/** **************************************************************************************** * * @file trng.c * * @brief True Random Number Generator. * * Copyright (C) 2012. Dialog Semiconductor Ltd, unpublished work. This computer * program includes Confidential, Proprietary Information and is a Trade Secret of * Dialog Semiconductor Ltd. All use, disclosure, and/or reproduction is prohibited * unless authorized in writing. All Rights Reserved. * * and contributors. * **************************************************************************************** */ /* Revision History (ver. 1.1) ver. 1.0 Initial version ver. 1.1 Modified rfpt_init() , Added save/restore of the TEST_CTRL_REG in trng_acquire() */ #include "arch.h" #if (USE_TRNG) #include #include "global_io.h" #include "gpio.h" #include "datasheet.h" #include "arch_wdg.h" bool DCoffsetCalibration(void); bool IffCalibration(void); // RFPT acquisition definitions //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #define NUM_POINTS 0x200 // Number of points per acquisition #define NUM_POINTS_MUL_2_M_4 NUM_POINTS*2-4 // Number of iters to run the mean_calc loop // Bul def... #define WAIT100() for (wait=0; wait < 0x91; wait++) {} // wait about 100 us /** **************************************************************************************** * @brief Initialize the rfpt **************************************************************************************** */ extern void rf_regs(void); void rfpt_init(void) { volatile uint16 wait; SetWord16(CLK_RADIO_REG, 0x0089); // En BLE clk, dis BLE timer, En RFCU, RFCU div by 2 SetWord16(BLE_CNTL2_REG, 0x2000); // SetBits16 (CLK_AMBA_REG, OTP_ENABLE, 1); SetBits16 (CLK_AMBA_REG, HCLK_DIV, 0); SetBits16 (TEST_CTRL_REG, ENABLE_RFPT, 1); // Recommended settings //set_recommended_settings(); rf_regs(); IffCalibration(); DCoffsetCalibration(); WAIT100(); // Wait 100 us to finish all DCF signals } /** **************************************************************************************** * @brief Override RF preferred settings for TRNG mode **************************************************************************************** */ void trng_init(void) { volatile uint16 wait; // Override preferred settings for TRNG mode SetWord16(RF_ENABLE_CONFIG1_REG, 0x0000); // LNA off SetWord16(RF_ENABLE_CONFIG2_REG, 0x0000); // Mixer off SetWord16(RF_DC_OFFSET_CTRL1_REG, 0x8080); // Fixed DC offset compensation values for I and Q SetWord16(RF_DC_OFFSET_CTRL2_REG, 0x01D1); // Use the manual DC offset compensation values SetWord16(RF_ENABLE_CONFIG4_REG, 0x0000); // VCO_LDO_EN=0, MD_LDO_EN=0. You need this for more isolation from the RF input // SetWord16(RF_ENABLE_CONFIG14_REG, 0x0000); // LOBUF_RXIQ_EN=0, DIV2_EN=0. This increases the noise floor for some reason. So you get more entropy. Need to understand it and then decide... // SetWord16(RF_SPARE1_REG, 0x0001); // Set the IFF in REAL transfer function, to remove I-Q correlation. But it affects the DC offsets! SetWord16(RF_AGC_CTRL2_REG, 0x00C3); // AGC=0 i.e. max RX gain // Overrule-start the RX SetWord16(RF_OVERRULE_REG,0x8); // Start up receiver WAIT100(); // Wait for the DCFs to finish WAIT100(); // Wait for the DCFs to finish WAIT100(); // Wait for the DCFs to finish } /** **************************************************************************************** * @brief