED and SW. :)
io__write(LED, io__read(SW));
}
}As you can see, the logic of the code is completely isolated from the physical locations of the pins! And guess what? The code is efficient as well! Take a look at the generated assembly.
Sometimes it is not possible (due physical constraints) to route all positions from a bus to the same port on the microcontroller. For example: you have a 4 bit wide bus where 2 bits are on port C and 2 bits are on port F. A real mess! You know what I'm talking about if you ever had this situation before! Well, those days are finally gone! The included I/O module provides an easy and straightforward solution to that problem!
How? You simply define each position with the io__sfr macro and then join them together with the io__bus macro:
#include <AVRUtils/IO/IO.h>
/*!
* Target: ATMega2560
*/
// Define some switches
#define I0 io__sfr(L, 1) // PL1
#define I1 io__sfr(B, 3) // PB3
#define I2 io__sfr(F, 0) // PF0
#define I3 io__sfr(F, 1) // PF1
#define I4 io__sfr(F, 4) // PF4
#define I5 io__sfr(F, 7) // PF7
#define I6 io__sfr(K, 1) // PK1
#define I7 io__sfr(K, 4) // PK4
// Define some LEDs
#define Q0 io__sfr(H, 4) // PH4
#define Q1 io__sfr(H, 3) // PH3
#define Q2 io__sfr(E, 3) // PE3
#define Q3 io__sfr(G, 5) // PG5
#define Q4 io__sfr(E, 5) // PE5
#define Q5 io__sfr(E, 4) // PE4
#define Q6 io__sfr(C, 1) // PC1
#define Q7 io__sfr(C, 3) // PC3
// Create the 8 bit wide bus
// where I0 = LSB ; Q0 = LSB
// and I7 = MSB ; Q7 = MSB
#define I io__bus(8, I0, I1, I2, I3, I4, I5, I6, I7)
#define Q io__bus(8, Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7)
int main(void) {
// Configure the whole `I` bus as INPUT
io__setDirection(I, IO__INPUT);
// Configure the whole `Q` bus as OUTPUT
io__setDirection(Q, IO__OUTPUT);
for (;;) {
// Continuously write the state of `I`
// to `Q`.
io__write(Q, io__read(I));
}
}Easy!
Have a look at this wiki page, where each macro / function is explained in more detail.
Just download the library and include it in your project.
Don't forget to compile at least with Os optimization level, also use the -flto flag while compiling. (very important!)
The library is tested to work with avr-gcc 4.8.3.
- Enable mocking functions to test I/O without a microcontroller.
- Add statemachine module.
- Even more optimization for I/O operations.
- Comprehensive tests (Assembly / Oscilloscope).
- Timer / TWI / UART module...
Please report bugs by the issues function provided by GitHub.
Contributions are very welcome! Please use the issues tool for these as well, thank you.