1.22 PIT Period Change
This example application shows how PIT period can be changed during run time.
Description
The LED starts blinking at one second intervals. When the switch is pushed the timer is stopped. When the switch is pressed again, the period is cut in half and the timer is restarted. The timer is turned off and on every alternate switch press. When the timer is started on every alternate switch press, the period is also toggled from .5 second, .25 second intervals, .125 second intervals and 1 second intervals. There is no debounce in the switch so it is possible that pressing the switch will jump more than one interval.
Downloading and Building the Application
To clone or download this application from Github, go to the main page of this repository and then click Clone button to clone this repository or download as zip file. This content can also be downloaded using content manager by following these instructions.
Path of the application within the repository is apps/pit/period_change/firmware.
To build the application, refer to the following table and open the project using its IDE.
| Project Name | Description |
|---|---|
| sam_9x60_curiosity.X | MPLABX project for SAM9X60 Curiosity Development Board |
Setting Up AT91Bootstrap Loader
To load the application binary onto the target device, we need to use at91bootstrap loader. Refer to the at91bootstrap loader documentation for details on how to configure, build and run bootstrap loader project and use it to bootstrap the application binaries.
Setting Up the Hardware
The following table shows the target hardware for the application projects.
| Project Name | Description |
|---|---|
| sam_9x60_curiosity.X | SAM9X60 Curiosity Development Board |
Setting Up SAM9X60 Curiosity Development Board
- Connect a programming cable from JTAG connector J12 on board to programmer(J-32 Debugger).
- Connect programmer(J-32 Debugger) to computer using a micro USB cable.
- Connect the USB port J1 on board to the computer using a micro USB cable (to power the board).
Running the Application
- Build and program the application using its IDE
- LED toggles every 1000 ms
- Press switch to stop the timer and hence the LED toggle
- Pressing the switch again starts the timer and changes the rate of LED toggle
- The application alternates between step 3 and 4 on each switch press
| Board | Switch Name | LED Name |
|---|---|---|
| SAM9X60 Curiosity Development Board | USER SW | RGB_LED (Green) |