Seed

Positron16 · Revision 1.1.3.5 · PDF page 356

Syntax

Seed Value

Overview

Seed the pseudo random number generator, in order to obtain a more random result.

Parameters

Value can be a variable, constant or expression, with a value from 1 to 65535. A value of $0345 is a good starting point.

Example

' Create and display a Random number
  Device = 24FJ64GA002             ' Select the device to compile for
  Declare Xtal = 32

  Declare Hserial_Baud = 9600      ' UART1 Baud rate
  Declare Hrsout1_Pin = PORTB.14   ' Select the pin for TX with USART1

  Dim MyWord as Word

  RPOR7 = 3                       ' Make Pin RP14 U1TX

  Seed $0345                       ' Seed the pseudo random generator with $0345
  Do
     MyWord = Random
     HRsoutLn Dec MyWord
     DelayMs 500
  Loop

Note

All microcontrollers use a pseudo random number generator because they do not have a random noise generator peripheral, so the parameter that is used for Seed will always produce the same sequence of random values from the Random command.

It is important to be aware of this because each microcontroller will produce the same pseudo random values. If true random number generation is required, find a source of random noise that can be fed into the microcontroller’s ADC and use this value to place in the Seed command.