How micro is your micro? There are embedded TLS stacks such as wolfSSL[1]. If you carefully select the cipher suite and certificate requirements, and perhaps limit TLS payload sizes, you may be able to fit on a lot more systems than you initially suspect. x.509 is expensive in code space though, if that's the constraint, you may do better with an application specific certificate replacement of some sort.
How micro is your micro? There are embedded TLS stacks such as wolfSSL[1]. If you carefully select the cipher suite and certificate requirements, and perhaps limit TLS payload sizes, you may be able to fit on a lot more systems than you initially suspect. x.509 is expensive in code space though, if that's the constraint, you may do better with an application specific certificate replacement of some sort.
[1] https://www.wolfssl.com/