GD32F103ZET6 Fixing Unexpected Reset Behavior

Troubleshooting Unexpected Reset Behavior on GD32F103ZET6

Introduction

If you are experiencing unexpected reset behavior on the GD32F103ZET6 microcontroller, it can be caused by various issues related to Power supply, watchdog timers, configuration settings, and external influences. This guide will break down potential causes of the problem, and provide a step-by-step approach to diagnosing and fixing the issue.

Step 1: Identify the Symptoms of Unexpected Reset

Unexpected System Restart: The microcontroller resets without user intervention. Loss of Settings or Data: Certain settings or variables may reset to their default values unexpectedly. Booting Behavior: The system may behave as if it is starting up again, even if there were no intentional power cycle.

Step 2: Check for Power Supply Issues

A common cause for unexpected resets is a power supply issue. Microcontrollers like GD32F103ZET6 can reset if the voltage levels fluctuate or fall below a threshold.

Check Voltage Stability: Ensure that the supply voltage (Vcc) is within the specified range for the GD32F103ZET6 (typically 2.6V to 3.6V). Use an oscilloscope to check for any voltage dips or spikes. If you find significant fluctuations, consider adding a decoupling capacitor near the Vcc pin to stabilize the supply voltage.

Verify Power-On Reset Circuit: The GD32F103ZET6 includes an internal power-on reset (POR) circuit. Ensure that it is functioning correctly by reviewing the hardware design.

Check External Power Source: If you are powering the microcontroller from an external source, ensure the external power supply is stable and can provide sufficient current.

Step 3: Investigate Watchdog Timer Configuration

The GD32F103ZET6 comes with both independent and window watchdog timers to protect against system hangs. However, incorrect configuration or a malfunction can cause unexpected resets.

Watchdog Timer Enabled: Check if the independent watchdog (IWDG) or the window watchdog (WWDG) is enabled in your code. If enabled, the watchdog will reset the microcontroller if the software fails to feed the watchdog in time. Timeout Settings: If the watchdog timer has a very short timeout, it might reset the system frequently, even under normal operation. Increase the timeout period in the configuration to give your system enough time between resets.

Feed the Watchdog Properly: Ensure that the watchdog is being fed in the main application loop, and no part of the software is blocking the feeding of the watchdog.

Check for Software Hangs: Ensure the software isn’t stuck in a loop or blocking code, preventing the watchdog from being fed.

Step 4: Review Bootloader and Firmware

Sometimes, unexpected resets are caused by errors or issues in the bootloader or firmware.

Bootloader Conflicts: If you are using a bootloader for firmware updates, ensure there is no conflict with the reset vectors. An incorrectly configured bootloader can cause the microcontroller to reset repeatedly.

Firmware Initialization: Ensure your firmware does not include any code that inadvertently triggers a reset. Double-check the initialization sequence in your main program for any unintended resets.

Reset Source Register: Use the microcontroller’s reset source register (RCC_CFGR) to check what caused the last reset. The register will show if the reset was caused by a watchdog timer, external pin reset, software reset, or power-on reset.

Step 5: Check for External Reset Triggers

The GD32F103ZET6 microcontroller has several pins that can trigger an external reset (NRST pin). External components connected to the reset pin could unintentionally cause resets.

External Reset Pin: Check the state of the NRST pin, and verify that no external devices are pulling it low inadvertently. Use a pull-up resistor on the NRST pin if necessary, to ensure it stays high when no reset is needed. Interference from External Circuits: If you have peripherals or external components that interact with the microcontroller, ensure they are not inadvertently causing resets. This could happen due to noise or power spikes.

Step 6: Update Firmware and Tools

Outdated firmware, development tools, or libraries might be causing the reset behavior.

Firmware Update: Make sure you are using the latest firmware version for the GD32F103ZET6. Manufacturers frequently release updates that address various stability issues, including unexpected resets.

IDE and Debugger: Ensure that your development environment (IDE) and debugger are correctly configured. Sometimes debugging settings or certain breakpoints can cause the system to reset unexpectedly.

Step 7: Perform Systematic Debugging

If none of the above steps resolve the issue, it’s time to conduct a deeper investigation.

Check System Logs: Review any system logs or debug output that may provide clues on where the reset occurs.

Use Debugging Tools: Employ debugging tools such as JTAG or SWD (Serial Wire Debug) to step through your code. Look for any functions that may be causing a reset.

Incremental Code Testing: Isolate sections of your code and test them individually. This can help identify if a particular piece of functionality is triggering the reset.

Conclusion

By systematically checking power supply issues, watchdog configuration, firmware setup, external triggers, and other system aspects, you can pinpoint the cause of unexpected reset behavior in the GD32F103ZET6 microcontroller. Following the above steps should help resolve the issue, but if problems persist, consider seeking further support from the manufacturer or a community forum.

By isolating the problem and applying these troubleshooting steps, you'll be able to ensure the reliability of your system and prevent unexpected resets from interfering with your application.