These targets below just support PRNG, not real TRNG. They cannot annouce TRNG.
- NUMAKER_PFM_NUC472
- NUMAKER_PFM_M487
- NUMAKER_IOT_M487
On targets without TRNG, to run mbedtls applications which require entropy source,
there are two alternatives to TRNG:
- Custom entropy source:
Define MBEDTLS_ENTROPY_HARDWARE_ALT and provide custom mbedtls_hardware_poll(...)
- NV seed:
1. Define MBEDTLS_ENTROPY_NV_SEED
2. Define MBEDTLS_PLATFORM_NV_SEED_READ_MACRO/MBEDTLS_PLATFORM_NV_SEED_WRITE_MACRO and provide custom mbedtls_nv_seed_read(...)/mbedtls_nv_seed_write(...).
3. Don't define MBEDTLS_PSA_INJECT_ENTROPY. Meet mbedtls_psa_inject_entropy(...) undefined and then provide custom one, which must be compatible with mbedtls_nv_seed_read(...)/mbedtls_nv_seed_write(...) above.
4. For development, simulating partial provision process, inject entropy seed via mbedtls_psa_inject_entropy(...) pre-main.
Without free-up of peripheral pins, peripheral pins of the same peripheral may
share by multiple ports after port iteration, and this peripheral may fail with
pin interference.
Chun-Chieh Li
Cruz Monrreal