CRC-CCITT 16-bit Python Manual Calculation

Question

Problem

I am writing code for an embedded device. A lot of solutions out there for CRC-CCITT 16-bit calculations require libraries.

Given that u

Answer 1

Here's a function that I use:

def crc16_ccitt(crc, data):
    msb = crc >> 8
    lsb = crc & 255
    for c in data:
        x = ord(c) ^ msb
        x ^= (x >> 4)
        msb = (lsb ^ (x >> 3) ^ (x << 4)) & 255
        lsb = (x ^ (x << 5)) & 255
    return (msb << 8) + lsb