Intermediate
30 min
0

Harness the power of our captivating random number generator with ADS1115 and PIC18F2682

Random wonders: Numbers beyond predictions!

RNG Click with Curiosity HPC

Published Jan 23, 2024

Click board™

RNG Click

Development board

Curiosity HPC

Compiler

NECTO Studio

MCU

PIC18F2682

Enhance your decision-making processes by integrating our innovative random number generator into your applications, ensuring selection fairness and eliminating biases

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Hardware Overview

How does it work?

RNG Click is a random number generator (RNG) based on the ADS1115, 16-bit, I2C-compatible, analog-to-digital converter from Texas Instruments that generates a sequence of numbers or symbols that cannot be reasonably predicted better than by a random chance. In computing, a hardware random number generator (HRNG) or true random number generator (TRNG) is a device that generates random numbers from a physical process rather than using an algorithm. Such devices are often based on microscopic phenomena that generate low-level, statistically random "noise" signals, as in this Click board™. That process is, in theory, completely unpredictable, and the theory's assertions of unpredictability are subject to experimental tests. This is in contrast to the paradigm of pseudo-random number generation, which is commonly implemented by the

software. The heart of the RNG click is the avalanche noise generated from an internal diode of the transistor Q1 (BC846B). Avalanche breakdown is a phenomenon that can occur in both insulating and semiconducting materials. It is a form of electric current multiplication that can allow large currents within materials that are otherwise good insulators. The avalanche occurs when the electric field accelerates carriers in the transition region to energies sufficient to create mobile or free electron-hole pairs via collisions with bound electrons. To achieve that, RNG Click also has a boost converter onboard, based on TPS61041 from Texas Instruments, and creates the +18V power supply for the job. The noise signal, created by the transistors Q1 and Q2, is then amplified with Q3, voltage-limited using the Zener diode, and digitalized using the NC7S14M5X inverter. After that, the string of random ones and

zeros is achieved, which is brought to the ADS1115 - 16BIT sigma-delta ADC from Texas Instruments. The potentiometer P1 is used to set the distribution of ones and zeros as near as possible, which is indicated by the LD2 and LD3 LED diodes. The potentiometer P1 should be set to illuminate the LD2 and LD3 diodes equally. That way, when the single-shot measurement is performed using the ADS1115 over the I2C protocol, the true, 16-bit random number is obtained. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

RNG Click hardware overview image

Features overview

Development board

Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All

these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware

quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.

Curiosity HPC double image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

80

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

3328

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
RB5
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
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Take a closer look

Schematic

RNG Click Schematic schematic

Step by step

Project assembly

Curiosity HPC front no-mcu image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity HPC as your development board.

Curiosity HPC front no-mcu image hardware assembly
IR Sense 4 Click front image hardware assembly
MCU DIP 28 hardware assembly
Prog-cut hardware assembly
Curiosity HPC 28pin-DIP - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for RNG Click driver.

Key functions:

  • rng_get_voltage - This function gets voltage in millivolts

  • rng_set_config - This function sets configuration

  • rng_set_vref - This function sets desired vref.

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \file 
 * \brief Rng Click example
 * 
 * # Description
 * This click is a random number generator. The device contain potentiometer which control voltage
 * so it generates a sequence of numbers or symbols that cannot be reasonably predicted better 
 * by a random chance. Random number generators have applications in gambling, statistical sampling,
 * computer simulation, cryptography, completely randomized design, and various other areas. 
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver, then sets configuration and voltage reference.
 * 
 * ## Application Task  
 * It reads ADC value from AIN0 channel then converts it to voltage and 
 * displays the result on USB UART each second.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rng.h"

// ------------------------------------------------------------------ VARIABLES

static rng_t rng;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    rng_cfg_t cfg;

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, "---- Application Init ----" );

    //  Click initialization.

    rng_cfg_setup( &cfg );
    RNG_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rng_init( &rng, &cfg );

    rng_default_cfg( &rng );
}

void application_task ( void )
{
    float voltage;

    voltage = rng_get_voltage( &rng );

    log_printf( &logger, "Voltage from AIN0: %.2f mV\r\n", voltage );
    log_printf( &logger, "-----------------------\r\n" );
    Delay_ms( 1000 );
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}


// ------------------------------------------------------------------------ END

Additional Support

Resources