I am working on TLS communication with mbedTLS on an STM32F303CCT6 MCU (256KB flash). The current implementation uses almost the entire flash (~256KB). Can anyone provide examples or guidance on the minimum memory space required for mbedTLS and how to optimize it for a resource-constrained environment?
The biggest issue here is RAM. Flash is relatively cheaper and easier to come by. Top of my head, I believe some 60 ~ 90KB additional RAM is needed by TLS. If you are doing anything serious beside TLS, you probably will need to start with MCUs with at least 192KB RAM. I would suggest experiment with some development board with 256KB or more RAM, and print out actual memory usage.