SIM800L SMS Sending: Why We Use a Pre-Allocated Buffer

This project uses a pre-allocated buffer approach to handle SMS command construction for the SIM800L module. Below is a quick comparison of this approach versus dynamically constructing commands, and why we chose pre-allocation.

Comparison Table

Aspect	Pre-Allocated Buffer	Dynamic Command Construction	Reason for Choosing Pre-Allocated
Memory Usage	Fixed, predictable	Slightly less but variable	Stability is key in embedded systems
Safety	Low risk of overflow	Higher risk with variable data	Pre-allocation minimizes errors
Performance	Faster, no repeated allocation	Minor overhead with each function call	Efficient for frequent SMS operations
Readability	Simple, dedicated buffer	Requires more handling for each command	Clearer for maintenance

Conclusion

Using a pre-allocated buffer keeps memory usage predictable and the code safer, making it an ideal choice for embedded systems like STM32 where resources are limited.