CRC: Cyclic Redundancy Check Driver

Overview

Peripheral features and how this peripheral works

A Cyclic Redundancy Check (CRC) or polynomial code checksum is a hash function designed to detect data integrity. The 88MW320/322 CRC unit calculates a short, fixed-length binary sequence, known as the CRC code. For each block of data, CRC code and original data are sent or stored together. When a block of data is used, the same CRC calculation is processed. If the new CRC does not match the one pre-calculated earlier in the block of data, then the block contains a data error and the device may take corrective action, such as resending or requesting the block again. Otherwise the data is assumed to be error free (though, with some small probability, it may contain undetected errors; this is the fundamental nature of error-checking).

Features

• Supports 32-bit parallel bit stream input, and supports up to 32-bit CRC output
• Supports up to 2^32 (4294967296) byte length to calculate CRC
• Supports the following CRC standards
  • CRC-16-CCITT, the polynomial is x^16+x^12+x^5+1
  • CRC-16-IBM, the polynomial is x^16+x^15+x^2+1
  • CRC-16-T10-DIF, the polynomial is x^16+x^15+x^11+x^9+x^8+x^7+x^5+x^4+x^2+x+1
  • CRC-32-IEEE 802.3, the polynomial is 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-16-DNP, the polynomial is x^16+x^13+x^12+x^11+x^10+x^8+x^6+x^5+x^2+1

How this peripheral works

1. Configure the CRC MODE properly, enable CRC
2. Write stream in and waiting for calculation finished
3. Get CRC calculation result

How this driver is designed to make this peripheral works.

1. Call CRC_Init() function to initialize the CRC module
2. Call CRC_SetMode() to select the work mode.
3. Call CRC_Calculate() to calculate the CRC for input data block.

Enumerations
enum	crc_mode_t {   kCRC_16BitsCcitt = 0U,   kCRC_16BitsIbm = 1U,   kCRC_16BitsT10Dif = 2U,   kCRC_32BitsIeee = 3U,   kCRC_16BitsDnp = 4U }
	CRC mode type definition. More...

Driver version
#define	FSL_CRC_DRIVER_VERSION   (MAKE_VERSION(2, 0, 0))

Initialization Interfaces
void	CRC_Init (CRC_Type *base)
	Initializes CRC module. More...
void	CRC_Deinit (CRC_Type *base)
	Disable the interrupt and clear all the interrupts. More...

CRC Operation Interfaces
static void	CRC_SetMode (CRC_Type *base, crc_mode_t crcMode)
	Set CRC mode. More...
static void	CRC_Enable (CRC_Type *base, bool enable)
	Enable the CRC module. More...
static void	CRC_FeedData (CRC_Type *base, uint32_t data)
	Feed data in CRC stream. More...
static void	CRC_SetStreamLen (CRC_Type *base, uint32_t strLen)
	Set CRC stream length. More...
static uint32_t	CRC_GetResult (CRC_Type *base)
	Get CRC result. More...
uint32_t	CRC_Calculate (CRC_Type *base, const uint8_t *dataStr, uint32_t dataLen)
	Calculate the CRC value for input data block. More...

Interrupt Control Interfaces
static void	CRC_EnableInterrupt (CRC_Type *base)
	Enable the CRC Interrupt. More...
static void	CRC_DisableInterrupt (CRC_Type *base)
	Disable the CRC Interrupt. More...
static void	CRC_ClearInterruptStatus (CRC_Type *base)
	brief Clears interrupt flags. More...
static bool	CRC_GetInterruptStatus (CRC_Type *base)
	Get base interrupt status. More...
static bool	CRC_GetRawInterruptStatus (CRC_Type *base)
	Get CRC raw interrupt status. More...

Enumeration Type Documentation

enum crc_mode_t

Enumerator
kCRC_16BitsCcitt	CRC mode: CRC-16-CCITT.
kCRC_16BitsIbm	CRC mode: CRC-16-IBM.
kCRC_16BitsT10Dif	CRC mode: CRC-16-T10-DIF.
kCRC_32BitsIeee	CRC mode: CRC-32-IEEE.
kCRC_16BitsDnp	CRC mode: CRC-16-DNP.

Function Documentation

void CRC_Init

(

CRC_Type *

base

)

Call this function to initialize the CRC module.

Parameters

base	CRC peripheral base address

void CRC_Deinit

(

CRC_Type *

base

)

Parameters

base	CRC peripheral base address

static void CRC_SetMode ( CRC_Type *  base, crc_mode_t  crcMode  )

inlinestatic

Parameters

base	CRC peripheral base address.
crcMode	The CRC work mode to set.

static void CRC_Enable ( CRC_Type *  base, bool  enable  )

inlinestatic

This function enable/disables the CRC.

Parameters

base	CRC peripheral base address.
enable	Use true to enable, false to disable.

static void CRC_FeedData ( CRC_Type *  base, uint32_t  data  )

inlinestatic

Parameters

base	CRC peripheral address.
data	input data.

static void CRC_SetStreamLen ( CRC_Type *  base, uint32_t  strLen  )

inlinestatic

Parameters

base	CRC peripheral address.
strLen	stream length in byte.

static uint32_t CRC_GetResult ( CRC_Type *  base )

inlinestatic

Parameters

base	CRC peripheral base address.

Returns

CRC calculation result.

uint32_t CRC_Calculate	(	CRC_Type *	base,
		const uint8_t *	dataStr,
		uint32_t	dataLen
	)

Parameters

base	CRC peripheral base address.
dataStr	input data stream.
dataLen	data length in byte.

Returns

CRC calculation result.

static void CRC_EnableInterrupt ( CRC_Type *  base )

inlinestatic

Parameters

base	CRC peripheral base address.

static void CRC_DisableInterrupt ( CRC_Type *  base )

inlinestatic

Parameters

base	CRC peripheral base address.

static void CRC_ClearInterruptStatus ( CRC_Type *  base )

inlinestatic

Parameters

base	CRC peripheral base address.

static bool CRC_GetInterruptStatus ( CRC_Type *  base )

inlinestatic

Parameters

base	CRC peripheral base address.

Returns

true if interrupt flag is asserted, else false.

static bool CRC_GetRawInterruptStatus ( CRC_Type *  base )

inlinestatic

This function is similar with CRC_GetInterruptStatus, the only difference is, the raw interrupt status is not affected by interrupt enable status.

Parameters

base	CRC peripheral base address.

Returns

true if CRC status is asserted, else false.