This example implements the LED program with a tiny cooperative multitasking scheduler for the target with the 8-bit microcontroller. This example is similar to the previous example chapter02_03. Example chapter02_03a, however, includes a tiny cooperative multitasking scheduler for managing the tasks that ultimately control the timing and delays of the LED blinking. This example contains some techniques that are described in later chapters of the book. It does, however, provide intuitive insight at an early stage into a more complete form of project.
Building the example can be done with GNUmake
in the command batch or shell script,
as is the case for all examples including and above
example chapter02_02. The results of the build will be stored
in the bin directory.
Project workspaces providing code visualization and single-click build are provided for both VC as well as Atmel Studio.
In the LED program with timing, the blinking is controlled
in the application task app::led::task_func
in the file app_led.cpp.
void app::led::task_func()
{
if(app_led_timer.timeout())
{
app_led_timer.start_interval(timer_type::seconds(1U));
mcal::led::led0.toggle();
}
}
The multitasking scheduler combined with utilities such as timer and LED objects allow for convenient, intuitive programming that is both straightforward to implement as well as simple to comprehend. In this small snippet from the application task, for instance it is intuitively clear that Led0 is toggled once per second.
Cross development is also used. This means that the application layer runs both on the PC as well as in the embedded target. On the PC, the LED toggle is expressed with text on the standard output console, while the target system controls the actual hardware used LED that is present on the board.