CRC

A cyclic redundancy check (CRC) is an error-detecting code commonly used in digital networks and storage devices to identify accidental changes to raw data. Blocks of data entering these systems receive a short check value based on the remainder of a polynomial division of their contents. This method primarily detects data errors during data transmission and reception. Different types of Cheks are available based on the number of bits used.

The sender and receiver share a generator polynomial. They utilize it whenever storing or transmitting digital data. The risk of data corruption exists in such processes. To address this risk, transmitted messages undergo segmentation into predetermined lengths. Subsequently, these segments are divided by a fixed divisor, and the remainder of this division gets calculated and appended to the message before transmission. Upon message reception, the recipient recalculates the remainder and compares it to the transmitted remainder. If the numbers fail to match, an error is detected. This process contributes to ensuring the integrity of transmitted data in digital systems.

You can access web-based online tools for Error Check calculation at this link: https://crccalc.com/

CRC Types

• Many different types are available for error detection.
• Mainly based on the bits we can segregate some types are 1Bit, 4Bits, 8 Bits, 16 Bits, 32Bits, 64bits.
• Some other types MD5/SHA1/SHA256.
• We do have an IP within the device, but the application needs to call and use it specifically when applicable. It is a 64 implementation.

Algorithm	Algorithm	Algorithm	Hash Algo Result (Only HEX)
8/CDMA2000	16/CCITT-FALSE	32/BZIP2	MD5
8/DARC	16/ARC	32C	SHA1
8/DVB-S2	16/AUG-CCITT	32D	SHA256
8/EBU	16/BUYPASS	32/MPEG-2
8/I-CODE	16/CDMA2000	32/POSIX
8/ITU	16/DDS-110	32Q
8/MAXIM	16/DECT-R	32/JAMCRC
8/ROHC	16/DECT-X	32/XFER
8/WCDMA	16/DNP
	16/EN-13757
	16/GENIBUS
	16/MAXIM
	16/MCRF4XX
	16/RIELLO
	16/T10-DIF
	16/TELEDISK
	16/TMS37157
	16/USB
	A
	16/KERMIT
	16/MODBUS
	16/X-25
	16/XMODEM

Error Detection using CRC

A simple error-detection scheme in which each transmitted message is accompanied by a numerical value based on the number of set bits in the message. The receiving station then applies the same formula to the message and checks to make sure the accompanying numerical value is the same. If not, the receiver can assume that the message has been garbled.

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ARC 16 Algorithm

The below code is for ARC 16

/*ArunEworld*/
#include <stdio.h>
#include <stdint.h>

//Table for CRC values
static const uint16_t CrcArc16Table[] =
{
	0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
	0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
	0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
	0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
	0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
	0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
	0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
	0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
	0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
	0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
	0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
	0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
	0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
	0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
	0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
	0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
	0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
	0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
	0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
	0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
	0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
	0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
	0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
	0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
	0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
	0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
	0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
	0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
	0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
	0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
	0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
	0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,
};

uint16_t CrcArc16(const uint8_t* BufPtr, uint16_t Length, uint16_t SeedValue)
{
	const uint8_t* BufPtrAddr = BufPtr;
	uint32_t CrcVal = SeedValue;

	if (BufPtrAddr)
	{
		while (Length != 0)
		{
			Length -= 1;
			CrcVal = (CrcVal >> 8) ^ CrcArc16Table[(*BufPtrAddr ^ CrcVal) & 0x00FF];
			BufPtrAddr += 1;
		}
	}
	return (uint16_t)CrcVal;
}

int main()
{
	char Buf[]={'A','r','u','n','E','w','o','r','l','d','\0'};
	int result = CrcArc16(Buf,sizeof(Buf), 0);
	printf("Given String :%s \n",Buf);
	printf("CRC ARC 16 value :%x \n",result );

	return 0;
}

/************* OutPut *********/
/*
Given String :ArunEworld
CRC ARC 16 value :514

...Program finished with exit code 0
Press ENTER to exit console.
*/
/***********************************/

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Reference

• https://aruneworld.com/embedded/embedded-protocol/xmodem/
• All Codes: rosettacode
• http://www.bdtic.com/download/ti/spna146.pdf

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