diff options
| -rw-r--r-- | ports/stm32/rng.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/ports/stm32/rng.c b/ports/stm32/rng.c index b23941998..eea02f726 100644 --- a/ports/stm32/rng.c +++ b/ports/stm32/rng.c @@ -24,6 +24,7 @@ * THE SOFTWARE. */ +#include "rtc.h" #include "rng.h" #if MICROPY_HW_ENABLE_RNG @@ -63,16 +64,26 @@ MP_DEFINE_CONST_FUN_OBJ_0(pyb_rng_get_obj, pyb_rng_get); #else // MICROPY_HW_ENABLE_RNG // For MCUs that don't have an RNG we still need to provide a rng_get() function, -// eg for lwIP. A pseudo-RNG is not really ideal but we go with it for now. We +// eg for lwIP and random.seed(). A pseudo-RNG is not really ideal but we go with +// it for now, seeding with numbers which will be somewhat different each time. We // don't want to use urandom's pRNG because then the user won't see a reproducible // random stream. // Yasmarang random number generator by Ilya Levin // http://www.literatecode.com/yasmarang STATIC uint32_t pyb_rng_yasmarang(void) { - static uint32_t pad = 0xeda4baba, n = 69, d = 233; + static bool seeded = false; + static uint32_t pad = 0, n = 0, d = 0; static uint8_t dat = 0; + if (!seeded) { + seeded = true; + rtc_init_finalise(); + pad = *(uint32_t *)MP_HAL_UNIQUE_ID_ADDRESS ^ SysTick->VAL; + n = RTC->TR; + d = RTC->SSR; + } + pad += dat + d * n; pad = (pad << 3) + (pad >> 29); n = pad | 2; |