diff options
Diffstat (limited to 'circuitpython/lib/nrfutil/nordicsemi/dfu/crc16.py')
| -rw-r--r-- | circuitpython/lib/nrfutil/nordicsemi/dfu/crc16.py | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/circuitpython/lib/nrfutil/nordicsemi/dfu/crc16.py b/circuitpython/lib/nrfutil/nordicsemi/dfu/crc16.py new file mode 100644 index 0000000..2db4af6 --- /dev/null +++ b/circuitpython/lib/nrfutil/nordicsemi/dfu/crc16.py @@ -0,0 +1,44 @@ +# Copyright (c) 2015, Nordic Semiconductor +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are met: +# +# * Redistributions of source code must retain the above copyright notice, this +# list of conditions and the following disclaimer. +# +# * Redistributions in binary form must reproduce the above copyright notice, +# this list of conditions and the following disclaimer in the documentation +# and/or other materials provided with the distribution. +# +# * Neither the name of Nordic Semiconductor ASA nor the names of its +# contributors may be used to endorse or promote products derived from +# this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE +# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +def calc_crc16(binary_data, crc=0xffff): + """ + Calculates CRC16 on binary_data + + :param int crc: CRC value to start calculation with + :param bytearray binary_data: Array with data to run CRC16 calculation on + :return int: Calculated CRC value of binary_data + """ + + for b in binary_data: + crc = (crc >> 8 & 0x00FF) | (crc << 8 & 0xFF00) + crc ^= ord(b) + crc ^= (crc & 0x00FF) >> 4 + crc ^= (crc << 8) << 4 + crc ^= ((crc & 0x00FF) << 4) << 1 + return crc & 0xFFFF |