Cyclic Redundancy Check#

Introduction#

The Cyclic Redundancy Check (CRC) in embedded systems identifies inadvertent data changes. It generates a checksum, which is applied to the data before transmission or storage. When data is received or retrieved, the CRC is recalculated and compared to the original checksum to confirm its integrity.

Configuration#

Configuring CRC typically involves several parameters like below:

Modify SL_CRC_POLYNOMIAL to set the desired polynomial value.
Modify SL_CRC_POLY_WIDTH to set the desired polynomial width.

Usage#

The common CRC functions can be used after the CRC Structures are specified, passing an instance of sl_crc_params_t. The following functions will initiate and configure the CRC below, which is the flow for implementation.

sl_si91x_crc_set_gen_control
sl_si91x_crc_enable
sl_si91x_crc_polynomial
sl_si91x_crc_polynomial_width
sl_si91x_crc_lfsr_init
sl_si91x_crc_use_swapped_init
sl_si91x_crc_set_data_width_type
sl_si91x_crc_set_fifo_thresholds
sl_si91x_crc_monitor_crc_calc
sl_si91x_crc_disable

Typedefs#

typedef RSI_CRC_PARAMS_T

sl_crc_params_t

Renamed CRC param structure.

Functions#

sl_status_t

sl_si91x_crc_set_gen_control(void)

sl_status_t

sl_si91x_crc_get_general_status(uint32_t *reg_status)

sl_status_t

sl_si91x_crc_polynomial(sl_crc_params_t *pCRCParams)

sl_status_t

sl_si91x_crc_polynomial_width(sl_crc_params_t *pCRCParams, uint32_t *reg_status)

sl_status_t

sl_si91x_crc_lfsr_init(sl_crc_params_t *pCRCParams)

sl_status_t

sl_si91x_crc_use_swapped_init(sl_crc_params_t *pCRCParams, uint32_t *reg_status)

sl_status_t

sl_si91x_crc_set_data_width_type(sl_crc_params_t *pCRCParams, uint32_t *oper_status)

sl_status_t

sl_si91x_crc_set_fifo_thresholds(sl_crc_params_t *pCRCParams, uint32_t *oper_status)

sl_status_t

sl_si91x_crc_write_data(sl_crc_params_t *pCRCParams, uint32_t data, uint32_t *oper_status)

sl_status_t

sl_si91x_crc_monitor_crc_calc(sl_crc_params_t *pCRCParams, uint32_t *crc)

sl_status_t

sl_si91x_crc_lfsr_dynamic_write(sl_crc_params_t *pCRCParams)

sl_status_t

sl_si91x_crc_reset_fifo(void)

sl_status_t

sl_si91x_crc_get_fifo_status(uint32_t *reg_status)

sl_status_t

sl_si91x_crc_enable(void)

Enables the CRC peripheral.

sl_status_t

sl_si91x_crc_disable(void)

Disable the CRC peripheral.

Macros#

#define

SL_CRC_POLYNOMIAL 0x04C11DB7

Polynomial used for CRC calculation.

#define

SL_CRC_POLY_WIDTH 31

Width of the polynomial.

#define

SL_CRC_LFSR_VAL 0x0000

Initial LFSR value.

#define

SL_CRC_WIDTH_TYPE 0

Width type of the CRC.

#define

SL_CRC_DIN_WIDTH 31

Width of the input data.

#define

SL_CRC_NUM_BYTES 3

Number of bytes to be written to the CRC.

#define

SL_CRC_AEMPTY 6

Almost empty threshold level.

#define

SL_CRC_AFULL 2

Almost full threshold level.

#define

SL_CRC_SWAP_DIN 0

Whether to swap the input data.

#define

SL_CRC_USE_UDMA 1

Whether to use uDMA for CRC calculation.

#define

SL_CRC_SWAP_LFSR 1

Whether to swap the LFSR value.

Typedef Documentation#

sl_crc_params_t#

typedef RSI_CRC_PARAMS_T sl_crc_params_t

Renamed CRC param structure.

Function Documentation#

sl_si91x_crc_set_gen_control#

sl_status_t sl_si91x_crc_set_gen_control (void )

Parameters

Type	Direction	Argument Name	Description
void	N/A

sl_si91x_crc_get_general_status#

sl_status_t sl_si91x_crc_get_general_status (uint32_t * reg_status)

Parameters

Type	Direction	Argument Name	Description
uint32_t *	N/A	reg_status

sl_si91x_crc_polynomial#

sl_status_t sl_si91x_crc_polynomial (sl_crc_params_t * pCRCParams)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams

sl_si91x_crc_polynomial_width#

sl_status_t sl_si91x_crc_polynomial_width (sl_crc_params_t * pCRCParams, uint32_t * reg_status)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams
uint32_t *	N/A	reg_status

sl_si91x_crc_lfsr_init#

sl_status_t sl_si91x_crc_lfsr_init (sl_crc_params_t * pCRCParams)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams

sl_si91x_crc_use_swapped_init#

sl_status_t sl_si91x_crc_use_swapped_init (sl_crc_params_t * pCRCParams, uint32_t * reg_status)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams
uint32_t *	N/A	reg_status

sl_si91x_crc_set_data_width_type#

sl_status_t sl_si91x_crc_set_data_width_type (sl_crc_params_t * pCRCParams, uint32_t * oper_status)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams
uint32_t *	N/A	oper_status

sl_si91x_crc_set_fifo_thresholds#

sl_status_t sl_si91x_crc_set_fifo_thresholds (sl_crc_params_t * pCRCParams, uint32_t * oper_status)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams
uint32_t *	N/A	oper_status

sl_si91x_crc_write_data#

sl_status_t sl_si91x_crc_write_data (sl_crc_params_t * pCRCParams, uint32_t data, uint32_t * oper_status)

Parameters

Type	Direction	Argument Name
sl_crc_params_t *	N/A	pCRCParams
uint32_t	N/A	data
uint32_t *	N/A	oper_status

sl_si91x_crc_monitor_crc_calc#

sl_status_t sl_si91x_crc_monitor_crc_calc (sl_crc_params_t * pCRCParams, uint32_t * crc)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams
uint32_t *	N/A	crc

sl_si91x_crc_lfsr_dynamic_write#

sl_status_t sl_si91x_crc_lfsr_dynamic_write (sl_crc_params_t * pCRCParams)

Parameters

Type	Direction	Argument Name	Description
sl_crc_params_t *	N/A	pCRCParams

sl_si91x_crc_reset_fifo#

sl_status_t sl_si91x_crc_reset_fifo (void )

Parameters

Type	Direction	Argument Name	Description
void	N/A

sl_si91x_crc_get_fifo_status#

sl_status_t sl_si91x_crc_get_fifo_status (uint32_t * reg_status)

Parameters

Type	Direction	Argument Name	Description
uint32_t *	N/A	reg_status

sl_si91x_crc_enable#

sl_status_t sl_si91x_crc_enable (void )

Enables the CRC peripheral.

Parameters

Type	Direction	Argument Name	Description
void	N/A

This function enables the CRC peripheral by enabling its clock.

Returns

status 0 if successful, else error code as follow
- SL_STATUS_OK (0x0000) - Success
- SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.

sl_si91x_crc_disable#

sl_status_t sl_si91x_crc_disable (void )

Disable the CRC peripheral.

Parameters

Type	Direction	Argument Name	Description
void	N/A

This function Disables the CRC peripheral by disabling its clock.

Returns

status 0 if successful, else error code as follow
- SL_STATUS_OK (0x0000) - Success
- SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.