mirror of
https://github.com/RIOT-OS/RIOT.git
synced 2025-01-18 12:52:44 +01:00
66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
/*
|
|
* Copyright (C) 2014-2016 Freie Universität Berlin
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU Lesser
|
|
* General Public License v2.1. See the file LICENSE in the top level
|
|
* directory for more details.
|
|
*/
|
|
|
|
/**
|
|
* @ingroup cpu_nrf51
|
|
* @{
|
|
*
|
|
* @file
|
|
* @brief Driver for the NRF51822 random number generator
|
|
*
|
|
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
|
|
* @author Frank Holtz <frank-riot2015@holtznet.de>
|
|
*
|
|
* @}
|
|
*/
|
|
|
|
#include "cpu.h"
|
|
#include "periph/hwrng.h"
|
|
|
|
void hwrng_init(void)
|
|
{
|
|
/* The RNG is initiated every time when RNG read is called
|
|
* This reduces power consumption when RNG is not needed
|
|
*/
|
|
}
|
|
|
|
void hwrng_read(uint8_t *buf, unsigned int num)
|
|
{
|
|
unsigned int count = 0;
|
|
|
|
/* power on RNG */
|
|
NRF_RNG->POWER = 1;
|
|
/* Generate events when RNG is finished */
|
|
NRF_RNG->INTENSET = RNG_INTENSET_VALRDY_Msk;
|
|
/* Start Task */
|
|
NRF_RNG->TASKS_START = 1;
|
|
/* NRF51 PAN #21 */
|
|
NRF_RNG->EVENTS_VALRDY = 0;
|
|
|
|
while (count < num) {
|
|
/* sleep until number is generated */
|
|
while (NRF_RNG->EVENTS_VALRDY == 0) {
|
|
/* enable wake up on events for __WFE CPU sleep */
|
|
SCB->SCR |= SCB_SCR_SEVONPEND_Msk;
|
|
/* sleep until next event */
|
|
__SEV();
|
|
__WFE();
|
|
__WFE();
|
|
}
|
|
|
|
buf[count++] = (uint8_t)NRF_RNG->VALUE;
|
|
/* NRF51 PAN #21 */
|
|
NRF_RNG->EVENTS_VALRDY = 0;
|
|
/* clear interrupt state */
|
|
NVIC_ClearPendingIRQ(RNG_IRQn);
|
|
}
|
|
|
|
/* power off RNG */
|
|
NRF_RNG->POWER = 0;
|
|
}
|