TRNGCC26XX.h File Reference

Detailed Description

TRNG driver implementation for a CC26XX device.

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Driver Include

The TRNG header file should be included in an application as follows:

#include <ti/drivers/trng/TRNGCC26XX.h>

Overview

The TRNGCC26XX driver provides reentrant access to the TRNG module within the CC26XX. Reentrant access is controlled by creating a global critical section when requesting a random number. This critical section disables all Hwi's from running.

General Behavior

Initialing the TRNGCC26XX Driver

• TRNGCC26XX_init must be called prior to calling any other TRNGCC26xx API.
• This function need only be called once per reset, but may be called multiple times without affect.

Opening the TRNGCC26XX Driver

• TRNGCC26XX_open is used to open the driver prior to requesting a number.
• This function powers on the TRNG peripheral.
• Calling this function is optional, but will increase the latency of the first call to TRNGCC26XX_getNumber().
• This function need only be called once per reset, but may be called multiple times without affect.

// Open the driver
TRNGCC26XX_open(Board_TRNG);

Initializing client parameters

• Client parameters are optional. The Driver may be called with a NULL pointer to the client parameters, in which case it will use the default parameters. The default parameters configurate the TRNG to produce 256 samples per cycle at 1 clock per sample. a call to TRNGCC26XX_getNumber with default values has a latency of 14us. Increasing any of the configuration parameters will result in an increase in latency.
• The application initializes its parameters by calling TRNGCC26XX_Params_init() and passing a pointer to a TRNGCC26XX_Params variable as an argument to it.
• This function can be called once or more to each initialization of parameters.
• This function can be called once or more with the same TRNGCC26XX_Params variable.
• The client parameter are initialized to valid default values, but may be changed by the client after this function returns. See trng.h for full details.

TRNGCC26XX_Params trngParams;

// Initialize parameters.
TRNGCC26XX_Params_init(&trngParams);

// Optionally modify trngParams
...

Validating client parameters

• a client may optionally choose to validate its configuration parameters before attempting to generate a number.
• when a client passes configuration parameters to TRNGCC26XX_getNumber these parameters will automatically be checked.

TRNGCC26XX_Params trngParams;

// Initialize parameters.
TRNGCC26XX_Params_init(&trngParams);

// Set client parameters.
trngParams.minSamplesPerCycle = 256;
trngParams.maxSamplesPerCycle = 256;
trngParams.clocksPerSample = 1;

// Validate parameters.
if (TRNGCC26XX_isParamValid(&trngParams) == TRNGCC26XX_STATUS_SUCCESS)
{
   // Parameters are valid.
}

Generating a random number

• The TRNG may be called without client configuration parameters and pass a NULL pointer as an argument instead. This will result in the default values being used.
• Using the initialized client configuration parameters, a random number can be generated.
• an optional status flag pointer may be passed as an argument to check if the call successfully generated a random number.

TRNGCC26XX_Params trngParams;
uint8_t trngStatusFlag;
uint32_t trngNum1;
uint32_t trngNum2;

// Init driver.
TRNGCC26XX_init();

// Open TRNG peripheral.
TRNGCC26XX_open(Board_TRNG);

// Initialize parameters.
TRNGCC26XX_Params_init(&trngParams);

// Generate a random number.  Use optional status flag.
trngNum1 = TRNGCC26XX_getNumber(&trngParams, &trngStatusFlag);

// Check if status was okay
if (trngStatusFlag == TRNGCC26XX_STATUS_SUCCESS)
{
  // Random number was generated successfully
}

// Generate a second random number using the default values and no
// status flag.
trngNum2 = TRNGCC26XX_getNumber(NULL, NULL);

Supported transaction modes

• all calls to TRNGCC26XX_getNumber are blocking until the TRNG has a new random number available.

Error handling

If an error occurs during a call to TRNGCC26XX_getNumber, the error status will be set into the status flag and the returned random number shall be 0. passing the status flag is optional.

Supported Functions

API function	Description
TRNGCC26XX_open()	Open driver (stub)
TRNGCC26XX_close()	Close driver (stub)
TRNGCC26XX_Params_init()	Initialize parameters for random number generation
TRNGCC26XX_init()	Generates a random number
TRNGCC26XX_isParamValid	Validate client configuration parameters

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Go to the source code of this file.

Data Structures
struct	TRNGCC26XX_Config
	TRNGCC26XX Global Configuration. More...
struct	TRNGCC26XX_HWAttrs
	TRNGCC26XX Hardware Attributes. More...
struct	TRNGCC26XX_Object
	TRNGCC26XX Object. More...
struct	TRNGCC26XX_Params
	TRNGCC26XX Parameters. More...

Macros
#define	TRNGCC26XX_CLOCKS_PER_SAMPLES_MAX   15
#define	TRNGCC26XX_ILLEGAL_PARAM_RETURN_VALUE   0
#define	TRNGCC26XX_MAX_SAMPLES_MAX   16777216
#define	TRNGCC26XX_MAX_SAMPLES_MIN   256
#define	TRNGCC26XX_MIN_SAMPLES_MAX   16384
#define	TRNGCC26XX_MIN_SAMPLES_MIN   64
#define	TRNGCC26XX_STATUS_ILLEGAL_PARAM   -1
#define	TRNGCC26XX_STATUS_SUCCESS   0

Typedefs
typedef struct TRNGCC26XX_Config	TRNGCC26XX_Config
	TRNGCC26XX Global Configuration.
typedef struct TRNGCC26XX_Config *	TRNGCC26XX_Handle
	A handle that is returned from a TRNGCC26XX_open() call.
typedef struct TRNGCC26XX_HWAttrs	TRNGCC26XX_HWAttrs
	TRNGCC26XX Hardware Attributes. More...
typedef struct TRNGCC26XX_Object	TRNGCC26XX_Object
	TRNGCC26XX Object. More...
typedef struct TRNGCC26XX_Params	TRNGCC26XX_Params
	TRNGCC26XX Parameters. More...

Functions
void	TRNGCC26XX_close (TRNGCC26XX_Handle handle)
	Close the TRNG driver. More...
uint32_t	TRNGCC26XX_getNumber (TRNGCC26XX_Handle handle, TRNGCC26XX_Params *params, int8_t *status)
	This routine returns a 32 bit TRNG number. More...
void	TRNGCC26XX_init (void)
	TRNG Driver initialization. More...
int8_t	TRNGCC26XX_isParamValid (TRNGCC26XX_Params *params)
	Check that the parameters used are valid configurations. More...
TRNGCC26XX_Handle	TRNGCC26XX_open (uint8_t index)
	Open the TRNGCC26XX peripheral specified by the index value. This peripheral will be configured as specified by pParams. Alternatively, if pParams is NULL, default values will be used. More...
int8_t	TRNGCC26XX_Params_init (TRNGCC26XX_Params *params)
	Initialize TRNG configuration parameters to their defaults. More...