Identify the Scope of Incorrect Delay
- Examine the delay implementation code, focusing on the functions responsible for generating the timing logic.
- Check if there are discrepancies between expected and actual delay times through logs or performance measurements.
- Understand if the issue is consistent across different hardware platforms or specific to a certain environment.
Evaluate External Factors
- Check if external interrupts or hardware timers are influencing delay calculations, potentially disrupting timing accuracy.
- Ensure that your system clock is correctly configured. An incorrect clock configuration might lead to wrong delay calculations.
- Investigate potential compiler optimizations that might alter the delay logic, by examining compiler flags.
Adjust Delay Logic
- Review the algorithm used for delay to ensure it uses precise integer math or scaled timing units appropriate for your hardware.
- If using loops for delays, ensure the loop calculation accounts for instruction cycles and execution path.
- Consider using hardware timers instead of software-based delays for more accurate timing.
Code Example for Correcting Delay
- Implement or refine hardware timer-based delays to increase accuracy. Here is an example implementation:
```c
void delay_ms(uint32_t milliseconds) {
// Assumes a hardware timer interrupt configured for 1ms
uint32_t start = get_current_time();
while ((get_current_time() - start) < milliseconds);
}
```
get_current_time() should return the current time captured from a hardware timer, ensuring millisecond precision.
Test and Validate
- Write unit tests or use embedded testing tools to validate that delays are accurate under different conditions.
- Measure actual delay times using an oscilloscope or logic analyzer to ensure alignment with calculated delays.
- If available, automate timing validation in your build process, continuously verifying delay correctness with each firmware update.
Iterate Based on Feedback
- Use user or stakeholder feedback to identify remaining discrepancies in delay implementation.
- Adjust and refine the delay mechanisms based on real-world usage scenarios and patterns.
