ESPRNG/ESPRNG.cpp at master · ffosilva/ESPRNG · GitHub

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#include <ESPRNG.h>

#if defined ESP8266 || defined ESP32
/**
 * ESP8266 and ESP32 specific hardware true random number generator.
 *
 * Acording to the ESP32 documentation, you should not call the tRNG
 * faster than 5MHz
 *
 */

void ESPRNG::fill(uint8_t *dst, unsigned int length)
{
    // ESP8266 and ESP32 only
    for (int i = 0; i < length; i++)
    {
        dst[i] = get();
    }
#if defined ESP8266
    ESP.wdtFeed();
#endif
}

byte ESPRNG::get()
{
#if defined ESP32
    // ESP32 only
    uint32_t* randReg = (uint32_t*) 0x3FF75144;
    return (byte) *randReg;
#elif defined ESP8266
    // ESP8266 only
    uint32_t* randReg = (uint32_t*) 0x3FF20E44L;
    return (byte) *randReg;
#else
    // NOT SUPPORTED
    return 0;
#endif
}

uint32_t ESPRNG::getLong()
{
#if defined ESP32
    // ESP32 only
    uint32_t* randReg = (uint32_t*) 0x3FF75144;
    return (byte) *randReg;
#elif defined ESP8266
    // ESP8266 only
    uint32_t* randReg = (uint32_t*) 0x3FF20E44L;
    return *randReg;
#else
    // NOT SUPPORTED
    return 0;
#endif
}
#endif