modbus/__init__.py
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Sun, 06 Jan 2019 01:22:46 +0300
changeset 2499 68f4f2d4516b
parent 2019 92f02bb17c7e
permissions -rw-r--r--
use pregenerated CRC32 lookup tables for retain on Win32 and GNU/Linux

This code could be possible reused on low-end targets with limited RAM.

code to generate lookup table:
[---------------------------------------------------------------------]

/* CRC lookup table and initial state. */
uint32_t crc32_table[256];

/* Generate CRC32 lookup table. */
void GenerateCRC32Table(void)
{
unsigned int i, j;
/* Use CRC-32-IEEE 802.3 polynomial 0x04C11DB7 (bit reflected). */
uint32_t poly = 0xEDB88320;

for (i = 0; i <= 0xFF; i++)
{
uint32_t c = i;
for (j = 0 ; j < 8 ; j++)
c = (c & 1) ? (c >> 1 ) ^ poly : (c >> 1);
crc32_table[i] = c;
}
}

void main(void)
{
GenerateCRC32Table();
int j=0;
for(int i=0; i<256; i++) {
printf("0x%08X, ", crc32_table[i]);
if (++j >= 8) {
j = 0;
printf("\n");
}
}
}
[---------------------------------------------------------------------]
1909
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     1
#!/usr/bin/env python
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     2
# -*- coding: utf-8 -*-
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     3
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     4
# This file is part of Beremiz, a Integrated Development Environment for
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     5
# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     6
#
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     7
# Copyright (c) 2016 Mario de Sousa (msousa@fe.up.pt)
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     8
#
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
     9
# This program is free software: you can redistribute it and/or modify
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    10
# it under the terms of the GNU General Public License as published by
2019
92f02bb17c7e Make Modbus extension license compatible with the rest of Beremiz IDE python code : GPLv2.
Edouard Tisserant
parents: 1919
diff changeset
    11
# the Free Software Foundation, either version 2 of the License, or
1909
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    12
# (at your option) any later version.
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    13
#
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    14
# This program is distributed in the hope that it will be useful,
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    15
# but WITHOUT ANY WARRANTY; without even the implied warranty of
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    16
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    17
# GNU General Public License for more details.
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    18
#
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    19
# You should have received a copy of the GNU General Public License
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    20
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
1918
e7b6478b4ebc PEP8 conformity for modbus. Most of it done by autopep8, plus some easy refactoring.
Edouard Tisserant
parents: 1909
diff changeset
    21
#
1909
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    22
# This code is made available on the understanding that it will not be
bb883e063175 Add support for Modbus (TCP and RTU) working as master & slave
Mario de Sousa <msousa@fe.up.pt>
parents:
diff changeset
    23
# used in safety-critical situations without a full and competent review.