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USB Superspeed Peripherals

Anonymous
Not applicable

Hi there,

   

 

   

is there a way to generate random numbers by facilities on the ARM9? I don't want to use the libc rand()/srand() but would rather resort to the processors native RNG, which does exist in the NXP MCU product (http://www.nxp.com/documents/data_sheet/LPC3130_31.pdf), so it might as well be present in the FX3.

   

 

   

If it is, is there an easy way to use it? If not, is there any other recommended way to generate a decent amount of entropy (about 4k at a shot)?

   

 

   

Thanks in advance,

   

/Markus

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3 Replies
Anonymous
Not applicable

Hi Markus,

   

 

   

We do not have a random generator on the FX3 silicon. The only hardware option is to set up a GPIO timer with a low period (period = range of values to be generated) and sample it to get the random number.

   

 

   

The CyU3PGpioSetComplexConfig function can be used as follows to set up the timer:

   

 

   

CyU3PGpioComplexConfig_t gpioConf = {

   

                CyFalse, CyFalse, CyFalse, CyFalse,

   

                CY_U3P_GPIO_MODE_STATIC,                 /* The GPIO itself is not to be affected, we just use the timer. */

   

                CY_U3P_GPIO_NO_INTR,                            /* No interrupts associated with this timer. */

   

                CY_U3P_GPIO_TIMER_HIGH_FREQ,       /* Run the GPIO at the high clock frequency selected at GpioInit. */

   

                0,                                                                            /* Start timer at 0. */

   

                RANDOM_MAX,                                              /* Set the period to the range of the numbers to be generated. */

   

                0                                                                              /* The threshold is don't care. */

   

};

   

CyU3PGpioSetComplexConfig (0, &gpioConf);

   

 

   

The CyU3PGpioComplexSampleNow function can then be used to get the current timer value to serve as a random number.

   

 

   

Please note that the RANDOM_MAX needs to be set to a low value to be able to get good entropy.

   

 

   

Thanks,

   

Sai Krishna.

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RaN_283461
New Contributor

 I think you can also use the api CyU3PGetTime to get the system time. I do some operation on it to get a random number .

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Anonymous
Not applicable

hi

   

who  can tell me how to convert the number of tick from CyU3PGpioComplexSampleNow  to time 

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