This page gives an overview of the bare-metal driver support for AXI Watchdog Timer.

Introduction

This page gives an overview of Axi Watchdog timer driver /Window watchdog timer which is available as part of the Xilinx Vivado and SDK distribution.

The Xilinx® LogiCORE? IP AXI4-Lite Timebase Watchdog Timer (WDT) is a 32-bit peripheral that provides a 32-bit free-running
timebase and watchdog timer.

For more information, please refer AXI_Timebase_Wdt_Doc

Same Driver supports for Versal platform , on versal supports Generic watchdog and window watchdog features.

For more information, please refer Chapter 59: System Watchdog Timer Versal Trm which includes links to the official documentation and resource utilization.

Driver Sources

The source code for the driver is included with the Vitis Unified Software Platform installation, as well as being available in the Xilinx Github repository.

Driver	Path in vitis	Path in Git Hub
wdttb	<Vitis Install Directory>/data/embedded/XilinxProcessorIPLib/drivers/wdttb	https://github.com/Xilinx/embeddedsw/tree/master/XilinxProcessorIPLib/drivers/wdttb

Note: To view the sources for a particular release, use the rel-version tag in github. For example, for the 2020.1 release, the proper version of the code is: https://github.com/Xilinx/embeddedsw/tree/master/XilinxProcessorIPLib/drivers/wdttb

The driver source code is organized into different folders. The table below shows the wdttb driver source organization.

Directory	Description
src	Driver source files, make and cmakelists file
examples	Example applications that show how to use the driver features
doc	Provides the API and data structure details
data	Driver .tcl , .mdd and .yaml files

Note: AMD Xilinx embeddedsw build flow is changed from 2023.2 release to adapt to the new system device tree based flow. For further information, refer to the wiki page Porting embeddedsw components to system device tree (SDT) based flow - Xilinx Wiki - Confluence (atlassian.net).

The .yaml(in data folder) and CMakeLists.txt(in src folder) files are needed for the System Device Tree based flow. The Driver .tcl and .mdd files are for the older build flow which will be deprecated in the future.

Driver Implementation

For a full list of features supported by this IP, please refer AXI_Timebase_Wdt_Doc

For a full list of features supported by this IP, please refer 59: System Watchdog Timer Versal Trm

Features

Driver Supported Features

The Axi watchdog timer Standalone driver support the below things.
All Controller Features supported.

WWDT Driver support:

Supports Generic Watch dog timer and polled and interrupt mode window watch dog feature.
Q&A mode not implemented.

Known Issues and Limitataions

None

Example Applications

Refer to the driver examples directory for various example applications that exercise the different features of the driver. Each application is linked in the table below. The following sections describe the usage and expected output of the various applications. These example applications can be imported into the Vitis IDE from the Board Support Package settings tab.

Links to Examples

Examples Path:

https://github.com/Xilinx/embeddedsw/tree/master/XilinxProcessorIPLib/drivers/wdttb/examples

Test Name	Example source	Description
	xwdttb_low_level_example.c	This example checks for Watchdog timer reset condition in two timer expiry state
	xwdttb_selftest_example.c	This example does a minimal test on the watchdog timer timebase device and drive
	xwdttb_example.c	This example tests the functioning of the TimeBase WatchDog Timer module in the polled mode
	xwdttb_intr_example.c	This example tests the functioning of the TimeBase WatchDog Timer module in the interrupt mode
	xwdttb_winwdt_example.c	This exampletests the functioning of the TimeBase WatchDog Timer module with window feature in the polled mode.
	xwdttb_winwdt_intr_example.c	This example tests the functioning of the TimeBase WatchDog Timer module with window feature in the interrupt mode.
	xwdttb_gwdt_selftest_example.c	This example does a minimal test on Generic watchdog timer device
	xwdttb_gwdt_example.c	This example tests the functioning of the Generic watch dog Timer Feature in Polled mode
	xwdttb_gwdt_intr_example.c	This example tests the functioning of the Generic watch dog Timer Feature in interrupt mode

Example Application Usage

WDTTB examples

Expected Output

xwdttb_low_level_example.c
OUTPUT:
Successfully ran WDTTB low level example.

xwdttb_selftest_example.c 
OUTPUT:
Successfully ran WDTTB self test example.

xwdttb_example.c
OUTPUT:
Restart kick 1
.........................
Restart kick 2
.........................
Successfully ran WDTTB example

xwdttb_intr_example.c
OUTPUT:
Successfully ran Window WDT interrupt example.

xwdttb_winwdt_example.c
OUTPUT:
Restart kick 1
.........................
Restart kick 2
.........................
Successfully ran Window WDT example.

xwdttb_winwdt_intr_example.c
OUTPUT:
Successfully ran Window WDT interrupt example.

xwdttb_gwdt_selftest_example.c
OUTPUT:
Successfully ran GWDT self test example

xwdttb_gwdt_example.c
OUTPUT:
Self test completed
.................................................................................................................................
 Refresh kick1
................................................................................................................
 Refresh kick2
................................................................................................................
 Refresh kick3
................................................................................................................................................................................................................................................
Generic watchdog second window expired

xwdttb_gwdt_intr_example.c
OUTPUT:
Successfully ran GWDT interrupt example