This library contains a set of header only utility classes for native C++ AVR development.
At the core is the file pin_definitions.hpp which allows Arduino-like pin manipulations with native (2 clock ticks) performance. This library is described in some detail on the dedicated project page. An example of the syntax:
PIN_TYPE( B, 5) led_pin; // LED is attached to pin 5 of port B
void f()
{
make_output( led_pin);
set( led_pin); // LED on
_delay_ms( 500);
clear( led_pin); // LED off
}On top of this are a few other utilities and hardware drivers, for example:
Sometimes it's convenient to have an SPI driver on configurable pins. The bit_banged_spi template takes care of that. Example use
#include "avr_utilities/pin_definitions.hpp"
#include "avr_utilities/devices/bitbanged_spi.h"
PIN_TYPE( B, 4) chip_select;
struct spi_pins
{
PIN_TYPE( D, 4) miso;
PIN_TYPE( C, 4) mosi;
PIN_TYPE( D, 3) clk;
};
typedef bitbanged_spi< spi_pins> spi;From here on, you have two choices. You can either only use the static functions of the spi type. In this case you are required to call the static init() function before doing anything else:
void f()
{
spi::init();
make_output( chip_select);
set( chip_select);
// send a message
clear( chip_select);
spi::transmit( "hello, world!");
set( chip_select);
// send a byte and receive one at the same time
clear( chip_select);
uint8_t reply = spi::transmit_receive( (uint8_t)42);
set( chip_select);
// etc..
}Or, at the cost of a few bytes of program space, you can declare an instance of the spi type and use it as a local object, in which case the initialization is done automatically:
spi my_spi;
void f()
{
clear( chip_select);
my_spi.transmit("hi there!");
set( chip_select);
}This driver can be used to control an attached hd44780 LCD display in 4-bit mode. Usage is as follows:
#include "avr_utilities/pin_definitions.hpp"
#include "avr_utilities/devices/hd44780.hpp"
struct hd44780_pins
{
PIN_TYPE( C, 5) rs;
PIN_TYPE(D, 2) rw;
PIN_TYPE(D, 3) e;
PIN_GROUP_TYPE( D, 4, 4) data; // 4 bits starting at D4 (D4, D5, D6, D7) are the data lines.
};
typedef hd44780::lcd<hd44780_pins> lcd;
And again, you can choose between using static functions and calling init yourself, or instantiating an object and enjoy auto-initialization. The following example shows only the instantiated version (note: controlling this device may take some more low-level calls):
lcd my_lcd;
void example()
{
my_lcd.cls();
// Go to the second line on my lcd display, which starts at address 64.
// This address may be different on other types of display.
my_lcd.command_out( hd44780::commands::dd_addr( 64));
my_lcd.string_out( "Hi Planet!");
}Originally, this library re-implemented small parts of mpl and preprocessor. Now, this library contains, in sub-directory 'boost' a subset of boost libraries. See the boost/README.md for more information.