Where do the CRC18 and CRC12 polynomials come from?

[regregex]

Hello all,

Some of the Freescale processors contain hardwired CRC algorithms. [1]  I am looking for the source of two of these; please can you refer me to a document specifying the algorithms that use them?  Namely:--

CRC18 = x^18 + x^17 + x^14 + x^13 + x^11 + x^10 + x^8 + x^7 + x^6 + x^3 + x^2 + 1 {0x26dcd, 0x2ced9}

CRC12 = x^12 + x^11 + x^10 + x^8 + x^5 + x^4 + 1 {0xd31, 0x8cb}

If it helps, you could search your code for the given hex constants, which may have a reference nearby.

Thank you for your help.

Greg

[1] p.25-234 (1718) http://cache.nxp.com/files/dsp/doc/ref_manual/MSC8158RM.pdf

[regregex]

I have since found the CRC-12 polynomial mentioned several times in one of the GSM specifications, ETSI TS 100 909, starting in section 5.1.5.1.4, p.72.

The source of the CRC-18 polynomial is still required.

[xiangjun_rong]

Hi, greg,

I am sorry, this is a starCore question, I am not familiar with starcore, I ask the other engineer, but he has little knowledge about CRC.

BR

Xiangjun Rong