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// # << NEORV32 - TRNG Demo Program >>                                                             #

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// # BSD 3-Clause License                                                                          #

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// # Copyright (c) 2020, Stephan Nolting. All rights reserved.                                     #

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// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #

// #################################################################################################

/**********************************************************************//**

 * @file demo_trng/main.c

 * @author Stephan Nolting

 * @brief TRNG demo program.

 **************************************************************************/

#include <neorv32.h>

/**********************************************************************//**

 * @name User configuration

 **************************************************************************/

/**@{*/

/** UART BAUD rate */

#define BAUD_RATE 19200

/**@}*/

/**********************************************************************//**

 * This program generates a simple dimming sequence for PWM channel 0,1,2.

 *

 * @note This program requires the UART and the TRNG to be synthesized.

 *

 * @return Irrelevant.

 **************************************************************************/

int main(void) {

  uint8_t lucky_numbers_5of50[5];

  uint8_t lucky_numbers_2of10[2];

  uint8_t i, j, tmp;

  uint16_t trng_data;

  unsigned int num_samples;

  // check if UART unit is implemented at all

  if (neorv32_uart_available() == 0) {

    return 0;

  }

  // capture all exceptions and give debug info via UART

  // this is not required, but keeps us safe

  neorv32_rte_enable_debug_mode();

  // init UART at default baud rate, no rx interrupt, no tx interrupt

  neorv32_uart_setup(BAUD_RATE, 0, 0);

  // intro

  neorv32_uart_printf("\n--- TRNG Demo ---\n\n");

  // check if TRNG unit is implemented at all

  if (neorv32_trng_available() == 0) {

    neorv32_uart_printf("No TRNG implemented.");

    return 0;

  }

  // configure TRNG with defaul GARO tap mask

  neorv32_uart_printf("Configuring TRNG...\n");

  uint16_t trng_tap_config = neorv32_trng_find_tap_mask();

  neorv32_uart_printf("TRNG: Using tap mask: 0x%x ", (uint32_t)trng_tap_config);

  neorv32_trng_setup(trng_tap_config);

  while(1) {

    // main menu

    neorv32_uart_printf("\nCommands:\n"

                        " n: Print 8-bit random numbers (abort by pressing any key)\n"

                        " l: Print your lucky numbers\n");

    neorv32_uart_printf("CMD:> ");

    char cmd = neorv32_uart_getc();

    neorv32_uart_putc(cmd); // echo

    neorv32_uart_printf("\n");

    // output RND data

    if (cmd == 'n') {

      num_samples = 0;

      while(1) {

        if (neorv32_trng_get(&trng_data)) {

          neorv32_uart_printf("\nTRNG error!\n");

          break;

        }

        neorv32_uart_printf("%u ", (uint32_t)(trng_data & 0xFF));

        num_samples++;

        if (neorv32_uart_char_received()) { // abort when key pressed

          neorv32_uart_printf("\nPrinted samples: %u", num_samples);

          break;

        }

      }

    }

    // print lucky numbers

    if (cmd == 'l') {

      // reset array

      for (i=0; i<5; i++) {

        lucky_numbers_5of50[i] = 0;

      }

      lucky_numbers_2of10[0] = 0;

      lucky_numbers_2of10[1] = 0;

      // get numbers

      i = 0;

      while (i<5) {

        if (neorv32_trng_get(&trng_data)) {

          neorv32_uart_printf("\nTRNG error!\n");

          break;

        }

        // valid range?

        tmp = (uint8_t)(trng_data & 0xff);

        if ((tmp == 0) || (tmp > 50)) {

          continue;

        }

        // already sampled?

        for (j=0; j<5; j++) {

          if (lucky_numbers_5of50[j] == tmp) {

            continue;

          }

        }

        lucky_numbers_5of50[i] = tmp;

        i++;

      }

      // get numbers part 2

      i = 0;

      while (i<2) {

        if (neorv32_trng_get(&trng_data)) {

          neorv32_uart_printf("\nTRNG error!\n");

          break;

        }

        // valid range?

        tmp = (uint8_t)(trng_data & 0xff);

        if ((tmp == 0) || (tmp > 10)) {

          continue;

        }

        // already sampled?

        for (j=0; j<2; j++) {

          if (lucky_numbers_2of10[j] == tmp) {

            continue;

          }

        }

        lucky_numbers_2of10[i] = tmp;

        i++;

      }

      // output

      neorv32_uart_printf("\n");

      for (j=0; j<5; j++) {

        if (i==4) {

          neorv32_uart_printf("%u", (uint32_t)lucky_numbers_5of50[j]);

        }

        else {

          neorv32_uart_printf("%u, ", (uint32_t)lucky_numbers_5of50[j]);

        }

      }

      neorv32_uart_printf("\nLucky numbers: %u, %u\n", (uint32_t)lucky_numbers_2of10[0], (uint32_t)lucky_numbers_2of10[1]);

    }

  }

  return 0;

}