Acquires the raw RFADC IQ samples **************************************************************************************** */ void trng_get_raw_data(uint32 address, uint32 length) { SetWord16(RFPT_ADDR_REG, address); SetWord16(RFPT_LEN_REG, length); SetWord16(RFPT_CTRL_REG, 0x1); while ((GetWord16(RFPT_STAT_REG) & RFPT_ACTIVE)== RFPT_ACTIVE); } /** **************************************************************************************** * @brief Acquires 128 bits, saves them in trng_bits[]and restores the modified regs **************************************************************************************** */ void trng_acquire(uint8_t *trng_bits_ptr) { uint16_t i,i_acq; uint16_t save_TEST_CTRL_REG, save_RF_ENABLE_CONFIG1_REG,save_RF_ENABLE_CONFIG2_REG,save_RF_DC_OFFSET_CTRL1_REG,save_RF_DC_OFFSET_CTRL2_REG; uint16_t save_RF_ENABLE_CONFIG4_REG,save_RF_ENABLE_CONFIG14_REG,save_RF_SPARE1_REG,save_RF_AGC_CTRL2_REG; uint8_t bit_cnt, rnd_byte, single_rnd_bit; uint16_t byte_idx; uint8_t rfadc_data[NUM_POINTS*2]; uint8_t * vq_uint8=(uint8_t *)&rfadc_data[0]; // The Q RFADC channel uint8_t * vi_uint8=(uint8_t *)&rfadc_data[2]; // The I RFADC channel save_TEST_CTRL_REG =GetWord16(TEST_CTRL_REG); rfpt_init(); // Init system and radio, set pref settings, and perform radio calibrations. Do not Radio Overrule yet... // Implement Save-Modify-Restore for the prefered settings that will be changed for the TRNG mode /////////////////////////////////////////////////////////////////////////////////////////////////////////// save_RF_ENABLE_CONFIG1_REG = GetWord16(RF_ENABLE_CONFIG1_REG); // LNA off save_RF_ENABLE_CONFIG2_REG = GetWord16(RF_ENABLE_CONFIG2_REG); // Mixer off save_RF_DC_OFFSET_CTRL1_REG = GetWord16(RF_DC_OFFSET_CTRL1_REG); // Fixed DC offset compensation values for I and Q save_RF_DC_OFFSET_CTRL2_REG = GetWord16(RF_DC_OFFSET_CTRL2_REG); // Use the manual DC offset compensation values save_RF_ENABLE_CONFIG4_REG = GetWord16(RF_ENABLE_CONFIG4_REG); // VCO_LDO_EN=0, MD_LDO_EN=0. You need this for more isolation from the RF input save_RF_ENABLE_CONFIG14_REG = GetWord16(RF_ENABLE_CONFIG14_REG); // LOBUF_RXIQ_EN=0, DIV2_EN=0. This increases the noise floor for some reason. So you get more entropy. Need to understand it and then decide... save_RF_SPARE1_REG = GetWord16(RF_SPARE1_REG); // Set the IFF in REAL transfer function, to remove I-Q correlation. But it affects the DC offsets! save_RF_AGC_CTRL2_REG = GetWord16(RF_AGC_CTRL2_REG); // AGC=0 i.e. max RX gain // Configure radio for TRNG mode (modifies some pref settings, starts RX in overrule) /////////////////////////////////////////////////////////////////////////////////////////////////////////// trng_init(); // Start acquiring raw IQ RFADC data and then extract the random bits /////////////////////////////////////////////////////////////////////////////////////////////////////////// byte_idx=0; for (i_acq=0; i_acq < 128/(NUM_POINTS*2/16); i_acq++) { trng_get_raw_data((uint32)&rfadc_data[0], NUM_POINTS/2-1); // acquires the raw RFADC IQ samples bit_cnt=0; rnd_byte=0; for (i=0;i<=NUM_POINTS_MUL_2_M_4;i=i+16) { single_rnd_bit = (vq_uint8[i] & 0x01) ^ (vi_uint8[i] & 0x01) ; // This way it can pass ALL the NIST tests! This solves a small bias in 1s or 0s which appears due to the actual value of the DC offset... rnd_byte= rnd_byte | (single_rnd_bit<