SAMV71 Xplained Ultra Software Package 1.3

trng.c

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00001 /* ----------------------------------------------------------------------------
00002  *         SAM Software Package License
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00029 
00030 /** \addtogroup rtng_module Working with RTNG
00031  * \ingroup peripherals_module
00032  * The TRNG driver provides the interface to configure and use the TRNG 
00033  * peripheral.\n
00034  *
00035  * The True Random Number Generator (TRNG) passes the American NIST Special 
00036  * Publication 800-22 and Diehard Random Tests Suites. As soon as the TRNG is 
00037  * enabled (TRNG_Enable()),  the generator provides one 32-bit value every 84 
00038  * clock cycles.  Interrupt trng_int can be enabled through TRNG_EnableIt()
00039  * (respectively disabled in TRNG_IDR).
00040  * This interrupt is set when a new random value is available and is cleared 
00041  * when the status  register is read (TRNG_SR register). The flag DATRDY of 
00042  * the status register (TRNG_ISR) is set when the random data is ready to be 
00043  * read out on the 32-bit output data through TRNG_GetRandData().
00044  *
00045  * For more accurate information, please look at the SHA section of the
00046  * Datasheet.
00047  *
00048  * Related files :\n
00049  * \ref trng.c\n
00050  * \ref trng.h\n
00051  */
00052 /*@{*/
00053 /*@}*/
00054 
00055 /**
00056  * \file
00057  *
00058  * Implementation of True Random Number Generator (TRNG)
00059  *
00060  */
00061 
00062 /*----------------------------------------------------------------------------
00063  *        Headers
00064  *----------------------------------------------------------------------------*/
00065 
00066 #include "chip.h"
00067 
00068 /*----------------------------------------------------------------------------
00069  *        Exported functions
00070  *----------------------------------------------------------------------------*/
00071 
00072 /**
00073  * \brief Enables the TRNG to provide Random Values.
00074  * \param key  This key is to be written when the ENABLE bit is set.
00075  */
00076 void TRNG_Enable(void)
00077 {
00078     TRNG->TRNG_CR = TRNG_CR_ENABLE | TRNG_CR_KEY_PASSWD;
00079 }
00080 
00081 /**
00082  * \brief Disables the TRNG to provide Random Values.
00083  * \param key  This key is to be written when the DISABLE bit is set.
00084  */
00085 void TRNG_Disable(void)
00086 {
00087     TRNG->TRNG_CR = TRNG_CR_KEY_PASSWD;
00088 }
00089 
00090 /**
00091  * \brief Data Ready Interrupt enable.
00092  */
00093 void TRNG_EnableIt(void)
00094 {
00095     TRNG->TRNG_IER = TRNG_IER_DATRDY;
00096 }
00097 
00098 /**
00099  * \brief Data Ready Interrupt Disable.
00100  */
00101 void TRNG_DisableIt(void)
00102 {
00103     TRNG->TRNG_IDR = TRNG_IDR_DATRDY;
00104 }
00105 
00106 /**
00107  * \brief Get the current status register of the given TRNG peripheral.
00108  * \return  TRNG status register.
00109  */
00110 uint32_t TRNG_GetStatus(void)
00111 {
00112     return TRNG->TRNG_ISR;
00113 }
00114 
00115 /**
00116  * \brief Get the  32-bit Output Data from TRNG peripheral.
00117  * \return  TRNG output data.
00118  */
00119 uint32_t TRNG_GetRandData(void)
00120 {
00121     return TRNG->TRNG_ODATA;
00122 }
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