README

Example Summary

This application demonstrates how to use the Watchdog driver to cause a reset.

Peripherals Exercised

• Board_GPIO_LED0 - Indicator LED
• Board_GPIO_BUTTON0 - Used to control the application
• Board_WATCHDOG0 - Timer to reset the device

Resources & Jumper Settings

If you’re using an IDE (such as CCS or IAR), please refer to Board.html in your project directory for resources used and board-specific jumper settings. Otherwise, you can find Board.html in the directory <SDK_INSTALL_DIR>/source/ti/boards/<BOARD>.

Example Usage

• The application turns ON Board_GPIO_LED0 to indicate driver initialization is complete.

• Board_GPIO_LED0 is toggled repeatedly until Board_GPIO_BUTTON0 is pressed. A device reset occurs on the second watchdog timeout after Board_GPIO_BUTTON0 is pushed.

What happens after the reset depends on whether there is a debugger attached or not.

• In the debugger case, the reset will either cause the application to restart or cause it to halt, depending on your device. Again depending on your device, you can set a breakpoint at the beginning of main to see that the device was reset after pressing the button.

• If the debugger is not in use and Board_GPIO_BUTTON0 is pressed, there may be a brief flicker in the blinking of Board_GPIO_LED0 as the reset occurs.

Application Design Details

• The application supplies a callback function to the Watchdog module which is executed on every watchdog timer time-out (in watchdog interrupt context). The callback repeatedly clears the watchdog timer, thus preventing a device reset, and toggles Board_GPIO_LED0.

• When Board_GPIO_BUTTON0 is pressed, the mainThread clears a flag used by the callback. The callback sees the flag and stops calling Watchdog_clear().

• The mainThread performs the following actions: Determine if Board_GPIO_BUTTON0 had been pressed. If so, clear the reset flag; allow watchdog timer to reset device on next interrupt.

TI-RTOS:

• When building in Code Composer Studio, the kernel configuration project will be imported along with the example. The kernel configuration project is referenced by the example, so it will be built first. The “release” kernel configuration is the default project used. It has many debug features disabled. These feature include assert checking, logging and runtime stack checks. For a detailed difference between the “release” and “debug” kernel configurations and how to switch between them, please refer to the SimpleLink MCU SDK User’s Guide. The “release” and “debug” kernel configuration projects can be found under <SDK_INSTALL_DIR>/kernel/tirtos/builds/<BOARD>/(release|debug)/(ccs|gcc).

FreeRTOS:

• Please view the FreeRTOSConfig.h header file for example configuration information.