This page gives an overview of SCU Watchdog BareMetal driver

Table of Contents

Introduction

The watchdog timer can be used to prevent system lockup; for example, when software becomes trapped in a deadlock.
In normal operation, the user restarts the watchdog at regular intervals before the timer counts down to zero.
In cases where the timer does reach zero and the watchdog is enabled, one or a combination of the following signals is

generated: a system reset, an interrupt, or an external signal. The watchdog timeout period and the duration of any output signals are programmable.

For more information, please refer Chapter 14: Timers and clocks in Zynqmp 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. 

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

Note: The .yaml(in data folder) and CMakeLists.txt(in src folder) files would be used in System Device Tree based flow.

Driver Implementation

For a full list of features supported by this IP, please refer Chapter 14: Timers and clocks in Zynqmp Trm

Features

Controller/Driver features supported

• 32-bit counter that generates an interrupt when it reaches zero

• 8-bit prescaler to enable better control of the interrupt period

• Configurable single-shot or auto-reload modes

• Configurable starting values for the counter

• can be used in watchdog mode or timer mode

Known issues and Limitations

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/scuwdt/examples

Example Application Usage

SCUWDT examples

Expected Output

Polled mode example

https://github.com/Xilinx/embeddedsw/blob/master/XilinxProcessorIPLib/drivers/scuwdt/examples/xscuwdt_polled_example.c

This test contains a design example using the Xilinx SCU Private Watchdog Timer driver (XScuWdt) and hardware device in watchdog mode. It
illustrates how to initialize the watchdog device and restart it periodially in polling mode to avoid the assertion of the WDRESETREQ pin.

Output

Interrupt mode example

https://github.com/Xilinx/embeddedsw/blob/master/XilinxProcessorIPLib/drivers/scuwdt/examples/xscuwdt_intr_example.c

This file contains a design example using the Xilinx SCU Private Watchdog Timer driver (XScuWdt) and hardware in Timer mode using interrupts. It illustrates
how to use Watchdog device in the timer mode.

Output

Example Design Architecture

• NA

Changelog

2025.2

• None

2025.1

• None

2024.2

• https://github.com/Xilinx/embeddedsw/blob/xlnx_rel_v2024.2/doc/ChangeLog#L114

2024.1

• None

2023.2

• https://github.com/Xilinx/embeddedsw/blob/xilinx_v2023.2/doc/ChangeLog#L299

2023.1

• None

Related Links

• http://www.wiki.xilinx.com/Baremetal+Drivers+and+Libraries