CRC Interface

Detailed Description

Interface for cyclic redundancy checking.

Summary

The CRC (Cyclic Redundancy Check) calculator generates CRC codes using five different polynomials including 8 bit, 16 bit, and 32 bit variations. Calculation can be performed by sending data to the block using the CPU or by snooping on read or write activity on one of SCI channels.

Data Structures
struct	crc_input_t
struct	crc_cfg_t
struct	crc_api_t
struct	crc_instance_t

Typedefs
typedef void	crc_ctrl_t

Enumerations
enum	crc_polynomial_t
enum	crc_bit_order_t
enum	crc_snoop_direction_t

---

Data Structure Documentation

crc_input_t

struct crc_input_t

Structure for CRC inputs

Data Fields
uint32_t	num_bytes	Length of input buffer. It must be 4-byte aligned when a 32-bit CRC polynomial function is used.
uint32_t	crc_seed	CRC seed value.
const void *	p_input_buffer	Pointer to input buffer.

crc_cfg_t

struct crc_cfg_t

User configuration structure, used in open function

Data Fields
uint8_t	channel	Channel number.
crc_polynomial_t	polynomial	CRC Generating Polynomial Switching (GPS)
crc_bit_order_t	bit_order	CRC Calculation Switching (LMS)
uint32_t	snoop_address	Register Snoop Address (CRCSA)
void const *	p_extend	CRC Hardware Dependent Configuration.

crc_api_t

struct crc_api_t

CRC driver structure. General CRC functions implemented at the HAL layer will follow this API.

Data Fields
fsp_err_t(*	open )(crc_ctrl_t *const p_ctrl, crc_cfg_t const *const p_cfg)
fsp_err_t(*	close )(crc_ctrl_t *const p_ctrl)
fsp_err_t(*	crcResultGet )(crc_ctrl_t *const p_ctrl, uint32_t *crc_result)
fsp_err_t(*	snoopEnable )(crc_ctrl_t *const p_ctrl, uint32_t crc_seed)
fsp_err_t(*	snoopDisable )(crc_ctrl_t *const p_ctrl)
fsp_err_t(*	calculate )(crc_ctrl_t *const p_ctrl, crc_input_t *const p_crc_input, uint32_t *p_crc_result)

Field Documentation

open

fsp_err_t(* crc_api_t::open) (crc_ctrl_t *const p_ctrl, crc_cfg_t const *const p_cfg)

Open the CRC driver module.

Parameters

[in]	p_ctrl	Pointer to CRC device handle.
[in]	p_cfg	Pointer to a configuration structure.

close

fsp_err_t(* crc_api_t::close) (crc_ctrl_t *const p_ctrl)

Close the CRC module driver

Parameters

[in]

p_ctrl

Pointer to CRC device handle

Return values

FSP_SUCCESS

Configuration was successful.

crcResultGet

fsp_err_t(* crc_api_t::crcResultGet) (crc_ctrl_t *const p_ctrl, uint32_t *crc_result)

Return the current calculated value.

Parameters

[in]	p_ctrl	Pointer to CRC device handle.
[out]	crc_result	The calculated value from the last CRC calculation.

snoopEnable

fsp_err_t(* crc_api_t::snoopEnable) (crc_ctrl_t *const p_ctrl, uint32_t crc_seed)

Configure and Enable snooping.

Parameters

[in]	p_ctrl	Pointer to CRC device handle.
[in]	crc_seed	CRC seed.

snoopDisable

fsp_err_t(* crc_api_t::snoopDisable) (crc_ctrl_t *const p_ctrl)

Disable snooping.

Parameters

[in]

p_ctrl

Pointer to CRC device handle.

calculate

fsp_err_t(* crc_api_t::calculate) (crc_ctrl_t *const p_ctrl, crc_input_t *const p_crc_input, uint32_t *p_crc_result)

Perform a CRC calculation on a block of data.

Parameters

[in]	p_ctrl	Pointer to CRC device handle.
[in]	p_crc_input	A pointer to structure for CRC inputs
[out]	crc_result	The calculated value of the CRC calculation.

crc_instance_t

struct crc_instance_t

This structure encompasses everything that is needed to use an instance of this interface.

Data Fields
crc_ctrl_t *	p_ctrl	Pointer to the control structure for this instance.
crc_cfg_t const *	p_cfg	Pointer to the configuration structure for this instance.
crc_api_t const *	p_api	Pointer to the API structure for this instance.

Typedef Documentation

crc_ctrl_t

typedef void crc_ctrl_t

CRC control block. Allocate an instance specific control block to pass into the CRC API calls.

Enumeration Type Documentation

crc_polynomial_t

enum crc_polynomial_t

CRC Generating Polynomial Switching (GPS).

Enumerator
CRC_POLYNOMIAL_CRC_8	8-bit CRC-8 (X^8 + X^2 + X + 1)
CRC_POLYNOMIAL_CRC_16	16-bit CRC-16 (X^16 + X^15 + X^2 + 1)
CRC_POLYNOMIAL_CRC_CCITT	16-bit CRC-CCITT (X^16 + X^12 + X^5 + 1)
CRC_POLYNOMIAL_CRC_32	32-bit CRC-32 (X^32 + X^26 + X^23 + X^22 + X^16 + X^12 + X^11 + X^10 + X^8 + X^7 + X^5 + X^4 + X^2 + X + 1)
CRC_POLYNOMIAL_CRC_32C	32-bit CRC-32C (X^32 + X^28 + X^27 + X^26 + X^25 + X^23 + X^22 + X^20 + X^19 + X^18 + X^14 + X^13 + X^11 + X^10 + X^9 + X^8 + X^6 + 1)

crc_bit_order_t

enum crc_bit_order_t

CRC Calculation Switching (LMS)

Enumerator
CRC_BIT_ORDER_LMS_LSB	Generates CRC for LSB first communication.
CRC_BIT_ORDER_LMS_MSB	Generates CRC for MSB first communication.

crc_snoop_direction_t

enum crc_snoop_direction_t

Snoop-On-Write/Read Switch (CRCSWR)

Enumerator
CRC_SNOOP_DIRECTION_RECEIVE	Snoop-on-read.
CRC_SNOOP_DIRECTION_TRANSMIT	Snoop-on-write.