Solving PWM Output Issues in GD32F103ZET6

Solving PWM Output Issues in GD32F103ZET6

When working with PWM (Pulse Width Modulation) outputs on the GD32F103ZET6 microcontroller, users may encounter issues such as the PWM not generating expected outputs, incorrect duty cycle, or the signal not being output at all. To resolve these issues, it is crucial to understand the potential causes and the necessary steps to address them. Below, we will break down the common causes and provide a detailed, step-by-step guide to troubleshooting and solving PWM output issues.

Possible Causes of PWM Output Issues

Incorrect Configuration of Timer Registers The GD32F103ZET6 microcontroller uses timers to generate PWM signals. If the timer registers (such as prescaler, period, and compare registers) are not properly configured, the PWM output may not function correctly.

Clock Source Issues The timer in the microcontroller relies on the correct clock source. If the system clock or timer clock is not properly set, the PWM signal may not be generated.

GPIO Pin Configuration Errors For PWM output, the corresponding GPIO pin must be configured correctly as an alternate function. If the pin is not set up for PWM output, no signal will be generated.

Incorrect Timer Channel Configuration The GD32F103ZET6 has multiple timer channels. If the wrong timer channel is selected for PWM output, the signal will not be generated on the expected pin.

Hardware Faults While rare, a hardware fault in the microcontroller, PCB traces, or external components can also affect PWM output.

Troubleshooting and Solution Steps

Follow these steps to systematically resolve PWM output issues on the GD32F103ZET6:

Step 1: Check Timer Configuration Timer Initialization Ensure that the timer is correctly initialized by setting the proper prescaler, auto-reload value, and compare value. For example, use the following initialization code to configure Timer 3 for PWM output: // Enable the timer clock RCM->APB1EN |= RCM_APB1EN_TIMER3EN; // Configure the timer for PWM mode TIMER3->CTL1 &= ~TIMER_CTL1_DIR; // Set timer to up-counting mode TIMER3->PSC = 7999; // Prescaler (adjust for your desired frequency) TIMER3->ARR = 999; // Auto-reload register (period) TIMER3->CCR1 = 499; // Compare register (duty cycle) // Enable the PWM output TIMER3->CCMR1 &= ~TIMER_CCMR1_OC1M; TIMER3->CCMR1 |= TIMER_CCMR1_OC1M_PWM1; // PWM Mode 1 TIMER3->CCER |= TIMER_CCER_CC1E; // Enable output on channel 1 TIMER3->CR1 |= TIMER_CR1_CEN; // Start the timer Check Timer Overflow Ensure that the timer is not overflowing due to incorrect configuration of the prescaler or period. Step 2: Verify Clock Source

Check System Clock Verify that the system clock is running at the expected frequency. The timer clock typically derives from the APB1 or APB2 peripheral clock. If the system clock or peripheral clock is not configured properly, the timer might not generate the correct PWM frequency.

You can verify the clock source in the microcontroller configuration and ensure it matches your expectations.

Step 3: Confirm GPIO Pin Configuration Set GPIO to Alternate Function PWM signals are output on GPIO pins that must be configured to the correct alternate function. For example, to configure pin PA6 for PWM output on Timer 3 channel 1, use the following code: // Enable GPIOA clock RCM->APB2EN |= RCM_APB2EN_GPIOAEN; // Set PA6 as alternate function GPIOA->CFGR2 &= ~GPIO_CFGR2_MODE6; GPIOA->CFGR2 |= GPIO_CFGR2_MODE6_1; GPIOA->CFGR2 |= GPIO_CFGR2_AFSEL6; // Set AF to PWM output

Ensure that the GPIO pin is correctly mapped to the timer channel and is configured for PWM output.

Step 4: Check Timer Channel Configuration Verify Timer Channel Double-check that the correct timer channel is selected for the PWM signal. For example, if you want to output PWM on Timer 3, channel 1, ensure that the correct registers are set for this channel. Step 5: Verify PWM Output with an Oscilloscope or Logic Analyzer Test the Output After ensuring the timer, clock, GPIO, and channel configuration are correct, use an oscilloscope or logic analyzer to check the output on the configured GPIO pin. Verify that the expected PWM signal (with the correct frequency and duty cycle) is present. Step 6: Check for Hardware Faults Check for Damaged Components If everything is configured correctly but the PWM signal still doesn't appear, consider checking the microcontroller itself, the PCB traces, or any external components that might affect the signal.

Summary of Troubleshooting Process

Ensure correct timer configuration by setting the prescaler, period, and compare registers. Verify the clock source for the timer and ensure the timer clock is running at the expected frequency. Correctly configure the GPIO pins for PWM output by setting them to the proper alternate function. Select the appropriate timer channel to output the PWM signal. Test the output with an oscilloscope to ensure the signal is correct. Check for hardware faults if the issue persists after all software configurations are verified.

By following these steps, you should be able to identify and resolve PWM output issues on the GD32F103ZET6 microcontroller.